Stream Water Quality in the Bosque River Watershed Oct 1

TIAERPR 97-05

STREAM WATER QUALITYIN THE BOSQUE RIVER WATERSHED

October 1, 1995 through March 15, 1997

Anne McFarland and Larry M. Hauck

June 1998

Texas Institute for Applied Environmental ResearchTarleton State University • Box T0410 • Tarleton Station • Stephenville • Texas • 76402

(254) 968-9567 • FAX (254) 968-9568

Stream Water Quality in the Bosque River Watershed • i

Acknowledgments

TIAER acknowledges the support of landowners who allowed access to theirproperty for monitoring and installation of equipment. Without the willingcooperation of these individuals, this study would not have been possible.Funding sources for the water quality monitoring include the Clean RiversProgram of the Texas Natural Resource Conservation Commission and theUnited States Department of Agriculture, Natural Resources ConservationService. This report was funded through the Brazos River Authority with aClean Rivers Program grant. The authors would like to personally thank Ms.Amy Truman for her work on the data analysis and graphics, Ms. Teresa Salyerfor her work with the Geographic Information System databases, and Ms. JudyJames for report formatting. The cooperation of the Brazos River Authority insharing monitoring duties throughout the watershed and providing access to theirdata for this report is also recognized, along with the dedicated work of the manyfield personnel and laboratory chemists who processed samples.

Mention of trade names or equipment manufacturers does not representendorsement of these products or manufacturers by TIAER.

ii Stream Water Quality in the Bosque River Watershed

Stream Water Quality in the Bosque River Watershed • iii

TABLE OF CONTENTS

1. INTRODUCTION .........................................................................................................1

2. BACKGROUND ..........................................................................................................42.1 Description of Study Area..............................................................................................................................4

2.2 Findings of Existing Water Quality Studies and Reports ...........................................................................8

2.3 Summary of Bosque Pilot Project .................................................................................................................8

3. CURRENT WATER QUALITY MONITORING IN THE BOSQUE RIVERWATERSHED.....................................................................................................11

3.1 Sites on Micro-Watersheds ..........................................................................................................................18

3.2 Sites on Major Tributaries to the North Bosque River .............................................................................19

3.3 Sites on the North Bosque River..................................................................................................................20

3.4 Sites on Rivers and Tributaries to Lake Waco...........................................................................................21

3.5 Sites at Wastewater Treatment Plant Effluents .........................................................................................22

3.6 Precipitation Monitoring Sites ....................................................................................................................22

4. SAMPLE COLLECTION AND ANALYSIS METHODS .............................................244.1 Quality Assurance Procedures ....................................................................................................................24

4.2 General Collection Procedures for Grab Samples.....................................................................................24

4.3 General Collection Procedures for Automated Storm Samples................................................................25

4.4 Streamflow Monitoring at Automated Sampler Sites................................................................................25

4.5 Measurement of Physical and Chemical Constituents...............................................................................26

5. DATA ANALYSIS METHODS ...................................................................................285.1 Outliers ..........................................................................................................................................................28

5.2 Censored Data...............................................................................................................................................28

5.3 Derived Water Quality Variables................................................................................................................29

5.4 Methods for Comparing Concentrations between Sites and Sampling Types ........................................29

5.5 Methods for Assessment of Stream Water Quality....................................................................................31

5.6 Methods for Estimating Nutrient Loadings to the Bosque River Watershed..........................................33

iv Stream Water Quality in the Bosque River Watershed

6. RESULTS AND DISCUSSION OF WATER QUALITY COMPARISONS ANDASSESSMENTS.................................................................................................34

6.1 Evaluation of Water Quality Data for Micro-Watershed Sites ................................................................356.1.1 Statistical Comparison of Micro-Watershed Sites ................................................................................366.1.2 Assessment of Water Quality at Micro-Watershed Sites ......................................................................43

6.2 Evaluation of Water Quality Date for North Bosque River Tributary Sites...........................................456.2.1 Statistical Comparison for North Bosque River Tributary Sites...........................................................456.2.2 Assessment of Water Quality for North Bosque River Tributary Sites ................................................52

6.3 Evaluation of Water Quality Data for North Bosque River Sites ............................................................546.3.1 Statistical Comparison of North Bosque River Sites ............................................................................546.3.2 Assessment of Water Quality for North Bosque River Sites ................................................................62

6.4 Evaluation of Water Quality for Rivers or Tributaries to Lake Waco....................................................646.4.1 Statistical Comparisons of Lake Waco Tributary Sites ........................................................................646.4.2 Assessment of Water Quality at Lake Waco Tributary Sites ................................................................70

7. PRELIMINARY NUTRIENT LOADING ESTIMATIONS ............................................727.1 Estimation of Loadings by Sampling Site ...................................................................................................72

7.2 Calculation of Nutrient Export Coefficients...............................................................................................747.2.1 Preliminary Phosphorus Export Coefficients........................................................................................767.2.2 Preliminary Nitrogen Export Coefficients ............................................................................................77

7.3 Verification of Preliminary Export Coefficients ........................................................................................78

7.4 Preliminary Loadings by Contributing Sector to the Bosque River Watershed.....................................80

8. SUMMARY AND RECOMMENDATIONS .................................................................848.1 Comparison of Water Quality between Sites .............................................................................................84

8.2 Water Quality Assessment of Sites ..............................................................................................................85

8.3 Nutrient Loading Contributions..................................................................................................................86

8.4 Recommendations.........................................................................................................................................87

9. LITERATURE CITED ................................................................................................89

APPENDIX A: AVERAGE DAILY FLOW AT STREAM SITES ..............................TAB 3

APPENDIX B: BASIC STATISTICS FOR BASEFLOW AND STORM EVENT WATERQUALITY AT STREAM SITES .....................................................................TAB 4

APPENDIX C: BASIC STATISTICS FOR MUNICIPAL WASTEWATER TREATMENTPLANT EFFLUENTS....................................................................................TAB 5

APPENDIX D: AVERAGE MONTHLY EFFLUENT DISCHARGE FROM MUNCIPALWASTEWATER TREATMENT PLANTS......................................................TAB 6

APPENDIX E: ACRONYMS & ABBREVIATIONS..................................................TAB 6

Stream Water Quality in the Bosque River Watershed 1

1. INTRODUCTION

The Bosque River watershed of north-central Texas is defined by the drainagearea of Lake Waco (Figure 1). Commonly referred to as the Bosque Riverwatershed, it actually includes the North Bosque River, Hog Creek, MiddleBosque River, and South Bosque River— all major tributaries to Lake Waco.Since 1965, the U.S. Army Corps of Engineers has operated Lake Waco forflood control and water conservation. Lake Waco is formed by a rolled earthfilldam and provides the public water supply for the city of Waco and surroundingcommunities with a service population of approximately 140,000.

Figure 1 Bosque River watershed.

2 Stream Water Quality in the Bosque River Watershed

Statewide attention has focused on the North Bosque River largely as the resultof the prominence of the dairy industry in the northern portion of the watershed.Erath and Hamilton Counties are ranked first and eighth, respectively, for milkproduction in Texas (USDA-AMS, 1997). The prominence of the region’s dairyindustry has been a relatively recent occurrence with rapid growth from the mid-1980s through the early 1990s (Neal et al., 1996). Government officials at thestate level have expressed concerns about the potential negative influences to thewatershed’s water quality from confined animal feeding operations (CAFOs).The Texas Natural Resource Conservation Commission (TNRCC) responded towater quality concerns in the watershed and elsewhere by promulgating strictregulations on CAFOs. The “Subchapter B” rules, 30 TEX. ADMIN. CODE §§321.34-321.46, and the “Subchapter K” rules, 30 TEX. ADMIN. CODE §§321.181-321.198, detail acceptable best management practices and landapplication methods for CAFOs, generally, and dairies, specifically.

A nonpoint source pollution assessment conducted by the Texas WaterCommission, predecessor to TNRCC, and the Texas State Soil and WaterConservation Board identified the North Bosque River as a “known” problemwatershed as the result of dairy waste (TWC & TSSWCB, 1991). In the mostrecent State of Texas Water Quality Inventory (TNRCC, 1996), severalcomments address the water quality of classified stream segments within theBosque River watershed. For the North Bosque River (segments 1226 and1255),1 nonpoint source loadings are described as the most serious threat tomeeting designated uses due to elevated levels of nutrients and fecal coliforms.Elevated nitrogen levels and nonpoint source pollution loadings fromagricultural operations are noted as concerns for the Middle Bosque/SouthBosque River (segment 1246).2 TNRCC (1996) also notes that advancedwastewater treatment for the cities of McGregor and Stephenville is required forthe attainment of stream standards of segment 1246 in the Middle Bosque/SouthBosque River and of segment 1255 in the Upper North Bosque River,respectively. The State of Texas 1996 303(d) list contains the two North BosqueRiver segments; 1226 and 1255 (TNRCC, 1997). The 303(d) list reports thatsegments 1226 and 1255 are scheduled for total maximum daily load (TMDL)development work over the next two years.

In addition to the statements and findings of state agencies, there is a growingbody of data that associates in-stream nutrient levels, in particular phosphorus, inthe upper portion of the North Bosque River watershed to the dairy industry(e.g., McFarland & Hauck, 1995, 1997b, 1998). While local impacts from thedairy industry in the upper reaches of the North Bosque River are welldocumented, the authors are unaware of any scientific reports that havecomprehensively assessed the contribution of point and nonpoint sources ofwater pollution throughout the greater Bosque River watershed regardingnutrient loadings to Lake Waco.

1 Segment 1226, named the North Bosque River, is defined as the North Bosque River from a point 328 feet upstream of Farm-to-Market Road185 in McLennan County to a point immediately above the confluence of Indian Creek in Erath County. Segment 1255, named the UpperNorth Bosque River, is defined from a point immediately above the confluence of Indian Creek with the North Bosque River to the confluenceof the North and South Forks of the North Bosque River.

2 Segment 1246, named the Middle Bosque/South Bosque River, includes those portions of the Middle and South Bosque Rivers located inMcLennan County as well as a small portion of the Middle Bosque River in Coryell County up to the confluence of Cave and Middle BosqueCreeks.


The intent of this report is to provide initial analyses and findings from extensivesurface water monitoring programs in the Bosque River watershed conducted bythe Brazos River Authority (BRA), the City of Waco, and the Texas Institute forApplied Environmental Research (TIAER). Intensive monitoring of streamflowand water quality at a number of river and stream sites throughout the BosqueRiver watershed began in October and November 1995 as part of a joint effort ofthe BRA and TIAER. Monitoring and analyses for nutrients at all eight of thepublic-owned municipal wastewater treatment plants in the watershed hasoccurred since December 1995.

In this report, baseflow and storm event water quality for the period of October1, 1995 through March 15, 1997 will be compared for stream monitoring sites.Statistical methods will be used to rank or differentiate between the waterborneconstituent concentrations at the various sites. In these statistical analyses, siteswill be categorized according to drainage area size or location within thewatershed. Category one includes sites with small drainage areas (or micro-watersheds), category two includes sites on major tributaries to the NorthBosque River, category three includes sites along the mainstem of the NorthBosque River, and category four includes sites on river and tributaries flowingdirectly into Lake Waco. A water quality assessment will also be conducted foreach site by comparing pertinent constituent concentrations to TNRCC screeninglevels and criteria.3 Finally, a preliminary estimate of nutrient loads within thewatershed will be determined for major point and nonpoint source contributors,e.g., municipal wastewater treatment plants, cropland, dairies, woods, rangeland,urban, and improved pasture.

3 Subsequent to the data analysis and draft versions of this report, TNRCC fianlized new screening levels (TNRCC and TCRP, 1998). Thescreening levels in place prior to 1998 are utilized in this report.


2. BACKGROUND

2.1 Description of Study AreaThe Bosque River watershed encompasses 1,660 square miles in north-centralTexas. Comprised of the North Bosque River, Hog Creek, Middle Bosque Riverand South Bosque River as major tributaries to Lake Waco, the Bosque Riverwatershed includes all the drainage area to Lake Waco. From a regulatoryperspective, the classified stream segments are Segment 1226, the North BosqueRiver from Lake Waco to Indian Creek in Erath County; Segment 1255, theUpper Bosque River from Indian Creek to the confluence of the North Fork andSouth Fork above Stephenville; and Segment 1246, the Middle and SouthBosque Rivers as located primarily in McLennan County. The State of Texashas designated the following uses for each classified segment, 20 Tex. Reg. 4701(1995):

Segment 1226: North Bosque River Contact recreationHigh aquatic lifePublic water supply

Segment 1246: Middle Bosque/South Contact recreation Bosque River High aquatic life

Segment 1255: Upper North Bosque Contact recreation River Intermediate aquatic life.

As the only major reservoir in the watershed, Lake Waco has a conservationpool capacity of 149,200 acre-feet. Lake Waco serves as flood control and thewater supply for a service population of approximately 140,000.

The climatic classification of the watershed is represented by subtropical-subhumid areas in the northern and western portions and by subtropical-humidareas in the southern and eastern portions (Larkin and Bomar, 1983). TheBosque River watershed receives an average annual rainfall of about 33 inches atLake Waco which decreases northwesterly to about 30 inches at the headwatersin Erath County. The wettest month is typically May, and the driest monthsgenerally occur in the winter (December - March) and summer (July andAugust). Surface evaporation increases from 65 inches at Lake Waco, at thesouthern end of the watershed, to 72 inches at Stephenville, near the northernend of the watershed. Prevailing winds are from the southeast.

From an ecological perspective, the watershed is dominated by the CentralOklahoma-Texas Plains ecoregion except the southern portion of the watershedwhich is within the Texas Blackland Prairies ecoregion (Bayer et al., 1992). Assummarized in Bayer et al. (1992), the Central Oklahoma-Texas Plainsecoregion contains irregular plains with dominate land uses of cropland, pasture,and woodland, whereas the Texas Blackland Prairies also contain irregularplains but feature cropland as a single, dominate land use.


The watershed is predominately rural with high densities of individual land usesin specific regions (Figure 2). For ease of visual presentation and based on thegeneral similarity of nonpoint source nutrient contribution, the wood and rangeland-use categories were combined, as were the pasture and cropland land-usecategories in Figure 2. The southwestern portion of the watershed and areasimmediately adjacent to the North Bosque River contain areas of row-cropagriculture. Confined animal feeding operations, typically dairies, are generallylocated in the northern portion of the watershed in Erath and Hamilton counties(Figure 3). Prominent agricultural crops of the watershed include hay, oats,peanuts, sorghum, wheat, sunflowers, corn, peaches, and pecans. Much of thewatershed is used for ranching, and wildlife is an important natural resource aslarge areas are leased for hunting and fishing. Urban areas within the watershedcomprise a relatively small portion compared to rural or agricultural areas andare primarily represented by the cities of Stephenville (16,000),4 Hico (1,500),Iredell (370), Meridian (1,500), Clifton (3,600), Valley Mills (1,200), Crawford(700) and McGregor (4,800) and portions of the cities of Waco (109,000) andDublin (3,600). Although the city of Waco represents the largest municipal areawithin the watershed and adjoins the eastern shores of Lake Waco, less than athird of the urban area of the city of Waco (about 13 square miles) drains intoLake Waco. Most of the stormwater runoff from the city of Waco drains to thesouth and east of Lake Waco.

Figure 2. General land use for the Bosque River watershed.

4 Numbers in parentheses represent the estimated population of each city as presented in the 1998-99 Texas Almanac (Dallas Morning News,1997).


Figure 3. Dairy locations within the Bosque River watershed.

General land use based on the broad land-use categories of wood, range,improved pasture, cropland, dairy waste application fields, urban, barren andwater for the entire watershed is provided in Table 1. Land-use information wasobtained using the most recently available digital sources. For the upper portionof the Bosque River watershed including most of Erath County and the northernextremity of Hamilton County, general land use was determined from LandsatThematic Mapper (TM) imagery classification from a 1992 overflight. For theremainder of the watershed, land use estimates were obtained from the USDAComputer-Based Mapping System (CBMS) digital database. The CBMS land-use data were processed in 1990 from aerial photography taken in 1977 forBosque, Coryell, Hamilton and McLennan counties. While somewhat dated, theCBMS data represent the best available land use information for all but the


upper portion of the watershed. Anecdotal information indicates that some land-use changes, principally involving conversion of cropland to improved pasture,have occurred since 1977; however, detailed surveys have not been conducted toverify this observation. An updated land-use map is being developed by USDANatural Resources Conservation Service for the Bosque River watershed from aJune 1996 Landsat TM overflight; however, these data were unavailable in timefor this report.

Table 1. General land use estimates in acres and percent for the Bosque River watershed.

Land-Use Category

Wood Range ImprovedPasture

Cropland DairyWaste

Appl. Fields

Urban Barren Water TotalWatershed

Area

Acres 267,589 321,744 182,640 191,135 23,361 31,856 9,557 12,742 1,061,860

Percent 25.2 30.3 17.2 18.0 2.2 3.0 0.9 1.2 100.0

Waste application fields were determined from public information availablefrom the TNRCC including permit information for all dairies exceeding 250cows in confinement and for dairies less than 250 cows that submitted waterquality management or waste management plans to the TNRCC as of January1995. For small dairies (less than 250 milking head) for which informationregarding location, size and type of application fields was unavailable, TNRCCpermit guidelines were used to estimate the size of waste application fieldsassuming the use of coastal bermudagrass pastures near each dairy. The locationof each waste application field was digitized and overlaid on the general land-use information layer using GRASS (Geographic Resources Analysis SupportSystem) to classify the land area used for dairy waste application. The land areaassociated with dairy waste application fields was subtracted from the othergeneral land-use categories to consider dairy waste application fields as a distinctland use category.

While strongly rural and agricultural in land use, eight municipal wastewatertreatment plants (WWTP) are permitted to discharge into the Bosque Riverwatershed. These eight municipal WWTPs, their permitted daily averagedischarge in million gallons per day (MGD), and the nearest major receivingriver downstream of the point of discharge are presented in Table 2.

Table 2. Permitted discharge for WWTPs within the Bosque River watershed.

WWTPPermitted Daily Average Discharge

(MGD)Major Receiving

StreamCrawford 0.026 Middle Bosque RiverClifton 0.400 North Bosque RiverHico 0.200 North Bosque RiverIredell 0.050 North Bosque RiverMcGregor 1.100 South Bosque RiverMeridian 0.214 North Bosque RiverStephenville 3.000 North Bosque RiverValley Mills 0.360 North Bosque River


2.2 Findings of Existing Water Quality Studies and ReportsWhile not intended to be exhaustive, reported herein are the readily availableinformation from publications and sources on water quality and related issues forthe Bosque River watershed. Most of these publications were authored byagencies, and, generally, these publications pertain to the North Bosque River.The focus on the North Bosque River sub-basin is understandable in that itcomprises over 70 percent of drainage area within the Bosque River watershed.Six of the eight municipal WWTP discharges within the Bosque River watershedalso occur along the North Bosque River as well as the majority of the CAFOs.

A summary of chemical and biological data through approximately the late1980s is provided in the Texas Water Commission’s Use Attainability Analysisof the North, Middle and South Bosque River (TWC, 1991). This reportindicated that the upper portion of the North Bosque River supported anintermediate aquatic life use rather than a high aquatic life use as designated inthe state’s surface water quality standards for that time. As stated:

Maintaining the high aquatic life use for most of the North BosqueRiver is recommended. Assignment of this use appearscommensurate with physical and biological characteristics of the riverexcept for the most upstream reach of the river. In this reach of theriver, dissolved oxygen concentrations do not attain the establishedcriteria even above the city of Stephenville’s discharge and fisherydata indicates that the existing use is intermediate. Water qualitysimulation modeling indicates that the intermediate aquatic life usedissolved oxygen criterion of 4/3 mg/L (24-hour average/minimum) isattainable at effluent limits of 10/2/6 (BOD5 [five-day biochemicaloxygen demand], NH3-N [ammonia-nitrogen], DO [dissolvedoxygen]). Attainment of more stringent treatment levels at theStephenville facility would not necessarily result in a higher aquaticcommunity locally, due to marginal differences in projected oxygenlevels (TWC, 1991).

The intermediate aquatic life use designation was later incorporated into thestate’s surface water quality standards through creation of classified streamsegment 1255, Upper North Bosque River. The water quality modeling referredto in the use attainability study is the waste load allocation performed by theTexas Water Commission which assessed the level of treatment required bypermitted point sources to maintain required dissolved oxygen levels in theNorth, Middle and South Bosque Rivers (TWC, 1990).

TWC (1991) reported that the biological data on fish and benthicmacroinvertebrates from the North Bosque River provided somewhatcontradictory pictures of environmental suitability of the river. The fishery dataindicated the highest biotic integrity at the most downstream site below ValleyMills, while the macroinvertebrate data showed the highest biotic integrity atClifton and other upstream sites (TWC, 1991).

In its biennium report to the U.S. Environmental Protection Agency pursuant toSection 305(b) of the Federal Clean Water Act, the TNRCC provides aninventory of the state’s classified stream segments (TNRCC, 1996). Within thisinventory, water quality parameters are evaluated to determine the support ornon-support of the designated uses of each classified segment. Criteria are


considered water quality conditions which must be met in order to support andprotect the desired uses of each classified segment. Parameters for which a state-regulatory water quality criteria exist are evaluated in the following manner:

a) if less than 10 percent of the samples exceed the numeric criterion,the segment is considered as “fully supporting,”

b) if between 11 and 25 percent of the samples exceed the numericcriterion, the segment is considered as “partially supporting,” and

c) if greater than 25 percent of the samples exceed the numericcriterion, the segment is considered as “not supporting” (TNRCC,1996).

Water quality criteria are generally designated for constituents, such as dissolvedoxygen (DO), pH, and fecal coliform on a segment-by-segment basis.

In considering the potential for eutrophication as a water quality problem, statewater quality criteria do not presently exist for nutrients or chlorophyll-a. TheTNRCC has developed nonregulatory screening levels for these parameters inorder to identify areas where elevated levels may be a concern. In an analogousmanner to criteria, water quality parameters without criteria are evaluated in thefollowing manner to determine segment specific conditions:

a) if less than 10 percent of the samples exceed the screening level,the segment is considered of “no concern,”

b) if between 11 and 25 percent of the samples exceed the screeninglevel, the segment is considered of “potential concern,” and

c) if greater than 25 percent of the samples exceed the screening level,the segment is considered of “concern” (TNRCC, 1996).

Using data collected for TNRCC’s Surface Water Quality Monitoring (SWQM)Program for the period January 1991 through December 1994, several waterquality parameters were evaluated for classified segments in the Bosque Riverwatershed (TNRCC, 1996). A summary of criteria and screening levels forsegments 1226, 1246 and 1255 are presented in Table 3 along with TNRCC’sevaluation of each segment. This summary indicates broad nutrient and otherwater quality issues in segment 1255, and lower levels or concentrations ofnutrients downstream in segment 1226. Interestingly, in segment 1246 onlynitrite (NO2-N) plus nitrate (NO3-N) concentrations were found at elevatedlevels with all samples (100 percent) exceeding the screening level.

Table 3. Summary the State of Texas Water Quality Inventory (TNRCC, 1996) for classified streamsegments of the Bosque River watershed based on data collected between January 1991 andDecember 1994. Results are in percent of values outside criteria or screening levels.

Parameter Screening Levelor Criteria

Segment 1226North Bosque

River(%)

Segment 1246Middle/South Bosque

River(%)

Segment 1255Upper North Bosque

River(%)

Dissolved Oxygen 4 mg/L (1255);5 mg/L (1226 & 1246)

—0

—0

21—


pH 6.5-9.0 standard units 0 0 0

Ammonia 1.0 mg/L 0 0 15

Nitrite+Nitrate 1.0 mg/L 27 100 82

Orthophosphate 0.1 mg/L 35 0 90

Total Phosphorus 0.2 mg/L 26 0 90

Chlorophyll-a 30 µg/L 17 0 36

Fecal Coliforms 400 colonies/100 ml 34 14 54

Only one report comprehensively reviews historical water quality data within thewatershed. Funded by the BRA, this May 1996 report (Miertschin, 1996)provides an analysis of available water quality data from the U.S. GeologicalSurvey and the TNRCC for nonpoint source effects in the North Bosque River.Key conclusions and findings from the report indicate a tendency for decreasingconcentrations of total phosphorus, total suspended solids, total Kjeldahlnitrogen and nitrate in a downstream direction along the North Bosque River.While localized effects from point sources may occur, total phosphorus loadingsdid not appear to be significantly affected by point source contributions. TheClifton station on the North Bosque River was the only site indicated as havingsufficient data for long-term trend analysis. Consistent temporal trends were notindicated for the Clifton site. However, because the Clifton station was the onlysite for this study reported as having sufficient data for long-term analysis, theauthor notes that temporal trends could be occurring at other sites in thewatershed but could not be documented. Finally, higher total phosphorusconcentrations were associated with nonsteady state flow conditions, i.e., highstreamflow, indicating that nonpoint sources may be affecting the observed waterquality. However, the existing historical database is insufficient to clearlyidentify nonpoint source contributors.

A series of reports by TIAER has focused on water quality and its relationship toland uses in the 360 square-mile North Bosque River watershed above Hico,Texas; an area typically referred to as the upper North Bosque River watershed5

(McFarland & Hauck, 1995, 1997a, 1997b, 1998). These four TIAER reportsprovide statistical analyses of water quality data from about 20 monitoring siteswith contributing drainage areas including various dominant land uses, i.e.,urban, range, wooded, dairy waste application fields and forage (nondairy-related improved pasture and sudan fields). While the emphasis of the first threereports (McFarland & Hauck, 1995, 1997a, 1997b) varies, some similar findingsare reported. Major findings for the upper North Bosque River watershedinclude: (1) that at many sites nutrient concentrations exceeded TNRCC’snonregulatory screening levels used to give an indication of potential waterquality problems, and that, overall, phosphorus forms (both dissolved and total)were more problematic than nitrogen forms, (2) correlation analyses indicatedthe stormwater concentrations of nutrients increased with an increasingpercentage of intensive agricultural land uses in the drainage area above a site,(3) stormwater phosphorus concentrations were most strongly related to the

5 The upper North Bosque River watershed designation in these reports should not be confused with the TNRCC designated stream segment1255 which is named Upper North Bosque River. Segment 1255 is located within the upper North Bosque River watershed above Hico,Texas.


intensive agricultural land use of dairy waste application fields, whereas nitrogenconcentrations were most strongly related with the combined category ofintensive agricultural, which included both dairy waste application fields andimproved pasture, and (4) stormwater nutrient concentrations were negativelycorrelated with range and wooded land uses, indicating a decrease in streamnutrient concentrations as the percentage range and woods increased in adrainage area.

The most recent TIAER report (McFarland & Hauck, 1998) provides an estimateof nutrient contribution by source into the North Bosque River above Hico,Texas. The contributing sectors and the percentage of the drainage area aboveHico, Texas they comprise are: (a) dairy waste application fields (7 percent), (b)forage fields, i.e., nondairy related improved pasture and forage fields, (23percent), (c) Stephenville wastewater treatment plant (0 percent), (d) wood andrange land (66 percent), and (e) urban (2 percent). The land-use categories ofpeanuts, orchard, water and barren were considered insignificant contributors tonutrient loadings at the watershed scale, because they collectively comprised lessthan 3 percent of the area. The estimated percent nutrient contribution by sectorwere reported by McFarland and Hauck (1998) for the sampling period ofNovember 10, 1993 through January 31, 1997 as shown in Table 4.

Table 4. Estimated nutrient contribution by sector for November 10, 1993 through January 31, 1997 forthe upper North Bosque River watershed.

Contributing Sector SolublePhosphorus

(%)

TotalPhosphorus

(%)

TotalNitrogen

(%)

Dairy Waste Application Fields 65 48 33

Forage Fields 12 24 37

Stephenville WWTP 12 7 8

Wood/Range 8 16 16

Urban 3 5 6

These results indicate that the primary phosphorus loadings are occurring fromdairy waste application fields, while the primary nitrogen loadings are from dairywaste application fields and forage fields within the upper North Bosque Riverwatershed. It should be noted that these load predictions reflect the weather andhydrologic conditions of the estimation period and, thus, may not be directlytransferable to other time periods. For example, during dry periods, the percentcontribution from the point source discharge of the Stephenville WWTP to totalloadings will increase as nonpoint sources, reliant on rainfall runoff, decrease,yet total loadings during dry periods should be much smaller than total loadingsduring wet periods. The sampling timeframe, November 10, 1993 throughJanuary 31, 1997, used to estimate these contributions includes wet and dryperiods with overall rainfall for this timeframe at about 26 percent above normal.

2.3 Summary of the Bosque Pilot Project


In 1993, the TNRCC Clean Rivers Program funded the Bosque Pilot Project toexamine nonpoint source and point source nutrient issues in the Bosque Riverwatershed. A prioritized goal of the Bosque River Pilot Project was to examinethe effects of BMPs for agricultural operations and their effects on water quality.The development of computerized models was included in the project to helppredict impacts of nonpoint source pollution such as nutrients throughout thewatershed. The following BMP scenarios were performed:

• Baseline scenario which had no wastewater treatment discharges,no confined animal feeding operations, and no commercial ororganic fertilizer applied to cropland or pasture;

• Municipal wastewater treatment plants scenario which wasbased on the computed average of flow and allowable totalsuspended solids or sediment as given in the “wastewater permitmonthly effluent report” for the eight permitted WWTPs in thebasin;

• With and without cropland scenario which was used to simulatea fertilized corn/grain sorghum rotation on all of the cropland inthe basin; and

• Dairy waste application scenario which was used to simulatenutrient loadings for a typical dairy (one that incorporatesadopted local management techniques and meets design criteriafor USDA – NRCS animal waste management systems, andmeets all TNRCC rules and regulations for Concentrated AnimalFeeding Operations).

USDA – NRCS applied to the Lake Waco/Bosque River Watershed the SurfaceWater Assessment Tool (SWAT) which is a distributed parameter, continuoustime, nonpoint source pollution model. The SWAT model was developed usingGIS technology which allows for visualization and analysis of the model. Thefollowing GIS layers were developed for the project:

• State Soil Geographic Data Base (STATSGO);

• Digital Elevation Model (DEM);

• Climatological data;

• Stream flow using United States Geological Survey flow stations;

• Stream network using US Geological Survey data;

• Topologically Integrated Geographic Encoding and ReferencingSystem (TIGER) for hydrologic units in watershed;

• Land use and land cover at the county level; and

• Land use and land cover at the watershed or subwatershed level.

These layers provide the tools and information to compare land use and waterquality constituents throughout the basin. Detailed information on the individual


GIS layers can be found in the Bosque Watershed Pilot Project written by theUSDA – NRCS (1996, pg. 15 – 54). Copies of this report and the SWAT modeldeveloped for this project have been forwarded to the TNRCC. Copies are alsoavailable from the following sources: USDA – NRCS Blacklands ResearchCenter (Temple, Texas) or the Brazos River Authority (Waco, Texas).

In addition to the GIS layers, stream monitoring was performed to provide datato calibrate the model for water quality constituents, such as nutrients. Thecalibration required water quality data for base flow and stormwater conditionsto assess the model’s capabilities to predict loading impacts throughout thewatershed. The water quality information used for the model calibration wasprovided through the BRA and TIAER databases. This initial SWAT modelingis providing the basis for additional model development and application by TheTexas A&M University System Blackland Research Center through a differentfunding source and for a different project.

The water quality data obtained through the Bosque Pilot Project was the basisfor expansion of nonpoint source, i.e., stormwater monitoring to the entireBosque River watershed, from the previous monitoring focus that was limited tothe Upper North Bosque River watershed. Thus the data collected through theBosque Pilot Project and the expansion and continuation of this monitoringthrough USDA–NRCS funding provides the basis for this report. Highlightedresults of the Bosque River Pilot Project are as follows:

• Monitoring analyses and efforts from different agencies wereconsolidated throughout the watershed.

• Water quality data collected for the Bosque River Pilot Projectprovided the first set of comprehensive data on nutrient loadingsin the Lake Waco watershed.

• Modeling and monitoring efforts of the Bosque River PilotProject provided the starting point for the comprehensivedevelopment of a SWAT model that includes in-streamdynamics.

• Substantial Geographic Information System information wascompiled as part of the Bosque River Pilot Project to assist inwater quality assessment and planning for the watershed.

• The models developed for the Bosque River Pilot Project can beused by public and private entities needing these types of toolsfor water quality and quantity modeling.

• Cooperative partnerships were developed as part of the BosqueRiver Pilot Project between Federal, State, and educationalagencies to achieve watershed protection efforts in the BosqueRiver watershed.


3. CURRENT WATER QUALITY MONITORINGIN THE BOSQUE RIVER WATERSHED

The monitoring program reported herein includes samples collected andlaboratory analyses performed by the BRA and TIAER. While comprehensivemonitoring throughout the Bosque River watershed was initiated in lateSeptember 1995, many of the sites located in the North Bosque River watershedabove Hico, Texas began operation in 1992 or 1993. The monitoring program iscontinually evaluated, and in late 1996 and early 1997, the system was expandedto include two additional urban stormwater monitoring sites by the City of Wacoand an additional stream site on the South Bosque River immediately upstreamof Lake Waco. Insufficient data existed at the time of this report to includestormwater data from the City of Waco urban sites, though they will be includedin future data reporting. The South Bosque River site was not included in thestatistical comparisons of water quality between sites, because of the limitedtimeframe of data collection. A general assessment of the water quality datafrom the South Bosque River site is presented in comparison to TNRCCscreening levels and criteria.

The location of sampling sites within the Bosque River watershed is indicated inFigure 4. All sampling sites are labeled using a five-digit alphanumeric code.The first two digits specify the tributary or river where the site is located, whilethe last three digits indicate the relative location of the site. Lower numericvalues indicate sites nearer the headwaters, while larger numeric values indicatesites further downstream. The general monitoring history of each sampling siteis outlined in Table 5. The differing initiation dates (and ending dates) for waterquality and water level data reflect the different objectives of various monitoringefforts within the watershed. The estimated land use for the drainage area aboveeach site is presented in Table 6. The land use data are based on the CBMS datafrom 1977 aerial photographs for the lower portion of the watershed, i.e., thedrainage area below BO070 at Hico, and LandSat TM data from 1992 for theupper portion of the watershed, i.e., the drainage area above BO070. Thedrainage basins above each sampling site were delineated from a digitalelevation map.


Figure 4. Location of sampling sites within the Bosque River watershed.

Table 5. Sampling history of stream monitoring sites in the Bosque River watershed.

Site Watershed SampleType†

Date of FirstGrab

Sample

Date of FirstAutomatic

Storm Sample

Date of FirstWater Level

Record

BRASampling

Site

TIAERSampling

Site

Category 1: Sites on Micro-Watershed

GB020 Goose Branch C 11-May-95 05-May-95 03-May-95 x

IC020 Indian Creek C 08-Jun-94 18-Oct-93 25-Sep-93 x

MB040 Methodist Branch S — 01-Aug-93 04-Aug-93 x

NF005 North Fork North Bosque River C 08-Jun-94 25-Jun-92 10-Nov-93 x


NF009 North Fork North Bosque River C 18-Apr-91 16-May-92 21-Nov-92 x

NF020 North Fork North Bosque River C 30-Oct-91 19-May-92 04-Dec-92 x

SC020 Sims Creek C 21-Sep-94 17-Jan-95 05-Jan-95 x

SF020 South Fork North Bosque River C 01-Jun-93 16-May-92 09-Apr-93 x

SF050 South Fork North Bosque River C 19-Jun-91 18-Jan-95 11-Jan-95 x

SP020 Spring Creek C 08-Jun-94 20-Oct-93 23-Sep-93 x

TC020 Tonk Creek C 26-Sep-95 05-Apr-96 17-Oct-95 x x

WC020 Wasp Creek C 26-Sep-95 12-Jul-96 17-Oct-95 x x

Category 2: Sites on Major Tributaries to the North Bosque River

AL040 Alarm Creek C 18-Apr-91 12-Aug-91 02-Dec-92 x

DC060 Duffau Creek C 26-Feb-96 27-Mar-96 28-Feb-96 x x

GC100 Green Creek C 06-Jan-93 01-Sep-92 02-Nov-92 x x

MC060 Meridian Creek G 07-May-94 — — x x

NC060 Neils Creek C 26-Sep-95 01-Nov-95 05-Oct-95 x x

NF050‡ North Fork North Bosque River C 04-Apr-91 07-Jun-91 02-Nov-92 x

SF075‡ South Fork North Bosque River C 06-Jan-93 01-Jun-92 01-Nov-92 x

Category 3: Sites on the North Bosque River

BO020‡ North Bosque River above Stephenville C 26-May-94 06-Feb-97 04-Feb-97 x

BO040 North Bosque River below Stephenville C 04-Apr-91 25-Aug-93 14-Aug-93 x x

BO060 North Bosque River at Green Creek G 04-Apr-91 — — x x

BO070 North Bosque River at Hico C 04-Apr-91 08-May-91 01-Nov-92 x x

BO080 North Bosque River at Iredell G 07-May-96 — — x x

BO085 North Bosque River at Meridian G 07-May-96 — — x x

BO090 North Bosque River at Clifton C 26-Sep-95 04-Nov-95 24-Oct-95 x x

BO100 North Bosque River at Valley Mills C 26-Feb-96 05-Apr-96 20-Mar-96 x x

Category 4: Sites on Rivers and Tributaries to Lake Waco

BO100 (See Category 3)

HC060 Hogg Creek C 26-Sep-95 01-Nov-95 21-Sep-95 x x

MB060 Middle Bosque near Crawford C 26-Sep-95 06-Apr-96 19-Oct-95 x x

SB060¥ South Bosque C 05-Nov-96 23-Jan-97 — x

† G= routine grab sampling site, S = storm sampling site, and C = combined grab and storm sampling site.‡ Sites NF050 and SF075 were discontinued on February 4, 1997. An automatic sampler and level recorder was implemented at BO020 on this

date.¥ Level readings taken at SB060 are influenced by backwater impacts from Lake Waco during major runoff events.

Table 6. Land use estimates for the drainage areas above sampling sites in the Bosque River Watershed.Land use estimates were based on 1992 LandSat imagery for Erath County and CBMS data forthe remainder of the watershed.

Site Wood(%)

Range(%)

Pasture(%)

Cropland(%)

Dairy WasteAppl. Fields

(%)

Urban(%)

Barren(%)

Water(%)

Total Area(Acres)

Category 1: Sites on Micro-Watersheds

GB020 26.6 24.4 2.3 5.8 40.7 0.0 0.2 0.0 1,007

IC020 16.0 49.3 9.5 7.5 17.3 0.0 0.4 0.0 4,494


MB040 0.0 0.0 0.0 0.0 0.0 100.0 0.0 0.0 421

NF005 10.6 33.3 12.2 1.6 41.7 0.0 0.3 0.2 1,106

NF009 17.7 40.6 27.2 10.8 3.4 0.0 0.3 0.0 1,278

NF020† 12.9 25.9 8.5 6.8 45.4 0.0 0.2 0.3 1,953

SC020 20.7 58.5 11.6 2.5 5.9 0.0 0.3 0.4 4,495

SF020 35.6 60.5 2.7 1.0 0.0 0.0 0.1 0.2 2,095

SF050 15.8 41.6 23.8 2.2 15.9 0.0 0.3 0.4 1,847

SP020 30.6 53.6 10.9 4.7 0.0 0.0 0.1 0.1 3,924

TC020 0.0 0.0 19.7 79.6 0.0 0.4 0.3 0.0 7,476

WC020 0.0 0.0 20.7 78.1 0.0 0.8 0.4 0.0 2,396


AL040 19.2 44.8 17.4 7.6 10.1 0.0 0.7 0.3 13,423

DC060 29.9 31.9 13.7 13.3 7.7 1.8 0.9 0.8 57,390

GC100 22.2 49.0 13.3 7.2 6.9 0.7 0.2 0.5 64,605

MC060‡ 36.7 34.1 13.9 14.3 0.0 0.3 0.4 0.3 118,323

NC060 37.3 36.0 12.0 14.1 0.0 0.2 0.2 0.1 86,786

NF050 20.3 29.5 30.6 8.8 9.8 0.0 0.4 0.7 20,456

SF075 28.0 28.5 20.5 7.4 14.6 0.0 0.3 0.8 30,302

Category 3: Sites on the North Bosque River

BO020 23.2 26.2 30.1 6.4 12.3 0.8 0.4 0.7 53,264

BO040 23.7 27.4 23.8 8.4 11.7 3.8 0.7 0.7 63,504

BO060 20.9 39.6 19.1 7.3 9.2 2.8 0.6 0.6 120,936

BO070 23.2 45.0 15.4 6.5 7.2 1.7 0.4 0.5 230,243

BO080 29.3 36.5 17.6 7.6 6.4 1.6 0.5 0.5 360,924

BO085 28.8 39.0 16.2 8.4 5.0 1.5 0.5 0.7 468,120

BO090 30.5 38.0 15.5 9.9 3.7 1.3 0.5 0.6 626,744

BO100 31.0 37.8 15.3 10.4 3.1 1.3 0.5 0.5 746,783


BO100 31.0 37.8 15.3 10.4 3.1 1.3 0.5 0.5 746,783

HC060 8.7 30.7 20.7 38.8 0.0 0.6 0.5 0.1 50,537

MB060 19.3 21.2 15.1 43.7 0.0 0.3 0.4 0.1 76,422

SB060 5.8 8.7 23.0 52.2 0.0 9.4 0.7 0.1 56,387

† About 20 acres (1%) in the drainage above site NF020 is permitted for septage disposal.‡ About 34 acres (0.03%) in the drainage above site MC060 is permitted for dairy waste application.

Statistical comparisons between sites were made using the site categories setforth in Tables 5 and 6. These categories are as follows:

Category 1: Sites on Micro-Watersheds,

Category 2: Sites on Major Tributaries to the North Bosque River,

Category 3: Sites on the North Bosque River, and

Category 4: Sites on Rivers and Tributaries to Lake Waco.

A brief description of the individual sites by category is provided below.


3.1 Sites on Micro-WatershedsOne urban and eight agricultural micro-watersheds were evaluated. Thesemicro-watersheds represent sampling sites on Goose Branch, Indian Creek,Methodist Branch, North Fork, South Fork, Sims Creek and Spring Creek whichall discharge into the North Bosque River, and sites on Tonk Creek and WaspCreek, which discharge into the Middle Bosque River. Methodist Branch is thesole urban micro-watershed represented.

Goose Branch (site GB020): GB020 is an automated sampling site locatedon the Goose Branch of the South Fork of the North Bosque River off CountyRoad (CR) 297 on private property. Over 40 percent of the land area aboveGB020 is designated for dairy waste application (Table 6). The majority of theremaining land area is composed of native range and woodland.

Indian Creek (site IC020): IC020 is an automated sampling site located onIndian Creek near U.S. Highway 281. The majority of the land use above IC020(about 49 percent) is represented by rangeland (Table 6).

Methodist Branch (site MB040): MB040 is an automated sampling sitelocated on Methodist Branch within the city of Stephenville just above the CityPark. The drainage area above this site is entirely urban (Table 6) and includesmost of the downtown section of Stephenville. MB040 is located in a concrete,rectangular channel. This site is generally dry between storm events and, thus,was not included as part of the routine grab sampling program.

North Fork (sites NF005, NF009 and NF020): Sites NF009 and NF020 areautomated sampling sites located on separate tributaries discharging into aPublic Law 5666 (PL-566) reservoir along the North Fork of the North BosqueRiver. Site NF009 is located on an unnamed tributary near CR 423. Site NF020is located on the Scarborough Creek tributary at CR 423. NF005 represents anautomatic sampler site located about one mile upstream of site NF020. Thedominate land use above NF005 and NF020 is dairy waste application fields(over 40 percent) followed by range (over 25 percent; Table 6). The dominateland use above site NF009 is range (about 41 percent) followed by permanentpasture (about 27 percent).

Sims Creek (site SC020): Site SC020 is an automated sampling site locatedon Sims Creek near U.S. Highway 281. The majority of the land area aboveSC020 is considered non-intensive agriculture with range and woodlandrepresenting about 79 percent of the watershed (Table 6).

South Fork (sites SF020 and SF050): Site SF020 is an automated samplingsite located on an unnamed branch of the South Fork of the North Bosque Riveron private property, and SF050 is an automated sampling site located on theWood Hollow Branch to the South Fork near CR 416. Over 90 percent of theland use above SF020 is represented by range or wood making this site one of

6 PL-566 are small flood control structures built by the Soil Conservation Service, now the Natural Resources Conservation Service, in the 1950sand 60s.


the least impacted within the watershed (Table 6). Wood and range are also thedominate land uses above SF050 representing about 58 percent of the watershedarea, although permanent pasture and dairy waste application fields comprisemost of the remaining land in this watershed.

Spring Creek (site SP020): Site SP020 is an automated sampling site locatedon Spring Creek near CR 271. Site SP020 is also considered one of the leastimpacted sites within the watershed with over 80 percent of the land usedesignated as native wood or rangeland (Table 6).

Tonk Creek (site TC020): Site TC020 is an automated sampling site locatedon Tonk Creek at the crossing of Farm to Market (FM) Road 938 about 8 milesabove the confluence of Tonk Creek with the Middle Bosque River. About 80percent of the land area above TC020 is represented by cropland with most ofthe remaining land area in permanent pasture (Table 6).

Wasp Creek (WC020): Site WC020 is located on Wasp Creek at FM Road938 about 7 miles above the confluence of Wasp Creek with the Middle BosqueRiver. Like TC020, the majority of the land area above WC020 (about 78percent) is represented by cropland with the remaining land area mostlyrepresented by permanent pasture (Table 6).

3.2 Sites on Major Tributaries to the North Bosque RiverSites capturing the drainage from subwatersheds are located on the seven majortributaries to the North Bosque River. All seven tributaries are monitored usingmanual grab samples for routine sampling, and all but MC060 have automaticsamplers for sampling episodic storm events (Table 5).

The land uses above the major tributary sites do not vary as greatly as abovemicro-watershed sites (Table 6). Notably, most of the dairies (Figure 3) and,thus, dairy waste application fields, are located in the upper portion of the NorthBosque River watershed. No dairy waste application fields are located in thedrainage area above NC060 on Neils Creek, while a relatively small amount ofland (about 34 acres or 0.04 percent) is designated as dairy waste applicationfields above site MC060 (Table 6). The remaining five tributary sites (AL040,DC060, GC100, NF050 and SF075) have at least seven percent of their land areadesignated for dairy waste application.

Alarm Creek (site AL040): AL040 is located on Alarm Creek near theconfluence of Alarm Creek with the North Bosque River on private property. APL-566 reservoir is located about one-third of a mile above site AL040.

Duffau Creek (site DC060): An automated sampler is located on DuffauCreek near CR 2475 just above the confluence of Duffau Creek with the NorthBosque River.

Green Creek (site GC100): GC100 is located on Green Creek near itsconfluence with the North Bosque River close to CR 266 near Clairette.

Meridian Creek (site MC060): MC060 is a grab sampling site located onMeridian Creek near State Highway 6 just prior to its confluence with the NorthBosque River.


Neils Creek (site NC060): An automated sampler is located on Neils Creek atState Highway 6 just prior to the confluence of Neils Creek with the NorthBosque River.

North Fork (site NF050): NF050 is located on the North Fork of the NorthBosque River near State Highway 108.

South Fork (site SF075): SF075 is located on the South Fork of the NorthBosque River near its crossing of FM Road 2303 on private property.

3.3 Sites on the North Bosque RiverSampling on the mainstem of the North Bosque River is conducted at eight sitesstretching from BO020, located above Stephenville, to BO100, at Valley Mills(Figure 4). Routine grab samples are collected at all eight sites on the NorthBosque River, while storm event sampling with automated samplers occurs atBO040, BO070, BO090 and BO100 (Table 5).

As with the major tributary sites, the land uses above the North Bosque Riversites do not vary as greatly from site to site as with the micro-watershed sites. Ofnote is a decreasing trend in the percent of permanent pasture and dairy wasteapplication fields from BO020 to BO100 and an increasing trend in the percentof wood and cropland (Table 6). The percent of range is lowest above sitesBO020 and BO040 and highest above site BO070. The percent of urban areadecreases from BO040 to B0100, while site BO020, located almost at thebeginning of the North Bosque River, contains only a very small portion of thecity of Stephenville in its drainage area. All North Bosque River sites exceptBO020 also have a point source discharge above them in the form of a municipalWWTP discharge. The location of WWTP discharges in relation to thesampling sites is outlined below.

North Bosque River above Stephenville (site BO020): Site BO020 islocated on the North Bosque River below the confluence of the North and SouthForks with the North Bosque River near the crossing of State Highway 8 on thenortheast boundary of Stephenville.

North Bosque River below the Stephenville Wastewater TreatmentPlant (site BO040): An automated sampler site is located on the North BosqueRiver approximately a quarter mile below the Stephenville WWTP. Site BO040is located near the crossing of CR 454, about five river miles below site BO020.

North Bosque River near Green Creek (site BO060): Site BO060 islocated on the North Bosque River about 14 river miles downstream of siteBO040 at the crossing of CR 248. Tributaries entering the river between siteBO060 and BO040 include Alarm, Indian and Sims Creeks.

North Bosque River at Hico, Texas (site BO070): An automated sampleris located near U.S. Geological Survey (USGS) station 08094800 on the NorthBosque River at the crossing of U.S. Highway 281 in Hico, Texas. The drainagearea of this site is referred to as the upper North Bosque River watershed in otherTIAER data analysis reports (e.g., McFarland & Hauck, 1997a & 1997b). SiteBO070 is about seven river miles downstream from site BO060 and is locatedabout one mile above the WWTP discharge for the city of Hico.


North Bosque River at Iredell (site BO080): This site is located on theNorth Bosque River below the confluence of Duffau Creek with the NorthBosque River and above the effluent discharge for the city of Iredell.Monitoring is limited to monthly physical measurements and grab sampleanalysis. BO080 is located about 14 river miles downstream of site BO070.

North Bosque River at Meridian (site BO085): Site BO085 is located onthe North Bosque River at FM Road 2840, west of Meridian, above the WWTPdischarge for the city of Meridian. Monitoring is limited to monthly physicalmeasurements and grab sample analysis. BO085 is located about 17 river milesdownstream of site BO080.

North Bosque River at Clifton (site BO090): An automated sampler islocated near USGS station 08095000 on the North Bosque River near thecrossing of FM Road 219 about a half mile northeast of Clifton, Texas. BO090is located about 14 river miles downstream of BO085 and above the WWTPdischarge for the city of Clifton.

North Bosque River at Valley Mills (site BO100): An automated samplersite is located south of the USGS station 08095200 on the North Bosque Rivernear the crossing of FM Road 56 northeast of Valley Mills. This site is locatedabove the WWTP discharge for the city of Valley Mills. BO100 is located about12 river miles downstream of BO090 and about 28 river miles upstream from themouth of the North Bosque River at Lake Waco.

3.4 Sites on Rivers and Tributaries to Lake WacoSites BO100, MB060, SB060 and HC060 are located on the North, Middle andSouth Bosque Rivers and Hog Creek, respectively, to represent the majortributaries to Lake Waco. All four sites are monitored using automatic stormsamplers and manual grab samples. BO100 is included in this grouping, as wellas with the North Bosque River sites, because it is the nearest North BosqueRiver site to Lake Waco.

The land use above these four sites varies greatly (Table 6). The land area abovethe Middle and South Bosque sites is dominated by cropland. The majority ofthe land area above the Hog Creek site is divided between cropland and range,while the North Bosque River site is dominated by range and wood. SiteBO100, on the North Bosque River, is the only one of the four sites whichincludes land area designated for dairy waste application (about 3 percent). Thedrainage area above BO100 also comprises over 746,000 acres, while thedrainage area above each of the other three sites is less than 77,000 acres.

North Bosque River at Valley Mills (site BO100): See description aboveunder Section 3.3.

Hog Creek (HC060): An automated sampler is located on Hog Creek at thecrossing of FM Road 185 near USGS station 08095400 about 6 miles east ofCrawford, Texas. Site HC060 is about 10 river miles upstream from LakeWaco.


Middle Bosque River (site MB060): An automated sampler is located onthe Middle Bosque River at the crossing of FM Road 185, east of Crawford.Site MB060 is located about 12 river miles upstream from Lake Waco.

South Bosque River (site SB060): Site SB060 is located on the SouthBosque River at FM Road 2837, south of US Highway 84. Site SB060 islocated about 1.5 river miles upstream of Lake Waco. The WWTP dischargefrom the city of McGregor enters into the South Bosque River from an unnamedtributary and is over 10 river miles above site SB060.

3.5 Sites at Wastewater Treatment Plant EffluentsThe effluents from the eight municipal wastewater treatment plants locatedwithin the Bosque River watershed were monitored weekly through a joint effortof BRA and TIAER. The monitoring history and location of each plant ispresented in Table 7. Monitoring included physical measurements and grabsample analysis. Samples were collected at the discharge pipe or, when thedischarge pipe could not be safely accessed, after the last stage of the treatmentprocess. These samples, thus, may not reflect the same methodology used forTNRCC compliance samples, which are generally taken at the point thedischarge enters the stream, and should not be interpreted as such for the WWTPeffluents. Six of the eight WWTPs discharge into the North Bosque River.These include plants for the cities of Stephenville (TP040), Hico (LB010),Iredell (LB020), Meridian (LB030), Clifton (LB040) and Valley Mills (LB050).The Crawford WWTP (LB060) discharges into the Middle Bosque River, whilethe McGregor WWTP (LB070) discharges into the South Bosque River. A newWWTP was installed at Crawford in May 1996. No direct discharge from thenew WWTP at Crawford occurred between May and December 1996 astreatment lagoons were filling. In January 1997, the new Crawford WWTPsystem started to discharge and effluent sampling was resumed.

Table 7. History of grab sampling at Bosque River watershed municipal wastewater treatment planteffluents.

Site City Watershed Date of First Grab Sample

TP040 Stephenville North Bosque River 15-Dec-93

LB010 Hico North Bosque River 8-Jan-96

LB020 Iredell North Bosque River 8-Jan-96

LB030 Meridian North Bosque River 18-Dec-95

LB040 Clifton North Bosque River 18-Dec-95

LB050 Valley Mills North Bosque River 18-Dec-95

LB060a† Crawford (old system) Middle Bosque River 2-Jan-96

LB060b Crawford (new system) Middle Bosque River 15-Jan-97

LB070 McGregor South Bosque River 18-Dec-95

† Last sample collected at LB060a on April 30, 1996. The new system (LB060b) did not start to discharge until January 1997.

3.6 Precipitation Monitoring SitesDaily precipitation data from nine National Weather Service (NWS) observersites located within the Bosque River watershed are obtained monthly by TIAER


(Table 8). These sites include Stephenville, Dublin, Hico, Cranfills Gap,McGregor, Meridian, Valley Mills and the Lake Waco dam. A wet-dryatmospheric collector was installed at the Stephenville NWS observer site inOctober 1996. This instrument allows collection of samples for water qualityanalysis from precipitation and dry-atmospheric deposition. Water quality datafrom samples collected as wet precipitation will be used to estimate nutrientloadings associated with direct rainfall into Lake Waco.

Table 8. Total monthly rainfall in inches for National Weather Service Observer Stations within theBosque River watershed for October 1995 through March 1997. Location of cities provided onFigure 1.

National Weather Service Observer Station

Month Year Stephenville Dublin Hico Cranfills Gap McGregor Meridian Valley Mills Waco Dam

October 1995 2.6 2.7 0.2 0.1 0.4 0.4 0.2 0.3

November 0.6 3.1 1.3 0.9 1.9 1.9 1.0 1.7

December 0.7 0.8 1.0 1.6 1.4 1.4 2.1 1.3

January 1996 0.5 0.6 0.3 0.4 0.5 0.0 1.2 0.8

February 0.3 0.0 0.4 0.2 0.1 0.2 0.0 0.2

March 1.1 1.2 1.4 1.0 1.3 1.2 2.4 1.2

April 2.6 3.2 2.7 3.2 3.1 2.8 3.0 2.7

May 2.9 5.3 3.2 3.6 0.8 1.1 1.2 2.0

June 2.7 2.9 3.5 4.5 2.5 2.9 1.6 3.1

July 2.8 2.6 2.5 3.5 1.4 5.3 1.6 2.8

August 8.9 13.4 8.0 8.0 9.0 8.1 7.6 5.4

September 4.5 2.4 2.6 4.0 4.8 8.4 nd 3.6

October 2.9 3.3 3.2 2.0 0.7 3.5 1.6 1.1

November 4.0 3.9 3.2 3.7 4.7 4.0 3.0 4.3

December 0.1 0.3 0.8 1.5 3.3 1.8 2.8 3.1

January 1997 0.4 0.0 1.2 1.9 1.6 1.8 nd 1.0

February 8.3 12.2 10.1 7.7 6.3 7.8 nd 7.7

March 3.3 4.3 3.4 3.2 2.3 4.5 nd 2.1

Totals 49.2 62.0 49.1 50.9 45.9 57.0 na 44.2

‘nd’ indicates no data available‘na’ indicates not applicable


4. SAMPLE COLLECTION AND ANALYSISMETHODS

The present monitoring program evolved from several different research projectsdirected primarily at investigating agricultural nonpoint source pollution issues.The current monitoring program includes routine and storm event sampling atstream sites throughout the Bosque River watershed. Particular emphasis isgiven to sampling waterborne nutrient constituents.

4.1 Quality Assurance ProceduresAll monitoring by TIAER between October 1995 and August 1996 for sites inthe upper North Bosque River watershed (Hico, Texas and above) wasconducted under the approved quality assurance project plan (QAPP) for theU.S. Environmental Protection Agency funded project Livestock and theEnvironment: A National Pilot Project (TIAER, 1993). For the period October1995 through August 1996, BRA monitoring efforts throughout the BosqueRiver watershed and TIAER efforts for sites below Hico, Texas were conductedunder the approved QAPPs for the Bosque River Watershed Pilot Project (BRA,1995) and for the Clean Rivers Program of TNRCC (BRA, 1996). SinceSeptember 1996, all monitoring efforts have occurred under the TNRCCapproved QAPP for the U.S. Department of Agriculture funded LakeWaco/Bosque Rivers Initiative (TIAER, 1996). Monitoring efforts have beenperformed jointly by BRA and TIAER to avoid duplication of effort and toconsolidate monitoring resources within the watershed.

4.2 General Collection Procedures for Grab SamplesRoutine grab sample collection consists of a single, representative sample.During baseflow, most of the streams monitored are fairly shallow, thus, mostgrab samples are taken at a depth of 0.25 to 1.0 feet below the surface of thewater. Routine sampling occurred on a bi-weekly or weekly schedule throughoutthe report period (October 1, 1995 through March 15, 1997), regardless of flowconditions (no flow, baseflow or stormflow) at the scheduled sampling time. Agrab sample is not taken during routine monitoring if the site is dry or if thewater at the site is pooled and not flowing. Thus, these grab samples do notnecessarily represent only baseflow conditions. Routine grab samples were alsotaken of the effluent from the eight municipal WWTPs in the watershed. Thephysical water quality constituents of water temperature, DO, pH and specificconductance were measured in situ when grab samples were collected.


4.3 General Collection Procedures for Automated StormSamples

Each automated stormwater sampling site consists of an ISCO 32307 bubbler-type meter and an ISCO 3700 automatic sampler. Both are enclosed in a sheetmetal shelter. The ISCO 3230 meter operates by measuring the pressurerequired to force an air bubble through a one-eighth inch polypropylene tube(bubbler line) and records this pressure as water level. The ISCO 3230s areprogrammed to record the stream water level (stage) and initiate sample retrievalby the ISCO 3700 automatic samplers. Electrical power is provided by marine,deep-cycle batteries with recharge provided by solar cells.

ISCO 3230 meters initiate pre-set sampling programs for the ISCO 3700automatic samplers when threshold water levels are exceeded. Each meter isprogrammed to record water level at five-minute intervals and typically actuatethe samplers when a stream rise of 0.12 feet above the bubbler datum isregistered. The actuation level was selected by trial-and-error as the lowest levelwhich would actuate for rainfall-runoff events and avoid undesired actuationfrom non-rainfall event causes such as wave action. Once activated, samplersare programmed to retrieve 24 one-liter sequential samples. The typicalsampling sequence for small drainage area sites is (1) an initial sample, (2) threesamples taken at one-hour intervals, (3) four samples taken at two-hour intervalsand (4) all remaining samples taken at six-hour intervals. For major tributaryand mainstem sites, the typical sampling sequence is (1) an initial sample, (2)three samples taken at one-hour intervals, (3) two samples taken at two-hourintervals and (4) all remaining samples taken at eight-hour intervals. Thesesampling sequences allow more frequent sample collection during the typicalrapid hydrograph rise and peak periods following sampler actuation and lessfrequent sample collection during the longer, receding portion of a stormhydrograph.

4.4 Streamflow Monitoring at Automated Sampler SitesStreamflow is an important characteristic that greatly affects stream quality andallows quantification of loadings (flow multiplied by constituent concentrations);therefore, its quantification enhances the value of water quality information. Ateach automated sampler site, continuous (five-minute intervals) water level dataand site-specific stage-discharge relationships allow the calculation of flow. Tocharacterize water quality during a runoff event, a flow-weighted meanconcentration provides an intuitively more meaningful average than one basedsolely on the water quality data independent of flow. The size of a runoff event,as quantified by the amount of flow or total runoff volume, also puts intoperspective the relative importance of each event.

A stage-discharge relationship for each site is determined from individualmeasurements of flow taken at various water levels or stream stages. To develop

7 Mention of trade names or equipment manufacturers does not represent endorsement of these products or manufacturers by TIAER.


these relationships, manual flow measurements were made on an opportunisticbasis dependent upon streamflow conditions. Pairs of water level and flow datawere used to develop a site specific stage-discharge relationship. Theserelationships are updated if meaningful changes occur in the stream cross-sectional area at a sampling site. Because stream sites NF005 and WC020 arelocated at a road culverts, hydraulic equations were applied to determine thestage-discharge relationships for these sites. At sites BO090 and BO100,provisional flow data as of July 1, 1997 from corresponding USGS sites,08095000 and 08095200 respectively, were obtained for use in this report. Atsite BO070, the USGS stage-discharge relationship for station 08094800 wasused in conjunction with measured level data to calculate flow. For theremaining stream sites, a stage-discharge relationship was developed through asimple plot of stage versus discharge.

Typically stage-discharge relationships are parabolic in shape when plotted onarithmetic (i.e., non-transformed) axes, though irregularities often exist becauseof abrupt cross section changes and/or changes in downstream control withvariation in flow. Where necessary, extrapolation of these stage-dischargerelationships was made by surveying the stream cross-sectional area at eachsampling site and assuming a semi-logarithmic relationship of average streamvelocity to water level (log). The semi-log approach makes use of existing crosssection information at each site and extrapolates the velocity as opposed to othermethods that do not directly account for available cross section information (e.g.,Kennedy, 1984). The streamflow history as average daily flow for eachautomated monitoring site is presented graphically in Appendix A. The varyingdurations of the streamflow record for each site reflect the different dates ofinstrument installation.

4.5 Measurement of Physical and Chemical ConstituentsA variety of physical and chemical constituents are measured for each waterquality sample. A general outline of the water quality constituents measured, theabbreviations used in this report and the units of measurement are provided inTable 9. The methods of analysis and the laboratory method detection limits(MDL), if applicable, are listed in Table 10. For fecal coliform, estimatedvalues were determined as outlined in Standard Method 9222 B. of the totalcoliform membrane filter procedure (APHA, 1995). Field, i.e., in situ,constituents are measured only when routine grab samples are collected. Fieldconstituents include water temperature, dissolved oxygen, specific conductanceand pH which are measured with Hydrolab field sampling instruments.

Table 9. Descriptions, abbreviations and units of water quality constituents measured at stream sites inthe Bosque River watershed.

Constituent Abbreviation Units Description

Ammonia-Nitrogen NH3-N mg/L Inorganic form of nitrogen that is readily soluble and available for plantuptake. Elevated levels are toxic to many fish species.

Chemical Oxygen Demand COD mg/L Indication of oxygen demanding properties of the water in terms ofcomplete chemical oxidation.

Chlorophyll-α CHLA µg/L Indicator of phytoplankton biomass.

Specific Conductance Conductivity µmhos/cm Measure of the ability of water to carry an electric current. Used as anindicator of the salt content of the water.


Constituent Abbreviation Units Description

Dissolved Oxygen DO mg/L Indicator of the amount of oxygen available in the water for biologicalactivity and chemical reactions.

Fecal Coliform FC colonies/100 ml Indicator of public health hazards from infectious microorganisms.

Nitrite-Nitrogen NO2-N mg/L Inorganic form of nitrogen. Generally a transitory phase in thenitrification of NH3 to NO3.

Nitrate-Nitrogen NO3-N mg/L Inorganic form of nitrogen that is readily soluble and available for plantuptake. Considered the end product in the conversion of N from theammonia form to nitrite then to nitrate under aerobic conditions.

Orthophosphate-Phosphorus† PO4-P mg/L Inorganic form of phosphorus that is readily soluble and available forplant uptake.

pH standard units Measures the hydrogen ion activity in a water sample.

Total Kjeldahl Nitrogen TKN mg/L Organic and ammonia forms of nitrogen are included in TKN.

Total Phosphorus total-P mg/L Represents both organic and inorganic forms of phosphorus.

Total Suspended Solid TSS mg/L Measures the solid materials, i.e., clay, silts, sand and organic,suspended in the water.

Water Temperature ºC Indicator of temperature conditions for aquatic life.

† Dissolved reactive phosphorus (DRP) is another term for this constituent.

Samples collected for laboratory analysis during routine grab sampling andstorm event sampling with automated equipment were generally analyzed by theBRA and TIAER for nitrite-nitrogen (NO2-N), nitrate-nitrogen (NO3-N),orthophosphate-phosphorus (PO4-P) and total suspended solids (TSS). Inaddition, TIAER generally analyzed samples for ammonia-nitrogen (NH3-N),total Kjeldahl nitrogen (TKN), total phosphorus (total-P) and chemical oxygendemand (COD). Fecal coliform was included as part of the routine grab sampleanalysis. A special project involved the collection of water quality samplesduring storm events for fecal colifom analysis. These special storm-event fecalcoliform samples were collected only at sites on the mainstem of the NorthBosque River. Chlorophyll-a (CHLA) was also analyzed on a bi-weekly ormonthly basis as part of the routine grab sample analysis performed by TIAERfor all sites but the micro-watershed sites in the Bosque River watershed.


5. DATA ANALYSIS METHODS

5.1 OutliersGraphical screening and outlier detection methods as described by Ott (1984)were used to highlight questionable data points. Questionable data were thentracked through the Chain of Custody sheets and field and laboratory notebooks,as necessary, to verify if these points represented transcription errors in thedatabase. If a transcription error was found, the error was corrected prior tostatistical analysis of the data. No laboratory approved data were removed fromthe analysis dataset.

5.2 Censored DataLeft censored data (values measured below the laboratory method detectionlimit) for constituents other than fecal coliform were entered as one-half themethod detection limit (MDL) as recommended by Gilliom and Helsel (1986)and Ward et al. (1988). Left censored variables included: NH3-N, NO3-N, NO2-N, TKN, PO4-P, total-P and COD. Method detection limits for these variablesare listed in Table 10.

Table 10. Analysis methods and method dectection limits for water quality constituents. EPA refers to theEPA (1983) Methods for Chemical Analysis of Water and Wastes. SM refers to the StandardMethods for Examination of Water and Wastewater, 19th Edition (APHA, 1995).

Constituent Entity Method Estimated MDL†

Field Measurements

Conductivity BRA/TIAER SM 2510B 10 µmhos/cm

Dissolved Oxygen BRA/TIAER EPA 360.1 0.2 mg/L

pH BRA/TIAER EPA 150.1 0.2 units

Water Temperature BRA/TIAER EPA 170.1 -5ºC

Laboratory Measurements

Ammonia-Nitrogen TIAER EPA 350.1 0.01 - 0.037 mg/L

Chemical Oxygen Demand TIAER EPA 410.4 10 - 40 mg/L

Chlorophyll-α TIAER SM 10200H 5.36 - 12.2 µg/L

Fecal Coliform BRA/TIAER SM 9222D 40 colonies/100 ml

Nitrate-Nitrogen BRATIAER

SM 4110BEPA 353.2

0.01 mg/L0.006 - 0.016 mg/L

Nitrite-Nitrogen BRATIAER

SM 4110BEPA 353.2

0.01 mg/L0.002 - 0.01 mg/L

Total Kjeldahl Nitrogen TIAER EPA 351.2 0.173 - 0.50 mg/L


Orthophosphate-Phosphorus

BRATIAER

SM 4110BEPA 365.2

0.01 mg/L0.003 - 0.01 mg/L

Total Phosphorus TIAER EPA 365.4 0.01 - 0.11mg/L

Total Suspended Solids BRATIAER

EPA 160.1EPA 160.2

10 mg/L4 - 10 mg/L

† Estimated MDL’s are periodically updated by each laboratory. When more than one MDL was estimated during the monitoring period, therange of estimated MDL’s is presented.

5.3 Derived Water Quality VariablesThe following derived water quality variables were included as part of thestatistical analysis for their environmental relevance:

N).-(NH - (TKN) = N)-(org.nitrogen -organicand N),-(NO + N)-(NO + N)-(NH = N)-(inorg.nitrogen inorganic

N),-(NO + N)-(NO + (TKN) = N)-(totalnitrogen total

3

323

32

5.4 Methods for Comparing Concentrations between Sitesand Sampling Types

For comparing baseflow water quality between stream sites, grab sample datawere first compared to precipitation and flow records to determine which grabsamples were taken during baseflow and which grab samples were taken duringstorm or elevated flow conditions. Only grab samples taken during baseflowconditions were included in comparing baseflow water quality between sites.Grab samples taken during elevated or storm flow conditions were included inthe stormwater quality analyses.

To help illustrate the variability in rainfall conditions during the study period,monthly precipitation at NWS stations at Stephenville and the Waco Dam wascompared to the long-term average for 1967-1995 for these sites (Figure 5).Monthly totals from October 1995 through March 1996 at both sites wereconsistently below the long-term average, while monthly totals were well aboveaverage in August 1996 and February 1997. In general, precipitation during thefirst part of the sampling period was below normal, while several monthsindicated above normal conditions during the latter part of the monitoringperiod.

Figure 5. Monthly precipitation at Stephenville and Waco Dam National Weather Service


For each category of sites, a consistent sampling period was used for statisticalcomparisons. Due to the drought conditions starting in mid-1995 and extendinginto 1996, no flow or dry conditions precluded sampling at many sites, often forextended periods of time. The differences in the starting dates for sampling,especially for sites in the lower portion of the watershed also limited the timeperiod which could be used to uniformly compare data between sites. Thefollowing timeframes were used to statistically compare water quality atbaseflow between sites for each category:

Sites on Micro-watersheds: September 1996-March 1997

Sites on Major Tributaries to May 1996-March 1997the North Bosque River:

Sites on the North Bosque River: May 1996-March 1997

Sites on Rivers and Tributaries to February 1996-March 1997Lake Waco: excluding samples taken during

July and August 19968

Because water quality can vary greatly within a storm event, a flow-weightedmean value was calculated for each water quality constituent (except fecalcoliform) for each storm event. Flow-weighted means were calculated bycombining the storm hydrograph with the water quality data for each stormevent. The flow hydrograph was divided into intervals based on the date andtime when water quality samples were taken using a midpoint rectangularmethod between water quality samples (Stein, 1977). Constant flow wasassumed between each five-minute water level measurement to estimate thewater volume associated with each water quality sample.

The "beginning" of each storm event was set an hour before the first waterquality sample was taken to include any rise in the hydrograph that occurredbefore the sampler was initiated. The "end" of each storm event was set 24hours after the last water quality sample to include the receding portion of thestorm hydrograph. These volume-weighted mean storm values were then used tocharacterize the stormwater quality at each stream site and to compare waterquality between stream sites. Due to the drought during late 1995 and early1996, most stream sites were dry or had very low flow until about April 1996.Very few storm events were monitored at any of the sites between October 1995and April 1996. To evaluate a uniform time period between sites, only stormevents monitored after April 1, 1996 were included in the comparisons ofstormwater quality between sites.

Storm samples collected at sites on the mainstem of the North Bosque River aspart of a special study to analyze fecal coliform concentrations were statisticallyanalyzed separately from the other water quality constituents. Storm samples forfecal coliform analysis were collected at sites BO020, BO040, BO060 andBO070 starting in October 1995. Sites BO080, BO085, BO090 and BO100were added to the study in August 1996. Storm sampling for fecal coliformanalysis was continued through October 1996 at all eight North Bosque Riversites. One or two grab samples were collected per day during each storm event.

8 No samples were recorded at site MB060 during July and August 1996 due to no flow or dry conditions. For consistency in comparisonsbetween sites, samples collected at BO100 and HC060 during July and August 1996 were, thus, excluded from this analysis.


Fecal coliform data were not flow-weighted by storm event, but analyzed usingthe geometric mean of all storm event samples to characterize the storm fecalcoliform levels at each site. For consistency, fecal coliform comparisonsbetween sites for storm events included data from August 1996 through October1996.

For validity of the parametric statistical analyses performed in this report, thewater quality data are assumed to be sampled from a normal population. Foreach set of water quality data, the Shapiro-Wilks Test was performed to test datafor normality (SAS, 1992; Ott, 1984). If the null hypothesis of this test wasrejected, a natural log (loge) transformation was performed and the test re-run onthe transformed data as water quality concentrations often conform to a lognormal distribution rather than a normal distribution (Spooner, 1994).

In most cases, the natural log transformed data better fit the assumptions ofnormality at the a = 0.01 level of significance. Even when the transformed datadid not meet the statistical test for normality, if the distribution of thetransformed data was closer to normal than the distribution of the untransformeddata, the transformed data were used in the analyses. Minor deviations fromnormality were assumed to have a minimal impact on the validity of the analysisof variance test because of the inherent robustness of the ANOVA test to thenormality assumption (Spooner, 1994). For each of the data sets evaluated, anatural-log transformation was indicated to provide a more normal distributionof the data for all water quality constituents except water temperature, dissolvedoxygen and pH.

Mean values of the loge transformed data are presented in the original scale asthe geometric mean, i.e., the exponential (anti-log) of the lognormal mean value.The standard deviation of the natural log transformed data is not symmetricalabout the mean when presented in the original scale and is, therefore, presentedas a range about the mean:

data. ed transformlog natural theofdeviation standard = Std

and data, ed transformlog natural theofmean = Meanscale, original in thedeviation standard theplusmean = StdUpper

scale, original in thedeviation standard theminusmean = StdLower where

)Std + (Mean exp = StdUpper

and ),Std - exp(Mean = StdLower

(ln)

(ln)

(ln)(ln)

(ln)(ln)

An analysis of variance (ANOVA) was performed to evaluate all baseflow andstorm event water quality comparisons by site category considering all siteswhere at least 10 baseflow grab samples or 10 storm events were monitored. ALeast Significant Difference (LSD) test was then used as the multiplecomparison test to differentiate site-by-site differences within site categories ifthe ANOVA was significant at a = 0.05. Comparisons between baseflow andstormwater quality were also evaluated at sites where both grab and stormsampling was conducted.

5.5 Methods for Assessment of Stream Water Quality


While statistical comparisons allow distinctions to be made in the water qualitybetween sites, assessments are used to compare the water quality at a site to setguidelines or standards. Existing Texas surface water quality standards providenumeric criteria for key water quality constituents, such as dissolved oxygen, pHand fecal coliform, to evaluate the level at which water quality supports thedesignated uses of each segment. Criteria do not currently exist for nutrients orchlorophyll-a, although screening levels are defined by the TNRCC asguidelines in identifying concerns for these constituents.

Table 11 includes the criteria and screening levels for segments 1226, 1246 and1255, as specified in the State of Texas Water Quality Inventory provided toEPA by the TNRCC in accordance with Section 305(b) of the Clean Water Act(TNRCC, 1996). Other sources of information on criteria and screening levelsare included in Table 11 for comparison. For the purposes of this report, allmajor tributaries flowing into segments 1226, 1246 or 1255 were evaluatedbased on the criteria defined for these designated segments (Table 11). Thesampling site on Hog Creek was evaluated based on the guidelines for segment1246. For the smaller unclassified tributaries designated within micro-watersheds, the guidelines proposed for segment 1226 were used for allconstituents except DO which was evaluated using the 2.0 mg/L criterion(TNRCC, 1995a). A limited aquatic life use was assumed for all micro-watershed sites due to the strongly intermittent nature of these streams.

Table 11. Relevant water quality criteria and screening levels for stream sites in the Bosque Riverwatershed.

WaterQuality

Constituent

Segment1255

(TNRCC,1996)

Segments1226 &

1246(TNRCC,

1996)

UnclassifiedIntermittent

StreamCriteria

(TNRCC,1995a)

Section305(b)

ScreeningLevels

(TNRCC,1996)

CleanRivers

ProgramGuidance(TNRCC,

1993)

Clean RiversProgramGuidance

(TNRCC, 1995b)

EPARecom-

mendation(EPA, 1986)

ScreeningLevels and

Criteria Used inReport

DO (mg/L) 4.0 5.0 2.0 — 5.5 Segment Specific — 2.0, 4.0, 5.0†

pH (standard units) 6.5 - 9.0 6.5 - 9.0 — — 6.5 - 9.0 Segment Specific — 6.5 - 9.0

CHLA (µg/L) 30 30 — 30 — 30 — 30

Fecal Coliform‡(colonies/100 ml)

400 400 — 400 400 400 — 400

NH3-N (mg/L) 1.0 1.0 — 1.0 1.0 1.0 — 1.0

NO3-N (mg/L) — — — — 1.0 — — —

NO2-N + NO3-N(mg/L)

1.0 1.0 — 1.0 1.0 1.0 — 1.0

Organic-N (mg/L) — — — — 2.0 — — 2.0

Total-N (mg/L) — — — — 3.0 — — 3.0

PO4-P (mg/L) 0.1 0.1 — 0.1 0.2 0.1 — 0.1

Total-P (mg/L) 0.2 0.2 — 0.2 0.2 0.2 0.1¥ 0.2

† DO was measured only during routine grab sampling at stream sites. A value of 2.0 was used for the micro-watershed sites, while a value of4.0 was used for major tributary and main stem sampling sites along or feeding into Segment 1255 and a value of 5.0 for all other samplingsites.

‡ A value of 200 colonies/10 ml may be used if five or more samples are collected within a 31 day period. The geometric mean of these 5samples is compared to the 200 colonies/100 ml criteria to determine support or nonsupport using this method (TNRCC, 1996).

¥ EPA (1986) states that to prevent biological nuisances and to control accelerated eutrophication, total phosphate as phosphorus should notexceed 0.05 mg/L in any stream where it enters a lake, nor 0.025 mgk/L within the reservoir. Also, a desired goal to prevent plant nuisancesin flowing water not discharging directly to a reservoir is 0.1 mg/L total-P.


The numeric criteria and screening levels used for comparative purposes in thisreport are found in the rightmost column of Table 11. It should be noted that thescreening levels for nutrients were established by the TNRCC for the routinemonitoring performed by state and federal agencies. Therefore, the applicationof these screening levels to stormwater data must be tempered with theknowledge that the levels may be overly restrictive for the expected highernutrient concentrations during runoff events. These screening levels should bemore appropriate for the routine or baseflow stream sampling results in thisstudy but are compared to storm event and baseflow water quality values as thebest available guidelines for evaluating water quality data.

The guidelines proposed in TNRCC (1996) for evaluating water quality data inrelation to screening levels and criteria were used in this evaluation as outlinedin Section 2.2 of this report. The percentage of samples exceeding screeninglevels and criteria during baseflow and storm events were evaluated separatelyfor each stream site to give a general assessment of overall water quality at thesesites. Water quality data during the full period of record (October 1995 throughMarch 1997) at each site were used in the assessment of stream water quality.

5.6 Methods for Estimating Nutrient Loadings to the BosqueRiver Watershed

Nutrient export coefficients for major land uses within the Bosque Riverwatershed were estimated using regression methods as described by Hodge andArmstrong (1993) based on cumulative loadings of PO4 -P, total-P and total-Nmeasured for the various sampling sites within the watershed. A nutrient exportcoefficient provides an estimate of the quantity of a particular nutrient leaving aunit area of a single land use over time. Consequently, a nutrient exportcoefficient will have the units of nutrient mass per unit area per unit time, e.g.,pounds of phosphorus per acre of woodland per year. Export coefficients weremultiplied by the area of the watershed occupied by each land use to estimate thecontribution of each land use type to the nutrient loadings into the major riversand tributaries to Lake Waco. These export coefficients along with cumulativeloadings associated with the WWTP discharges and estimates of nitrogen andphosphorus in precipitation were used to estimate total loadings into the BosqueRiver watershed during the monitoring period. Due to variations in the timing ofsite installation, the mass loading evaluation was limited to November 1, 1995through March 15, 1997. Site MB040 on Methodist Branch within the city ofStephenville was used to represent urban loadings for the entire watershed as thesole urban site with data available for this report. Data from a wet-dryatmospheric collector installed at the Stephenville National Weather Serviceobserver site was used to estimate nutrient loadings associated with directrainfall to the surface of Lake Waco.9

9 The wet-dry atmospheric collector allows collection of samples for water quality analysis from precipitation and dry-atmospheric deposition.


6. RESULTS AND DISCUSSION OF WATERQUALITY COMPARISONS ANDASSESSMENTS

The results of comparing storm event and baseflow constituent concentrationsconfirm general expectations that stormwater runoff has a very important impacton in-stream water quality within the Bosque River watershed. Consistentlywhen statistically significant water quality differences were indicated betweenbaseflow and storm event water quality, higher constituent concentrations wereindicated during storm events than at baseflow for all sites (Table 12).

Table 12. Comparison of baseflow to storm event concentrations by site. ‘S’s indicate comparisons forwhich storm concentrations were significantly greater than baseflow concentrations (α = 0.05).‘B’s indicate comparisons for which baseflow concentrations were significantly greater thanstorm event concentrations (α = 0.05). ‘ns’ indicates that the difference between storm andbaseflow concentrations was statistically nonsignificant (α = 0.05).

Site NH3-N NO2-N NO3-N TKN Org.-N Inorg.-N Total-N PO4-P Total-P COD TSS

Category 1: Micro-Watershed Sites

IC020 S ns ns S S ns S S S S S

NF005 S ns S S S S S S S S S

NF009 S ns ns S S ns S S S S S

NF020 S S S S S S S S S S S

SC020 ns ns ns S S ns S S S S S

SF020 S ns S S S ns S ns S ns S

SF050 S ns ns S S ns S S S ns S

SP020 ns S ns S S ns S ns S ns ns

TC020 ns ns S S S S ns ns S S S

WC020 ns ns S S S S S S S S S


AL040 ns ns ns S S ns S ns ns ns S

DC060 S ns S S S S S S S S S

GC100 ns ns ns ns ns ns ns ns S ns S

NC060 ns ns ns S ns ns S ns ns S S

NF050 ns ns ns ns ns ns ns ns ns ns S

SF075 ns ns ns ns ns ns ns ns ns ns S

Category 3: North Bosque River Sites

BO040 ns ns ns S S ns ns ns ns S S

BO070 ns ns ns ns ns ns ns ns ns ns S

BO090 S ns S ns ns S S ns S ns S

BO100 ns ns S S S ns S ns S S S



BO100 ns ns ns S S ns S ns S S S

HC060 ns ns ns S S ns S ns ns S S

MB060 ns ns ns S S ns ns ns S S S

Comparisons between sites for baseflow and storm events are presented by sitecategory below. In comparing water quality between sites, a multiplecomparison test (LSD test) was conducted only if the ANOVA indicatedsignificant differences at a = 0.05. In the graphical presentation of the results(Figures 6-26), different letters above each site’s mean value indicate statisticallysignificant differences between sites for each water quality constituent evaluated.‘A’ is used to represent the lowest grouping of values that are significantlysimilar, ‘B’ represents the next higher grouping of similar values, and so forth.A mean value may have more than one letter associated with it, indicating that itis similar to several different groupings of mean values. If no letters areassociated with a graph for a constituent, no significant differences wereindicated. Basic statistics for each constituent are presented for each site bysample type (baseflow or storm event) in Appendix B.

The ANOVA and LSD statistical analyses provide a comparison of water qualityconcentrations between sites. While these statistical analyses provide acomparison of water quality concentrations at a monitoring site relative to othermonitoring sites, these analyses do not indicate the level of environmentalimpact or concern associated with measured concentrations for each site. Usingthe same methodology as TNRCC for its biennial report pursuant section 305(b)of the Clean Water Act (TNRCC 1996) and as discussed in Section 5.5 of thisreport, each site was assessed separately for baseflow and storm event data incomparison to appropriate criteria and screening levels. This water qualityassessment is provided as the percent of values for a particular constituent thatexceed the established regulatory criteria (for DO, pH and fecal coliforms) orexceed TNRCC established screening levels (for nutrients and chlorophyll-a).10

The results of the statistical comparisons and assessments are discussed belowby site category, i.e., sites on micro-watersheds, sites on major tributaries to theNorth Bosque River, sites on the North Bosque River and sites on rivers andtributaries to Lake Waco.

6.1 Evaluation of Water Quality Data for Micro-WatershedSites

Previous analyses of water quality data in the upper North Bosque River (e.g.,McFarland & Hauck, 1995, 1997a, 1997b) indicated strong correlations of in-stream water quality concentrations to the land use above sample sites. Inparticular, higher constituent concentrations were associated with intensive landuses, such as urban, dairy waste application fields, pasture and cropland; and

10 If less than 10 percent of the samples exceed the numeric criterion or screening level, the segment is considered as “fully supporting” or of“no concern”; if between 11 and 25 percent of the samples exceed the numeric criterion, the segment is considered as “partially supporting”or of “potential concern”; and if greater than 25 percent of the samples exceed the numeric criterion, the segment is considered as “notsupporting” or of “concern” (TNRCC, 1996).


lower constituent concentrations were associated with less intensive land uses,such as woodland and range. To facilitate the understanding of this statisticalcomparison of water quality between micro-watershed sites a generalizedcharacterization of dominating land use(s) above each site is provided along withan indication of the sample types (baseflow and/or storm) evaluated at each site(Table 13).

Table 13. Dominate land uses above micro-watershed sites and sample types evaluated. ‘NA’ indicates notapplicable.

Site Characterizing Land Use(s)BaseflowSamples

StormSamples

GB020 Dairy Application Fields NA X

IC020 Dairy Application Fields X X

MB040 Urban NA X

NF005 Dairy Application Fields X X

NF009 Pasture, Cropland, Dairy Application Fields X X

NF020 Dairy Application Fields X X

SC020 Pasture, Dairy Application Fields X X

SF020 Wood, Range X X

SF050 Pasture, Dairy Application Fields X X

SP020 Wood, Range X X

TC020 Cropland X X

WC020 Cropland X X

6.1.1 Statistical Comparison of Micro-Watershed Sites

In situ measurements of water temperature, DO, pH and specific conductance arepresented only for baseflow conditions. Relatively little variation was indicatedbetween sites for water temperature, DO and pH, while a very distinct variabilitybetween sites was indicated for conductivity (Figure 6). Sites with dairy wasteapplication fields as a characterizing land use were associated with the higherconductivity measurements, which is likely a runoff response to the saltsassociated with animal wastes.


0

5

10

15

NF020 NF005 NF009 SC020 SP020 WC020 SF020 SF050 TC020 IC020

DO

(mg/

L)0

10

20

SF050 SF020 NF005 NF009 NF020 SC020 IC020 SP020 TC020 WC020Wat

er T

emp.

( C

)

A AB BC BCD BCD BCD CD CD D D

6

7

8

9

NF005 NF009 WC020 SF050 SF020 SC020 NF020 TC020 IC020 SP020

pH (s

tand

ard

units

)

A A A AB BC CDDE E E

E

0

2000

4000

TC020 WC020 SP020 SC020 SF020 IC020 SF050 NF020 NF009 NF005

Con

duct

ivity

(u

mho

s/cm

)

A B BC BCD BCDEFBCDECDEF DEF

EF

F

0

1000

2000

3000

SP020 TC020 WC020 SC020 IC020 SF020 NF005 SF050 NF009 NF020

Feca

l Col

iform

(c

olon

ies/

100m

l)

Figure 6. Mean water temperature, DO and pH concentrations and geometric mean conductivity and fecalcoliform concentrations for micro-watershed sites during baseflow. Samples were collectedbetween September 1996 and March 1997. Different letters indicate significantly different meanor geometric mean values at a = 0.05.

The fecal coliform comparison (Figure 6) indicates large variations betweensites. Because fecal coliforms are indicator organisms of contamination frommammalian feces, the expectation would be that fecal coliforms would be closelyassociated with dairy waste application fields. However, the data do not indicatethat dairy waste application fields are the exclusive source of this contaminationnor always a major source. The presence of additional sources, such as beef


cattle, goats, wildlife and rural septic systems, within each micro-watershedscomplicates the interpretation of these data.

Comparisons of the various nitrogen species are provided in Figures 7 and 8 forbaseflow and storm events, respectively. Under baseflow and storm eventconditions the geometric mean concentrations of the nitrogen species exhibited awide variation between sites distinguishing several statistically significantgroupings of sites. Characterizing land uses provides some insight into themeasured concentrations of nitrogen. Runoff from cropland (sites TC020 andWC020) contributed the highest levels of NO3-N. Whereas NH3-N, TKN andorg.-N concentrations were highest from sites with drainage areas characterizedby dairy waste application fields (sites GB020, NF005 and NF020), reflectingthe runoff contribution from the organic matter applied to the land. Sitescharacterized with drainage areas of cropland had the highest total-Nconcentrations at baseflow (Figure 7), while during storm events, sitescharacterized by either cropland or dairy waste application fields had the highesttotal-N concentrations (Figure 8). Consistently, lower nitrogen constituentconcentrations occurred at sites with drainage areas characterized by wood/range(SF020 and SP020). The urban site (MB040) and mixed sites with pasture,cropland and dairy application fields (IC020, NF009, SC020 and SF050)displayed intermediate nitrogen concentrations in comparison to the other micro-watershed sites.


A A A A A AB AB ABC

BCC

0.0

0.1

0.2

SP020 TC020 WC020 SC020 SF020 IC020 NF009 SF050 NF020 NF005

NH

3-N

(mg/

L)

A AB AB BC BC BCCD CD

CDD

0.00

0.02

0.04

SP020 SF020 SC020 NF009 SF050 NF020 IC020 NF005 TC020 WC020NO

2-N

(mg/

L)

E

E

DCDBCDBCDBCBAA05

101520

SP020 SF020 NF020 SF050 SC020 NF009 NF005 IC020 TC020 WC020NO

3-N

(mg/

L)

A A B B BC C C

D D

0

2

4

SP020 WC020 TC020 SC020 SF020 NF009 IC020 SF050 NF020 NF005

TKN

(mg/

L)

EDECDCC

BBBAA0

2

4

WC020 SP020 TC020 SC020 SF020 NF009 IC020 SF050 NF020 NF005Org

.-N (m

g/L)

A A B B BC BC BC C

DD

05

101520

SP020 SF020 SF050 SC020 NF020 NF009 NF005 IC020 TC020 WC020Inor

g.-N

(mg/

L)

A B C D DE DEF EF FG

H

05

101520

SP020 SF020 SC020 SF050 NF009 IC020 NF020 NF005 TC020 WC020Tota

l-N (m

g/L)

Figure 7. . Geometric mean concentrations for nitrogen species at micro-watershed sites during baseflow.Samples were collected between September 1996 and March 1997. Different letters indicatesignificantly different mean or geometric mean values at a = 0.05.


A A AB AB BC CD CD D DE E

E

0

1

2

TC020 SP020 WC020 SF020 SC020 MB040 SF050 IC020 NF009 GB020 NF020 NF005

NH

3-N

(mg/

L)

A A AB BC CD CD CDE DEF DEF DEFEF F

0.00

0.05

0.10

SP020 SF020 SC020 MB040 NF009 IC020 TC020 WC020 SF050 GB020 NF020 NF005

NO

2-N

(mg/

L)

A B BC CDE CDE DE DEF EF F F

GG

0

5

10

SP020 SF020 SC020 MB040 IC020 NF009 SF050 GB020 NF020 NF005 TC020 WC020

NO

3-N

(mg/

L)

EEE

DCDCDCBBBBA0

5

10

SP020 TC020 SC020 SF020 WC020 MB040 SF050 IC020 NF009 NF020 GB020 NF005

TKN

(mg/

L)

EEEDCDCDC

BBBBA0

5

10

SP020 TC020 SC020 SF020 WC020 MB040 SF050 NF009 IC020 NF005 NF020 GB020

Org

.-N (m

g/L)

F

FEEEDDDCDCBA

0

5

10

SP020 SF020 SC020 MB040 NF009 IC020 SF050 GB020 NF020 NF005 TC020 WC020Inor

g.-N

(mg/

L)

EFFEFEFE

DDCDCBBA0

5

10

15

SP020 SF020 SC020 MB040 SF050 NF009 IC020 TC020 NF020 NF005 GB020 WC020Tota

l-N (m

g/L)

Figure 8. Geometric mean concentrations for nitrogen species at micro-watershed sites during stormevents. Samples were collected between April 1996 and March 1997. Different letters indicatesignificantly different mean or geometric mean values at a = 0.05.


The evaluation for the remaining constituents monitored (PO4-P, total-P, CODand TSS) indicates wide variations in concentrations between sites and severaldistinct statistical groupings (Figures 9 and 10; baseflow and storm events,respectively). For baseflow and storm event conditions, results for PO4-P andtotal-P indicate a pattern very similar to that for the organic-nitrogen relatedspecies, e.g., TKN and org.-N, with the highest concentrations occurring at sitesassociated with dairy waste application fields and the lowest concentrationsoccurring at sites associated with wood/range and cropland land uses. MeasuredTSS data at both cropland sites were lower than expected given the large amountof cultivated land in these watersheds relative to other micro-watershed sites.The presence of grassed waterways in both cropland micro-watersheds directlyabove the sampler locations may be instrumental in causing the low TSSconcentrations at these sites. The in-stream measurements of COD showed afairly similar response to that for organic-nitrogen related species, PO4-P andtotal-P, with the exception that the urban site, MB040. MB040 was in thegrouping of highest concentrations during storm events for COD and in anintermediate grouping for all nitrogen species, PO4-P and total-P.


AA AB AB BC CD DEEF

FG

G

0.0

0.5

1.0

1.5

TC020 SP020 WC020 SF020 SC020 NF009 SF050 IC020 NF020 NF005

PO

4-P

(mg/

L)

BCA A A A A BC

DD

0

1

2

SP020 TC020 WC020 SF020 SC020 NF009 SF050 IC020 NF020 NF005Tota

l-P (m

g/L)

A A AB BC CD D D

E E

0

20

40

60

TC020 WC020 SP020 SC020 SF020 SF050 NF009 IC020 NF020 NF005

CO

D (m

g/L)

A A A A AB AB ABC ABC BCC

0

10

20

30

TC020 SP020 IC020 SC020 SF020 WC020 NF005 NF009 SF050 NF020

TSS

(mg/

L)

Figure 9. Geometric mean concentrations for PO4-P, total-P, COD and TSS at micro-watershed sitesduring baseflow. Samples were collected between September 1996 and March 1997. Differentletters indicate significantly different mean or geometric mean values at a = 0.05.


FFF

EDEDCCBABABA0

1

2

3

SP020 TC020 SF020 WC020 SC020 MB040 NF009 IC020 SF050 GB020 NF020 NF005

PO

4-P

(mg/

L)

FFF

EEDEDCCBCABA

0

2

4

SP020 TC020 SF020 WC020 SC020 MB040 NF009 IC020 SF050 NF020 GB020 NF005

Tota

l-P (m

g/L)

A A AB B BCDCD

D DEEF EF EF F

0

50

100

150

SP020 TC020 WC020 SC020 SF020 SF050 NF009 IC020 MB040 NF020 GB020 NF005

CO

D (m

g/L)

GFG

EFGDEFDEDEDECDCDBCBA

0

200

400

600

800

SP020 TC020 SC020 WC020 SF050 IC020 NF005 SF020 MB040 GB020 NF009 NF020

TSS

(mg/

L)

Figure 10. Geometric mean concentrations for PO4-P, total-P, COD and TSS at micro-watershed sitesduring storm events. Samples were collected between April 1996 and March 1997. Differentletters indicate significantly different mean or geometric mean values at a = 0.05.

6.1.2 Assessment of Water Quality at Micro-Watershed Sites

The assessment by criteria and screening levels for the micro-watershed sitesshows a broad spectrum of responses (Table 14). While restricted to baseflowmonitoring only, DO and pH data were found to “fully support” designated usesat all sites except NF009 where the DO criterion was only “partially supported.”Fecal coliform concentrations supported recreational use only at site SP020. Atall other sites the fecal coliform criterion was either “partially supporting” or


“not supporting.” As expected, storm-event nutrient concentrations usually hada greater percentage of data exceeding screening levels than did the nutrientbaseflow concentrations. (Because TNRCC developed its nutrient screeninglevels to evaluate routine monitoring data, which are generally strongly biasedtoward baseflow samples, the screening levels may be more appropriate forassessment of baseflow conditions.) Consistent with the statistical comparisonbetween micro-watershed sites, the greatest percentage of samples exceeding thetotal-N screening level occurred at the cropland dominated sites TC020 andWC020. Over 80 percent of samples during either baseflow or storm events atTC020 and WC020 exceeded the screening levels for NO2-N + NO3-N and total-N indicating “concern” for these two constituents at these sites. The dataassessments for org.-N, PO4-P and total-P indicate that the sites associated withupstream dairy waste application fields (GB020, IC020, NF005, NF009, NF020and SF050) consistently had the greater percentage of data exceeding screeninglevels, and the assessment indicated “concern” over these nutrients for baseflowand storm events.

Table 14. Percent of baseflow and stormflow samples from micro-watershed sites which exceed therecommended criterion for DO, pH and fecal coliform and screening levels for nutrients for ‘n’samples collected between October 1, 1995 and March 15, 1997. ‘NA’ indicates not applicable,no samples for comparison.

Constituent and Associated Screening Level or Criteria

Site SampleType

DO(<2.0 mg/L)

PH(<6.5 or

>9.0)

FecalColiform

(>400colonies/100ml)

NH3-N(>1.0 mg/L)

NO2-N +NO3-N

(>1.0 mg/L)

Organic-N(>2.0 mg/L)

Total-N(>3.0 mg/L)

PO4-P(>0.1 mg/L)

Total-P(>0.2 mg/L)

GB020 baseflow NA NA NA NA NA NA NA NA NAn NA NA NA NA NA NA NA NA NAstormflow NA NA NA 39% 40% 94% 93% 100% 100%n NA NA NA 245 245 212 214 244 218

IC020 baseflow 0% 0% 26% 0% 31% 19% 23% 50% 54%n 26 26 27 26 26 27 26 26 26stormflow NA NA NA 13% 40% 67% 65% 97% 100%n NA NA NA 250 248 212 211 250 213

MB040 baseflow NA NA NA NA NA NA NA NA NAn NA NA NA NA NA NA NA NA NAstormflow NA NA NA 3% 17% 32% 33% 91% 96%n NA NA NA 261 261 247 248 260 248

NF005 baseflow 0% 0% 43% 14% 18% 57% 46% 96% 100%n 22 22 21 22 22 23 22 22 22stormflow NA NA NA 36% 53% 98% 98% 100% 100%n NA NA NA 259 257 215 214 257 228



SC020 baseflow 0% 0% 30% 0% 3% 3% 0% 12% 6%n 33 33 33 33 33 34 33 33 33stormflow NA NA NA 0% 3% 21% 15% 62% 67%n NA NA NA 261 260 218 217 261 218

SF020 baseflow 0% 0% 50% 0% 0% 0% 0% 7% 0%


n 14 14 14 14 14 16 14 14 14stormflow NA NA NA 1% 4% 16% 13% 10% 34%n NA NA NA 325 325 283 285 325 287

SF050 baseflow 8% 0% 92% 0% 0% 29% 25% 67% 58%n 12 12 11 12 12 14 12 12 12stormflow NA NA NA 14% 36% 69% 63% 99% 99%n NA NA NA 338 337 287 289 337 298

SP020 baseflow 0% 0% 6% 0% 0% 0% 0% 0% 0%n 16 16 17 16 16 18 16 16 16stormflow NA NA NA 0% 0% 0% 0% 10% 20%n NA NA NA 278 277 229 234 278 245

TC020 baseflow 2% 0% 16% 0% 82% 0% 94% 8% 3%n 52 52 51 33 48 31 32 49 33stormflow NA NA NA 0% 96% 11% 95% 14% 24%n NA NA NA 276 280 239 240 280 243

WC020 baseflow 0% 0% 22% 0% 92% 3% 100% 4% 6%n 50 50 50 32 48 30 31 47 32stormflow NA NA NA 0% 99% 12% 94% 16% 38%n NA NA NA 212 203 179 174 213 179

6.2 Evaluation of Water Quality Data for North Bosque RiverTributary Sites

Baseflow sampling occurred at all seven major tributary sites to the NorthBosque River. These sites are AL040 on Alarm Creek, DC060 on Duffau Creek,GC100 on Green Creek, MC060 on Meridian Creek, NC060 on Neils Creek,NF050 on the North Fork to the North Bosque and SF075 on the South Fork ofthe North Bosque River. Storm event samples were collected at all majortributary sites to the North Bosque River but MC060. In September 1997, stormsampling was discontinued on Duffau Creek at site DC060 and initiated onMeridian Creek, so future data reports will contain storm event data for MeridianCreek.

Neils Creek is a reference or least disturbed stream site for the Central Texas-Oklahoma Plains ecoregion (Bayer et al., 1992). The land use above site NC060on Neils Creek and the other six tributary sites is provided in Table 6. Generallythe percentage of dairy waste application fields in the drainage area above eachsite decreases in an upstream to downstream direction for these major tributarysites. As with the micro-watershed sites, the amount of dairy waste applicationfields above a monitoring site appears to be important in explaining the waterquality results.

6.2.1 Statistical Comparison for North Bosque River Tributary Sites

The results for constituents monitored only during baseflow (water temperature,DO, pH, conductivity, CHLA and fecal coliforms) are provided in Figure 11.Small, albeit statistically significant, differences in DO and pH are exhibitedbetween tributary sites with slightly higher levels occurring at DC060 than at anyof the other sites. The streambed of Duffau Creek upstream of site DC060 iscomprised of limestone with numerous riffles, which most likely accounts forthis site’s higher DO and pH levels. Conductivity, CHLA and fecal coliformconcentrations were generally higher for tributaries in the upper portion of the


watershed; likely in response to the percentage of dairy waste application fieldsabove each site as established in earlier analyses (McFarland & Hauck, 1997a,b).


A A A A A AB

0

5

10

15

AL040 GC100 SF075 NC060 MC060 NF050 DC060

DO

(mg/

L)

0

10

20

30

NF050 SF075 GC100 AL040 NC060 MC060 DC060Wat

er T

emp.

(C)

A A A A A AB

6

7

8

9

GC100 NC060 NF050 SF075 MC060 AL040 DC060

pH (s

tand

ard

units

)

A A ABBC C C

D

0

500

1000

1500

DC060 MC060 NC060 SF075 AL040 GC100 NF050

Con

duct

ivity

(u

mho

s/cm

)

A A AB AB B

CC

0

200

400

600

DC060 MC060 NC060 GC100 AL040 SF075 NF050Feca

l Col

iform

(c

olon

ies/

100m

l)

A A AB

BCC

C

01020

3040

MC060 NC060 DC060 GC100 SF075 AL040 NF050

CH

LA (u

g/L)

Figure 11. Mean water temperature, DO and pH concentrations and geometric mean conductivity, CHLAand fecal coliform concentrations for sites on major tributaries to the North Bosque Riverduring baseflow. Samples were collected between May 1996 and March 1997. Different lettersindicate significantly different mean or geometric mean values at a = 0.05.


The pattern of statistical groupings for the nitrogen species (Figures 12 and 13;baseflow and storm event, respectively) is similar to that displayed forconductivity, CHLA and fecal coliforms. Higher concentrations were associatedwith the sample sites in the upper portion of the North Bosque River watershedand lower concentrations were associated with the sample sites in the lowerportion of the North Bosque River watershed. The Neils Creek site, NC060, hadhigher than expected levels of inorganic-nitrogen species, though organic-nitrogen was lowest at this site. In particular, the concentrations of NO3-N atNC060, seemed high for a “less impacted” site, although similar concentrationswere also indicated from intensive survey storm samples taken in June 1993(BRA, 1994). The source of these relatively high NO3-N levels is unknown, butmay be related to cropland areas located immediately adjacent to Neils Creekand near the NC060 sampling site.


A A A ABBC

CDD

0.00

0.10

0.20

NC060 MC060 DC060 GC100 NF050 SF075 AL040NH

3-N

(mg/

L)

A A A A

B B B

0.00

0.01

0.02

MC060 DC060 GC100 NC060 SF075 AL040 NF050NO

2-N

(mg/

L)

A B BC C CD CD

D

0.0

0.5

1.0

DC060 MC060 AL040 GC100 NC060 SF075 NF050NO

3-N

(mg/

L)

A A B BC

C C

0

1

2

NC060 MC060 DC060 GC100 SF075 AL040 NF050

TKN

(mg/

L)

A A B B

C C C

0

1

2

NC060 MC060 DC060 GC100 AL040 SF075 NF050Org

.-N (m

g/L)

A A B BC BC CDD

0

1

2

DC060 MC060 NC060 AL040 GC100 SF075 NF050Inog

r.-N

(mg/

L)

A A BB

C C

C

0

2

4

MC060 NC060 DC060 GC100 AL040 SF075 NF050Tota

l-N (m

g/L)

Figure 12. Geometric mean concentrations for nitrogen species at sites on major tributaries to the NorthBosque River during baseflow. Samples were collected between May 1996 and March 1997.Different letters indicate significantly different mean or geometric mean values at a = 0.05.


DCD

BCBBA

0.0

0.2

0.4

NC060 DC060 GC100 AL040 NF050 SF075N

H3-

N (m

g/L)

CC

BCBABA

0.00

0.02

0.04

NC060 GC100 DC060 AL040 NF050 SF075

NO

2-N

(mg/

L)

DCD

BCBABA

0.00.20.4

0.60.8

AL040 DC060 NC060 GC100 NF050 SF075

NO

3-N

(mg/

L)

CCBC

BBA

0

2

4

NC060 GC100 DC060 AL040 NF050 SF075

TKN

(mg/

L)

CCBC

BBA

0

2

4

NC060 GC100 DC060 AL040 NF050 SF075

Org

.-N (m

g/L)

CBC

ABAAA

0

1

2

AL040 DC060 NC060 GC100 NF050 SF075Inor

g.-N

(mg/

L)

CC

BBBA

0

2

4

NC060 DC060 GC100 AL040 NF050 SF075Tota

l-N (m

g/L)

Figure 13. Geometric mean concentrations for nitrogen species at sites on major tributaries to the NorthBosque River during storm events. Samples were collected between April 1996 and March 1997.Different letters indicate significantly different mean or geometric mean values at a = 0.05.

Generally, similar patterns of baseflow and storm event concentrations andstatistical groupings for PO4-P, total-P, COD and TSS to that for the nitrogen


species occurred for the North Bosque River tributary sites (Figures 14 and 15;baseflow and storm events, respectively). Typically the higher concentrationsand groupings were associated with tributary sample sites in the upper portion ofthe watershed.

A A AB B

C CC

0.0

0.1

0.2

0.3

MC060 NC060 DC060 GC100 SF075 NF050 AL040

PO

4-P

(mg/

L)

BBB

AAAA

0.0

0.2

0.4

0.6

NC060 GC100 MC060 DC060 SF075 NF050 AL040Tota

l-P (m

g/L)

A A B B

C C C

010203040

NC060 MC060 GC100 DC060 AL040 SF075 NF050

CO

D (m

g/L)

A AB AB ABBC

C C

0

10

20

NC060 DC060 MC060 GC100 NF050 AL040 SF075

TSS

(mg/

L)

Figure 14. Geometric mean concentrations for PO4-P, total-P, COD and TSS at sites on major tributaries tothe North Bosque River during baseflow. Samples were collected between May 1996 and March1997. Different letters indicate significantly different mean or geometric mean values at a = 0.05.


DD

CBBA

0.0

0.2

0.4

0.6

NC060 DC060 GC100 AL040 SF075 NF050

PO

4-P

(mg/

L)

DD

C

BBA

0.0

0.2

0.4

0.6

0.8

NC060 GC100 DC060 AL040 SF075 NF050

Tota

l-P (m

g/L)

CC

BCB

BA

0

20

40

60

NC060 GC100 DC060 AL040 SF075 NF050

CO

D (m

g/L)

0

50

100

150

200

AL040 NC060 GC100 DC060 SF075 NF050

TSS

(mg/

L)

Figure 15. Geometric mean concentrations for PO4-P, total-P, COD and TSS at sites on major tributaries tothe North Bosque River during storm events. Samples were collected between April 1996 andMarch 1997. Different letters indicate significantly different mean or geometric mean values at a= 0.05.

6.2.2 Assessment of Water Quality for North Bosque River TributarySites

The assessment by criteria and screening levels (Table 15) generally indicatesmore prominent water quality issues with North Bosque River tributaries in theupper portion of the watershed, especially, the North Fork (site NF050) and the


South Fork (site SF075). For pH, data for all sites were found to “fully support”designated uses. DO concentrations were indicated as “not supporting” in AlarmCreek (AL040), “partially supporting” in Green Creek (GC100), and “fullysupporting” of aquatic life uses in all other major tributaries monitored along theNorth Bosque River. CHLA levels were of “concern” at sites AL040, NF050and SF075, and fecal coliform concentrations indicated “partial support” atAL040 and “no support” at sites NF050 and SF075 for the use of contactrecreation. Of the nutrient constituents, higher concentrations of nutrients andhigher percentages of concentrations exceeding screening levels were found forthe more upstream tributaries, especially North Fork, South Fork and AlarmCreek. For Neils Creek (NC060), the data indicated concentrations that “fullysupport” designated uses or “no concern,” except for storm event levels of total-P which were of “potential concern.” While restricted to baseflow monitoringresults, no water quality issues arose from the data on Meridian Creek (MC060).

Table 15. Percent of baseflow and storm flow samples from sites on major tributaries to the North BosqueRiver which exceed the recommended criterion for DO, pH and fecal coliform and screeninglevels for nutrients for ‘n’ samples collected between October 1, 1995 and March 15, 1997. ‘NA’indicates not applicable, no samples for comparison.


Site SampleType

DO(<5.0 or 4.0

mg/L )†

PH(<6.5 or

>9.0)

CHLA(>30 µg/L)

FecalColiform


NH3-N(>1.0mg/L)

NO2-N +NO3-N(>1.0mg/L)

Organic-N(>2.0mg/L)

Total-N(>3.0mg/L)

PO4-P(>0.1mg/L)

Total-P(>0.2mg/L)

AL040 baseflow 26% 0% 56% 24% 0% 0% 11% 6% 64% 71%n 35 35 27 34 34 33 36 33 33 34stormflow NA NA NA NA 0% 1% 31% 13% 86% 98%n NA NA NA NA 176 176 158 160 175 160

DC060 baseflow 0% 0% 6% 0% 0% 0% 0% 0% 20% 5%n 27 27 18 27 21 25 26 21 25 21stormflow NA NA NA NA 2% 4% 15% 17% 49% 59%n NA NA NA NA 249 250 220 225 248 224

GC100 baseflow 12% 0% 14% 5% 0% 10% 3% 0% 5% 3%n 42 42 22 40 29 39 33 29 39 29stormflow NA NA NA NA 0% 5% 8% 7% 33% 48%n NA NA NA NA 319 319 269 274 320 276

MC060 baseflow 0% 0% 0% 10% 0% 0% 0% 0% 5% 7%n 21 21 12 20 15 19 2 15 19 15stormflow NA NA NA NA NA NA NA NA NA NAn NA NA NA NA NA NA NA NA NA NA

NC060 baseflow 4% 0% 0% 4% 0% 7% 0% 0% 2% 3%n 48 48 22 46 29 41 32 29 41 29stormflow NA NA NA NA 0% 3% 4% 4% 7% 15%n NA NA NA NA 317 319 275 286 319 286

NF050 baseflow 4% 0% 48% 44% 5% 56% 31% 67% 63% 81%n 28 28 21 27 27 27 35 27 27 27stormflow NA NA NA NA 7% 25% 63% 56% 99% 97%n NA NA NA NA 309 309 268 276 306 277

SF075 baseflow 7% 0% 48% 37% 0% 26% 24% 22% 59% 70%n 28 28 21 27 27 27 33 27 27 27stormflow NA NA NA NA 5% 18% 46% 40% 93% 94%n NA NA NA NA 297 297 265 268 297 269

† A value of 4.0 mg/L was to assess DO concentrations at sites NF050 and SF075 based on their proximity to Segment 1255. A DO value of 5.0mg/L was used to assess DO concentrations at sites AL040, DC060, GC100, MC060 and NC060 based on their proximity to Segment 1226.


6.3 Evaluation of Water Quality Data for North Bosque RiverSites

Baseflow samples were collected at eight sites on the North Bosque River. In adownstream direction the sites are BO020 above Stephenville, BO040 belowStephenville, BO060 above the confluence of Green Creek, BO070 at Hico,BO080 at Iredell, BO085 at Meridian, BO090 at Clifton and BO100 at ValleyMills. Storm event sampling was restricted to four of the eight sites (sitesBO040, BO070, BO090 and BO100). As a special study, grab samples for fecalcoliforms analysis were collected during storm events at all eight sites fromAugust 1996 through October 1996.

6.3.1 Statistical Comparison of North Bosque River Sites

For the North Bosque River sites, the graphical results are provided by site in astrict downstream ordering to aid in visualizing water quality trends along theRiver. The statistical groupings through letter identification are still provided.

While visually exhibiting only small longitudinal variation (Figure 16), DO andpH results indicate the lowest concentrations occur in the upper reaches of theNorth Bosque River at sites BO020 and BO040. The highest pH occurs at siteBO080 near Iredell. Geometric mean values of conductivity show a generaldecline in the downstream direction (Figure 16), which is most likely a dilutionresponse from the tributaries feeding into the North Bosque River (Figure 11).The CHLA results exhibit a high degree of variability, although differences inmean values were not statistically significant. As an important note, CHLAprovides a measure of planktonic algae, though several sources (e.g., TWC,1991) note dense growths of periphyton (attached) algae along the North BosqueRiver, which are not directly included in the CHLA data.


CBCCCC

ABABC

0

5

10

15

BO020 BO040 BO060 BO070 BO080 BO085 BO090 BO100

DO

(mg/

L)

0

10

20

30

BO020 BO040 BO060 BO070 BO080 BO085 BO090 BO100Wat

er T

emp.

(C)

AB ACD D

ECD BC C

6

7

8

9

BO020 BO040 BO060 BO070 BO080 BO085 BO090 BO100pH (s

tand

ard

units

)

A

BCC

AB AB A A A

0

500

1000

1500


Con

duct

ivity

(u

mho

s/cm

)

0

10

20

30

40


CH

LA (u

g/L)

Figure 16. Mean water temperature, DO and pH concentrations and geometric mean conductivity, andCHLA concentrations for sites on the North Bosque River during baseflow. Samples werecollected between May 1996 and March 1997. Different letters indicate significantly differentmean or geometric mean values at a = 0.05.

The fecal coliform data for baseflow and storm events indicate similarlongitudinal trends with the highest geometric mean concentrations occurring inthe Stephenville area and decreasing in a downstream direction (Figure 17). Thegeometric mean concentrations from storm event sampling are roughly one orderof magnitude higher than the baseflow sampling values. The observed trend infecal coliform concentrations can probably be attributed to higher livestock


densities and greater urban influences in the headwaters of the North BosqueRiver than further downstream.

C

C

BC

AB AB A AAB

0

200

400

600

800


Feca

l Col

iform

s (c

olon

ies/

100m

l)Baseflow

C

CD

BCD

ABCABC

ABC A A

0

2000

4000

6000

8000


Feca

l Col

iform

s (c

olon

ies/

100m

l)

Storm Event

Figure 17. Geometric mean fecal coliform concentrations during baseflow and storm events. Baseflowsamples were collected between May 1996 and March 1997. Storm event samples were collectedbetween August 1996 and October 1996. Different letters indicate significantly different mean orgeometric mean values at a = 0.05.

The baseflow measurements for nitrogen species indicate that the highestconcentrations and statistical groupings generally occur at the upstream sites(Figure 18). The contribution by the Stephenville WWTP effluent to inorganicnitrogen species (NH3-N, NO2-N and NO3-N) at site BO040 is readily apparentin the mean concentrations and statistical groupings. Site BO040 indicates thehighest concentrations during baseflow for the inorganic nitrogen constituents.While WWTP discharges are found directly below many of the North BosqueRiver sites, site BO040 is the only North Bosque River with a WWTP dischargedirectly above it. The Stephenville WWTP effluent discharge is about ¼ mileupstream of site BO040. A more subtle trend apparent in the results is anincrease in mean inorganic nitrogen concentrations beginning at about siteBO090 (at Clifton). This downstream increase in inorganic nitrogen can not beattributed solely to the Clifton WWTP effluent, as the sample point at BO090 isabove the outfall of the Clifton WWTP. The inorg.-N concentrations forMeridian Creek, the only major tributary discharging into the North Bosque


River between BO085 (at Meridian) and BO090 (at Clifton), were also belowthe concentrations found at BO090. Cropland land use in the bottomlands orfloodplain of the North Bosque River, which is evident along State Highway 6 inthis area, is speculated to be a contributor. The enhanced land use forthcomingfrom the NRCS may assist in answering this issue. Org.-N and TKN generallydecrease in a downstream direction.


AAAAA

BB

A

0.00

0.10

0.20

BO020 BO040 BO060 BO070 BO080 BO085 BO090 BO100NH

3-N

(mg/

L)

ABAAABBC

D

CDAB

0.00

0.02

0.04

BO020 BO040 BO060 BO070 BO080 BO085 BO090 BO100NO

2-N

(mg/

L)

C

E

BC BC A A BC BC0

2

4


NO

3-N

(mg/

L)

C CB B B

A A A

0

1

2


TKN

(mg/

L)

D CD BC B B A A A

0

1

2

BO020 BO040 BO060 BO070 BO080 BO085 BO090 BO100Org

.-N (m

g/L)

D

E

CD B A A BC BC0

2

4

6

BO020 BO040 BO060 BO070 BO080 BO085 BO090 BO100Inor

gan.

-N (m

g/L)

E

F

D C BC A AB AB

0

2

4

6

BO020 BO040 BO060 BO070 BO080 BO085 BO090 BO100Tota

l-N (m

g/L)

Figure 18. Geometric mean concentrations for nitrogen species at sites the North Bosque River duringbaseflow. Samples were collected between May 1996 and March 1997. Different letters indicatesignificantly different mean or geometric mean values at a = 0.05.


The storm event results for the nitrogen species (Figure 19) indicate generallydecreasing concentrations in the downstream direction. The reduced number ofstorm sample sites, as compared to baseflow sites, does not allow additionalinsight into the increase in inorganic nitrogen species occurring at baseflowbeginning in the vicinity of Clifton, Texas.


DCD

BCBBA

0.0

0.2

0.4

NC060 DC060 GC100 AL040 NF050 SF075N

H3-

N (m

g/L)

CC

BCBABA0.00

0.02

0.04

NC060 GC100 DC060 AL040 NF050 SF075

NO

2-N

(mg/

L)

DCD

BCBABA

0.00.20.4

0.60.8

AL040 DC060 NC060 GC100 NF050 SF075

NO

3-N

(mg/

L)

CCBC

BBA

0

2

4

NC060 GC100 DC060 AL040 NF050 SF075

TKN

(mg/

L)

CCBC

BBA

0

2

4

NC060 GC100 DC060 AL040 NF050 SF075

Org

.-N (m

g/L)

CBC

ABAAA

0

1

2

AL040 DC060 NC060 GC100 NF050 SF075Inor

g.-N

(mg/

L)

CC

BBBA

0

2

4

NC060 DC060 GC100 AL040 NF050 SF075Tota

l-N (m

g/L)

Figure 19. Geometric mean concentrations for nitrogen species at sites the North Bosque River duringstorm events. Samples were collected between April 1996 and March 1997. Different lettersindicate significantly different mean or geometric mean values at a = 0.05. ND indicates no data.

The statistical results for PO4-P and total-P for the North Bosque River indicatethe significance of contribution from the Stephenville WWTP during baseflow


conditions (Figure 20). Downstream of site BO040 the phosphorusconcentrations decrease nearly monotonically during baseflow and storm events(Figures 20 and 21). COD results also indicate a general trend of decreasingconcentrations in the downstream direction, while TSS results provide nodiscernible pattern during baseflow or storm events (Figures 20 and 21).

C

D

CC

B A A A0.0

0.5

1.0

1.5


PO

4-P

(mg/

L)

CD

E

DC B AB A A

0

1

2


Tota

l-P (m

g/L)

C

C CBC

CAB

AB A

0

10

20

30


CO

D (m

g/L)

0

10

20


TSS

(mg/

L)

Figure 20. Geometric mean concentrations for PO4-P, total-P, COD and TSS at sites on the North BosqueRiver during baseflow. Samples were collected between May 1996 and March 1997. Differentletters indicate significantly different mean or geometric mean values at a = 0.05.


ANDND

B

ND

C

ND A0.0

0.2

0.4

0.6

0.8


PO

4-P

(mg/

L)

ANDND

B

ND

C

NDA

0

1

2


Tota

l-P (m

g/L)

ND

B

ND

AB

ND ND

AA

0

10

20

30

40


CO

D (m

g/L)

ND

ND

ND ND

0

50

100

150


TSS

(mg/

L)

Figure 21. Geometric mean concentrations for PO4-P, total-P, COD and TSS at sites on the North BosqueRiver during storm events. Samples were collected between April 1996 and March 1997.Different letters indicate significantly different mean or geometric mean values at a = 0.05. NDindicates no data.

6.3.2 Assessment of Water Quality for North Bosque River Sites

Based on the TNRCC assessment approach, fewer water quality concerns wereindicated at downstream sites than for upstream sites along the North BosqueRiver (Table 16). All sites “fully support” designated uses related to DO andpH, with the exception of “partial support” indicated for DO at the mostupstream site, BO020. The CHLA assessment showed cause for “potentialconcern” or “concern” along the entire North Bosque River. The baseflow fecalcoliform data indicate that contact recreation is “not supported” in the upper


portions of the North Bosque River but is “supported” at site BO085 (nearMeridian) and below. Storm event fecal coliform data indicate that thedesignated use of contact recreation is “not supported” during elevated flows allalong the North Bosque River. The impact of the Stephenville WWTP effluenton receiving water at BO040 is most manifest at baseflow for NO2-N + NO3-Nand total-N where concentrations are cause for “concern.” “Concern” for NO2-N+ NO3-N was also indicated at baseflow at sites BO060 and BO090. Duringstorm events, “concern” for NO2-N + NO3-N, org.-N and total-N was indicatedonly at sites BO020 and BO040. Baseflow total-P concentrations were assessedas being of “concern” or “potential concern” at all sites but BO090 (near Clifton)and BO100 (near Valley Mills). Storm event PO4-P and total-P concentrationscause “concern” along the entire the North Bosque River, except PO4-Pconcentrations at BO100 which were at levels of “potential concern.”

Table 16. Percent of baseflow and stormflow samples from North Bosque River sites which exceed therecommended criterion for DO, pH and fecal coliform and screening levels for nutrients for ‘n’samples collected between October 1, 1995 and March 15, 1997. ‘NA’ indicates not applicable, nosamples for comparison.

Constituent and Associated Screening Level or CriteriaSite Sample

TypeDO

(< 5.0 or4.0mg/L )†

PH(<6.5 or

>9.0)

CHLA(>30 µg/L)

FecalColiform


NH3-N(>1.0mg/L)


Organic-N(>2.0mg/L)

Total-N(>3.0mg/L)

PO4-P(>0.1mg/L)

Total-P(>0.2mg/L)

BO020 baseflow 13% 0% 39% 52% 3% 17% 22% 17% 67% 77%n 30 30 23 33 30 30 37 30 30 30stormflow NA NA NA 96% 0% 30% 64% 67% 86% 98%n NA NA NA 54 95 95 82 89 95 89


BO060 baseflow 0% 0% 42% 16% 0% 40% 0% 13% 95% 100%n 43 43 24 44 30 40 27 30 40 38stormflow NA NA NA 84% NA NA NA NA NA NAn NA NA NA 57 NA NA NA NA NA NA







† A value of 4.0 mg/L was used to assess DO concentrations at sites BO020 and BO040 based on their proximity along Segment 1255. A DOvalue of 5.0 mg/L was used to assess DO concentrations at sites BO070, BO080, BO085, BO090 and BO100 based on their proximity alongSegment 1226.

6.4 Evaluation of Water Quality for Rivers or Tributaries toLake Waco

Three of the four major tributaries to Lake Waco were monitored (site BO100,the North Bosque River at Valley Mills; site HC060, Hogg Creek; and siteMB060, the Middle Bosque River) for baseflow and storm events during thisreporting period. Monitoring results from the South Bosque River (site SB060)were not included in the statistical comparisons, since sampling did not begin atthis site until November 1996 as the result of logistical and technical difficulties.However, available monitoring results from the South Bosque River were usedin the water quality assessment comparison to TNRCC screening levels andcriteria.

6.4.1 Statistical Comparisons of Lake Waco Tributary Sites

For the in-situ measurements of water temperature, DO, pH and conductivity, themagnitude of variability between mean values for the Lake Waco tributary siteswas slight, though some statistically significant groupings or differences weredetermined for pH and conductivity (Figure 22). No statistically significantdifferences were indicated between sites for CHLA or fecal coliformconcentrations.


0

10

20

HC060 BO100 MB060

DO

(mg/

L)0

10

20

30

MB060 HC060 BO100Wat

er T

emp.

(C)

BAA

6

7

8

9

HC060 BO100 MB060

pH (s

tand

ard

units

)

A AB

0

200

400

600

HC060 MB060 BO100

Con

duct

ivity

(u

mho

s/cm

)

0

50

100

150

MB060 HC060 BO100

Feca

l Col

iform

(c

olon

ies/

100m

l)

0

5

10

MB060 HC060 BO100

CH

LA (u

g/L)

Figure 22. Mean water temperature, DO and pH concentrations and geometric mean conductivity, CHLAand fecal coliform concentrations for sites on tributaries to Lake Waco during baseflow.Samples were collected between February 1996 and March 1997. Different letters indicatesignificantly different mean or geometric mean values at a = 0.05.

The results for nitrogen species indicate some interesting differences betweenbaseflow and storm event concentrations (Figures 23 and 24; baseflow and storm


events, respectively). At baseflow, mean nitrogen concentrations for the LakeWaco tributary sites were not statistically different except for organic species(TKN and org.-N) where BO100, on the North Bosque River, has the highestconcentrations of organic nitrogen and MB060, on the Middle Bosque River, hasthe lowest concentrations. For storm events, significantly higher mean NO3-Nand inorg.-N concentrations occurred at MB060, and, while not statisticallydifferent, the highest mean TKN and org.-N concentrations occurred at BO100.The high NO3-N concentrations at MB060 are largely responsible for the highestmean total-N concentrations occurring at MB060, and the high organic nitrogenconcentrations at BO100 are largely responsible for this site having the secondhighest mean total-N concentrations.


0.00

0.05

0.10

MB060 BO100 HC060NH

3-N

(mg/

L)

0.0000.0020.0040.0060.008

MB060 BO100 HC060NO

2-N

(mg/

L)

0.0

0.2

0.4

HC060 MB060 BO100

NO

3-N

(mg/

L)

AAB

B

0.00.20.40.6

MB060 HC060 BO100

TKN

(mg/

L)

A A

B

0.00.20.40.6

MB060 HC060 BO100Org

.-N (m

g/L)

0.00.2

0.40.6

BO100 HC060 MB060Inog

r.-N

(mg/

L)

0.0

0.5

1.0

HC060 MB060 BO100Tota

l-N (m

g/L)

Figure 23. Geometric mean concentrations for nitrogen for sites on tributaries to Lake Waco duringbaseflow. Samples were collected between May 1996 and March 1997. Different letters indicatesignificantly different mean or geometric mean values at a = 0.05.


0.00

0.04

0.08

MB060 HC060 BO100N

H3-

N (m

g/L)

0.000

0.005

0.010

HC060 MB060 BO100

NO

2-N

(mg/

L)

B

AA

0

1

2

BO100 HC060 MB060

NO

3-N

(mg/

L)

0

1

2

HC060 MB060 BO100

TKN

(mg/

L)

A A

B

0

1

2

BO100 HC060 MB060

Inor

g.-N

(mg/

L)

0

1

2

HC060 MB060 BO100

Org

.-N (m

g/L)

B

ABA

0

1

2

3

HC060 BO100 MB060

Tota

l-N (m

g/L)

Figure 24. Geometric mean concentrations for nitrogen for sites on tributaries to Lake Waco during stormevents. Samples were collected between April 1996 and March 1997. Different letters indicatesignificantly different mean or geometric mean values at a = 0.05.


The analyses for the remaining four measured constituents, PO4-P, total-P, CODand TSS are provided on Figures 25 and 26 for baseflow and storm events,respectively. Statistically significant differences between sites were indicatedonly for TSS at baseflow with the highest concentrations indicated at BO100.

0.00

0.02

0.04

HC060 MB060 BO100

PO

4-P

(mg/

L)

0.00

0.04

0.08

MB060 HC060 BO100Tota

l-P (m

g/L)

0

5

10

MB060 HC060 BO100

CO

D (m

g/L)

A A

B

0

10

20

MB060 HC060 BO100

TSS

(mg/

L)

Figure 25. Geometric mean concentrations for PO4-P, total-P, COD and for sites on tributaries to LakeWaco during baseflow. Samples were collected between February 1996 and March 1997.Different letters indicate significantly different mean or geometric mean values at a = 0.05.


0.00

0.02

0.04

HC060 MB060 BO100

PO

4-P

(mg/

L)

0.0

0.1

0.2

0.3

HC060 MB060 BO100

Tota

l-P (m

g/L)

0

5

10

15

20

HC060 MB060 BO100

CO

D (m

g/L)

0

50

100

150

HC060 MB060 BO100

TSS

(mg/

L)

Figure 26. Geometric mean concentrations for PO4-P, total-P, COD and for sites on tributaries to LakeWaco during storm events. Samples were collected between April 1996 and March 1997.Different letters indicate significantly different mean or geometric mean values at a = 0.05.

6.4.2 Assessment of Water Quality at Lake Waco Tributary Sites

As with the other monitoring site categories, the water quality assessment tocriteria and screening levels indicates varying responses for the Lake Wacotributary sites (Table 17). DO and pH concentrations “supported” designateduses at all Lake Waco tributary sites, except for “partial support” for DO at siteHC060 on Hogg Creek. The CHLA assessment indicates “no concern” at allsites, except “potential concern” at BO100. Baseflow fecal coliformconcentrations were assessed as “supporting” the contact recreation use at HoggCreek (HC060), the Middle Bosque River (MB060), and the North Bosque


River at Valley Mills (BO100), and “not supporting” at the South Bosque River(SB060). As indicated in Table 5, the database for the South Bosque River islimited in the number of samples, such that all conclusions of this assessment forSB060 should be tempered by this restriction. Storm event fecal coliform datawere obtained only at site BO100, and the assessment indicates that storm fecalcoliforms concentrations do “not support” the contact recreation use. NH3-Nand org.-N concentrations are consistently assessed as “no concern” for baseflowand storm event conditions. For NO2-N + NO3-N and total-N, the assessmentindicates an increasing percentage of data exceeding screening levels in asouthern direction (BO100 to HC060 to MB060 to SB060) for baseflow andstorm events, which is likely a response to increased cropland land use in thesouthwestern portion of the watershed (Figure 2). Correspondingly, the siteswith assessed “concern” over NO2-N + NO3-N and total-N are those mostsouthward in location. For PO4-P, “potential concern” was indicated at siteBO100 and “concern” at site SB060 for baseflow and storm events. For total-P,“no concern” was indicated at all sites except SB060 at baseflow, while“concern” or “potential concern” was indicated at all four sites during stormevents.

Table 17. Percent of baseflow and stormflow samples from sites on rivers and tributaries to Lake Wacowhich exceed the recommended criterion for DO, pH and fecal coliform and screening levels fornutrients for ‘n’ samples collected between October 1, 1995 and March 15, 1997. ‘NA’ indicatesnot applicable, no samples for comparison.


Site SampleType

DO(<5.0 mg/L )

PH(<6.5 or

>9.0)

CHLA(>30 µg/L)

FecalColiform


NH3-N(>1.0mg/L)


Organic-N(>2.0mg/L)

Total-N(>3.0mg/L)

PO4-P(>0.1mg/L)

Total-P(>0.2mg/L)


HC060 baseflow 13% 0% 0% 8% 0% 16% 0% 0% 6% 0%n 52 52 27 51 34 51 35 33 52 34stormflow NA NA NA NA 0% 31% 10% 10% 8% 27%n NA NA NA NA 277 275 230 254 275 256

MB060 baseflow 2% 0% 5% 5% 0% 27% 0% 13% 7% 3%n 44 44 22 41 31 44 28 31 43 31stormflow NA NA NA NA 0% 86% 4% 33% 5% 15%n NA NA NA NA 242 246 207 248 239 216

SB060 baseflow 0% 0% 0% 33% 0% 100% 0% 100% 100% 22%n 9 9 5 9 9 9 8 8 9 9stormflow NA NA NA NA 0% 100% 7% 100% 26% 29%n NA NA NA NA 62 60 61 59 62 62


7. PRELIMINARY NUTRIENT LOADINGESTIMATIONS

The data analyses in the previous section demonstrated that baseflow and stormevent water quality vary between sites and that some of the statisticallysignificant differences in water quality may be attributed to differences in landuse above sample sites. These same monitoring data are amenable to furtherstatistical analyses to allow an estimation of loadings by sampling sites and anestimation of the nutrient loading contribution by major land-use sector, i.e.,wood, range, pasture, cropland, dairy waste application fields and urban. Furtherthis analysis of nutrient contribution was expanded to include contributions frommunicipal wastewater treatment plant (WWTP) effluents and direct precipitationon Lake Waco.

Nutrient loading estimates by land-use sector were calculated for total-P andtotal-N. Because in-stream soluble reactive phosphorus (PO4-P) is highlybioavailable and is strongly associated with dairy operations (McFarland andHauck, 1995, 1997a, 1997b), PO4-P was also included in the nutrient loadingestimates. These nutrient loading estimates are considered preliminary in thesense that the land use information is somewhat dated and is being updated byNRCS (see Section 2.1 - Description of Study Area), and the period ofmonitoring used to determine the estimates was complicated with extremes inrainfall varying from drought conditions for several months to very high rainfallperiods in several months (Figure 5). The preliminary nature and properinterpretation of the nutrient loading estimates will be further developedthroughout this section.

7.1 Estimation of Loadings by Sampling SiteWhile concentrations are important indicators of current water quality, especiallywhen considering toxic impacts on aquatic communities such as ammoniaconcentrations, loadings are important in evaluating the cumulative impact of in-stream water quality constituents on downstream waterbodies. Loadings aregenerally calculated by multiplying the concentration of each waterborneconstituent by the volume of water associated with a particular sample. Tocalculate loadings for the stream sites monitored in the Bosque River watershed,a mid-point rectangular integration method between sample times was used todetermine the volume of flow associated with each grab and storm event sample.

Runoff volume and cumulative loadings for sampling sites with automated stormsampling equipment are presented in Table 18 for the period November 1, 1995through March 15, 1997. These data are standardized on a per acre basis. Allsites with a complete period of record from November 1, 1995 through March15, 1997 were included in the loading estimations, except sites GB020, NF005,NC060 and BO100 which is explained below.


Table 18. Runoff volume and nutrient loadings standardized by site on per acre basis for November 1,1995 through March 15, 1997 (500 days).

SITE RunoffVolume(ft3/acre)

PO4-P(lbs/acre)

Total-P(lbs/acre)

Total-N(lbs/acre)

AL040 22,400 0.32 0.63 2.60

BO040* 32,400 1.52 2.29 10.33

BO070† 27,700 0.52 1.08 4.49

BO090* 25,900 0.27 0.96 4.35

GC100 27,600 0.21 0.61 3.22

HC060 42,100 0.13 0.63 5.72

IC020 23,300 0.82 2.06 8.29

MB040‡ 101,000 1.61 4.38 19.70

MB060 33,400 0.16 0.42 5.99

NF009 32,400 0.65 1.86 7.44

NF020 36,000 4.48 7.82 20.40

SC020 27,700 0.35 0.63 3.04

SF020 37,200 0.09 0.52 3.15

SF050 19,700 0.87 1.25 4.69

SP020 46,600 0.23 0.51 2.69

TC020 35,500 0.16 0.68 18.10

WC020 21,000 0.13 0.66 16.40

† The data for BO040, BO070 and BO090 were not directly used in the determination of export coefficients due to the direct point sourceinfluences. These sites were used in the verification of preliminary nutrient export coefficients.

‡ MB040 was used to estimate urban nutrient export coefficients.

Loadings from NF005 and NC060 were not calculated due to suspectedbackwater effects during the large February 1997 storm events. About 25percent of the rainfall and generally over 50 percent of the streamflow atsampling sites for the monitoring timeframe occurred during the February 1997storm events. The suspected backwater effects at NF005 and NC060, thus,result in unreliable flow calculations during these important February stormevents, and, thus, unreliable loading estimations for the monitoring period. Therating curve at GB020 was considered too provisional at this time for use inestimating loadings with any confidence, although it was considered suitable forthe less demanding rigor of providing the flow weighted storm eventconcentrations presented in Section 6. At BO100, the sampler was removed onFebruary 20, 1997 due to erosion of the streambank. Daily grab samples duringstorm events were collected at BO100 from February 20 through March 15,1997, but these storm event grab samples were considered less reliable inestimating loadings during this peak streamflow period due to the variability thatcan occur in stormwater concentrations. The accuracy of the provisional USGSflow data at BO100 (USGS station 08095200) for the large February 1997 stormevents was also under consideration due to obvious sedimentation at the gagelocation.

In comparing the volume of water associated with each site, the largest volumeper acre, by a notable amount, was associated with the urban site, MB040,located within the city of Stephenville. Runoff volumes from all other sites wereof the same general magnitude. Although the highest runoff volume per acre


was associated with site MB040, similar total-N loadings per acre were indicatedat sites MB040 and NF020 at about 20 lbs total-N/acre. The highest phosphorusloadings were indicated at site NF020 with 4.5 lbs PO4-P/acre and 7.8 lbs total-P/acre. The next highest phosphorus loadings were indicated at MB040 with 1.6lbs PO4-P/acre and 4.4 lbs total-P/acre. About 45 percent of the drainage areaabove NF020 is comprised of dairy waste application fields (Table 6). The dairywaste application fields above NF020 are considered the dominant source ofthese relatively high nutrient loadings at this site (McFarland and Hauck, 1997b).The two predominately cropland sites, TC020 and WC020, displayed relativelylow phosphorus loadings with 0.7 lbs total-P/acre at both sites, although thenitrogen loadings at TC020 (18 lbs total-N/acre) and WC020 (16 lbs total-N/acre) were nearly as high as the loadings observed at sites MB040 and NF020.The total-P loadings at TC020 and WC020 were fairly similar to loadingsindicated at less intensively impacted rural sites, such as SF020 and SP020,which have drainage areas comprised primarily of wood and range.

Loadings from the effluent of the eight municipal WWTPs within the watershedwere calculated in a manner similar to that for stream sites using a midpointrectangular integration method. The effluent water quality data collected foreach WWTP are summarized in Appendix C. The self-reporting dischargeinformation provided to the TNRCC was used to estimate the volume of effluentdischarged by each WWTP on a monthly basis (Appendix D). Loadings for theeight municipal WWTPs within the watershed are presented in Table 19. Asexpected, the largest volume and nutrient loadings are associated with theeffluent from the Stephenville WWTP, while the next highest volume andloadings occurred from the McGregor WWTP. The smallest volume andloadings are associated with the Crawford WWTP where new treatment lagoonswere being filled and, thus, not discharging during a large portion of themonitoring period (Table 7).

Table 19. Measured loadings of wastewater treatment plant discharges into the Bosque River watershedfor November 1, 1995 through March 15, 1997.

WWTP SiteID

Numberof Days

Total Volume(cubic feet)

PO4-P(lbs)

Total-P(lbs)

Total-N(lbs)

Stephenville TP040 500 108,000,000 16,200 19,760 60,000

Hico LB010 500 4,450,000 720 890 2,600

Iredell LB020 500 1,790,000 250 290 1,780

Meridian LB030 500 13,900,000 2,390 2,820 14,300

Clifton LB040 500 19,600,000 2,570 3,430 10,900

Valley Mills LB050 500 5,650,000 860 1,010 4,860

Crawford† LB060 194 385,000 70 80 300

McGregor LB070 500 47,400,000 2,860 4,900 27,300

† The Crawford WWTP underwent an upgrade during the monitoring period. During part of the period, the new treatment lagoons were fillingand no discharge occurred.

7.2 Calculation of Nutrient Export CoefficientsThe loadings by sampling site help to target areas of high nutrient loadings. Tofurther refine targeting efforts, it is important to quantify loadings by land-use


sector. To determine the contribution of nutrient loadings by land use, exportcoefficients for the major land uses in the watershed were developed from thesampling site loading information for the monitoring period. Nutrient exportcoefficients are estimates of the quantity of nutrients leaving or being exportedfrom a unit land area via rainfall runoff (Loehr et al., 1989). While exportcoefficients are often estimated for single land uses from small field plotexperiments (Reckhow et al., 1980), procedures described by Hodge andArmstrong (1993) outline the use of multiple regression techniques using in-stream data to estimate export coefficients by land use in heterogeneouswatersheds.

The regression approach used herein for determining the nutrient exportcoefficients for the agricultural land uses maximizes the use of mass loadinginformation contained within the Bosque River watershed monitoring. Theregression method allows for calculating nutrient export coefficients fromheterogeneous land-use drainage areas without the need for isolating individualland uses. Further, the regression method provides export coefficientsrepresenting the average of conditions and practices (e.g., soils, planting andharvest dates, fertilization timing and amounts, slopes, tillage practices, andproximity to streams) of each land use across the entire Bosque River watershed,as opposed to export coefficients determined for the more limited practices andconditions of single land use drainage areas of field plot experiments. Thesecoefficients, thus, do not mimic any one particular land management practice fora land use category, but take into account the variability of managementpractices across the watershed.

A disadvantage of using in-stream loadings to estimate nutrient exportcoefficients rather than field plot data is that some in-stream losses andtransformations undoubtedly occur between edge-of-field runoff and in-streammonitoring sites. In the estimation of nutrient export coefficients for land uses inthe Bosque River watershed, these losses and transformations were consideredinsignificant for the size of the drainage areas and limited in-stream travel timesfor the monitoring sites used in this analysis. However, these factors may beimportant when extrapolating loadings to larger drainage areas, such as to theentire Bosque River watershed as loadings to Lake Waco.

Once nutrients enter a stream or other waterbody, physical and biochemicallosses and transformations occur that are not considered in export coefficients.The importance of these losses and transformations generally increase with thesize of the watershed and the travel time of water transport. Nutrient exportcoefficients provide estimates of the direct contribution of nutrients fromparticular land uses to waterbodies, such as streams. Either computer-basedwater quality models or rough estimates of nutrient reductions, e.g., percentlosses, are typically applied to the export coefficient loading estimates to accountfor these in-stream losses and transformations but were considered beyond thescope of the current report. Therefore, the results provided herein estimatenutrient contributions or loadings by land-use sector into the receiving streams ofthe Bosque River watershed, but probably over-estimate how much of theloadings actually reach downstream points, such as Lake Waco, due to the longerin-stream travel times. This point is further developed in the comparison ofpredicted and measured loadings using sites BO040, BO070 and BO090 asvalidation sites for the developed nutrient export coefficients.

Land uses were judiciously categorized to minimize multicolinearity effects inthe multiple regression model procedures and to obtain reasonable export


coefficient estimates. Different groupings of sites were used to evaluatephosphorus and nitrogen export coefficients due to observed loading differencesbetween cropland sites throughout the watershed. All regression models weredeveloped using a forced zero intercept in accounting for loadings. Specificmethods used for estimating the phosphorus and nitrogen export coefficients aredescribed below.

7.2.1 Preliminary Phosphorus Export Coefficients

Urban phosphorus export coefficients were directly estimated from the loadingsfor the urban site MB040 as presented in Table 18 and are standardized on anannual per acre basis in Table 20. Three land-use categories were used todevelop the phosphorus export coefficients for the rural land uses in thewatershed: dairy waste application fields, pasture/cropland and range/wood. Tominimize the impacts of multicolinearity, the wood and range land-usecategories and the pasture and cropland categories were combined into the landuse categories of range/wood and pasture/cropland, respectively. All other landuses in the watershed, such as barren, were considered too small to calculatereasonable coefficient values (Table 6), and, thus, were considered part of theerror term of the regression models.

Table 20. Preliminary land use export coefficients for PO4-P and total-P. Phosphorus export coefficientswere based on a 500-day period from November 1, 1995 through March 15, 1997.

Nutrient Export Coefficients

PO4-P (lb/ac) Total-P (lb/ac)

Land Use Mean Std p-value Mean Std p-value

Urban † 1.61 + 1.18 na 4.38 + 3.20 na

Dairy Waste Appl. Fields 8.15 + 0.79 0.0001 13.92 + 1.49 0.0001

Pasture/Cropland 0.15 + 0.03 0.0139 0.65 + 0.05 0.0003

Range/Wood 0.15 + 0.04 0.0198 0.48 + 0.06 0.0017

† Standard deviation for urban export coefficients was estimated from literature values as 73 percent of the mean value.‘na’ indicates a statistical analysis was not applicable.

Due to the dominance and relatively large variability associated with phosphorusloadings from dairy waste application fields, those sites without (or withminimal) dairy waste application fields or major urban influences in theirdrainage areas were grouped to estimate phosphorus export coefficients for lessimpacted land uses, such as wood and range. The sites with no or minimal dairywaste application fields included HC060, MB060, SF020, SP020, TC020 andWC020. A multiple regression model using the fraction of pasture/cropland andwood/range as the independent variables and the phosphorus loading at thesesites as the dependent variable was used to estimate the phosphorus exportcoefficients for pasture/cropland and range/wood as presented in Table 20.

The phosphorus export coefficients for dairy waste application fields wereestimated, first by subtracting the loading due to pasture/cropland andrange/wood using the export coefficients developed in Table 20. Then aregression model evaluating the change in phosphorus loadings with changes inthe percent of dairy waste application fields was determined using all sites not


impacted by urban discharges, either point or nonpoint, i.e., all sites but BO040,BO070, BO090 and MB040.

7.2.2 Preliminary Nitrogen Export Coefficients

The same land-use categories as for the phosphorus export coefficients wereused to estimate the total-N export coefficients, i.e., wood/range,pasture/cropland, dairy waste application fields and urban, except a refinementwas made to the pasture/cropland category. Even though previously developedexport coefficients for the upper North Bosque River watershed had indicatedthe validity of grouping pasture and cropland together for all nutrients(McFarland and Hauck, 1998), both the nutrient loading data (Table 18) andknown differences in farming practices in the Bosque River watershed south ofHico indicated the need to provide a row-crop land-use category. Much of thecropland in the upper portion of the watershed involves a two-crop pattern ofsummer sudan followed by a winter small grain, such as wheat or rye.Conditions, particularly soils, in the lower portion of the watershed are favorablefor row crops such as corn and cotton, which are typically not associated with awinter crop. The nutrient loading data for sites in the lower portion of thewatershed dominated by row crop agriculture (TC020 and WC020, and to alesser extent HC060 and MB060) showed relatively high nitrogen loadings butfairly low phosphorus loadings in comparison to the other sites in the watershed(Table 18). These same high nitrogen loadings did not appear to be associatedwith the cropland agriculture in the upper portion of the watershed. Because thecurrent digital land-use database did not distinguish between row-crop and non-row crop agriculture, the assumption was made to consider cropland above theNorth Bosque River at Hico, Texas (BO070) as non-row crop and croplandbelow BO070 as row crop. Because relatively little difference in phosphorusloadings was indicated between cropland sites in the upper and lower portions ofthe watershed, this refinement was not considered necessary in estimating thephosphorus export coefficients. Further refinement of this assumption will bepossible when new land-use information becomes available.

As with the phosphorus export coefficients, site MB040 was used directly toprovide the total-N export coefficient for urban lands (Table 21). A multipleregression model was used to estimate the total-N export coefficients for theland-use categories of dairy waste application fields, pasture/non-row crop, andrange/wood based on loading data using sites only in the upper portion of thewatershed, i.e., sites above BO070. This approach was comparable to theprocedures used in McFarland and Hauck (1998) to estimate nutrient exportcoefficients for the upper North Bosque River watershed. Although statisticallynonsignificant (a = 0.05) coefficient values were estimated for pasture/non-rowcrop and range/wood using this procedure, these coefficient values still representthe best optimized estimates from the current data set and appeared to bereasonable values for these land use categories when compared to literaturevalues for similar land uses (see Frink, 1991 and Reckhow et al., 1980).

Table 21. Preliminary land use export coefficients for total-N. Nitrogen export coefficients were based on a500-day period from November 1, 1995 through March 15, 1997.

Nutrient Export Coefficients

Total-N (lb/ac)

Land Use Mean Std p-value


Urban † 19.70 + 14.97 na

Dairy Waste Appl. Fields 38.48 + 6.32 0.0009

Pasture/Non-Row Crops 3.72 + 8.17 0.6647

Row Crops 18.84 + 2.35 0.0041

Range/Wood 1.40 + 2.34 0.5718

† Standard deviation for urban export coefficients was estimated from literature values as 76 percent of the mean value.‘na’ indicates a statistical analysis was not applicable.

To estimate the nitrogen export coefficient for row crops, the loadings associatedwith dairy waste application fields, pasture/non-row crop and range/wood weresubtracted from the loadings for sites HC060, MB060, TC020 and WC020. Aregression model using these modified nitrogen loadings was then developedversus the percent row crop in the drainage area above these four sites. Thenitrogen export coefficient for row crop was estimated at 18.8 lbs total-N/ac/yr(Table 21).

7.3 Verification of Preliminary Export CoefficientsAs verification of the estimated export coefficients, predicted loadings based onthe export coefficients along with measured WWTP loadings were compared tomeasured loadings for North Bosque River sites BO040, BO070 and BO090.Because relatively large standard deviations were associated with the nutrientexport coefficients for the agricultural land-use sectors using the regressionmethods, these estimated coefficients, thus, represent a range of values ratherthan absolute values. To take into account the variability associated with thenutrient export coefficients estimated from the regression models, predictedloadings were calculated assuming a normal probability distribution for eachcoefficient as defined by its standard deviation. For each simulation, the exportcoefficient for each land use was determined as the value of the mean exportcoefficient plus or minus the quantity of a value from a normal-distirbutionrandom number generator multiplied by the standard deviation associated witheach export coefficient. While MB040 represents urban runoff from only onesite within the watershed, a review of literature values for urban exportcoefficients was used to set the standard deviation for urban nutrient exportcoefficients. Based on literature values presented by Frink (1991) and Reckhowet al. (1980) for a variety of urban situations, the standard deviation for urbannutrient export coefficients was estimated as 73 percent for total-P and 76percent for total-N of the export coefficient value. Literature values for PO4-Pwere not presented in these reviews, so the variance indicated for total-P wasalso associated with the export coefficient value for PO4-P for the urban exportcoefficient. A total of 10,000 simulations were run each for PO4-P, total-P andtotal-N. The results from the 10,000 simulations were then statistically analyzedto provide the predicted values for comparison with measured loadings atsampling sites BO040, BO070 and BO090 (Figure 27).


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Figure 27. Comparison of predicted with measured nutrient loadings at sites BO040, BO070 and BO090 forNovember 10, 1997 through March 15, 1997.

Predicted loadings generally overestimated measured values. Thisoverestimation was expected to some degree, because export coefficients do nottake into account in-stream losses and transformations, but reflect overallloadings into the stream system. Because PO4-P is readily available for plantuptake, in-stream transformations would have the largest impact on PO4-Ploadings with increasing differences occurring with increasing drainage basinsize or travel time. This is reflected in the increasing overestimation of PO4-Pvalues from site BO070 to site B0090. Values for all three constituents weremost closely predicted for site BO040. The smaller drainage area above BO040


and the proximity of BO040 to the Stephenville WWTP discharge probablyaccount for the close agreement of predicted and measured nutrient loadings atthis site. The relatively large standard deviation on predicted nitrogen loadingsat all three sites reflects the large variability associated with the nitrogen exportcoefficients, particularly for pasture/non-row crop (see Table 22).

Table 22. Land use estimates for the drainage areas of major rivers and tributaries within the BosqueRiver watershed and for the total Bosque River watershed.

Watershed Wood(%)

Range(%)

Pasture(%)

Non-RowCrop

(%)

RowCrop

(%)


(%)

Urban(%)

Barren(%)

Water(%)

Total Area(Acres)

TotalArea(%)

Bosque River Watershed 25.2 30.3 17.2 4.2 15.8 2.2 3.0 0.9 1.2 1,061,860 100

North Bosque River Watershed 30.5 35.4 16.2 10.5 5.7 3.0 2.1 0.8 0.7 781,794 74

Hog Creek Watershed 9.3 27.8 20.1 0.0 41.4 0.0 0.8 0.4 0.2 57,336 5

Middle Bosque River Watershed 13.9 18.7 17.7 0.0 48.1 0.2 1.0 0.3 0.1 127,543 12

South Bosque River Watershed 6.8 8.7 22.6 0.0 51.1 0.0 9.4 1.3 0.1 58,160 5

Other Small Drainages and UrbanRunoff from the City of Waco

6.7 2.7 28.3 0.0 30.3 0.0 27.6 4.3 0.1 29,727 3

Surface Area of Lake Waco 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 7,300 1

The difference between estimated and measured loadings generally increases in adownstream direction potentially as a response to in-stream losses andtransformations. The differences between estimated and measured nutrientloadings are well within the range of what could reasonably be explained by thelimitations of the present land-use information, the accuracy of the exportcoefficients, and in-stream losses and transformations. This verificationexercise corroborates the validity of the nutrient export coefficients for theintended use of providing preliminary estimates of nutrient loadings within theBosque River watershed by contributing sector.

7.4 Preliminary Loadings by Contributing Sector to theBosque River Watershed

The nutrient export coefficients for land uses and the loadings from WWTPswere used to estimate total loadings into the major rivers and tributaries to LakeWaco. These sub-watersheds included the North Bosque River, Hog Creek,Middle Bosque River, South Bosque River, and a combined group includingurban runoff from the city of Waco and smaller drainage areas near Lake Waco,not included in the other sub-watershed areas. The land uses for each sub-watershed and for the entire Bosque River watershed are provided in Table 22.Predicted loadings for each watershed for November 1, 1995 through March 15,1997 are presented in Table 23. To reflect the preliminary nature of thesenutrient loadings, they are presented as a range represented by the mean minusand plus one standard deviation as calculated from 10,000 simulations asdescribed previously for the nutrient export coefficients.


Table 23. Preliminary nutrient loadings estimations by major rivers and tributaries to the Bosque Riverwatershed for November 1, 1995 through March 15, 1997.

Watershed PO4-P (lbs) Total-P (lbs) Total-N (lbs)

North Bosque River Watershed 316,000 - 386,000 747,000 - 884,000 2,621,000 - 5,433,000

Hog Creek Watershed 8,000 - 11,000 33,000 - 38,000 462,000 - 656,000

Middle Bosque River Watershed 20,000 - 27,000 78,000 - 91,000 498,000 - 1,252,000

South Bosque River Watershed 14,000 - 26,000 45,000 - 78,000 657,000 - 915,000

Other Small Watersheds 8,000 - 26,000 26,000 - 75,000 267,000 - 522,000

Bosque River Watershed (Lake Waco) 369,000 - 466,000 932,000 - 1,150,000 5,311,000 - 8,958,000

As expected, the North Bosque River was estimated to contribute by far thelargest amount of nutrients to the Bosque River watershed compared to the othersub-watersheds (Table 23). The North Bosque River watershed represents about74 percent of the entire Bosque River watershed (Table 22). A break-down ofthe estimated percent contribution by land use is provided in Table 24. Whilecomprising about 2 percent of the watershed area (Table 22), dairy wasteapplication fields were estimated to contribute 41 to 52 percent of the PO4-P, 28to 35 percent of the total-P and 10 to 17 percent of the total-N within the BosqueRiver watershed during the period November 1, 1995 through March 15, 1997(Table 24). Row crops were estimated to contribute the largest proportion oftotal-N ranging from 35 to 59 percent of the total loadings.

Table 24. Preliminary estimates of percent contribution of various land uses† to the loadings of majorrivers and tributaries within the Bosque River watershed for November 1, 1995 through March15, 1997. Estimates are provided as a range representing the mean minus and plus one standarddeviation.

Bosque River Watershed


Row Crop Pasture/ Non-Row Crop

Pasture/Cropland

Range/Wood

Urban WWTP

PO4-P (%) (41-52) na na (12-17) (16-27) (5-19) (5-7)

Total-P (%) (28-35) na na (22-28) (24-31) (5-21) (3-3)

Total-N (%) (10-17) (35-59) (1-30) na (2-26) (3-16) (1-2)

North Bosque River Watershed



Pasture/Cropland

Range/Wood

Urban WWTP

PO4-P (%) (49-60) na na (8-11) (17-28) (3-12) (6-7)

Total-P (%) (36-44) na na (15-19) (27-34) (3-14) (3-4)

Total-N (%) (16-34) (15-32) (1-38) na (3-38) (2-15) (1-3)

Hog Creek Watershed



Pasture/Cropland

Range/Wood

Urban WWTP

PO4-P (%) (0) na na (50-66) (26-42) (3-13) (0)

Total-P (%) (0) na na (61-69) (26-32) (2-9) (0)

Total-N (%) (0) (70-92) (0-20) na (0-13) (1-3) (0)

Middle Bosque River Watershed




Pasture/Cropland

Range/Wood

Urban WWTP

PO4-P (%) (8-11) na na (48-62) (20-34) (3-14) (<1)

Total-P (%) (4-5) na na (61-69) (21-27) (2-11) (<1)

Total-N (%) (1-2) (36-78) (4-54) na (0-18) (1-6) (<1)

South Bosque River Watershed



Pasture/Cropland

Range/Wood

Urban WWTP

PO4-P (%) (0) na na (24-49) (4-11) (21-60) (10-21)

Total-P (%) (0) na na (35-62) (5-10) (18-53) (6-10)

Total-N (%) (0) (60-83) (0-17) na (0-4) (5-22) (3-4)

Other Small Drainages and Urban Areas from the City of Waco



Pasture/Cropland

Range/Wood

Urban WWTP

PO4-P (%) (0) na na (3-47) (0-8) (45-96) (0)

Total-P (%) (0) na na (10-55) (1-7) (39-89) (0)

Total-N (%) (0) (31-67) (0-23) na (0-3) (18-58) (0)

† Because of the high nitrogen contribution in the monitored data for row crop dominated samples sites, the pasture/cropland land-use categorywas separated into row crop and pasture/non-row crop for the nitrogen estimates.

‘na’ indicates not applicable.

In addition to the land use and WWTP loadings, the loadings of solublephosphorus and nitrogen in precipitation to the surface area of Lake Waco wereestimated based on analysis of precipitation data collected in the wet-dryatmospheric sampler located in Stephenville. During the monitoring period, atotal of 44.67 inches of rain was measured at the NWS station at Waco Dam.The surface area of Lake Waco was estimated at 7,300 acres. During themonitoring period, 15 measurements were made of precipitation for PO4-P, NH3-N, NO2-N and NO3-N. The median concentration values from these rainfallevents were used to estimate loadings due to precipitation. Median values were0.02 mg/L PO4-P, 0.23 mg/L NH3-N, 0.005 mg/L NO2-N and 0.15 mg/L NO3-N.Based on these values, less than 0.4 percent of the PO4-P and total-N wascontributed by rainfall during the monitoring based on total predicted loadings.Direct loadings of nitrogen and phosphorus from precipitation do occur, but areminor contributions to the overall loadings to Lake Waco.

It should be emphasized that large storm events carry the majority of theloadings within the Bosque River watershed. For the monitoring period October1, 1995 and March 15, 1997 almost 70 percent of the flow at BO090, nearClifton, occurred between February 1 and March 15, 1997 (Figure 28). Diffuserunoff drives nonpoint source nutrient loadings and single large storm eventsoften dominant the loadings for any given time period. Care is needed in theapplication of export coefficients, because they are highly dependent on theenvironmental conditions from which they are based and extrapolation to othertime periods or regions can be problematic.


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umm

ulat

ive

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olum

e (f

t3

in m

illio

ns)

Figure 28. Flow at site BO090 along the North Bosque River near Clifton for October 1, 1995 throughMarch 15, 1997 as average daily flow and cumulative volume. Flow information is based onprovisional flow data form USGS gauging station 08095000.


8. SUMMARY AND RECOMMENDATIONS

This report presents a synthesis of water quality and flow data for stream sites inthe Bosque River watershed for October 1, 1995 through March 15, 1997. Forconvenience in organizing this information, sites monitored were arranged intofour categories based on drainage area size and location within the watershed; 1)sites with small drainage areas -- or micro-watershed sites, 2) sites on majortributaries to the North Bosque River, 3) sites along the mainstem of the NorthBosque River and 4) sites on rivers and major tributaries to Lake Waco.Emphasis in the monitoring program is given to the North Bosque River,because it comprises 74 percent of the total watershed area of the Bosque Riverwatershed. Besides the North Bosque River, other major sub-watersheds withinthe Bosque River watershed include Hog Creek, Middle Bosque River and SouthBosque River.

Stormwater sampling is a very important component of the monitoring program.At 26 of the 30 sites evaluated, ISCO automatic samplers are installed to collectsamples during storm events. Water level data are also recorded at these stormsampling sites continuously at 5-minute intervals allowing the determination offlow with water quality information. Grab sampling on a monthly or bi-monthlybasis is used to support the storm sampling program. In comparing baseflow andstormwater quality at each site, consistently, when statistically significantdifferences were indicated (a = 0.05), constituent concentrations measuredduring storm events were greater than constituent concentrations at baseflowemphasizing the importance of storm event sampling.

8.1 Comparison of Water Quality between SitesIn comparing sites, water quality differences between micro-watershed sites werebest explained through association with the dominant land uses within eachdrainage area. High levels of phosphorus constituents and organic-N wereassociated with drainage areas characterized by dairy waste application fields,while high inorganic-N levels were associated with drainage areas characterizedby cropland. High total-N (inorganic-N plus organic-N) concentrations werecomparable for drainage areas characterized by either dairy waste applicationfields or cropland. The lowest nutrient concentrations were generally associatedwith micro-watershed sites with drainage areas characterized by wood and range.

Similar trends to that with the micro-watershed sites were observed in the waterquality data for sites on major tributaries to the North Bosque River. Tributarysites in the upper portion of the North Bosque River watershed containeddrainage areas with a larger percentage of dairy waste application fields andgenerally higher water quality constituent concentrations than tributary siteslower in the watershed.

Along the North Bosque River, water quality concentrations generally showed adecreasing trend from upstream to downstream sites, although site BO040,below the Stephenville WWTP discharge, often experienced higherconcentrations than the site above Stephenville (BO020). Site BO040 was the


only North Bosque River site with a WWTP discharge immediately above it,which most probably explains these higher concentrations. A more subtle, butnoticeable trend, was a slight increase in NO3-N concentrations at sites BO090(near Clifton) and BO100 (near Valley Mills). This increase in NO3-Nconcentrations is more likely associated with the cropland areas along the NorthBosque River between Clifton and Valley Mills than with WWTP discharges.

Three of the four major tributaries to Lake Waco were monitored (site BO100,the North Bosque River at Valley Mills; site HC060, Hogg Creek; and siteMB060, the Middle Bosque River) for baseflow and storm events during thisreporting period. Monitoring results from the South Bosque River (site SB060)were not included in the statistical comparisons between sites, since samplingdid not begin until November 1996 as the result of logistical and technicaldifficulties. However, the monitoring results that were available from the SouthBosque River were used in the water quality assessment in comparison tonumeric screening levels and criteria.

In general, very little difference was found in the water quality between the threetributaries to Lake Waco. The results for nitrogen species did indicate someinteresting differences between baseflow and storm event concentrations. Atbaseflow, mean nitrogen concentrations for the Lake Waco tributary sites werenot statistically different except for organic nitrogen species (TKN and organic-N) where BO100 has the highest concentrations of organic nitrogen and MB060has the lowest concentrations. For storm events, site MB060 had significantlyhigher mean NO3-N and inorganic-N concentrations than sites HC060 or BO100.During storm events, organic nitrogen species were not significantly differentbetween sites.

8.2 Water Quality Assessment of SitesUsing the TNRCC assessment methodology (TNRCC, 1996), the water qualityat all sites was compared to state numeric criteria and screening levels. Theassessment determines the degree of support (i.e., fully supporting, partiallysupporting or not supporting) at each site for constituents that have criteria, anddetermines the degree of concern (i.e., no concern, potential concern or concern)at each site for constituents that have screening levels. For the waterborneconstituents evaluated in this study, DO, pH and fecal coliform have numericcriteria and the various nutrient forms and chlorophyll-a have screening levels.

In the assessment of water quality by TNRCC nutrient screening levels,consistently, a greater proportion of storm event samples exceeded screeninglevels than baseflow samples. DO and pH criteria at baseflow were generally“supported” or “partially supported” at all sites. Only DO at site AL040 wasindicated to be “not supporting” of the designated uses.

For the micro-watershed sites, fecal coliform concentrations did “not support” oronly “partially supported” the designated use for contact recreation based on theTNRCC criterion. The greatest percentage of samples exceeding the organic-Nand phosphorus (PO4-P and total-P) screening levels occurred at micro-watershed sites characterized by dairy waste application fields, while the greatestpercentage of samples exceeding the inorganic-N and total-N screening levelsoccurred at micro-watershed sites characterized by cropland.


For the tributaries to the North Bosque River, more prominent water qualityissues were indicated for tributaries in the upper portion of the watershed,especially, the North Fork (site NF050) and the South Fork (site SF075), than fortributaries in the lower portion of the watershed, e.g., Neils Creek (site NC060)and Meridian Creek (site MC060). CHLA levels were of “concern” at sitesAL040, NF050 and SF075, and fecal coliform concentrations indicated “partialsupport” at AL040 and “no support” at sites NF050 and SF075 for the use ofcontact recreation.

A general trend of improving water quality was also indicated along themainstem of the North Bosque River with a greater percentage of samplesexceeding criteria and screening levels at upstream sites than at downstreamsites. The baseflow fecal coliform data indicate that contact recreation is “notsupported” in the upper portions of the North Bosque River but is “supported” atsite BO085 (near Meridian) and below. Storm event fecal coliform data indicatethat the designated use of contact recreation is “not supported” during elevatedflows along the entire North Bosque River. The impact of the StephenvilleWWTP effluent did manifest itself on the receiving water at BO040 with agreater percentage of samples exceeding nutrient screening levels at baseflow atsite BO040 than at the upstream site, BO020.

For the Lake Waco tributary sites, “concern” for nutrient concentrations wasprimarily indicated only for storm event samples except at SB060 on the SouthBosque River. Baseflow fecal coliform concentrations were assessed as“supporting” the use of contact recreation at Hogg Creek (HC060), the MiddleBosque River (MB060) and the North Bosque River at Valley Mills (BO100),and “not supporting” at the South Bosque River (SB060). At baseflow, a largepercentage of samples at SB060 exceeded screening levels for several of thenutrient constituents. A much more limited database was available for theassessment of samples at site SB060 than at the other Lake Waco tributary sites,so the results at SB060 must be tempered by this restriction until more samplingdata are collected. Only site BO100 did not indicate “concern” for any of thenitrogen constituents during storm events, while “concern” or “potentialconcern” was indicated for total-P during storm events at all four sites.

8.3 Nutrient Loading ContributionsWhile concentrations are important indicators of current water quality, especiallywhen considering toxic impacts on aquatic communities such as ammoniaconcentrations, loadings are important in evaluating the cumulative impact of in-stream water quality constituents on downstream waterbodies. Loadings aregenerally calculated by multiplying the concentration of each waterborneconstituent by the volume of water associated with a particular sample. Loadinginformation by land-use sector is often estimated through the use of nutrientexport coefficients. Nutrient export coefficients represent the mass of nutrientsleaving or being exported from a unit land area via rainfall runoff per unit time,e.g., lbs/acre of cropland/yr.

Whether determined from in-stream monitoring data or estimated from land-useexport coefficients, loadings are a reflection of the weather conditions, especiallythe rainfall, under which they were derived. The longer the duration of themonitoring data set, the more likely that loadings will include a range of weatherconditions (e.g., high and low rainfall periods) to typify average nutrient


contributions rather than including potentially undesirable biases from the overrepresentation of meteorological extremes. An understanding of the conditionsunder which loadings were determined is, thus, very important before using themin watershed planning. Of note with the current dataset are the temporal rainfallpatterns throughout the monitoring period as reflected in Table 8 and Figure 5.Because of the dominant impact of nonpoint source runoff on the stream systemwithin the Bosque River watershed, loadings are highly influenced by runofffrom major storm events. The dominant storms during the November 1, 1995through March 15, 1997 monitoring period occurred in late August 1996, earlySeptember 1996, and throughout February 1997 (see Figure 28). During most ofthe early part of the monitoring period, below normal precipitation conditionswere occurring. While it is beyond the scope of this report to evaluate variationsin loading response to variation in rainfall and streamflow, it can be expectedthat point source loadings, i.e., the municipal WWTP discharges, will increasein importance during low flow conditions and that nonpoint source loadings fromthe various land uses in the watershed will increase in importance during highflow conditions.

Notwithstanding the preliminary nature of these nutrient loading estimates andextremes in rainfall during the period, the approach and results presented arebased on a statistically valid approach using an abundance of in-streammonitoring data. These preliminary estimates indicate that nutrient loadings tostreams within the Bosque River watershed are provided by a variety of sources.Soluble reactive phosphorus or PO4-P loadings from the entire watershed arecontributed primarily from dairy waste application fields thoughpasture/cropland and range/wood are also important contributing sources, albeitat a lower level. For total-P loadings to the Bosque River watershed, dairy wasteapplication fields, pasture/cropland and range/wood land uses emerge as themajor contributing sectors. The row crop land use is indicated to be the majorcontributor of total-N loadings with all other land use categories, i.e., dairy wasteapplication fields, range/wood and urban, roughly of equal, yet secondary,importance.

8.4 RecommendationsAs data continue to be collected and analyzed from sites within the Bosque Riverwatershed, a better understanding of the relationships and contributors to thewater quality response of the watershed should emerge. The followingrecommendations are made with reference to future monitoring and analyses:

1. Monitoring at the urban sampling sites within the city of Waco should be apriority in quantifying urban nonpoint source loadings to the watershed due tothe City’s proximity to Lake Waco. In a cooperative arrangement with ongoingstudies in the Bosque River watershed, the city of Waco began monitoring twourban sites during the spring of 1997.

2. A longer period of sampling is needed on the South Bosque River toconfidently evaluate its nutrient contribution, particularly of nitrogen, to theBosque River watershed.

3. When an updated land use for the watershed becomes available, the estimatesof nutrient loadings by contributing sector need to be re-analyzed and refined.This refinement of nutrient loadings and land uses, especially for the lower


portion of the watershed, will allow a more accurate quantification of nutrientcontributions within the watershed and actual nutrient delivery to Lake Waco.

4. An investigation of in-stream losses and transformations is needed todetermine where the nutrients entering the stream system are going, particularlyalong the North Bosque River. This investigation should involve a mass balanceanalysis of monitoring data along with the use of physically and biologicallybased computer models and will help better estimate the long-term nutrientloading impact on Lake Waco and other important points in the watershed.

5. As a longer period of record is established for sampling sites in the BosqueRiver watershed, trends in water quality should be evaluated to assess changes inwater quality over time. As indicated in the report by Miertschin (1996), thescarcity of long-term data at any one site currently precludes a definitiveevaluation of changes in water quality over time at stream sites within theBosque River watershed.


9. LITERATURE CITED

APHA, American Public Health Association, American Water Works Association, andWater Environment Federation. 1995. Standard Methods for the Examination ofWater and Wastewater. 19th edition. APHA, Washington, D.C.

Bayer, C.W., J.R. Davis, S.R. Twidwell, R. Kleinsasser, G. Linam, K. Mayes and E.Hornig. 1992. Texas Aquatic Ecoregion Project: An Assessment of LeastDisturbed Streams. Texas Natural Resource Conservation Service, Texas Parksand Wildlife Department, and U.S. Environmental Protection Agency, Region 6(DRAFT).

BRA, Brazos River Authority. 1994. Intensive Survey of the North Bosque River(Segment 1226). Brazos River Authority, Waco, Texas. April 1994.

BRA, Brazos River Authority. 1995. Quality Assurance Project Plan for the Bosque RiverWatershed Pilot Project. Brazos River Authority, Waco, Texas.

BRA, Brazos River Authority. 1996. Quality Assurance Project Plan for Clean RiversProgram Contract #6500000014. Brazos River Authority, Waco, Texas.

Dallas Morning News, 1997. 1998-99 Texas Almanac and State Industrial Guide. Eds. M.Kingston and M.G. Crawford. Dallas Morning News, Inc., Dallas, Texas.

EPA, United States Environmental Protection Agency. 1983. Methods for ChemicalAnalysis of Water and Wastes. Environmental Monitoring and SupportLaboratory, Office of Research and Development, US-EPA, Cincinnati, Ohio.EPA-600/4-79-020, Revised March 1983.

EPA, United States Environmental Protection Agency. 1986. Quality Criteria for Water1986. USEPA, Office of Water, Washington, D.C. EPA 440/5-86-001.

Frink, C.R. 1991. Estimating nutrient exports to estuaries. Journal of EnvironmentalQuality, 20:717-724.

Gilliom, R.J. and D.R. Helsel. 1986. Estimation of distributional parameters for censoredtrace level water quality data. 1. Estimation techniques. Water ResourcesResearch 22:135-126.

Hodge, T.A. and L.J. Armstrong. 1993. Chapter 9. Use of a Multiple Linear RegressionModel to Estimate Stormwater Pollutant Loading, pp. 201-214. In: NewTechniques for Modelling the Management of Stormwater Quality Impacts, ed.W. James. Lewis Publishers, Boca Raton, Florida.

Kennedy, E. J. 1984. Techniques of Water-Resources Investigations of the United StatesGeological Survey - Chapter 10 - Discharge Ratings at Gaging Stations - Book 3- Applications of Hydraulics. U.S. Geological Survey, Alexandria, Virginia.

Larkin, T.J. and G.W. Bomar. 1983. Climatic Atlas of Texas. LP-192. Texas Departmentof Water Resources, Austin, Texas.

Loehr, R.C., S.O. Ryding, and W.C. Sonzogni. 1989. Chapter 7. Estimating the NutrientLoad to a Waterbody, pp.115-146. In: The Control of Eutrophication of Lakesand Reservoirs, eds. S.O. Ryding and W. Rast. Volume I, Man and theBiosphere Series, United Nations Educational Scientific and CulturalOrganization, Paris, France and The Parthenon Publishing Group, Park Ridge,New Jersey.


McFarland, A. and Hauck, L. 1995. Livestock and the Environment: ScientificUnderpinnings for Policy Analysis: Analysis of Agricultural Nonpoint PollutionSources and Land Characteristics. Texas Institute for Applied EnvironmentalResearch, Tarleton State University, Stephenville, Texas. September 1995.

McFarland, A. and L. Hauck. 1997a. Livestock and the Environment: A National PilotProject - NPP Report on the Water Quality of Eight PL-566 Reservoirs in theUpper North Bosque River Watershed. Texas Institute for AppliedEnvironmental Research, Tarleton State University, Stephenville, Texas. PR97-02, February 1997.

McFarland, A. and L. Hauck. 1997b. Livestock and the Environment: A National PilotProject - NPP Report on the Stream Water Quality in the Upper North BosqueRiver Watershed. Texas Institute for Applied Environmental Research, TarletonState University, Stephenville, Texas. PR97-03, June 1997.

McFarland, A. and L. Hauck. 1998. Lake Waco/Bosque River Watershed InitiativeReport: Determining Nutrient Contribution by Land Use for the Upper NorthBosque River Watershed. Texas Institute for Applied Environmental Research,Tarleton State University, Stephenville, Texas. PR98-01, January 1998 (revisedMay 1998).

Miertschin, J. 1996. Analysis of Available Water Quality Data for Nonpoint SourceEffects - North Bosque River. Prepared for Brazos River Authority, JamesMiertschin & Associates, Inc., Austin, Texas.

Neal, R., K. Jay, L. Beran. 1996. A National Pilot Project: Livestock and theEnvironment - Analysis of the Nonmarket Impacts of Dairy Sector Growth in theCross Timbers Region. Prepared for U.S. Environmental Protection Agency.Texas Institute for Applied Environmental Research, Tarleton State University,Stephenville, Texas. August, 1996.

Ott, L. 1984. An Introduction to Statistical Methods and Data Analysis, 2nd Edition.Duxbury Press, Boston, Massachusetts.

Reckhow, K. H., M.N. Beaulac, J.T. Simpson. 1980. Modeling Phosphorus Loading andLake Response Under Uncertainty: A Manual and Compilation of ExportCoefficients. USEPA Clean Lakes Section, Washington, D.C. EPA 440/5-80-011, June 1980.

SAS. 1992. Chapter 42, The UNIVARIATE Procedure, pp. 617-634. In: SAS ProceduresGuide, Version 6, Third Edition. SAS Institute, Cary, North Carolina.

Spooner, J. 1994. Comparisons between parametric and nonparametric statistical trendtests, presented at the 2nd National Nonpoint Source Watershed MonitoringConference, Chicago, Illinois, September 27-29, 1994.

Stein, S.K. 1977. Calculus and Analytic Geometry, second edition. McGraw-Hill BookCompany, New York, New York.

TIAER, Texas Institute for Applied Environmental Research. 1993. Quality AssuranceProject Plan for the National Pilot Project. TIAER, Tarleton State University,Stephenville, Texas.

TIAER, Texas Institute for Applied Environmental Research. 1996. Quality AssuranceProject Plan for the United States Department of Agriculture Bosque RiverInitiative. TIAER, Tarleton State University, Stephenville, Texas.

TNRCC, Texas Natural Resource Conservation Commission. 1993. Texas Clean RiverProgram: FY94-95 Program Guidance. TNRCC, Texas Clean Rivers Program,Austin, Texas.


TNRCC, Texas Natural Resource Conservation Commission. 1995a. Implementation ofthe Texas Natural Resource Conservation Commission Standards via Permitting.TNRCC, Water Planning and Assessment Division, Austin, Texas. RG-194,August 1995.

TNRCC, Texas Natural Resource Conservation Commission. 1995b. Texas Clean RiverProgram: FY96-97 Program Guidance. TNRCC, Texas Clean Rivers Program,Austin, Texas. March 1995.

TNRCC, Texas Natural Resource Conservation Commission. 1996. The State of TexasWater Quality Inventory, 13th Edition, 1996: TNRCC, Austin, Texas. SFR-50,December 1996.

TNRCC, Texas Natural Resource Conservation Commission. 1997. State of Texas 1996303(d) List. TNRCC, Austin, Texas.

TNRCC, Texas Natural Resource Conservation Commission, and TCRP, Texas CleanRivers Program. 1998. Guidance for Screening and Assessing Texas Surface andFinished Drinking Water Quality Data. TNRCC, Austin, Texas.

TWC, Texas Water Commission. 1990. Waste Load Evaluation for the Bosque RiverSystem in the Brazos River Basin: Segment 1226 - North Bosque River,Segment 1246 - Middle Bosque/South Bosque River. WLE 90-02. TWC, Austin,Texas.

TWC, Texas Water Commission. 1991 (second revision). Use Attainability Analysis ofNorth, Middle, and South Bosque Rivers Segments 1226 and 1246. TWC,Austin, Texas

TWC, Texas Water Commission, and TSSWCB, Texas State Soil and WaterConservation Board. 1991. 1990 Update to the Nonpoint Source WaterPollution Assessment Report of the State of Texas. TWC, Austin, Texas.

USDA-AMS, United States Department of Agriculture, Agricultural Marketing Service.1997. The Market Administrator’s Report: Texas Marking Area, New Mexico-West Texas Marketing Area; Vol. XXIII, No. 5.

Ward, R.C., J.C. Loftis, H.P. DeLong, and H.F. Bell. 1988. Groundwater quality: A dataanalysis protocol. Journal of the Water Pollution Control Federation 60:1938-1945.



APPENDIX A.

Average Daily Flow at Stream Sites



AL040

0.1

1

10

100

1000

10000

100000

9527

4

9529

5

9531

6

9533

7

9535

8

9601

4

9603

5

9605

6

9607

7

9609

8

9611

9

9614

0

9616

1

9618

2

9620

3

9622

4

9624

5

9626

6

9628

7

9630

8

9632

9

9635

0

9700

5

9702

6

9704

7

9706

8

Julian Date (yyddd)

Ave

rgar

e D

aily

Flo

w (c

fs)

Figure A- 1. Average daily flow at site AL040 for October 1, 1995 through March 15, 1997.

BO040

0.1

1

10

100

1000

10000

9527

4

9529

7

9532

0

9534

3

9600

1

9602

4

9604

7

9607

0

9609

3

9611

6

9613

9

9616

2

9618

5

9620

8

9623

1

9625

4

9627

7

9630

0

9632

3

9634

6

9700

3

9702

6

9704

9

9707

2

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)

Figure A- 2. Average daily flow at site BO040 for October 1, 1995 through March 15, 1997.


BO070

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)


BO090

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)



BO100

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (yyddd)

Dai

ly A

vera

ge F

low

(cfs

)


DC060

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)

Date of first record:March 6, 1996 (96065)

Figure A- 6. Average daily flow at site DC060 for March 6, 1996 through March 15, 1997.


GB020

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)

Figure A- 7. Average daily flow at site GB020 for October 1, 1995 through March 15, 1997.

GC100

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)

Figure A- 8. Average daily flow at site GC100 for October 1, 1995 through March 15, 1997.


HC060

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)

Figure A- 9. Average daily flow at site HC060 for October 1, 1995 through March 15, 1997.

IC020

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)

Figure A- 10. Average daily flow at site IC020 for October 1, 1995 through March 15, 1997.


MB040

0.1

1

10

100

1000

10000

100000

9527

4

9529

9

9532

4

9534

9

9600

9

9603

4

9605

9

9608

4

9610

9

9613

4

9615

9

9618

4

9620

9

9623

4

9625

9

9628

4

9630

9

9633

4

9635

9

9701

8

9704

3

9706

8

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)

Figure A- 11. Average daily flow at site MB040 for October 1, 1995 through March 15, 1997.

MB060

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (cfs)

Ave

rage

Dai

ly F

low

(cfs

)

Date of first record:Oct. 19, 1995



NC060

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)

Figure A- 13. Average daily flow at site NC060 for October 1, 1995 through March 15, 1997.

NF005

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)

Figure A- 14. Average daily flow at site NF005 for October 1, 1995 through March 15, 1997.


NF009

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)


NF020

0.1

1

10

100

1000

10000

100000

9527

4

9530

0

9532

6

9535

2

9601

3

9603

9

9606

5

9609

1

9611

7

9614

3

9616

9

9619

5

9622

1

9624

7

9627

3

9629

9

9632

5

9635

1

9701

1

9703

7

9706

3

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)



NF035

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)


NF050

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

) Date of last record:Feb. 5, 1997 (97036)

Figure A- 18. Average daily flow at site NF050 for October 1, 1995 through February 5, 1997.


SC020

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)

Figure A- 19. Average daily flow at site SC020 for October 1, 1995 through March 15, 1997.

SF020

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)

Figure A- 20. Average daily flow at site SF020 for October 1, 1995 through March 15, 1997.


SF035

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)


SF050

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cf

s)



SF075

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

Julian date (yyddd)

Ave

rage

Dai

ly F

low

(cfs


Figure A- 23. Average daily flow at site SF075 for October 1, 1995 through February 4, 1997.

SP020

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

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9610

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9612

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9614

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9617

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9622

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9624

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9702

3

9704

7

9707

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Julian Date (yyddd)

Ave

rage

Dai

ly F

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(cfs

)

Figure A- 24. Average daily flow at site SP020 for October 1, 1995 through March 15, 1997.


TC020

0.1

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100

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9527

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Date of first record:Oct. 17, 1995 (95290)

Figure A- 25. Average daily flow at site TC020 for October 17, 1995 through March 15, 1997.

WC020

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9527

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Figure A- 26. Average daily flow at site WC020 for October 17, 1995 through March 15, 1997.


APPENDIX B.

Basic Statistics for Baseflow and Storm Event Water Qualityat Stream Sites


Table B- 1. Basic statistics for water quality constitutents by site for baseflow and storm event comparisons.Grab samples represent conditions at baseflow during routine monitoring. Storm samplesrepresent volume weighted storm values averaged across storm events. Geometric means arepresented for all constitutents except DO, water temperature and pH which were evaluated usingarithmetic means. Lstd equals the lower bound of the mean minus the standard deviation, whileUstd equals the upper bound of the mean plus the standard deviation. n equals the number ofgrab samples or storm events evaluated.

Site SampleType

Constituent Mean orGeo. Mean

Lstd Ustd n

Timeframe: May 1996 - March 1997

AL040 Grab Water Temp. (ºC) 18.9 10.4 27.4 19

AL040 Grab DO (mg/L) 7.4 3.6 11.1 19

AL040 Grab pH (standard units) 8.0 7.7 8.3 19

AL040 Grab Conductivity (µmhos/cm) 651 461 919 19

AL040 Grab CHLA (µg/L) 26 13 55 16

AL040 Grab Fecal Coliform (colonies/100ml) 127 25 637 19

AL040 Grab NH3-N (mg/L) 0.16 0.09 0.28 19

AL040 Grab NO2-N (mg/L) 0.013 0.003 0.049 18

AL040 Grab NO3-N (mg/L) 0.11 0.04 0.35 19

AL040 Grab TKN (mg/L) 1.56 1.26 1.93 19

AL040 Grab Inorganic -N (mg/L) 0.35 0.21 0.58 18

AL040 Grab Organic -N (mg/L) 1.38 1.10 1.72 19

AL040 Grab Total-N (mg/L) 1.76 1.44 2.16 18

AL040 Grab PO4-P (mg/L) 0.25 0.15 0.42 19

AL040 Grab Total-P (mg/L) 0.38 0.24 0.61 19

AL040 Grab COD (mg/L) 25 18 35 19

AL040 Grab TSS (mg/L) 12 5 25 19

Timeframe: April 1996 - March 1997

AL040 Storm NH3-N (mg/L) 0.14 0.08 0.26 12

AL040 Storm NO2-N (mg/L) 0.009 0.002 0.034 12

AL040 Storm NO3-N (mg/L) 0.11 0.03 0.35 12

AL040 Storm TKN (mg/L) 1.95 1.63 2.33 12

AL040 Storm Inorganic -N (mg/L) 0.30 0.16 0.57 12

AL040 Storm Organic -N (mg/L) 1.77 1.45 2.17 12

AL040 Storm Total-N (mg/L) 2.14 1.79 2.56 12

AL040 Storm PO4-P (mg/L) 0.19 0.07 0.51 12

AL040 Storm Total-P (mg/L) 0.47 0.26 0.84 12

AL040 Storm COD (mg/L) 34 28 42 12

AL040 Storm TSS (mg/L) 52 23 116 12


BO020 Grab Water Temp. (ºC) 15.7 7.6 23.8 14


Site SampleType


Lstd Ustd n

BO020 Grab DO (mg/L) 6.9 2.7 11.0 14

BO020 Grab pH (standard units) 7.9 7.7 8.1 14

BO020 Grab Conductivity (µmhos/cm) 764 394 1479 14

BO020 Grab CHLA (µg/L) 23 6 92 10

BO020 Grab Fecal Coliform (colonies/100ml) 672 54 8314 16

BO020 Grab NH3-N (mg/L) 0.11 0.04 0.32 14

BO020 Grab NO2-N (mg/L) 0.012 0.003 0.045 14

BO020 Grab NO3-N (mg/L) 0.41 0.07 2.28 14

BO020 Grab TKN (mg/L) 1.62 1.19 2.22 14

BO020 Grab Inorganic -N (mg/L) 0.84 0.37 1.90 14

BO020 Grab Organic -N (mg/L) 1.45 1.08 1.96 14

BO020 Grab Total-N (mg/L) 2.50 1.89 3.31 14

BO020 Grab PO4-P (mg/L) 0.16 0.04 0.68 14

BO020 Grab Total-P (mg/L) 0.34 0.16 0.72 14

BO020 Grab COD (mg/L) 21 10 43 13

BO020 Grab TSS (mg/L) 11 6 22 14

Timeframe: August 1996 - October 1996

BO020 Storm Fecal Coliform (colonies/100ml) 5056 904 28270 28



BO040 Grab DO (mg/L) 7.6 4.2 10.9 14



BO040 Grab CHLA (µg/L) 14 5 39 10


BO040 Grab NH3-N (mg/L) 0.13 0.04 0.42 14

BO040 Grab NO2-N (mg/L) 0.027 0.007 0.114 14

BO040 Grab NO3-N (mg/L) 3.38 2.44 4.68 14

BO040 Grab TKN (mg/L) 1.52 1.08 2.14 14




BO040 Grab PO4-P (mg/L) 1.12 0.48 2.61 14


BO040 Grab COD (mg/L) 15 8 30 13

BO040 Grab TSS (mg/L) 7 4 12 14



Timeframe: April


Site SampleType


Lstd Ustd n

1996 - March 1997

BO040 Storm NH3-N (mg/L) 0.23 0.08 0.63 17

BO040 Storm NO2-N (mg/L) 0.026 0.007 0.089 17

BO040 Storm NO3-N (mg/L) 1.41 0.81 2.46 17

BO040 Storm TKN (mg/L) 2.42 1.73 3.39 17

BO040 Storm Inorganic -N (mg/L) 1.77 1.05 2.98 17

BO040 Storm Organic -N (mg/L) 2.12 1.56 2.89 17

BO040 Storm Total-N (mg/L) 4.08 3.13 5.31 17

BO040 Storm PO4-P (mg/L) 0.63 0.41 0.96 17

BO040 Storm Total-P (mg/L) 0.97 0.71 1.34 17

BO040 Storm COD (mg/L) 38 26 55 16

BO040 Storm TSS (mg/L) 77 16 381 17



BO060 Grab DO (mg/L) 10.0 7.5 12.5 15



BO060 Grab CHLA (µg/L) 23 7 79 11


BO060 Grab NH3-N (mg/L) 0.05 0.02 0.11 15

BO060 Grab NO2-N (mg/L) 0.006 0.002 0.021 15

BO060 Grab NO3-N (mg/L) 0.36 0.10 1.33 15

BO060 Grab TKN (mg/L) 1.09 0.79 1.51 15




BO060 Grab PO4-P (mg/L) 0.37 0.20 0.67 15


BO060 Grab COD (mg/L) 15 9 25 14

BO060 Grab TSS (mg/L) 10 5 22 15





BO070 Grab DO (mg/L) 10.7 7.2 14.3 16



BO070 Grab CHLA (µg/L) 15 6 40 12



Site SampleType


Lstd Ustd n

BO070 Grab NH3-N (mg/L) 0.04 0.02 0.10 16

BO070 Grab NO2-N (mg/L) 0.005 0.002 0.015 16

BO070 Grab NO3-N (mg/L) 0.14 0.02 1.01 16

BO070 Grab TKN (mg/L) 0.92 0.66 1.29 16




BO070 Grab PO4-P (mg/L) 0.16 0.06 0.41 16


BO070 Grab COD (mg/L) 10 4 23 15

BO070 Grab TSS (mg/L) 8 4 14 16




BO070 Storm NH3-N (mg/L) 0.14 0.06 0.33 14

BO070 Storm NO2-N (mg/L) 0.009 0.002 0.046 14

BO070 Storm NO3-N (mg/L) 0.46 0.23 0.93 14

BO070 Storm TKN (mg/L) 1.60 0.91 2.81 14




BO070 Storm PO4-P (mg/L) 0.27 0.17 0.44 14


BO070 Storm COD (mg/L) 23 10 50 13

BO070 Storm TSS (mg/L) 95 16 569 14



BO080 Grab DO (mg/L) 10.8 9.3 12.4 16



BO080 Grab CHLA (µg/L) 35 16 78 12


BO080 Grab NH3-N (mg/L) 0.03 0.02 0.07 16

BO080 Grab NO2-N (mg/L) 0.002 0.001 0.005 16

BO080 Grab NO3-N (mg/L) 0.03 0.01 0.15 16

BO080 Grab TKN (mg/L) 0.93 0.61 1.42 16





Site SampleType


Lstd Ustd n

BO080 Grab PO4-P (mg/L) 0.05 0.01 0.18 16


BO080 Grab COD (mg/L) 13 6 29 15

BO080 Grab TSS (mg/L) 18 7 50 16





BO085 Grab DO (mg/L) 9.3 7.2 11.4 16



BO085 Grab CHLA (µg/L) 20 8 54 12


BO085 Grab NH3-N (mg/L) 0.03 0.02 0.08 16

BO085 Grab NO2-N (mg/L) 0.002 0.001 0.006 16

BO085 Grab NO3-N (mg/L) 0.03 0.01 0.11 16

BO085 Grab TKN (mg/L) 0.66 0.43 1.01 16




BO085 Grab PO4-P (mg/L) 0.02 0.01 0.09 16


BO085 Grab COD (mg/L) 8 3 18 15

BO085 Grab TSS (mg/L) 12 4 36 16





BO090 Grab DO (mg/L) 9.7 7.9 11.6 16



BO090 Grab CHLA (µg/L) 10 3 33 12


BO090 Grab NH3-N (mg/L) 0.05 0.02 0.10 16

BO090 Grab NO2-N (mg/L) 0.004 0.001 0.012 16

BO090 Grab NO3-N (mg/L) 0.19 0.05 0.75 16

BO090 Grab TKN (mg/L) 0.59 0.37 0.95 16



Site SampleType


Lstd Ustd n



BO090 Grab PO4-P (mg/L) 0.01 0.00 0.06 16


BO090 Grab COD (mg/L) 6 3 13 15

BO090 Grab TSS (mg/L) 10 3 33 16




BO090 Storm NH3-N (mg/L) 0.09 0.05 0.15 15

BO090 Storm NO2-N (mg/L) 0.006 0.001 0.025 15

BO090 Storm NO3-N (mg/L) 0.27 0.12 0.63 15

BO090 Storm TKN (mg/L) 1.06 0.56 1.99 15




BO090 Storm PO4-P (mg/L) 0.05 0.02 0.13 15


BO090 Storm COD (mg/L) 15 7 35 14

BO090 Storm TSS (mg/L) 93 19 445 15



BO100 Grab DO (mg/L) 9.6 7.5 11.6 15



BO100 Grab CHLA (µg/L) 11 3 40 11


BO100 Grab NH3-N (mg/L) 0.04 0.02 0.10 15

BO100 Grab NO2-N (mg/L) 0.003 0.001 0.009 15

BO100 Grab NO3-N (mg/L) 0.20 0.08 0.48 15

BO100 Grab TKN (mg/L) 0.52 0.25 1.06 15




BO100 Grab PO4-P (mg/L) 0.02 0.00 0.05 15


BO100 Grab COD (mg/L) 5 3 11 14

BO100 Grab TSS (mg/L) 14 4 53 15

Timeframe: February 1996 - March 1997 (included BRA data)


Site SampleType


Lstd Ustd n


BO100 Grab DO (mg/L) 8.8 6.7 11.0 25



BO100 Grab CHLA (µg/L) 6 2 20 12


BO100 Grab NH3-N (mg/L) 0.05 0.02 0.10 16

BO100 Grab NO2-N (mg/L) 0.005 0.001 0.021 23

BO100 Grab NO3-N (mg/L) 0.35 0.10 1.23 23

BO100 Grab TKN (mg/L) 0.45 0.23 0.91 16




BO100 Grab PO4-P (mg/L) 0.02 0.00 0.08 23


BO100 Grab COD (mg/L) 5 3 11 15

BO100 Grab TSS (mg/L) 12 4 36 24




BO100 Storm NH3-N (mg/L) 0.06 0.03 0.15 14

BO100 Storm NO2-N (mg/L) 0.004 0.001 0.018 14

BO100 Storm NO3-N (mg/L) 0.36 0.27 0.48 14

BO100 Storm TKN (mg/L) 1.08 0.55 2.12 14




BO100 Storm PO4-P (mg/L) 0.03 0.01 0.13 14


BO100 Storm COD (mg/L) 19 8 46 13

BO100 Storm TSS (mg/L) 124 27 563 14


DC060 Grab Water Temp. (ºC) 21.3 10.9 31.6 16

DC060 Grab DO (mg/L) 12.3 10.3 14.2 16

DC060 Grab pH (standard units) 8.5 8.2 8.8 16

DC060 Grab Conductivity (µmhos/cm) 413 305 561 16

DC060 Grab CHLA (µg/L) 6 3 12 13

DC060 Grab Fecal Coliform (colonies/100ml) 32 6 162 16

DC060 Grab NH3-N (mg/L) 0.04 0.02 0.09 16


Site SampleType


Lstd Ustd n

DC060 Grab NO2-N (mg/L) 0.003 0.001 0.008 16

DC060 Grab NO3-N (mg/L) 0.02 0.00 0.09 16

DC060 Grab TKN (mg/L) 0.48 0.21 1.06 16

DC060 Grab Inorganic -N (mg/L) 0.09 0.04 0.21 16

DC060 Grab Organic -N (mg/L) 0.40 0.15 1.07 16

DC060 Grab Total-N (mg/L) 0.54 0.24 1.18 16

DC060 Grab PO4-P (mg/L) 0.01 0.00 0.06 16

DC060 Grab Total-P (mg/L) 0.08 0.05 0.13 16

DC060 Grab COD (mg/L) 8 4 19 16

DC060 Grab TSS (mg/L) 6 4 9 16


DC060 Storm NH3-N (mg/L) 0.11 0.04 0.26 15

DC060 Storm NO2-N (mg/L) 0.006 0.001 0.036 15

DC060 Storm NO3-N (mg/L) 0.15 0.03 0.69 15

DC060 Storm TKN (mg/L) 1.40 0.67 2.92 15

DC060 Storm Inorganic -N (mg/L) 0.31 0.10 0.92 15

DC060 Storm Organic -N (mg/L) 1.28 0.61 2.66 15

DC060 Storm Total-N (mg/L) 1.66 0.78 3.53 15

DC060 Storm PO4-P (mg/L) 0.06 0.02 0.22 15

DC060 Storm Total-P (mg/L) 0.29 0.14 0.59 15

DC060 Storm COD (mg/L) 25 10 64 14

DC060 Storm TSS (mg/L) 87 15 512 15


GB020 Storm NH3-N (mg/L) 0.68 0.22 2.15 15

GB020 Storm NO2-N (mg/L) 0.034 0.007 0.167 15

GB020 Storm NO3-N (mg/L) 0.94 0.32 2.79 15

GB020 Storm TKN (mg/L) 7.75 3.89 15.45 15

GB020 Storm Inorganic -N (mg/L) 1.93 0.72 5.22 15

GB020 Storm Organic -N (mg/L) 6.82 3.45 13.49 15

GB020 Storm Total-N (mg/L) 9.20 4.58 18.47 15

GB020 Storm PO4-P (mg/L) 1.53 0.56 4.13 15

GB020 Storm Total-P (mg/L) 3.00 1.40 6.41 15

GB020 Storm COD (mg/L) 107 64 179 12

GB020 Storm TSS (mg/L) 381 103 1408 15


Site SampleType


Lstd Ustd n


GC100 Grab Water Temp. (ºC) 17.8 9.3 26.3 14

GC100 Grab DO (mg/L) 7.6 5.0 10.2 14

GC100 Grab pH (standard units) 7.9 7.8 8.1 14

GC100 Grab Conductivity (µmhos/cm) 656 540 796 14

GC100 Grab CHLA (µg/L) 12 4 36 11

GC100 Grab Fecal Coliform (colonies/100ml) 66 23 190 14

GC100 Grab NH3-N (mg/L) 0.05 0.03 0.12 14

GC100 Grab NO2-N (mg/L) 0.003 0.001 0.010 14

GC100 Grab NO3-N (mg/L) 0.23 0.04 1.36 14

GC100 Grab TKN (mg/L) 0.65 0.43 0.98 14

GC100 Grab Inorganic -N (mg/L) 0.36 0.09 1.34 14

GC100 Grab Organic -N (mg/L) 0.57 0.36 0.92 14

GC100 Grab Total-N (mg/L) 1.19 0.81 1.76 14

GC100 Grab PO4-P (mg/L) 0.02 0.01 0.06 14

GC100 Grab Total-P (mg/L) 0.07 0.04 0.12 14

GC100 Grab COD (mg/L) 6 3 14 14

GC100 Grab TSS (mg/L) 6 4 9 14


GC100 Storm NH3-N (mg/L) 0.14 0.06 0.28 10

GC100 Storm NO2-N (mg/L) 0.006 0.002 0.020 10

GC100 Storm NO3-N (mg/L) 0.32 0.14 0.73 10

GC100 Storm TKN (mg/L) 1.38 0.73 2.60 10

GC100 Storm Inorganic -N (mg/L) 0.53 0.32 0.87 10

GC100 Storm Organic -N (mg/L) 1.23 0.64 2.37 10

GC100 Storm Total-N (mg/L) 1.81 1.04 3.15 10

GC100 Storm PO4-P (mg/L) 0.07 0.03 0.18 10

GC100 Storm Total-P (mg/L) 0.25 0.10 0.68 10

GC100 Storm COD (mg/L) 20 7 52 10

GC100 Storm TSS (mg/L) 87 15 511 10


HC060 Grab Water Temp. (ºC) 19.0 13.0 24.9 32

HC060 Grab DO (mg/L) 8.2 6.1 10.4 32

HC060 Grab pH (standard units) 7.9 7.7 8.1 32

HC060 Grab Conductivity (µmhos/cm) 391 351 435 32

HC060 Grab CHLA (µg/L) 4 2 7 16

HC060 Grab Fecal Coliform (colonies/100ml) 91 25 334 33

HC060 Grab NH3-N (mg/L) 0.06 0.03 0.12 20

HC060 Grab NO2-N (mg/L) 0.006 0.002 0.021 32


Site SampleType


Lstd Ustd n

HC060 Grab NO3-N (mg/L) 0.25 0.06 1.08 32

HC060 Grab TKN (mg/L) 0.32 0.17 0.60 19

HC060 Grab Inorganic -N (mg/L) 0.47 0.19 1.12 20

HC060 Grab Organic -N (mg/L) 0.22 0.08 0.58 19

HC060 Grab Total-N (mg/L) 0.77 0.42 1.40 19

HC060 Grab PO4-P (mg/L) 0.01 0.00 0.03 32

HC060 Grab Total-P (mg/L) 0.05 0.03 0.11 20

HC060 Grab COD (mg/L) 4 2 7 19

HC060 Grab TSS (mg/L) 5 3 11 33


HC060 Storm NH3-N (mg/L) 0.06 0.04 0.09 14

HC060 Storm NO2-N (mg/L) 0.002 0.001 0.007 14

HC060 Storm NO3-N (mg/L) 0.42 0.12 1.45 14

HC060 Storm TKN (mg/L) 0.69 0.34 1.43 14

HC060 Storm Inorganic -N (mg/L) 0.57 0.29 1.12 14

HC060 Storm Organic -N (mg/L) 0.62 0.27 1.39 14

HC060 Storm Total-N (mg/L) 1.29 0.72 2.31 14

HC060 Storm PO4-P (mg/L) 0.02 0.00 0.07 14

HC060 Storm Total-P (mg/L) 0.11 0.06 0.22 14

HC060 Storm COD (mg/L) 10 4 22 13

HC060 Storm TSS (mg/L) 34 8 151 14

Timeframe: September 1996 - March 1997

IC020 Grab Water Temp. (ºC) 12.7 5.2 20.1 12

IC020 Grab DO (mg/L) 10.3 6.6 13.9 12

IC020 Grab pH (standard units) 7.9 7.6 8.1 12

IC020 Grab Conductivity (µmhos/cm) 1178 846 1640 12

IC020 Grab Fecal Coliform (colonies/100ml) 388 63 2384 12

IC020 Grab NH3-N (mg/L) 0.06 0.03 0.15 12

IC020 Grab NO2-N (mg/L) 0.014 0.002 0.088 12

IC020 Grab NO3-N (mg/L) 0.75 0.11 5.11 12

IC020 Grab TKN (mg/L) 1.34 0.80 2.24 12

IC020 Grab Inorganic -N (mg/L) 1.07 0.27 4.26 12

IC020 Grab Organic -N (mg/L) 1.26 0.74 2.13 12

IC020 Grab Total-N (mg/L) 2.81 1.35 5.86 12

IC020 Grab PO4-P (mg/L) 0.31 0.09 1.11 12

IC020 Grab Total-P (mg/L) 0.44 0.15 1.24 12

IC020 Grab COD (mg/L) 23 12 45 10

IC020 Grab TSS (mg/L) 6 4 8 12



Site SampleType


Lstd Ustd n

IC020 Storm NH3-N (mg/L) 0.27 0.09 0.76 18

IC020 Storm NO2-N (mg/L) 0.017 0.003 0.104 18

IC020 Storm NO3-N (mg/L) 0.56 0.17 1.91 18

IC020 Storm TKN (mg/L) 3.77 2.38 5.96 18

IC020 Storm Inorganic -N (mg/L) 0.96 0.34 2.68 18

IC020 Storm Organic -N (mg/L) 3.44 2.24 5.28 18

IC020 Storm Total-N (mg/L) 4.64 2.77 7.77 18

IC020 Storm PO4-P (mg/L) 0.56 0.25 1.23 18

IC020 Storm Total-P (mg/L) 1.06 0.56 2.02 18

IC020 Storm COD (mg/L) 70 49 99 15

IC020 Storm TSS (mg/L) 163 34 771 18


MB040 Storm NH3-N (mg/L) 0.16 0.06 0.45 30

MB040 Storm NO2-N (mg/L) 0.008 0.001 0.041 30

MB040 Storm NO3-N (mg/L) 0.40 0.13 1.17 30

MB040 Storm TKN (mg/L) 2.71 1.33 5.51 30

MB040 Storm Inorganic -N (mg/L) 0.66 0.30 1.44 30

MB040 Storm Organic -N (mg/L) 2.46 1.18 5.17 30

MB040 Storm Total-N (mg/L) 3.29 1.71 6.34 30

MB040 Storm PO4-P (mg/L) 0.20 0.10 0.39 30

MB040 Storm Total-P (mg/L) 0.66 0.40 1.07 30

MB040 Storm COD (mg/L) 99 43 228 25

MB040 Storm TSS (mg/L) 260 106 641 30


MB060 Grab Water Temp. (ºC) 20.1 13.7 26.4 29

MB060 Grab DO (mg/L) 9.5 7.5 11.4 29

MB060 Grab pH (standard units) 8.0 7.8 8.2 29

MB060 Grab Conductivity (µmhos/cm) 398 350 452 29

MB060 Grab CHLA (µg/L) 4 2 7 15

MB060 Grab Fecal Coliform (colonies/100ml) 46 11 192 29

MB060 Grab NH3-N (mg/L) 0.05 0.02 0.09 18

MB060 Grab NO2-N (mg/L) 0.004 0.002 0.008 28

MB060 Grab NO3-N (mg/L) 0.32 0.05 1.91 28

MB060 Grab TKN (mg/L) 0.22 0.11 0.47 18

MB060 Grab Inorganic -N (mg/L) 0.47 0.10 2.21 18

MB060 Grab Organic -N (mg/L) 0.18 0.07 0.44 17

MB060 Grab Total-N (mg/L) 0.81 0.25 2.58 18

MB060 Grab PO4-P (mg/L) 0.01 0.00 0.03 27

MB060 Grab Total-P (mg/L) 0.06 0.03 0.12 18


Site SampleType


Lstd Ustd n

MB060 Grab COD (mg/L) 3 2 5 18

MB060 Grab TSS (mg/L) 5 3 9 29


MB060 Storm NH3-N (mg/L) 0.04 0.02 0.07 13

MB060 Storm NO2-N (mg/L) 0.003 0.001 0.013 13

MB060 Storm NO3-N (mg/L) 1.18 0.35 4.01 13

MB060 Storm TKN (mg/L) 0.80 0.37 1.72 13




MB060 Storm PO4-P (mg/L) 0.03 0.01 0.06 13


MB060 Storm COD (mg/L) 14 5 41 12

MB060 Storm TSS (mg/L) 52 9 302 13


MC060 Grab Water Temp. (ºC) 20.6 11.9 29.3 15

MC060 Grab DO (mg/L) 9.0 6.9 11.2 15

MC060 Grab pH (standard units) 8.0 7.9 8.1 15

MC060 Grab Conductivity (µmhos/cm) 413 364 468 15

MC060 Grab CHLA (µg/L) 3 2 5 12

MC060 Grab Fecal Coliform (colonies/100ml) 43 12 150 15

MC060 Grab NH3-N (mg/L) 0.04 0.02 0.09 15

MC060 Grab NO2-N (mg/L) 0.002 0.001 0.006 15

MC060 Grab NO3-N (mg/L) 0.05 0.02 0.16 15

MC060 Grab TKN (mg/L) 0.28 0.13 0.60 15

MC060 Grab Inorganic -N (mg/L) 0.12 0.06 0.23 15

MC060 Grab Organic -N (mg/L) 0.21 0.08 0.56 15

MC060 Grab Total-N (mg/L) 0.39 0.21 0.70 15

MC060 Grab PO4-P (mg/L) 0.01 0.00 0.02 15

MC060 Grab Total-P (mg/L) 0.07 0.04 0.12 15

MC060 Grab COD (mg/L) 4 2 7 15

MC060 Grab TSS (mg/L) 6 3 12 15


NC060 Grab Water Temp. (ºC) 19.8 12.1 27.4 13

NC060 Grab DO (mg/L) 8.9 6.7 11.1 13

NC060 Grab pH (standard units) 7.9 7.8 8.1 13

NC060 Grab Conductivity (µmhos/cm) 482 403 576 13

NC060 Grab CHLA (µg/L) 4 2 5 10

NC060 Grab Fecal Coliform (colonies/100ml) 66 28 158 13


Site SampleType


Lstd Ustd n

NC060 Grab NH3-N (mg/L) 0.03 0.02 0.08 13

NC060 Grab NO2-N (mg/L) 0.003 0.001 0.009 13

NC060 Grab NO3-N (mg/L) 0.26 0.14 0.48 13

NC060 Grab TKN (mg/L) 0.20 0.08 0.48 13

NC060 Grab Inorganic -N (mg/L) 0.32 0.19 0.53 13

NC060 Grab Organic -N (mg/L) 0.13 0.04 0.42 13

NC060 Grab Total-N (mg/L) 0.52 0.28 0.96 13

NC060 Grab PO4-P (mg/L) 0.01 0.00 0.03 13

NC060 Grab Total-P (mg/L) 0.06 0.03 0.11 13

NC060 Grab COD (mg/L) 3 2 5 13

NC060 Grab TSS (mg/L) 5 5 5 13


NC060 Storm NH3-N (mg/L) 0.05 0.03 0.08 14

NC060 Storm NO2-N (mg/L) 0.002 0.001 0.007 14

NC060 Storm NO3-N (mg/L) 0.27 0.15 0.48 14

NC060 Storm TKN (mg/L) 0.58 0.24 1.41 14

NC060 Storm Inorganic -N (mg/L) 0.33 0.20 0.54 14

NC060 Storm Organic -N (mg/L) 0.51 0.19 1.36 14

NC060 Storm Total-N (mg/L) 0.95 0.51 1.78 14

NC060 Storm PO4-P (mg/L) 0.02 0.01 0.04 14

NC060 Storm Total-P (mg/L) 0.14 0.06 0.29 14

NC060 Storm COD (mg/L) 10 4 26 13

NC060 Storm TSS (mg/L) 79 11 574 14


NF005 Grab Water Temp. (ºC) 11.7 5.0 18.4 12

NF005 Grab DO (mg/L) 7.7 4.3 11.2 12

NF005 Grab pH (standard units) 7.4 7.2 7.7 12

NF005 Grab Conductivity (µmhos/cm) 2749 961 7863 12

NF005 Grab Fecal Coliform (colonies/100ml) 675 113 4025 12

NF005 Grab NH3-N (mg/L) 0.17 0.03 0.84 12

NF005 Grab NO2-N (mg/L) 0.014 0.003 0.072 12

NF005 Grab NO3-N (mg/L) 0.44 0.11 1.69 12

NF005 Grab TKN (mg/L) 3.16 1.50 6.67 12

NF005 Grab Inorganic -N (mg/L) 0.74 0.17 3.14 12

NF005 Grab Organic -N (mg/L) 2.88 1.52 5.45 12

NF005 Grab Total-N (mg/L) 3.85 1.77 8.40 12

NF005 Grab PO4-P (mg/L) 1.10 0.40 3.03 12

NF005 Grab Total-P (mg/L) 1.42 0.58 3.52 12

NF005 Grab COD (mg/L) 48 29 79 10


Site SampleType


Lstd Ustd n

NF005 Grab TSS (mg/L) 10 4 27 12


NF005 Storm NH3-N (mg/L) 1.11 0.44 2.78 20

NF005 Storm NO2-N (mg/L) 0.056 0.013 0.233 20

NF005 Storm NO3-N (mg/L) 1.25 0.54 2.90 20

NF005 Storm TKN (mg/L) 7.25 4.81 10.93 20

NF005 Storm Inorganic -N (mg/L) 2.86 1.52 5.39 20

NF005 Storm Organic -N (mg/L) 5.88 4.09 8.47 20

NF005 Storm Total-N (mg/L) 9.04 6.04 13.53 20

NF005 Storm PO4-P (mg/L) 2.37 1.51 3.73 20

NF005 Storm Total-P (mg/L) 3.47 2.16 5.59 20

NF005 Storm COD (mg/L) 117 78 176 16

NF005 Storm TSS (mg/L) 174 59 515 20



NF009 Grab DO (mg/L) 8.3 4.6 11.9 13




NF009 Grab NH3-N (mg/L) 0.07 0.03 0.16 13

NF009 Grab NO2-N (mg/L) 0.008 0.003 0.028 13

NF009 Grab NO3-N (mg/L) 0.26 0.03 2.67 13

NF009 Grab TKN (mg/L) 1.28 0.78 2.09 13




NF009 Grab PO4-P (mg/L) 0.06 0.01 0.30 13


NF009 Grab COD (mg/L) 22 12 40 11

NF009 Grab TSS (mg/L) 10 4 26 13


NF009 Storm NH3-N (mg/L) 0.26 0.11 0.63 20

NF009 Storm NO2-N (mg/L) 0.014 0.003 0.066 20

NF009 Storm NO3-N (mg/L) 0.62 0.28 1.37 20

NF009 Storm TKN (mg/L) 3.61 2.29 5.71 20




NF009 Storm PO4-P (mg/L) 0.34 0.19 0.60 20


Site SampleType


Lstd Ustd n


NF009 Storm COD (mg/L) 64 46 91 16

NF009 Storm TSS (mg/L) 543 191 1542 20



NF020 Grab DO (mg/L) 7.2 3.3 11.1 12




NF020 Grab NH3-N (mg/L) 0.14 0.02 0.85 12

NF020 Grab NO2-N (mg/L) 0.009 0.002 0.046 12

NF020 Grab NO3-N (mg/L) 0.10 0.01 1.67 12

NF020 Grab TKN (mg/L) 2.71 0.99 7.42 12




NF020 Grab PO4-P (mg/L) 0.66 0.17 2.56 12


NF020 Grab COD (mg/L) 48 21 107 11

NF020 Grab TSS (mg/L) 20 7 55 12


NF020 Storm NH3-N (mg/L) 0.86 0.48 1.57 16

NF020 Storm NO2-N (mg/L) 0.050 0.018 0.140 16

NF020 Storm NO3-N (mg/L) 1.25 0.70 2.25 16

NF020 Storm TKN (mg/L) 7.07 5.58 8.96 16




NF020 Storm PO4-P (mg/L) 1.69 1.09 2.61 16


NF020 Storm COD (mg/L) 102 85 123 14

NF020 Storm TSS (mg/L) 683 193 2414 16



NF050 Grab DO (mg/L) 9.1 4.9 13.3 12



NF050 Grab CHLA (µg/L) 38 8 169 9



Site SampleType


Lstd Ustd n

NF050 Grab NH3-N (mg/L) 0.09 0.04 0.20 12

NF050 Grab NO2-N (mg/L) 0.013 0.003 0.052 12

NF050 Grab NO3-N (mg/L) 0.77 0.15 3.98 12

NF050 Grab TKN (mg/L) 1.78 0.98 3.23 12




NF050 Grab PO4-P (mg/L) 0.18 0.06 0.53 12


NF050 Grab COD (mg/L) 30 18 51 12

NF050 Grab TSS (mg/L) 10 4 23 12


NF050 Storm NH3-N (mg/L) 0.25 0.14 0.44 11

NF050 Storm NO2-N (mg/L) 0.025 0.008 0.079 11

NF050 Storm NO3-N (mg/L) 0.55 0.30 1.02 11

NF050 Storm TKN (mg/L) 2.69 1.78 4.06 11




NF050 Storm PO4-P (mg/L) 0.42 0.31 0.57 11


NF050 Storm COD (mg/L) 49 34 71 11

NF050 Storm TSS (mg/L) 175 42 722 11


SC020 Grab Water Temp. (ºC) 12.6 5.7 19.6 13

SC020 Grab DO (mg/L) 8.5 5.5 11.4 13

SC020 Grab pH (standard units) 7.8 7.4 8.1 13

SC020 Grab Conductivity (µmhos/cm) 697 632 769 13

SC020 Grab Fecal Coliform (colonies/100ml) 351 64 1915 13

SC020 Grab NH3-N (mg/L) 0.05 0.03 0.11 13

SC020 Grab NO2-N (mg/L) 0.005 0.002 0.015 13

SC020 Grab NO3-N (mg/L) 0.25 0.07 0.99 13

SC020 Grab TKN (mg/L) 0.52 0.35 0.77 13

SC020 Grab Inorganic -N (mg/L) 0.41 0.21 0.81 13

SC020 Grab Organic -N (mg/L) 0.45 0.30 0.69 13

SC020 Grab Total-N (mg/L) 0.92 0.63 1.35 13

SC020 Grab PO4-P (mg/L) 0.04 0.02 0.09 13

SC020 Grab Total-P (mg/L) 0.08 0.04 0.14 13

SC020 Grab COD (mg/L) 7 4 15 11


Site SampleType


Lstd Ustd n

SC020 Grab TSS (mg/L) 7 3 14 13


SC020 Storm NH3-N (mg/L) 0.14 0.06 0.32 20

SC020 Storm NO2-N (mg/L) 0.004 0.001 0.018 20

SC020 Storm NO3-N (mg/L) 0.32 0.18 0.57 20

SC020 Storm TKN (mg/L) 1.43 0.92 2.22 20

SC020 Storm Inorganic -N (mg/L) 0.52 0.33 0.80 20

SC020 Storm Organic -N (mg/L) 1.26 0.82 1.94 20

SC020 Storm Total-N (mg/L) 1.82 1.28 2.60 20

SC020 Storm PO4-P (mg/L) 0.14 0.08 0.24 20

SC020 Storm Total-P (mg/L) 0.29 0.15 0.56 20

SC020 Storm COD (mg/L) 29 14 62 16

SC020 Storm TSS (mg/L) 62 17 228 20


SF020 Grab Water Temp. (ºC) 10.4 4.0 16.8 12

SF020 Grab DO (mg/L) 9.6 6.7 12.5 12

SF020 Grab pH (standard units) 7.7 7.5 8.0 12

SF020 Grab Conductivity (µmhos/cm) 924 593 1440 12

SF020 Grab Fecal Coliform (colonies/100ml) 592 161 2179 12

SF020 Grab NH3-N (mg/L) 0.06 0.02 0.14 12

SF020 Grab NO2-N (mg/L) 0.003 0.001 0.008 12

SF020 Grab NO3-N (mg/L) 0.01 0.00 0.03 12

SF020 Grab TKN (mg/L) 0.53 0.38 0.73 12

SF020 Grab Inorganic -N (mg/L) 0.08 0.04 0.17 12

SF020 Grab Organic -N (mg/L) 0.45 0.32 0.63 12

SF020 Grab Total-N (mg/L) 0.55 0.40 0.76 12

SF020 Grab PO4-P (mg/L) 0.02 0.00 0.06 12

SF020 Grab Total-P (mg/L) 0.07 0.04 0.11 12

SF020 Grab COD (mg/L) 10 5 22 10

SF020 Grab TSS (mg/L) 7 4 15 12


SF020 Storm NH3-N (mg/L) 0.09 0.04 0.22 18

SF020 Storm NO2-N (mg/L) 0.003 0.001 0.012 18

SF020 Storm NO3-N (mg/L) 0.17 0.05 0.54 18

SF020 Storm TKN (mg/L) 1.45 0.81 2.60 18

SF020 Storm Inorganic -N (mg/L) 0.28 0.10 0.76 18

SF020 Storm Organic -N (mg/L) 1.34 0.76 2.38 18

SF020 Storm Total-N (mg/L) 1.69 0.91 3.15 18

SF020 Storm PO4-P (mg/L) 0.03 0.01 0.07 18


Site SampleType


Lstd Ustd n

SF020 Storm Total-P (mg/L) 0.20 0.11 0.40 18

SF020 Storm COD (mg/L) 32 15 70 15

SF020 Storm TSS (mg/L) 196 49 794 18



SF050 Grab DO (mg/L) 9.6 6.0 13.2 11




SF050 Grab NH3-N (mg/L) 0.07 0.03 0.19 11

SF050 Grab NO2-N (mg/L) 0.008 0.003 0.021 11

SF050 Grab NO3-N (mg/L) 0.19 0.04 1.01 11

SF050 Grab TKN (mg/L) 1.49 0.95 2.32 11




SF050 Grab PO4-P (mg/L) 0.15 0.05 0.48 11


SF050 Grab COD (mg/L) 21 11 39 9

SF050 Grab TSS (mg/L) 13 4 42 11


SF050 Storm NH3-N (mg/L) 0.25 0.11 0.56 14

SF050 Storm NO2-N (mg/L) 0.027 0.009 0.082 14

SF050 Storm NO3-N (mg/L) 0.68 0.34 1.38 14

SF050 Storm TKN (mg/L) 2.98 2.28 3.90 14




SF050 Storm PO4-P (mg/L) 0.71 0.41 1.23 14


SF050 Storm COD (mg/L) 48 35 66 13

SF050 Storm TSS (mg/L) 139 63 308 14



SF075 Grab DO (mg/L) 8.2 4.8 11.7 13



SF075 Grab CHLA (µg/L) 18 8 43 10



Site SampleType


Lstd Ustd n

SF075 Grab NH3-N (mg/L) 0.12 0.04 0.41 13

SF075 Grab NO2-N (mg/L) 0.011 0.003 0.040 13

SF075 Grab NO3-N (mg/L) 0.28 0.05 1.65 13

SF075 Grab TKN (mg/L) 1.29 0.54 3.07 13




SF075 Grab PO4-P (mg/L) 0.17 0.05 0.52 13


SF075 Grab COD (mg/L) 28 16 50 13

SF075 Grab TSS (mg/L) 14 7 32 13


SF075 Storm NH3-N (mg/L) 0.31 0.15 0.65 11

SF075 Storm NO2-N (mg/L) 0.026 0.007 0.097 11

SF075 Storm NO3-N (mg/L) 0.80 0.41 1.60 11

SF075 Storm TKN (mg/L) 2.90 2.37 3.53 11




SF075 Storm PO4-P (mg/L) 0.40 0.35 0.46 11


SF075 Storm COD (mg/L) 48 39 58 11

SF075 Storm TSS (mg/L) 169 87 329 11


SP020 Grab Water Temp. (ºC) 13.7 7.2 20.2 12

SP020 Grab DO (mg/L) 8.7 6.6 10.7 12

SP020 Grab pH (standard units) 7.9 7.5 8.2 12

SP020 Grab Conductivity (µmhos/cm) 524 470 584 12

SP020 Grab Fecal Coliform (colonies/100ml) 52 12 232 12

SP020 Grab NH3-N (mg/L) 0.04 0.02 0.08 12

SP020 Grab NO2-N (mg/L) 0.002 0.001 0.004 12

SP020 Grab NO3-N (mg/L) 0.01 0.00 0.03 12

SP020 Grab TKN (mg/L) 0.25 0.13 0.47 12

SP020 Grab Inorganic -N (mg/L) 0.06 0.03 0.11 12

SP020 Grab Organic -N (mg/L) 0.19 0.08 0.43 12

SP020 Grab Total-N (mg/L) 0.27 0.14 0.51 12

SP020 Grab PO4-P (mg/L) 0.02 0.01 0.04 12

SP020 Grab Total-P (mg/L) 0.06 0.04 0.07 12

SP020 Grab COD (mg/L) 4 2 10 10


Site SampleType


Lstd Ustd n

SP020 Grab TSS (mg/L) 6 3 11 12


SP020 Storm NH3-N (mg/L) 0.07 0.04 0.16 17

SP020 Storm NO2-N (mg/L) 0.002 0.001 0.006 17

SP020 Storm NO3-N (mg/L) 0.04 0.01 0.18 17

SP020 Storm TKN (mg/L) 0.60 0.33 1.10 17

SP020 Storm Inorganic -N (mg/L) 0.13 0.06 0.31 17

SP020 Storm Organic -N (mg/L) 0.51 0.26 0.98 17

SP020 Storm Total-N (mg/L) 0.66 0.35 1.27 17

SP020 Storm PO4-P (mg/L) 0.03 0.01 0.10 17

SP020 Storm Total-P (mg/L) 0.11 0.05 0.21 17

SP020 Storm COD (mg/L) 13 6 28 14

SP020 Storm TSS (mg/L) 16 4 65 17


TC020 Grab Water Temp. (ºC) 16.2 10.0 22.4 13

TC020 Grab DO (mg/L) 9.7 8.0 11.3 13

TC020 Grab pH (standard units) 7.8 7.7 7.9 13

TC020 Grab Conductivity (µmhos/cm) 507 429 599 13

TC020 Grab Fecal Coliform (colonies/100ml) 196 41 925 13

TC020 Grab NH3-N (mg/L) 0.04 0.02 0.08 13

TC020 Grab NO2-N (mg/L) 0.020 0.006 0.065 13

TC020 Grab NO3-N (mg/L) 10.14 6.72 15.31 13

TC020 Grab TKN (mg/L) 0.44 0.30 0.64 12

TC020 Grab Inorganic -N (mg/L) 10.23 6.80 15.39 13

TC020 Grab Organic -N (mg/L) 0.38 0.24 0.59 12

TC020 Grab Total-N (mg/L) 10.22 7.46 14.00 12

TC020 Grab PO4-P (mg/L) 0.01 0.00 0.03 13

TC020 Grab Total-P (mg/L) 0.06 0.04 0.10 13

TC020 Grab COD (mg/L) 4 2 6 11

TC020 Grab TSS (mg/L) 6 4 11 13


TC020 Storm NH3-N (mg/L) 0.06 0.03 0.12 16

TC020 Storm NO2-N (mg/L) 0.018 0.003 0.096 16

TC020 Storm NO3-N (mg/L) 4.94 2.52 9.71 16

TC020 Storm TKN (mg/L) 1.22 0.64 2.34 16

TC020 Storm Inorganic -N (mg/L) 5.09 2.65 9.76 16

TC020 Storm Organic -N (mg/L) 1.15 0.59 2.24 16

TC020 Storm Total-N (mg/L) 6.90 4.75 10.03 16

TC020 Storm PO4-P (mg/L) 0.02 0.01 0.09 16


Site SampleType


Lstd Ustd n

TC020 Storm Total-P (mg/L) 0.14 0.05 0.40 16

TC020 Storm COD (mg/L) 16 7 38 15

TC020 Storm TSS (mg/L) 47 7 335 16


WC020 Grab Water Temp. (ºC) 16.3 10.1 22.4 13

WC020 Grab DO (mg/L) 9.1 7.3 10.8 13

WC020 Grab pH (standard units) 7.7 7.5 7.8 13

WC020 Grab Conductivity (µmhos/cm) 520 388 698 13

WC020 Grab Fecal Coliform (colonies/100ml) 222 56 871 13

WC020 Grab NH3-N (mg/L) 0.05 0.02 0.12 13

WC020 Grab NO2-N (mg/L) 0.027 0.009 0.086 13

WC020 Grab NO3-N (mg/L) 16.14 11.70 22.28 13

WC020 Grab TKN (mg/L) 0.25 0.09 0.69 12

WC020 Grab Inorganic -N (mg/L) 16.27 11.82 22.4 13

WC020 Grab Organic -N (mg/L) 0.14 0.03 0.63 12

WC020 Grab Total-N (mg/L) 17.17 12.91 22.82 12

WC020 Grab PO4-P (mg/L) 0.02 0.01 0.04 13

WC020 Grab Total-P (mg/L) 0.06 0.04 0.12 13

WC020 Grab COD (mg/L) 4 2 6 11

WC020 Grab TSS (mg/L) 8 3 18 13


WC020 Storm NH3-N (mg/L) 0.08 0.03 0.21 13

WC020 Storm NO2-N (mg/L) 0.026 0.005 0.140 13

WC020 Storm NO3-N (mg/L) 7.41 3.44 15.96 13

WC020 Storm TKN (mg/L) 1.59 0.84 3.00 13

WC020 Storm Inorganic -N (mg/L) 7.77 3.83 15.74 13

WC020 Storm Organic -N (mg/L) 1.46 0.76 2.80 13

WC020 Storm Total-N (mg/L) 10.12 6.07 16.85 13

WC020 Storm PO4-P (mg/L) 0.04 0.01 0.15 13

WC020 Storm Total-P (mg/L) 0.26 0.09 0.74 13

WC020 Storm COD (mg/L) 20 10 38 10

WC020 Storm TSS (mg/L) 128 25 648 13



APPENDIX A.


AL040

0.1

1

10

100

1000

10000

100000

9527

4

9529

5

9531

6

9533

7

9535

8

9601

4

9603

5

9605

6

9607

7

9609

8

9611

9

9614

0

9616

1

9618

2

9620

3

9622

4

9624

5

9626

6

9628

7

9630

8

9632

9

9635

0

9700

5

9702

6

9704

7

9706

8

Julian Date (yyddd)

Ave

rgar

e D

aily

Flo

w (c

fs)



BO040

0.1

1

10

100

1000

10000

9527

4

9529

7

9532

0

9534

3

9600

1

9602

4

9604

7

9607

0

9609

3

9611

6

9613

9

9616

2

9618

5

9620

8

9623

1

9625

4

9627

7

9630

0

9632

3

9634

6

9700

3

9702

6

9704

9

9707

2

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)


BO070

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)



BO090

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)


BO100

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (yyddd)

Dai

ly A

vera

ge F

low

(cfs

)



DC060

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)



GB020

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)



GC100

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)


HC060

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)



IC020

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)


MB040

0.1

1

10

100

1000

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9527

4

9529

9

9532

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9600

9

9603

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9

9608

4

9610

9

9613

4

9615

9

9618

4

9620

9

9623

4

9625

9

9628

4

9630

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9633

4

9635

9

9701

8

9704

3

9706

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NF020

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NF035

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NF050

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SF075

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APPENDIX B.

Basic Statistics for Baseflow and Storm Event Water Qualityat Stream SitesTable B- 2. Basic statistics for water quality constituents by site for baseflow and storm event comparisons.

Grab samples represent conditions at baseflow during routine monitoring. Storm samplesrepresent volume weighted storm values averaged across storm events. Geometric means arepresented for all constituents except DO, water temperature and pH which were evaluated usingarithmetic means. Lstd equals the lower bound of the mean minus the standard deviation, whileUstd equals the upper bound of the mean plus the standard deviation. n equals the number ofgrab samples or storm events evaluated.

Site SampleType


Lstd Ustd n



AL040 Grab DO (mg/L) 7.4 3.6 11.1 19



AL040 Grab CHLA (µg/L) 26 13 55 16


AL040 Grab NH3-N (mg/L) 0.16 0.09 0.28 19

AL040 Grab NO2-N (mg/L) 0.013 0.003 0.049 18

AL040 Grab NO3-N (mg/L) 0.11 0.04 0.35 19

AL040 Grab TKN (mg/L) 1.56 1.26 1.93 19




AL040 Grab PO4-P (mg/L) 0.25 0.15 0.42 19


AL040 Grab COD (mg/L) 25 18 35 19

AL040 Grab TSS (mg/L) 12 5 25 19


AL040 Storm NH3-N (mg/L) 0.14 0.08 0.26 12

AL040 Storm NO2-N (mg/L) 0.009 0.002 0.034 12

AL040 Storm NO3-N (mg/L) 0.11 0.03 0.35 12

AL040 Storm TKN (mg/L) 1.95 1.63 2.33 12




Site SampleType


Lstd Ustd n


AL040 Storm PO4-P (mg/L) 0.19 0.07 0.51 12


AL040 Storm COD (mg/L) 34 28 42 12

AL040 Storm TSS (mg/L) 52 23 116 12



BO020 Grab DO (mg/L) 6.9 2.7 11.0 14



BO020 Grab CHLA (µg/L) 23 6 92 10


BO020 Grab NH3-N (mg/L) 0.11 0.04 0.32 14

BO020 Grab NO2-N (mg/L) 0.012 0.003 0.045 14

BO020 Grab NO3-N (mg/L) 0.41 0.07 2.28 14

BO020 Grab TKN (mg/L) 1.62 1.19 2.22 14




BO020 Grab PO4-P (mg/L) 0.16 0.04 0.68 14


BO020 Grab COD (mg/L) 21 10 43 13

BO020 Grab TSS (mg/L) 11 6 22 14





BO040 Grab DO (mg/L) 7.6 4.2 10.9 14



BO040 Grab CHLA (µg/L) 14 5 39 10


BO040 Grab NH3-N (mg/L) 0.13 0.04 0.42 14

BO040 Grab NO2-N (mg/L) 0.027 0.007 0.114 14

BO040 Grab NO3-N (mg/L) 3.38 2.44 4.68 14

BO040 Grab TKN (mg/L) 1.52 1.08 2.14 14





Site SampleType


Lstd Ustd n

BO040 Grab PO4-P (mg/L) 1.12 0.48 2.61 14


BO040 Grab COD (mg/L) 15 8 30 13

BO040 Grab TSS (mg/L) 7 4 12 14



Timeframe: April1996 - March 1997

BO040 Storm NH3-N (mg/L) 0.23 0.08 0.63 17

BO040 Storm NO2-N (mg/L) 0.026 0.007 0.089 17

BO040 Storm NO3-N (mg/L) 1.41 0.81 2.46 17

BO040 Storm TKN (mg/L) 2.42 1.73 3.39 17




BO040 Storm PO4-P (mg/L) 0.63 0.41 0.96 17


BO040 Storm COD (mg/L) 38 26 55 16

BO040 Storm TSS (mg/L) 77 16 381 17



BO060 Grab DO (mg/L) 10.0 7.5 12.5 15



BO060 Grab CHLA (µg/L) 23 7 79 11


BO060 Grab NH3-N (mg/L) 0.05 0.02 0.11 15

BO060 Grab NO2-N (mg/L) 0.006 0.002 0.021 15

BO060 Grab NO3-N (mg/L) 0.36 0.10 1.33 15

BO060 Grab TKN (mg/L) 1.09 0.79 1.51 15




BO060 Grab PO4-P (mg/L) 0.37 0.20 0.67 15


BO060 Grab COD (mg/L) 15 9 25 14

BO060 Grab TSS (mg/L) 10 5 22 15




Site SampleType


Lstd Ustd n



BO070 Grab DO (mg/L) 10.7 7.2 14.3 16



BO070 Grab CHLA (µg/L) 15 6 40 12


BO070 Grab NH3-N (mg/L) 0.04 0.02 0.10 16

BO070 Grab NO2-N (mg/L) 0.005 0.002 0.015 16

BO070 Grab NO3-N (mg/L) 0.14 0.02 1.01 16

BO070 Grab TKN (mg/L) 0.92 0.66 1.29 16




BO070 Grab PO4-P (mg/L) 0.16 0.06 0.41 16


BO070 Grab COD (mg/L) 10 4 23 15

BO070 Grab TSS (mg/L) 8 4 14 16




BO070 Storm NH3-N (mg/L) 0.14 0.06 0.33 14

BO070 Storm NO2-N (mg/L) 0.009 0.002 0.046 14

BO070 Storm NO3-N (mg/L) 0.46 0.23 0.93 14

BO070 Storm TKN (mg/L) 1.60 0.91 2.81 14




BO070 Storm PO4-P (mg/L) 0.27 0.17 0.44 14


BO070 Storm COD (mg/L) 23 10 50 13

BO070 Storm TSS (mg/L) 95 16 569 14



BO080 Grab DO (mg/L) 10.8 9.3 12.4 16



BO080 Grab CHLA (µg/L) 35 16 78 12


Site SampleType


Lstd Ustd n


BO080 Grab NH3-N (mg/L) 0.03 0.02 0.07 16

BO080 Grab NO2-N (mg/L) 0.002 0.001 0.005 16

BO080 Grab NO3-N (mg/L) 0.03 0.01 0.15 16

BO080 Grab TKN (mg/L) 0.93 0.61 1.42 16




BO080 Grab PO4-P (mg/L) 0.05 0.01 0.18 16


BO080 Grab COD (mg/L) 13 6 29 15

BO080 Grab TSS (mg/L) 18 7 50 16





BO085 Grab DO (mg/L) 9.3 7.2 11.4 16



BO085 Grab CHLA (µg/L) 20 8 54 12


BO085 Grab NH3-N (mg/L) 0.03 0.02 0.08 16

BO085 Grab NO2-N (mg/L) 0.002 0.001 0.006 16

BO085 Grab NO3-N (mg/L) 0.03 0.01 0.11 16

BO085 Grab TKN (mg/L) 0.66 0.43 1.01 16




BO085 Grab PO4-P (mg/L) 0.02 0.01 0.09 16


BO085 Grab COD (mg/L) 8 3 18 15

BO085 Grab TSS (mg/L) 12 4 36 16





BO090 Grab DO (mg/L) 9.7 7.9 11.6 16



Site SampleType


Lstd Ustd n


BO090 Grab CHLA (µg/L) 10 3 33 12


BO090 Grab NH3-N (mg/L) 0.05 0.02 0.10 16

BO090 Grab NO2-N (mg/L) 0.004 0.001 0.012 16

BO090 Grab NO3-N (mg/L) 0.19 0.05 0.75 16

BO090 Grab TKN (mg/L) 0.59 0.37 0.95 16




BO090 Grab PO4-P (mg/L) 0.01 0.00 0.06 16


BO090 Grab COD (mg/L) 6 3 13 15

BO090 Grab TSS (mg/L) 10 3 33 16




BO090 Storm NH3-N (mg/L) 0.09 0.05 0.15 15

BO090 Storm NO2-N (mg/L) 0.006 0.001 0.025 15

BO090 Storm NO3-N (mg/L) 0.27 0.12 0.63 15

BO090 Storm TKN (mg/L) 1.06 0.56 1.99 15




BO090 Storm PO4-P (mg/L) 0.05 0.02 0.13 15


BO090 Storm COD (mg/L) 15 7 35 14

BO090 Storm TSS (mg/L) 93 19 445 15



BO100 Grab DO (mg/L) 9.6 7.5 11.6 15



BO100 Grab CHLA (µg/L) 11 3 40 11


BO100 Grab NH3-N (mg/L) 0.04 0.02 0.10 15

BO100 Grab NO2-N (mg/L) 0.003 0.001 0.009 15

BO100 Grab NO3-N (mg/L) 0.20 0.08 0.48 15

BO100 Grab TKN (mg/L) 0.52 0.25 1.06 15


Site SampleType


Lstd Ustd n




BO100 Grab PO4-P (mg/L) 0.02 0.00 0.05 15


BO100 Grab COD (mg/L) 5 3 11 14

BO100 Grab TSS (mg/L) 14 4 53 15



BO100 Grab DO (mg/L) 8.8 6.7 11.0 25





BO100 Grab NH3-N (mg/L) 0.05 0.02 0.10 16

BO100 Grab NO2-N (mg/L) 0.005 0.001 0.021 23

BO100 Grab NO3-N (mg/L) 0.35 0.10 1.23 23

BO100 Grab TKN (mg/L) 0.45 0.23 0.91 16




BO100 Grab PO4-P (mg/L) 0.02 0.00 0.08 23


BO100 Grab COD (mg/L) 5 3 11 15

BO100 Grab TSS (mg/L) 12 4 36 24




BO100 Storm NH3-N (mg/L) 0.06 0.03 0.15 14

BO100 Storm NO2-N (mg/L) 0.004 0.001 0.018 14

BO100 Storm NO3-N (mg/L) 0.36 0.27 0.48 14

BO100 Storm TKN (mg/L) 1.08 0.55 2.12 14




BO100 Storm PO4-P (mg/L) 0.03 0.01 0.13 14


BO100 Storm COD (mg/L) 19 8 46 13

BO100 Storm TSS (mg/L) 124 27 563 14


Site SampleType


Lstd Ustd n



DC060 Grab DO (mg/L) 12.3 10.3 14.2 16





DC060 Grab NH3-N (mg/L) 0.04 0.02 0.09 16

DC060 Grab NO2-N (mg/L) 0.003 0.001 0.008 16

DC060 Grab NO3-N (mg/L) 0.02 0.00 0.09 16

DC060 Grab TKN (mg/L) 0.48 0.21 1.06 16




DC060 Grab PO4-P (mg/L) 0.01 0.00 0.06 16


DC060 Grab COD (mg/L) 8 4 19 16



DC060 Storm NH3-N (mg/L) 0.11 0.04 0.26 15

DC060 Storm NO2-N (mg/L) 0.006 0.001 0.036 15

DC060 Storm NO3-N (mg/L) 0.15 0.03 0.69 15

DC060 Storm TKN (mg/L) 1.40 0.67 2.92 15




DC060 Storm PO4-P (mg/L) 0.06 0.02 0.22 15


DC060 Storm COD (mg/L) 25 10 64 14

DC060 Storm TSS (mg/L) 87 15 512 15


GB020 Storm NH3-N (mg/L) 0.68 0.22 2.15 15

GB020 Storm NO2-N (mg/L) 0.034 0.007 0.167 15

GB020 Storm NO3-N (mg/L) 0.94 0.32 2.79 15

GB020 Storm TKN (mg/L) 7.75 3.89 15.45 15




GB020 Storm PO4-P (mg/L) 1.53 0.56 4.13 15


Site SampleType


Lstd Ustd n


GB020 Storm COD (mg/L) 107 64 179 12

GB020 Storm TSS (mg/L) 381 103 1408 15



GC100 Grab DO (mg/L) 7.6 5.0 10.2 14



GC100 Grab CHLA (µg/L) 12 4 36 11


GC100 Grab NH3-N (mg/L) 0.05 0.03 0.12 14

GC100 Grab NO2-N (mg/L) 0.003 0.001 0.010 14

GC100 Grab NO3-N (mg/L) 0.23 0.04 1.36 14

GC100 Grab TKN (mg/L) 0.65 0.43 0.98 14




GC100 Grab PO4-P (mg/L) 0.02 0.01 0.06 14


GC100 Grab COD (mg/L) 6 3 14 14



GC100 Storm NH3-N (mg/L) 0.14 0.06 0.28 10

GC100 Storm NO2-N (mg/L) 0.006 0.002 0.020 10

GC100 Storm NO3-N (mg/L) 0.32 0.14 0.73 10

GC100 Storm TKN (mg/L) 1.38 0.73 2.60 10




GC100 Storm PO4-P (mg/L) 0.07 0.03 0.18 10


GC100 Storm COD (mg/L) 20 7 52 10

GC100 Storm TSS (mg/L) 87 15 511 10



HC060 Grab DO (mg/L) 8.2 6.1 10.4 32





Site SampleType


Lstd Ustd n


HC060 Grab NH3-N (mg/L) 0.06 0.03 0.12 20

HC060 Grab NO2-N (mg/L) 0.006 0.002 0.021 32

HC060 Grab NO3-N (mg/L) 0.25 0.06 1.08 32

HC060 Grab TKN (mg/L) 0.32 0.17 0.60 19




HC060 Grab PO4-P (mg/L) 0.01 0.00 0.03 32



HC060 Grab TSS (mg/L) 5 3 11 33


HC060 Storm NH3-N (mg/L) 0.06 0.04 0.09 14

HC060 Storm NO2-N (mg/L) 0.002 0.001 0.007 14

HC060 Storm NO3-N (mg/L) 0.42 0.12 1.45 14

HC060 Storm TKN (mg/L) 0.69 0.34 1.43 14




HC060 Storm PO4-P (mg/L) 0.02 0.00 0.07 14


HC060 Storm COD (mg/L) 10 4 22 13

HC060 Storm TSS (mg/L) 34 8 151 14



IC020 Grab DO (mg/L) 10.3 6.6 13.9 12




IC020 Grab NH3-N (mg/L) 0.06 0.03 0.15 12

IC020 Grab NO2-N (mg/L) 0.014 0.002 0.088 12

IC020 Grab NO3-N (mg/L) 0.75 0.11 5.11 12

IC020 Grab TKN (mg/L) 1.34 0.80 2.24 12




IC020 Grab PO4-P (mg/L) 0.31 0.09 1.11 12



Site SampleType


Lstd Ustd n

IC020 Grab COD (mg/L) 23 12 45 10



IC020 Storm NH3-N (mg/L) 0.27 0.09 0.76 18

IC020 Storm NO2-N (mg/L) 0.017 0.003 0.104 18

IC020 Storm NO3-N (mg/L) 0.56 0.17 1.91 18

IC020 Storm TKN (mg/L) 3.77 2.38 5.96 18




IC020 Storm PO4-P (mg/L) 0.56 0.25 1.23 18


IC020 Storm COD (mg/L) 70 49 99 15

IC020 Storm TSS (mg/L) 163 34 771 18


MB040 Storm NH3-N (mg/L) 0.16 0.06 0.45 30

MB040 Storm NO2-N (mg/L) 0.008 0.001 0.041 30

MB040 Storm NO3-N (mg/L) 0.40 0.13 1.17 30

MB040 Storm TKN (mg/L) 2.71 1.33 5.51 30




MB040 Storm PO4-P (mg/L) 0.20 0.10 0.39 30


MB040 Storm COD (mg/L) 99 43 228 25

MB040 Storm TSS (mg/L) 260 106 641 30



MB060 Grab DO (mg/L) 9.5 7.5 11.4 29





MB060 Grab NH3-N (mg/L) 0.05 0.02 0.09 18

MB060 Grab NO2-N (mg/L) 0.004 0.002 0.008 28

MB060 Grab NO3-N (mg/L) 0.32 0.05 1.91 28

MB060 Grab TKN (mg/L) 0.22 0.11 0.47 18




Site SampleType


Lstd Ustd n


MB060 Grab PO4-P (mg/L) 0.01 0.00 0.03 27





MB060 Storm NH3-N (mg/L) 0.04 0.02 0.07 13

MB060 Storm NO2-N (mg/L) 0.003 0.001 0.013 13

MB060 Storm NO3-N (mg/L) 1.18 0.35 4.01 13

MB060 Storm TKN (mg/L) 0.80 0.37 1.72 13




MB060 Storm PO4-P (mg/L) 0.03 0.01 0.06 13


MB060 Storm COD (mg/L) 14 5 41 12

MB060 Storm TSS (mg/L) 52 9 302 13



MC060 Grab DO (mg/L) 9.0 6.9 11.2 15





MC060 Grab NH3-N (mg/L) 0.04 0.02 0.09 15

MC060 Grab NO2-N (mg/L) 0.002 0.001 0.006 15

MC060 Grab NO3-N (mg/L) 0.05 0.02 0.16 15

MC060 Grab TKN (mg/L) 0.28 0.13 0.60 15




MC060 Grab PO4-P (mg/L) 0.01 0.00 0.02 15



MC060 Grab TSS (mg/L) 6 3 12 15



NC060 Grab DO (mg/L) 8.9 6.7 11.1 13



Site SampleType


Lstd Ustd n




NC060 Grab NH3-N (mg/L) 0.03 0.02 0.08 13

NC060 Grab NO2-N (mg/L) 0.003 0.001 0.009 13

NC060 Grab NO3-N (mg/L) 0.26 0.14 0.48 13

NC060 Grab TKN (mg/L) 0.20 0.08 0.48 13




NC060 Grab PO4-P (mg/L) 0.01 0.00 0.03 13





NC060 Storm NH3-N (mg/L) 0.05 0.03 0.08 14

NC060 Storm NO2-N (mg/L) 0.002 0.001 0.007 14

NC060 Storm NO3-N (mg/L) 0.27 0.15 0.48 14

NC060 Storm TKN (mg/L) 0.58 0.24 1.41 14




NC060 Storm PO4-P (mg/L) 0.02 0.01 0.04 14


NC060 Storm COD (mg/L) 10 4 26 13

NC060 Storm TSS (mg/L) 79 11 574 14



NF005 Grab DO (mg/L) 7.7 4.3 11.2 12




NF005 Grab NH3-N (mg/L) 0.17 0.03 0.84 12

NF005 Grab NO2-N (mg/L) 0.014 0.003 0.072 12

NF005 Grab NO3-N (mg/L) 0.44 0.11 1.69 12

NF005 Grab TKN (mg/L) 3.16 1.50 6.67 12





Site SampleType


Lstd Ustd n

NF005 Grab PO4-P (mg/L) 1.10 0.40 3.03 12


NF005 Grab COD (mg/L) 48 29 79 10

NF005 Grab TSS (mg/L) 10 4 27 12


NF005 Storm NH3-N (mg/L) 1.11 0.44 2.78 20

NF005 Storm NO2-N (mg/L) 0.056 0.013 0.233 20

NF005 Storm NO3-N (mg/L) 1.25 0.54 2.90 20

NF005 Storm TKN (mg/L) 7.25 4.81 10.93 20




NF005 Storm PO4-P (mg/L) 2.37 1.51 3.73 20


NF005 Storm COD (mg/L) 117 78 176 16

NF005 Storm TSS (mg/L) 174 59 515 20



NF009 Grab DO (mg/L) 8.3 4.6 11.9 13




NF009 Grab NH3-N (mg/L) 0.07 0.03 0.16 13

NF009 Grab NO2-N (mg/L) 0.008 0.003 0.028 13

NF009 Grab NO3-N (mg/L) 0.26 0.03 2.67 13

NF009 Grab TKN (mg/L) 1.28 0.78 2.09 13




NF009 Grab PO4-P (mg/L) 0.06 0.01 0.30 13


NF009 Grab COD (mg/L) 22 12 40 11

NF009 Grab TSS (mg/L) 10 4 26 13


NF009 Storm NH3-N (mg/L) 0.26 0.11 0.63 20

NF009 Storm NO2-N (mg/L) 0.014 0.003 0.066 20

NF009 Storm NO3-N (mg/L) 0.62 0.28 1.37 20

NF009 Storm TKN (mg/L) 3.61 2.29 5.71 20



Site SampleType


Lstd Ustd n



NF009 Storm PO4-P (mg/L) 0.34 0.19 0.60 20


NF009 Storm COD (mg/L) 64 46 91 16

NF009 Storm TSS (mg/L) 543 191 1542 20



NF020 Grab DO (mg/L) 7.2 3.3 11.1 12




NF020 Grab NH3-N (mg/L) 0.14 0.02 0.85 12

NF020 Grab NO2-N (mg/L) 0.009 0.002 0.046 12

NF020 Grab NO3-N (mg/L) 0.10 0.01 1.67 12

NF020 Grab TKN (mg/L) 2.71 0.99 7.42 12




NF020 Grab PO4-P (mg/L) 0.66 0.17 2.56 12


NF020 Grab COD (mg/L) 48 21 107 11

NF020 Grab TSS (mg/L) 20 7 55 12


NF020 Storm NH3-N (mg/L) 0.86 0.48 1.57 16

NF020 Storm NO2-N (mg/L) 0.050 0.018 0.140 16

NF020 Storm NO3-N (mg/L) 1.25 0.70 2.25 16

NF020 Storm TKN (mg/L) 7.07 5.58 8.96 16




NF020 Storm PO4-P (mg/L) 1.69 1.09 2.61 16


NF020 Storm COD (mg/L) 102 85 123 14

NF020 Storm TSS (mg/L) 683 193 2414 16



NF050 Grab DO (mg/L) 9.1 4.9 13.3 12



Site SampleType


Lstd Ustd n


NF050 Grab CHLA (µg/L) 38 8 169 9


NF050 Grab NH3-N (mg/L) 0.09 0.04 0.20 12

NF050 Grab NO2-N (mg/L) 0.013 0.003 0.052 12

NF050 Grab NO3-N (mg/L) 0.77 0.15 3.98 12

NF050 Grab TKN (mg/L) 1.78 0.98 3.23 12




NF050 Grab PO4-P (mg/L) 0.18 0.06 0.53 12


NF050 Grab COD (mg/L) 30 18 51 12

NF050 Grab TSS (mg/L) 10 4 23 12


NF050 Storm NH3-N (mg/L) 0.25 0.14 0.44 11

NF050 Storm NO2-N (mg/L) 0.025 0.008 0.079 11

NF050 Storm NO3-N (mg/L) 0.55 0.30 1.02 11

NF050 Storm TKN (mg/L) 2.69 1.78 4.06 11




NF050 Storm PO4-P (mg/L) 0.42 0.31 0.57 11


NF050 Storm COD (mg/L) 49 34 71 11

NF050 Storm TSS (mg/L) 175 42 722 11



SC020 Grab DO (mg/L) 8.5 5.5 11.4 13




SC020 Grab NH3-N (mg/L) 0.05 0.03 0.11 13

SC020 Grab NO2-N (mg/L) 0.005 0.002 0.015 13

SC020 Grab NO3-N (mg/L) 0.25 0.07 0.99 13

SC020 Grab TKN (mg/L) 0.52 0.35 0.77 13





Site SampleType


Lstd Ustd n

SC020 Grab PO4-P (mg/L) 0.04 0.02 0.09 13


SC020 Grab COD (mg/L) 7 4 15 11

SC020 Grab TSS (mg/L) 7 3 14 13


SC020 Storm NH3-N (mg/L) 0.14 0.06 0.32 20

SC020 Storm NO2-N (mg/L) 0.004 0.001 0.018 20

SC020 Storm NO3-N (mg/L) 0.32 0.18 0.57 20

SC020 Storm TKN (mg/L) 1.43 0.92 2.22 20




SC020 Storm PO4-P (mg/L) 0.14 0.08 0.24 20


SC020 Storm COD (mg/L) 29 14 62 16

SC020 Storm TSS (mg/L) 62 17 228 20



SF020 Grab DO (mg/L) 9.6 6.7 12.5 12




SF020 Grab NH3-N (mg/L) 0.06 0.02 0.14 12

SF020 Grab NO2-N (mg/L) 0.003 0.001 0.008 12

SF020 Grab NO3-N (mg/L) 0.01 0.00 0.03 12

SF020 Grab TKN (mg/L) 0.53 0.38 0.73 12




SF020 Grab PO4-P (mg/L) 0.02 0.00 0.06 12


SF020 Grab COD (mg/L) 10 5 22 10

SF020 Grab TSS (mg/L) 7 4 15 12


SF020 Storm NH3-N (mg/L) 0.09 0.04 0.22 18

SF020 Storm NO2-N (mg/L) 0.003 0.001 0.012 18

SF020 Storm NO3-N (mg/L) 0.17 0.05 0.54 18

SF020 Storm TKN (mg/L) 1.45 0.81 2.60 18



Site SampleType


Lstd Ustd n



SF020 Storm PO4-P (mg/L) 0.03 0.01 0.07 18


SF020 Storm COD (mg/L) 32 15 70 15

SF020 Storm TSS (mg/L) 196 49 794 18



SF050 Grab DO (mg/L) 9.6 6.0 13.2 11




SF050 Grab NH3-N (mg/L) 0.07 0.03 0.19 11

SF050 Grab NO2-N (mg/L) 0.008 0.003 0.021 11

SF050 Grab NO3-N (mg/L) 0.19 0.04 1.01 11

SF050 Grab TKN (mg/L) 1.49 0.95 2.32 11




SF050 Grab PO4-P (mg/L) 0.15 0.05 0.48 11


SF050 Grab COD (mg/L) 21 11 39 9

SF050 Grab TSS (mg/L) 13 4 42 11


SF050 Storm NH3-N (mg/L) 0.25 0.11 0.56 14

SF050 Storm NO2-N (mg/L) 0.027 0.009 0.082 14

SF050 Storm NO3-N (mg/L) 0.68 0.34 1.38 14

SF050 Storm TKN (mg/L) 2.98 2.28 3.90 14




SF050 Storm PO4-P (mg/L) 0.71 0.41 1.23 14


SF050 Storm COD (mg/L) 48 35 66 13

SF050 Storm TSS (mg/L) 139 63 308 14



SF075 Grab DO (mg/L) 8.2 4.8 11.7 13



Site SampleType


Lstd Ustd n


SF075 Grab CHLA (µg/L) 18 8 43 10


SF075 Grab NH3-N (mg/L) 0.12 0.04 0.41 13

SF075 Grab NO2-N (mg/L) 0.011 0.003 0.040 13

SF075 Grab NO3-N (mg/L) 0.28 0.05 1.65 13

SF075 Grab TKN (mg/L) 1.29 0.54 3.07 13




SF075 Grab PO4-P (mg/L) 0.17 0.05 0.52 13


SF075 Grab COD (mg/L) 28 16 50 13

SF075 Grab TSS (mg/L) 14 7 32 13


SF075 Storm NH3-N (mg/L) 0.31 0.15 0.65 11

SF075 Storm NO2-N (mg/L) 0.026 0.007 0.097 11

SF075 Storm NO3-N (mg/L) 0.80 0.41 1.60 11

SF075 Storm TKN (mg/L) 2.90 2.37 3.53 11




SF075 Storm PO4-P (mg/L) 0.40 0.35 0.46 11


SF075 Storm COD (mg/L) 48 39 58 11

SF075 Storm TSS (mg/L) 169 87 329 11



SP020 Grab DO (mg/L) 8.7 6.6 10.7 12




SP020 Grab NH3-N (mg/L) 0.04 0.02 0.08 12

SP020 Grab NO2-N (mg/L) 0.002 0.001 0.004 12

SP020 Grab NO3-N (mg/L) 0.01 0.00 0.03 12

SP020 Grab TKN (mg/L) 0.25 0.13 0.47 12





Site SampleType


Lstd Ustd n

SP020 Grab PO4-P (mg/L) 0.02 0.01 0.04 12


SP020 Grab COD (mg/L) 4 2 10 10

SP020 Grab TSS (mg/L) 6 3 11 12


SP020 Storm NH3-N (mg/L) 0.07 0.04 0.16 17

SP020 Storm NO2-N (mg/L) 0.002 0.001 0.006 17

SP020 Storm NO3-N (mg/L) 0.04 0.01 0.18 17

SP020 Storm TKN (mg/L) 0.60 0.33 1.10 17




SP020 Storm PO4-P (mg/L) 0.03 0.01 0.10 17


SP020 Storm COD (mg/L) 13 6 28 14

SP020 Storm TSS (mg/L) 16 4 65 17



TC020 Grab DO (mg/L) 9.7 8.0 11.3 13




TC020 Grab NH3-N (mg/L) 0.04 0.02 0.08 13

TC020 Grab NO2-N (mg/L) 0.020 0.006 0.065 13

TC020 Grab NO3-N (mg/L) 10.14 6.72 15.31 13

TC020 Grab TKN (mg/L) 0.44 0.30 0.64 12




TC020 Grab PO4-P (mg/L) 0.01 0.00 0.03 13



TC020 Grab TSS (mg/L) 6 4 11 13


TC020 Storm NH3-N (mg/L) 0.06 0.03 0.12 16

TC020 Storm NO2-N (mg/L) 0.018 0.003 0.096 16

TC020 Storm NO3-N (mg/L) 4.94 2.52 9.71 16

TC020 Storm TKN (mg/L) 1.22 0.64 2.34 16



Site SampleType


Lstd Ustd n



TC020 Storm PO4-P (mg/L) 0.02 0.01 0.09 16


TC020 Storm COD (mg/L) 16 7 38 15

TC020 Storm TSS (mg/L) 47 7 335 16



WC020 Grab DO (mg/L) 9.1 7.3 10.8 13




WC020 Grab NH3-N (mg/L) 0.05 0.02 0.12 13

WC020 Grab NO2-N (mg/L) 0.027 0.009 0.086 13

WC020 Grab NO3-N (mg/L) 16.14 11.70 22.28 13

WC020 Grab TKN (mg/L) 0.25 0.09 0.69 12




WC020 Grab PO4-P (mg/L) 0.02 0.01 0.04 13



WC020 Grab TSS (mg/L) 8 3 18 13


WC020 Storm NH3-N (mg/L) 0.08 0.03 0.21 13

WC020 Storm NO2-N (mg/L) 0.026 0.005 0.140 13

WC020 Storm NO3-N (mg/L) 7.41 3.44 15.96 13

WC020 Storm TKN (mg/L) 1.59 0.84 3.00 13




WC020 Storm PO4-P (mg/L) 0.04 0.01 0.15 13


WC020 Storm COD (mg/L) 20 10 38 10

WC020 Storm TSS (mg/L) 128 25 648 13


APPENDIX C.

Basic Statistics for Municipal Wastewater Treatment PlantEffluents

Table C- 1. Basic statistics for water quality constituents by site for wastewater treatment plants for samplescollected between October 1, 1995 and March 15, 1997. Geometric means are presented for allconstituents except DO, water temperature and pH which were evaluated using arithmeticmeans. Lstd equals the lower bound of the mean minus the standard deviation, while Ustdequals the upper bound of the mean plus the standard deviation. n equals the number of grabsamples or storm events evaluated.

Site Constituent Mean orGeo. Mean

Lstd Ustd n

Stephenville

TP040 (Date of first sample: 10Oct95)

DO (mg/L) 8.4 7.4 9.4 69

Water Temp. (ºC) 19.8 14.7 24.9 69

pH (standard units) 7.7 7.5 7.9 69

Conductivity (µmhos/cm) 1163 1036 1305 69

NH3-N (mg/L) 0.1 0.03 0.28 56

NO2-N (mg/L) 0.005 0.001 0.028 69

NO3-N (mg/L) 6.31 3.44 11.57 69

TKN (mg/L) 1.25 0.7 2.23 56

Inorganic-N (mg/L) 7.51 4.87 11.59 56

Organic-N (mg/L) 1.1 0.65 1.87 55

Total-N (mg/L) 8.87 5.94 13.23 56

PO4-P (mg/L) 2.08 0.8 5.43 68

Total-P (mg/L) 2.72 1.45 5.12 57

COD (mg/L) 11 6 19 57

TSS (mg/L) 5 3 8 68

Fecal Coliform (colonies/100ml) 5 0 70 35

Hico

LB010 (Date of first sample: 08Jan96)

DO (mg/L) 5.7 3.9 7.4 60

Water Temp. (ºC) 19.1 12.8 25.4 60



Lstd Ustd n



NH3-N (mg/L) 0.08 0.02 0.24 49

NO2-N (mg/L) 0.004 0.001 0.013 61

NO3-N (mg/L) 4.43 1.03 19.02 61

TKN (mg/L) 1.07 0.62 1.86 48

Inorganic-N (mg/L) 4.19 1.01 17.42 49

Organic-N (mg/L) 0.9 0.51 1.6 48

Total-N (mg/L) 6.17 2.26 16.8 48

PO4-P (mg/L) 2.38 1.2 4.71 60

Total-P (mg/L) 3.17 2.11 4.76 49

COD (mg/L) 8 4 14 49

TSS (mg/L) 5 3 8 60


Iredell


DO (mg/L) 8.7 7.3 10.1 58

Water Temp. (ºC) 19.1 12.8 25.4 60



NH3-N (mg/L) 0.11 0.03 0.38 49

NO2-N (mg/L) 0.005 0.001 0.025 60

NO3-N (mg/L) 12.94 5.89 28.39 60

TKN (mg/L) 0.95 0.39 2.3 48

Inorganic-N (mg/L) 13.11 6.36 27.03 49

Organic-N (mg/L) 0.68 0.19 2.43 48

Total-N (mg/L) 14.83 8.77 25.07 48

PO4-P (mg/L) 2.07 1.29 3.33 58

Total-P (mg/L) 2.28 1.22 4.27 49

COD (mg/L) 7 3 18 49

TSS (mg/L) 7 3 13 59


Meridian

LB030 (Date of first sample: 18Dec95)

DO (mg/L) 7.8 6.3 9.2 59



Lstd Ustd n

Water Temp. (ºC) 18.6 12.4 24.9 60



NH3-N (mg/L) 0.12 0.03 0.5 34

NO2-N (mg/L) 0.008 0.001 0.041 57

NO3-N (mg/L) 7.25 0.84 62.37 57

TKN (mg/L) 1.39 0.68 2.83 33

Inorganic-N (mg/L) 15.4 9.31 25.5 34

Organic-N (mg/L) 1.12 0.62 2.02 33

Total-N (mg/L) 16.66 10.79 25.72 33

PO4-P (mg/L) 2.43 1.27 4.63 55

Total-P (mg/L) 2.98 1.92 4.62 34

COD (mg/L) 11 6 24 34

TSS (mg/L) 8 4 16 59


Clifton


DO (mg/L) 6.7 5.1 8.2 61

Water Temp. (ºC) 21.3 15.6 27.0 61



NH3-N (mg/L) 0.48 0.08 2.81 31

NO2-N (mg/L) 0.021 0.003 0.153 56

NO3-N (mg/L) 1.63 0.26 10.41 60

TKN (mg/L) 3.46 1.47 8.17 30

Inorganic-N (mg/L) 4.05 1.71 9.59 31

Organic-N (mg/L) 2.5 1.25 5.01 30

Total-N (mg/L) 7.14 3.73 13.65 30

PO4-P (mg/L) 1.52 0.46 5.03 58

Total-P (mg/L) 2.01 0.92 4.37 31

COD (mg/L) 29 13 63 31

TSS (mg/L) 9 3 27 56


Valley Mills




Lstd Ustd n

DO (mg/L) 6.2 4.2 8.2 60

Water Temp. (ºC) 19.2 12.8 25.7 60



NH3-N (mg/L) 0.08 0.02 0.29 31

NO2-N (mg/L) 0.006 0.002 0.021 58

NO3-N (mg/L) 4.83 0.41 57.66 60

TKN (mg/L) 1.27 0.65 2.5 30

Inorganic-N (mg/L) 14.11 9.06 21.97 31

Organic-N (mg/L) 1.13 0.62 2.06 30

Total-N (mg/L) 15.39 10.33 22.93 30

PO4-P (mg/L) 2.24 0.84 6 56

Total-P (mg/L) 2.68 1.87 3.83 31

COD (mg/L) 11 5 26 31

TSS (mg/L) 7 3 15 58


Crawford (1)

LB060a (Date of first sample: 02Jan96; Date of last sample:30Apr96- Old wastewater treatment system)

DO (mg/L) 10.8 6.9 14.7 15

Water Temp. (ºC) 14.0 8.8 19.1 17



NH3-N (mg/L) 1.37 0.17 11.29 8

NO2-N (mg/L) 0.015 0.003 0.082 17

NO3-N (mg/L) 0.63 0.11 3.58 17

TKN (mg/L) 11.9 4.35 32.55 8

Inorganic-N (mg/L) 3.91 1.67 9.17 8

Organic-N (mg/L) 9.18 3.62 23.3 8

Total-N (mg/L) 15.75 11.28 21.99 8

PO4-P (mg/L) 3.64 1.89 7 14

Total-P (mg/L) 3.62 2.08 6.29 8

COD (mg/L) 101 29 351 8

TSS (mg/L) 77 24 247 13




Lstd Ustd n

Crawford (2)

LB060b (Date of first sample: 15Jan97 - New wastewatertreatment system)

DO (mg/L) 10.8 8.7 12.9 7

Water Temp. (ºC) 12.2 7.4 17.0 7



NH3-N (mg/L) 0.11 0.04 0.27 5

NO2-N (mg/L) 0.01 0.002 0.054 7

NO3-N (mg/L) 0.2 0.04 1.03 7

TKN (mg/L) 2.63 2.09 3.32 5

Inorganic-N (mg/L) 0.48 0.18 1.27 5

Organic-N (mg/L) 2.44 1.84 3.25 5

Total-N (mg/L) 3.14 2.5 3.94 5

PO4-P (mg/L) 0.02 0.01 0.08 7

Total-P (mg/L) 0.28 0.16 0.47 5

COD (mg/L) 44 36 52 5

TSS (mg/L) 23 14 37 7


McGregor


DO (mg/L) 5.7 4.7 6.8 60

Water Temp. (ºC) 20.5 15.0 26.1 60



NH3-N (mg/L) 0.37 0.06 2.1 31

NO2-N (mg/L) 0.006 0.002 0.023 59

NO3-N (mg/L) 1.65 0.19 14 60

TKN (mg/L) 2.63 1.02 6.81 30

Inorganic-N (mg/L) 4.41 1.57 12.42 31

Organic-N (mg/L) 1.96 0.87 4.39 30

Total-N (mg/L) 7.34 3.6 14.96 30

PO4-P (mg/L) 0.69 0.18 2.64 57

Total-P (mg/L) 1.42 0.82 2.47 31

COD (mg/L) 21 9 45 31



Lstd Ustd n

TSS (mg/L) 10 4 25 59



APPENDIX D.

Average Monthly Effluent Discharge from MunicipalWastewater Treatment PlantsTable D- 1. Average monthly effluent discharge in cubic feet per second (cfs) for November 1995 through

March 1997.

Site

Stephenville Hico Iredell Meridian Clifton Valley Mills Crawford McGregorYear Month TP040 LB010 LB020 LB030 LB040 LB050 LB060† LB070

1995 Nov 1.835 0.122 0.040 0.274 0.423 0.122 0.023 0.738

1995 Dec 1.691 0.116 0.043 0.302 0.420 0.001 0.026 0.777

1996 Jan 1.902 0.105 0.040 0.298 0.395 0.100 0.025 0.825

1996 Feb 2.161 0.088 0.042 0.313 0.400 0.120 0.026 0.808

1996 Mar 2.258 0.084 0.043 0.302 0.307 0.107 0.012 0.784

1996 Apr 2.438 0.082 0.040 0.319 0.419 0.002 . 0.966

1996 May 2.089 0.057 0.042 0.307 0.427 0.002 . 0.736

1996 Jun 2.162 0.082 0.040 0.344 0.437 0.159 . 0.702

1996 Jul 2.170 0.073 0.043 0.364 0.439 0.170 . 0.684

1996 Aug 2.719 0.090 0.040 0.207 0.482 0.232 . 0.947

1996 Sep 2.604 0.081 0.042 0.477 0.484 0.222 . 1.818

1996 Oct 2.544 0.079 0.042 0.248 0.448 0.110 . 0.950

1996 Nov 2.922 0.085 0.042 0.273 0.498 0.147 . 1.215

1996 Dec 2.589 0.087 0.045 0.279 0.488 0.002 . 1.783

1997 Jan 2.451 0.091 0.039 0.301 0.496 0.172 . 1.426

1997 Feb 4.661 0.254 0.039 0.515 0.431 0.372 0.017 2.161

1997 Mar 4.687 0.285 0.039 0.380 1.006 0.299 0.040 1.796



APPENDIX E.

Acronyms and AbbreviationsAMS Agricultural Marketing ServiceANOVA analysis of varianceAPHA American Public Health AssociationBOD5 five-day biochemical oxygen demandBRA Brazos River AuthorityCAFO confined animal feeding operationCBMS Computer Based Mapping SystemCHLA chlorophyll-αCOD chemical oxygen demandCR county roadDO dissolved oxygenEPA Environmental Protection AgencyFM farm-to-marketGRASS Geographic Resources Analysis Support Systeminorg.-N inorganic nitrogenln natural logLSD least significant differenceMDL method detection limitMGD million gallons per dayNH3-N ammonia-nitrogenNO2-N nitrite-nitrogenNO3-N nitrate-nitrogenNRCS Natural Resources Conservation ServiceNWS National Weather Serviceorg.-N organic nitrogenPL-566 Public Law 566PO4-P orthophosphate-phosphorusQAPP Quality Assurance Project Planstd standard deviationTIAER Texas Institute for Applied Environmental ResearchTKN total Kjeldahl nitrogenTM thematic mapperTMDL total maximum daily loadTNRCC Texas Natural Resource Conservation Commissiontotal-N total nitrogentotal-P total phosphorusTSS total suspended solidsTSSWCB Texas State Soil and Water Conservation BoardTWC Texas Water CommissionUSDA United States Department of AgricultureUSGS United States Geological SurveyWWTP wastewater treatment plant


APPENDIX A.


AL040

0.1

1

10

100

1000

10000

100000

9527

4

9529

5

9531

6

9533

7

9535

8

9601

4

9603

5

9605

6

9607

7

9609

8

9611

9

9614

0

9616

1

9618

2

9620

3

9622

4

9624

5

9626

6

9628

7

9630

8

9632

9

9635

0

9700

5

9702

6

9704

7

9706

8

Julian Date (yyddd)

Ave

rgar

e D

aily

Flo

w (c

fs)



BO040

0.1

1

10

100

1000

10000

9527

4

9529

7

9532

0

9534

3

9600

1

9602

4

9604

7

9607

0

9609

3

9611

6

9613

9

9616

2

9618

5

9620

8

9623

1

9625

4

9627

7

9630

0

9632

3

9634

6

9700

3

9702

6

9704

9

9707

2

Julian Date (yyddd)

Ave

rage

Dai

ly F

low

(cfs

)


BO070

0.1

1

10

100

1000

10000

100000

9527

4

9529

8

9532

2

9534

6

9600

5

9602

9

9605

3

9607

7

9610

1

9612

5

9614

9

9617

3

9619

7

9622

1

9624

5

9626

9

9629

3

9631

7

9634

1

9636

5

9702

3

9704

7

9707

1

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Ave

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Dai

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(cfs

)



BO090

0.1

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9527

4

9529

8

9532

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9534

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9600

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9602

9

9605

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9607

7

9610

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9612

5

9614

9

9617

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9619

7

9622

1

9624

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9626

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9629

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9702

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BO100

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9529

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9602

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9610

1

9612

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9614

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9617

3

9619

7

9622

1

9624

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9626

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9631

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9702

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DC060

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9612

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9614

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9617

3

9619

7

9622

1

9624

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9626

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9629

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9631

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9634

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9636

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9702

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9704

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GB020

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9612

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9614

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9617

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9619

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9622

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9624

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9626

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9629

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9636

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9702

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GC100

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9617

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9619

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9622

1

9624

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9626

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9634

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9702

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HC060

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9617

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9702

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IC020

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MB040

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9603

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9608

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9613

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9615

9

9618

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9620

9

9623

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9625

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9628

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9635

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9701

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9704

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9706

8

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MB060

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9617

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9619

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9622

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9624

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9626

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9629

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NC060

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9617

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9619

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9622

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9626

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9702

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NF005

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NF009

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9617

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9622

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NF020

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9530

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9601

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9609

1

9611

7

9614

3

9616

9

9619

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9624

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9701

1

9703

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9706

3

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NF035

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NF050

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SC020

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SF020

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SF035

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SF050

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SF075

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SP020

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TC020

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WC020

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APPENDIX B.

Basic Statistics for Baseflow and Storm Event Water Qualityat Stream SitesTable B- 3. Basic statistics for water quality constituents by site for baseflow and storm event comparisons.

Grab samples represent conditions at baseflow during routine monitoring. Storm samplesrepresent volume weighted storm values averaged across storm events. Geometric means arepresented for all constituents except DO, water temperature and pH which were evaluated usingarithmetic means. Lstd equals the lower bound of the mean minus the standard deviation, whileUstd equals the upper bound of the mean plus the standard deviation. n equals the number ofgrab samples or storm events evaluated.

Site SampleType


Lstd Ustd n



AL040 Grab DO (mg/L) 7.4 3.6 11.1 19



AL040 Grab CHLA (µg/L) 26 13 55 16


AL040 Grab NH3-N (mg/L) 0.16 0.09 0.28 19

AL040 Grab NO2-N (mg/L) 0.013 0.003 0.049 18

AL040 Grab NO3-N (mg/L) 0.11 0.04 0.35 19

AL040 Grab TKN (mg/L) 1.56 1.26 1.93 19




AL040 Grab PO4-P (mg/L) 0.25 0.15 0.42 19


AL040 Grab COD (mg/L) 25 18 35 19

AL040 Grab TSS (mg/L) 12 5 25 19


AL040 Storm NH3-N (mg/L) 0.14 0.08 0.26 12

AL040 Storm NO2-N (mg/L) 0.009 0.002 0.034 12

AL040 Storm NO3-N (mg/L) 0.11 0.03 0.35 12

AL040 Storm TKN (mg/L) 1.95 1.63 2.33 12




Site SampleType


Lstd Ustd n


AL040 Storm PO4-P (mg/L) 0.19 0.07 0.51 12


AL040 Storm COD (mg/L) 34 28 42 12

AL040 Storm TSS (mg/L) 52 23 116 12



BO020 Grab DO (mg/L) 6.9 2.7 11.0 14



BO020 Grab CHLA (µg/L) 23 6 92 10


BO020 Grab NH3-N (mg/L) 0.11 0.04 0.32 14

BO020 Grab NO2-N (mg/L) 0.012 0.003 0.045 14

BO020 Grab NO3-N (mg/L) 0.41 0.07 2.28 14

BO020 Grab TKN (mg/L) 1.62 1.19 2.22 14




BO020 Grab PO4-P (mg/L) 0.16 0.04 0.68 14


BO020 Grab COD (mg/L) 21 10 43 13

BO020 Grab TSS (mg/L) 11 6 22 14





BO040 Grab DO (mg/L) 7.6 4.2 10.9 14



BO040 Grab CHLA (µg/L) 14 5 39 10


BO040 Grab NH3-N (mg/L) 0.13 0.04 0.42 14

BO040 Grab NO2-N (mg/L) 0.027 0.007 0.114 14

BO040 Grab NO3-N (mg/L) 3.38 2.44 4.68 14

BO040 Grab TKN (mg/L) 1.52 1.08 2.14 14





Site SampleType


Lstd Ustd n

BO040 Grab PO4-P (mg/L) 1.12 0.48 2.61 14


BO040 Grab COD (mg/L) 15 8 30 13

BO040 Grab TSS (mg/L) 7 4 12 14



Timeframe: April1996 - March 1997

BO040 Storm NH3-N (mg/L) 0.23 0.08 0.63 17

BO040 Storm NO2-N (mg/L) 0.026 0.007 0.089 17

BO040 Storm NO3-N (mg/L) 1.41 0.81 2.46 17

BO040 Storm TKN (mg/L) 2.42 1.73 3.39 17




BO040 Storm PO4-P (mg/L) 0.63 0.41 0.96 17


BO040 Storm COD (mg/L) 38 26 55 16

BO040 Storm TSS (mg/L) 77 16 381 17



BO060 Grab DO (mg/L) 10.0 7.5 12.5 15



BO060 Grab CHLA (µg/L) 23 7 79 11


BO060 Grab NH3-N (mg/L) 0.05 0.02 0.11 15

BO060 Grab NO2-N (mg/L) 0.006 0.002 0.021 15

BO060 Grab NO3-N (mg/L) 0.36 0.10 1.33 15

BO060 Grab TKN (mg/L) 1.09 0.79 1.51 15




BO060 Grab PO4-P (mg/L) 0.37 0.20 0.67 15


BO060 Grab COD (mg/L) 15 9 25 14

BO060 Grab TSS (mg/L) 10 5 22 15




Site SampleType


Lstd Ustd n



BO070 Grab DO (mg/L) 10.7 7.2 14.3 16



BO070 Grab CHLA (µg/L) 15 6 40 12


BO070 Grab NH3-N (mg/L) 0.04 0.02 0.10 16

BO070 Grab NO2-N (mg/L) 0.005 0.002 0.015 16

BO070 Grab NO3-N (mg/L) 0.14 0.02 1.01 16

BO070 Grab TKN (mg/L) 0.92 0.66 1.29 16




BO070 Grab PO4-P (mg/L) 0.16 0.06 0.41 16


BO070 Grab COD (mg/L) 10 4 23 15

BO070 Grab TSS (mg/L) 8 4 14 16




BO070 Storm NH3-N (mg/L) 0.14 0.06 0.33 14

BO070 Storm NO2-N (mg/L) 0.009 0.002 0.046 14

BO070 Storm NO3-N (mg/L) 0.46 0.23 0.93 14

BO070 Storm TKN (mg/L) 1.60 0.91 2.81 14




BO070 Storm PO4-P (mg/L) 0.27 0.17 0.44 14


BO070 Storm COD (mg/L) 23 10 50 13

BO070 Storm TSS (mg/L) 95 16 569 14



BO080 Grab DO (mg/L) 10.8 9.3 12.4 16



BO080 Grab CHLA (µg/L) 35 16 78 12


Site SampleType


Lstd Ustd n


BO080 Grab NH3-N (mg/L) 0.03 0.02 0.07 16

BO080 Grab NO2-N (mg/L) 0.002 0.001 0.005 16

BO080 Grab NO3-N (mg/L) 0.03 0.01 0.15 16

BO080 Grab TKN (mg/L) 0.93 0.61 1.42 16




BO080 Grab PO4-P (mg/L) 0.05 0.01 0.18 16


BO080 Grab COD (mg/L) 13 6 29 15

BO080 Grab TSS (mg/L) 18 7 50 16





BO085 Grab DO (mg/L) 9.3 7.2 11.4 16



BO085 Grab CHLA (µg/L) 20 8 54 12


BO085 Grab NH3-N (mg/L) 0.03 0.02 0.08 16

BO085 Grab NO2-N (mg/L) 0.002 0.001 0.006 16

BO085 Grab NO3-N (mg/L) 0.03 0.01 0.11 16

BO085 Grab TKN (mg/L) 0.66 0.43 1.01 16




BO085 Grab PO4-P (mg/L) 0.02 0.01 0.09 16


BO085 Grab COD (mg/L) 8 3 18 15

BO085 Grab TSS (mg/L) 12 4 36 16





BO090 Grab DO (mg/L) 9.7 7.9 11.6 16



Site SampleType


Lstd Ustd n


BO090 Grab CHLA (µg/L) 10 3 33 12


BO090 Grab NH3-N (mg/L) 0.05 0.02 0.10 16

BO090 Grab NO2-N (mg/L) 0.004 0.001 0.012 16

BO090 Grab NO3-N (mg/L) 0.19 0.05 0.75 16

BO090 Grab TKN (mg/L) 0.59 0.37 0.95 16




BO090 Grab PO4-P (mg/L) 0.01 0.00 0.06 16


BO090 Grab COD (mg/L) 6 3 13 15

BO090 Grab TSS (mg/L) 10 3 33 16




BO090 Storm NH3-N (mg/L) 0.09 0.05 0.15 15

BO090 Storm NO2-N (mg/L) 0.006 0.001 0.025 15

BO090 Storm NO3-N (mg/L) 0.27 0.12 0.63 15

BO090 Storm TKN (mg/L) 1.06 0.56 1.99 15




BO090 Storm PO4-P (mg/L) 0.05 0.02 0.13 15


BO090 Storm COD (mg/L) 15 7 35 14

BO090 Storm TSS (mg/L) 93 19 445 15



BO100 Grab DO (mg/L) 9.6 7.5 11.6 15



BO100 Grab CHLA (µg/L) 11 3 40 11


BO100 Grab NH3-N (mg/L) 0.04 0.02 0.10 15

BO100 Grab NO2-N (mg/L) 0.003 0.001 0.009 15

BO100 Grab NO3-N (mg/L) 0.20 0.08 0.48 15

BO100 Grab TKN (mg/L) 0.52 0.25 1.06 15


Site SampleType


Lstd Ustd n




BO100 Grab PO4-P (mg/L) 0.02 0.00 0.05 15


BO100 Grab COD (mg/L) 5 3 11 14

BO100 Grab TSS (mg/L) 14 4 53 15



BO100 Grab DO (mg/L) 8.8 6.7 11.0 25





BO100 Grab NH3-N (mg/L) 0.05 0.02 0.10 16

BO100 Grab NO2-N (mg/L) 0.005 0.001 0.021 23

BO100 Grab NO3-N (mg/L) 0.35 0.10 1.23 23

BO100 Grab TKN (mg/L) 0.45 0.23 0.91 16




BO100 Grab PO4-P (mg/L) 0.02 0.00 0.08 23


BO100 Grab COD (mg/L) 5 3 11 15

BO100 Grab TSS (mg/L) 12 4 36 24




BO100 Storm NH3-N (mg/L) 0.06 0.03 0.15 14

BO100 Storm NO2-N (mg/L) 0.004 0.001 0.018 14

BO100 Storm NO3-N (mg/L) 0.36 0.27 0.48 14

BO100 Storm TKN (mg/L) 1.08 0.55 2.12 14




BO100 Storm PO4-P (mg/L) 0.03 0.01 0.13 14


BO100 Storm COD (mg/L) 19 8 46 13

BO100 Storm TSS (mg/L) 124 27 563 14


Site SampleType


Lstd Ustd n



DC060 Grab DO (mg/L) 12.3 10.3 14.2 16





DC060 Grab NH3-N (mg/L) 0.04 0.02 0.09 16

DC060 Grab NO2-N (mg/L) 0.003 0.001 0.008 16

DC060 Grab NO3-N (mg/L) 0.02 0.00 0.09 16

DC060 Grab TKN (mg/L) 0.48 0.21 1.06 16




DC060 Grab PO4-P (mg/L) 0.01 0.00 0.06 16


DC060 Grab COD (mg/L) 8 4 19 16



DC060 Storm NH3-N (mg/L) 0.11 0.04 0.26 15

DC060 Storm NO2-N (mg/L) 0.006 0.001 0.036 15

DC060 Storm NO3-N (mg/L) 0.15 0.03 0.69 15

DC060 Storm TKN (mg/L) 1.40 0.67 2.92 15




DC060 Storm PO4-P (mg/L) 0.06 0.02 0.22 15


DC060 Storm COD (mg/L) 25 10 64 14

DC060 Storm TSS (mg/L) 87 15 512 15


GB020 Storm NH3-N (mg/L) 0.68 0.22 2.15 15

GB020 Storm NO2-N (mg/L) 0.034 0.007 0.167 15

GB020 Storm NO3-N (mg/L) 0.94 0.32 2.79 15

GB020 Storm TKN (mg/L) 7.75 3.89 15.45 15




GB020 Storm PO4-P (mg/L) 1.53 0.56 4.13 15


Site SampleType


Lstd Ustd n


GB020 Storm COD (mg/L) 107 64 179 12

GB020 Storm TSS (mg/L) 381 103 1408 15



GC100 Grab DO (mg/L) 7.6 5.0 10.2 14



GC100 Grab CHLA (µg/L) 12 4 36 11


GC100 Grab NH3-N (mg/L) 0.05 0.03 0.12 14

GC100 Grab NO2-N (mg/L) 0.003 0.001 0.010 14

GC100 Grab NO3-N (mg/L) 0.23 0.04 1.36 14

GC100 Grab TKN (mg/L) 0.65 0.43 0.98 14




GC100 Grab PO4-P (mg/L) 0.02 0.01 0.06 14


GC100 Grab COD (mg/L) 6 3 14 14



GC100 Storm NH3-N (mg/L) 0.14 0.06 0.28 10

GC100 Storm NO2-N (mg/L) 0.006 0.002 0.020 10

GC100 Storm NO3-N (mg/L) 0.32 0.14 0.73 10

GC100 Storm TKN (mg/L) 1.38 0.73 2.60 10




GC100 Storm PO4-P (mg/L) 0.07 0.03 0.18 10


GC100 Storm COD (mg/L) 20 7 52 10

GC100 Storm TSS (mg/L) 87 15 511 10



HC060 Grab DO (mg/L) 8.2 6.1 10.4 32





Site SampleType


Lstd Ustd n


HC060 Grab NH3-N (mg/L) 0.06 0.03 0.12 20

HC060 Grab NO2-N (mg/L) 0.006 0.002 0.021 32

HC060 Grab NO3-N (mg/L) 0.25 0.06 1.08 32

HC060 Grab TKN (mg/L) 0.32 0.17 0.60 19




HC060 Grab PO4-P (mg/L) 0.01 0.00 0.03 32



HC060 Grab TSS (mg/L) 5 3 11 33


HC060 Storm NH3-N (mg/L) 0.06 0.04 0.09 14

HC060 Storm NO2-N (mg/L) 0.002 0.001 0.007 14

HC060 Storm NO3-N (mg/L) 0.42 0.12 1.45 14

HC060 Storm TKN (mg/L) 0.69 0.34 1.43 14




HC060 Storm PO4-P (mg/L) 0.02 0.00 0.07 14


HC060 Storm COD (mg/L) 10 4 22 13

HC060 Storm TSS (mg/L) 34 8 151 14



IC020 Grab DO (mg/L) 10.3 6.6 13.9 12




IC020 Grab NH3-N (mg/L) 0.06 0.03 0.15 12

IC020 Grab NO2-N (mg/L) 0.014 0.002 0.088 12

IC020 Grab NO3-N (mg/L) 0.75 0.11 5.11 12

IC020 Grab TKN (mg/L) 1.34 0.80 2.24 12




IC020 Grab PO4-P (mg/L) 0.31 0.09 1.11 12



Site SampleType


Lstd Ustd n

IC020 Grab COD (mg/L) 23 12 45 10



IC020 Storm NH3-N (mg/L) 0.27 0.09 0.76 18

IC020 Storm NO2-N (mg/L) 0.017 0.003 0.104 18

IC020 Storm NO3-N (mg/L) 0.56 0.17 1.91 18

IC020 Storm TKN (mg/L) 3.77 2.38 5.96 18




IC020 Storm PO4-P (mg/L) 0.56 0.25 1.23 18


IC020 Storm COD (mg/L) 70 49 99 15

IC020 Storm TSS (mg/L) 163 34 771 18


MB040 Storm NH3-N (mg/L) 0.16 0.06 0.45 30

MB040 Storm NO2-N (mg/L) 0.008 0.001 0.041 30

MB040 Storm NO3-N (mg/L) 0.40 0.13 1.17 30

MB040 Storm TKN (mg/L) 2.71 1.33 5.51 30




MB040 Storm PO4-P (mg/L) 0.20 0.10 0.39 30


MB040 Storm COD (mg/L) 99 43 228 25

MB040 Storm TSS (mg/L) 260 106 641 30



MB060 Grab DO (mg/L) 9.5 7.5 11.4 29





MB060 Grab NH3-N (mg/L) 0.05 0.02 0.09 18

MB060 Grab NO2-N (mg/L) 0.004 0.002 0.008 28

MB060 Grab NO3-N (mg/L) 0.32 0.05 1.91 28

MB060 Grab TKN (mg/L) 0.22 0.11 0.47 18




Site SampleType


Lstd Ustd n


MB060 Grab PO4-P (mg/L) 0.01 0.00 0.03 27





MB060 Storm NH3-N (mg/L) 0.04 0.02 0.07 13

MB060 Storm NO2-N (mg/L) 0.003 0.001 0.013 13

MB060 Storm NO3-N (mg/L) 1.18 0.35 4.01 13

MB060 Storm TKN (mg/L) 0.80 0.37 1.72 13




MB060 Storm PO4-P (mg/L) 0.03 0.01 0.06 13


MB060 Storm COD (mg/L) 14 5 41 12

MB060 Storm TSS (mg/L) 52 9 302 13



MC060 Grab DO (mg/L) 9.0 6.9 11.2 15





MC060 Grab NH3-N (mg/L) 0.04 0.02 0.09 15

MC060 Grab NO2-N (mg/L) 0.002 0.001 0.006 15

MC060 Grab NO3-N (mg/L) 0.05 0.02 0.16 15

MC060 Grab TKN (mg/L) 0.28 0.13 0.60 15




MC060 Grab PO4-P (mg/L) 0.01 0.00 0.02 15



MC060 Grab TSS (mg/L) 6 3 12 15



NC060 Grab DO (mg/L) 8.9 6.7 11.1 13



Site SampleType


Lstd Ustd n




NC060 Grab NH3-N (mg/L) 0.03 0.02 0.08 13

NC060 Grab NO2-N (mg/L) 0.003 0.001 0.009 13

NC060 Grab NO3-N (mg/L) 0.26 0.14 0.48 13

NC060 Grab TKN (mg/L) 0.20 0.08 0.48 13




NC060 Grab PO4-P (mg/L) 0.01 0.00 0.03 13





NC060 Storm NH3-N (mg/L) 0.05 0.03 0.08 14

NC060 Storm NO2-N (mg/L) 0.002 0.001 0.007 14

NC060 Storm NO3-N (mg/L) 0.27 0.15 0.48 14

NC060 Storm TKN (mg/L) 0.58 0.24 1.41 14




NC060 Storm PO4-P (mg/L) 0.02 0.01 0.04 14


NC060 Storm COD (mg/L) 10 4 26 13

NC060 Storm TSS (mg/L) 79 11 574 14



NF005 Grab DO (mg/L) 7.7 4.3 11.2 12




NF005 Grab NH3-N (mg/L) 0.17 0.03 0.84 12

NF005 Grab NO2-N (mg/L) 0.014 0.003 0.072 12

NF005 Grab NO3-N (mg/L) 0.44 0.11 1.69 12

NF005 Grab TKN (mg/L) 3.16 1.50 6.67 12





Site SampleType


Lstd Ustd n

NF005 Grab PO4-P (mg/L) 1.10 0.40 3.03 12


NF005 Grab COD (mg/L) 48 29 79 10

NF005 Grab TSS (mg/L) 10 4 27 12


NF005 Storm NH3-N (mg/L) 1.11 0.44 2.78 20

NF005 Storm NO2-N (mg/L) 0.056 0.013 0.233 20

NF005 Storm NO3-N (mg/L) 1.25 0.54 2.90 20

NF005 Storm TKN (mg/L) 7.25 4.81 10.93 20




NF005 Storm PO4-P (mg/L) 2.37 1.51 3.73 20


NF005 Storm COD (mg/L) 117 78 176 16

NF005 Storm TSS (mg/L) 174 59 515 20



NF009 Grab DO (mg/L) 8.3 4.6 11.9 13




NF009 Grab NH3-N (mg/L) 0.07 0.03 0.16 13

NF009 Grab NO2-N (mg/L) 0.008 0.003 0.028 13

NF009 Grab NO3-N (mg/L) 0.26 0.03 2.67 13

NF009 Grab TKN (mg/L) 1.28 0.78 2.09 13




NF009 Grab PO4-P (mg/L) 0.06 0.01 0.30 13


NF009 Grab COD (mg/L) 22 12 40 11

NF009 Grab TSS (mg/L) 10 4 26 13


NF009 Storm NH3-N (mg/L) 0.26 0.11 0.63 20

NF009 Storm NO2-N (mg/L) 0.014 0.003 0.066 20

NF009 Storm NO3-N (mg/L) 0.62 0.28 1.37 20

NF009 Storm TKN (mg/L) 3.61 2.29 5.71 20



Site SampleType


Lstd Ustd n



NF009 Storm PO4-P (mg/L) 0.34 0.19 0.60 20


NF009 Storm COD (mg/L) 64 46 91 16

NF009 Storm TSS (mg/L) 543 191 1542 20



NF020 Grab DO (mg/L) 7.2 3.3 11.1 12




NF020 Grab NH3-N (mg/L) 0.14 0.02 0.85 12

NF020 Grab NO2-N (mg/L) 0.009 0.002 0.046 12

NF020 Grab NO3-N (mg/L) 0.10 0.01 1.67 12

NF020 Grab TKN (mg/L) 2.71 0.99 7.42 12




NF020 Grab PO4-P (mg/L) 0.66 0.17 2.56 12


NF020 Grab COD (mg/L) 48 21 107 11

NF020 Grab TSS (mg/L) 20 7 55 12


NF020 Storm NH3-N (mg/L) 0.86 0.48 1.57 16

NF020 Storm NO2-N (mg/L) 0.050 0.018 0.140 16

NF020 Storm NO3-N (mg/L) 1.25 0.70 2.25 16

NF020 Storm TKN (mg/L) 7.07 5.58 8.96 16




NF020 Storm PO4-P (mg/L) 1.69 1.09 2.61 16


NF020 Storm COD (mg/L) 102 85 123 14

NF020 Storm TSS (mg/L) 683 193 2414 16



NF050 Grab DO (mg/L) 9.1 4.9 13.3 12



Site SampleType


Lstd Ustd n


NF050 Grab CHLA (µg/L) 38 8 169 9


NF050 Grab NH3-N (mg/L) 0.09 0.04 0.20 12

NF050 Grab NO2-N (mg/L) 0.013 0.003 0.052 12

NF050 Grab NO3-N (mg/L) 0.77 0.15 3.98 12

NF050 Grab TKN (mg/L) 1.78 0.98 3.23 12




NF050 Grab PO4-P (mg/L) 0.18 0.06 0.53 12


NF050 Grab COD (mg/L) 30 18 51 12

NF050 Grab TSS (mg/L) 10 4 23 12


NF050 Storm NH3-N (mg/L) 0.25 0.14 0.44 11

NF050 Storm NO2-N (mg/L) 0.025 0.008 0.079 11

NF050 Storm NO3-N (mg/L) 0.55 0.30 1.02 11

NF050 Storm TKN (mg/L) 2.69 1.78 4.06 11




NF050 Storm PO4-P (mg/L) 0.42 0.31 0.57 11


NF050 Storm COD (mg/L) 49 34 71 11

NF050 Storm TSS (mg/L) 175 42 722 11



SC020 Grab DO (mg/L) 8.5 5.5 11.4 13




SC020 Grab NH3-N (mg/L) 0.05 0.03 0.11 13

SC020 Grab NO2-N (mg/L) 0.005 0.002 0.015 13

SC020 Grab NO3-N (mg/L) 0.25 0.07 0.99 13

SC020 Grab TKN (mg/L) 0.52 0.35 0.77 13





Site SampleType


Lstd Ustd n

SC020 Grab PO4-P (mg/L) 0.04 0.02 0.09 13


SC020 Grab COD (mg/L) 7 4 15 11

SC020 Grab TSS (mg/L) 7 3 14 13


SC020 Storm NH3-N (mg/L) 0.14 0.06 0.32 20

SC020 Storm NO2-N (mg/L) 0.004 0.001 0.018 20

SC020 Storm NO3-N (mg/L) 0.32 0.18 0.57 20

SC020 Storm TKN (mg/L) 1.43 0.92 2.22 20




SC020 Storm PO4-P (mg/L) 0.14 0.08 0.24 20


SC020 Storm COD (mg/L) 29 14 62 16

SC020 Storm TSS (mg/L) 62 17 228 20



SF020 Grab DO (mg/L) 9.6 6.7 12.5 12




SF020 Grab NH3-N (mg/L) 0.06 0.02 0.14 12

SF020 Grab NO2-N (mg/L) 0.003 0.001 0.008 12

SF020 Grab NO3-N (mg/L) 0.01 0.00 0.03 12

SF020 Grab TKN (mg/L) 0.53 0.38 0.73 12




SF020 Grab PO4-P (mg/L) 0.02 0.00 0.06 12


SF020 Grab COD (mg/L) 10 5 22 10

SF020 Grab TSS (mg/L) 7 4 15 12


SF020 Storm NH3-N (mg/L) 0.09 0.04 0.22 18

SF020 Storm NO2-N (mg/L) 0.003 0.001 0.012 18

SF020 Storm NO3-N (mg/L) 0.17 0.05 0.54 18

SF020 Storm TKN (mg/L) 1.45 0.81 2.60 18



Site SampleType


Lstd Ustd n



SF020 Storm PO4-P (mg/L) 0.03 0.01 0.07 18


SF020 Storm COD (mg/L) 32 15 70 15

SF020 Storm TSS (mg/L) 196 49 794 18



SF050 Grab DO (mg/L) 9.6 6.0 13.2 11




SF050 Grab NH3-N (mg/L) 0.07 0.03 0.19 11

SF050 Grab NO2-N (mg/L) 0.008 0.003 0.021 11

SF050 Grab NO3-N (mg/L) 0.19 0.04 1.01 11

SF050 Grab TKN (mg/L) 1.49 0.95 2.32 11




SF050 Grab PO4-P (mg/L) 0.15 0.05 0.48 11


SF050 Grab COD (mg/L) 21 11 39 9

SF050 Grab TSS (mg/L) 13 4 42 11


SF050 Storm NH3-N (mg/L) 0.25 0.11 0.56 14

SF050 Storm NO2-N (mg/L) 0.027 0.009 0.082 14

SF050 Storm NO3-N (mg/L) 0.68 0.34 1.38 14

SF050 Storm TKN (mg/L) 2.98 2.28 3.90 14




SF050 Storm PO4-P (mg/L) 0.71 0.41 1.23 14


SF050 Storm COD (mg/L) 48 35 66 13

SF050 Storm TSS (mg/L) 139 63 308 14



SF075 Grab DO (mg/L) 8.2 4.8 11.7 13



Site SampleType


Lstd Ustd n


SF075 Grab CHLA (µg/L) 18 8 43 10


SF075 Grab NH3-N (mg/L) 0.12 0.04 0.41 13

SF075 Grab NO2-N (mg/L) 0.011 0.003 0.040 13

SF075 Grab NO3-N (mg/L) 0.28 0.05 1.65 13

SF075 Grab TKN (mg/L) 1.29 0.54 3.07 13




SF075 Grab PO4-P (mg/L) 0.17 0.05 0.52 13


SF075 Grab COD (mg/L) 28 16 50 13

SF075 Grab TSS (mg/L) 14 7 32 13


SF075 Storm NH3-N (mg/L) 0.31 0.15 0.65 11

SF075 Storm NO2-N (mg/L) 0.026 0.007 0.097 11

SF075 Storm NO3-N (mg/L) 0.80 0.41 1.60 11

SF075 Storm TKN (mg/L) 2.90 2.37 3.53 11




SF075 Storm PO4-P (mg/L) 0.40 0.35 0.46 11


SF075 Storm COD (mg/L) 48 39 58 11

SF075 Storm TSS (mg/L) 169 87 329 11



SP020 Grab DO (mg/L) 8.7 6.6 10.7 12




SP020 Grab NH3-N (mg/L) 0.04 0.02 0.08 12

SP020 Grab NO2-N (mg/L) 0.002 0.001 0.004 12

SP020 Grab NO3-N (mg/L) 0.01 0.00 0.03 12

SP020 Grab TKN (mg/L) 0.25 0.13 0.47 12





Site SampleType


Lstd Ustd n

SP020 Grab PO4-P (mg/L) 0.02 0.01 0.04 12


SP020 Grab COD (mg/L) 4 2 10 10

SP020 Grab TSS (mg/L) 6 3 11 12


SP020 Storm NH3-N (mg/L) 0.07 0.04 0.16 17

SP020 Storm NO2-N (mg/L) 0.002 0.001 0.006 17

SP020 Storm NO3-N (mg/L) 0.04 0.01 0.18 17

SP020 Storm TKN (mg/L) 0.60 0.33 1.10 17




SP020 Storm PO4-P (mg/L) 0.03 0.01 0.10 17


SP020 Storm COD (mg/L) 13 6 28 14

SP020 Storm TSS (mg/L) 16 4 65 17



TC020 Grab DO (mg/L) 9.7 8.0 11.3 13




TC020 Grab NH3-N (mg/L) 0.04 0.02 0.08 13

TC020 Grab NO2-N (mg/L) 0.020 0.006 0.065 13

TC020 Grab NO3-N (mg/L) 10.14 6.72 15.31 13

TC020 Grab TKN (mg/L) 0.44 0.30 0.64 12




TC020 Grab PO4-P (mg/L) 0.01 0.00 0.03 13



TC020 Grab TSS (mg/L) 6 4 11 13


TC020 Storm NH3-N (mg/L) 0.06 0.03 0.12 16

TC020 Storm NO2-N (mg/L) 0.018 0.003 0.096 16

TC020 Storm NO3-N (mg/L) 4.94 2.52 9.71 16

TC020 Storm TKN (mg/L) 1.22 0.64 2.34 16



Site SampleType


Lstd Ustd n



TC020 Storm PO4-P (mg/L) 0.02 0.01 0.09 16


TC020 Storm COD (mg/L) 16 7 38 15

TC020 Storm TSS (mg/L) 47 7 335 16



WC020 Grab DO (mg/L) 9.1 7.3 10.8 13




WC020 Grab NH3-N (mg/L) 0.05 0.02 0.12 13

WC020 Grab NO2-N (mg/L) 0.027 0.009 0.086 13

WC020 Grab NO3-N (mg/L) 16.14 11.70 22.28 13

WC020 Grab TKN (mg/L) 0.25 0.09 0.69 12




WC020 Grab PO4-P (mg/L) 0.02 0.01 0.04 13



WC020 Grab TSS (mg/L) 8 3 18 13


WC020 Storm NH3-N (mg/L) 0.08 0.03 0.21 13

WC020 Storm NO2-N (mg/L) 0.026 0.005 0.140 13

WC020 Storm NO3-N (mg/L) 7.41 3.44 15.96 13

WC020 Storm TKN (mg/L) 1.59 0.84 3.00 13




WC020 Storm PO4-P (mg/L) 0.04 0.01 0.15 13


WC020 Storm COD (mg/L) 20 10 38 10

WC020 Storm TSS (mg/L) 128 25 648 13


APPENDIX C.

Basic Statistics for Municipal Wastewater Treatment PlantEffluents

Table C- 2. Basic statistics for water quality constituents by site for wastewater treatment plants for samplescollected between October 1, 1995 and March 15, 1997. Geometric means are presented for allconstituents except DO, water temperature and pH which were evaluated using arithmeticmeans. Lstd equals the lower bound of the mean minus the standard deviation, while Ustdequals the upper bound of the mean plus the standard deviation. n equals the number of grabsamples or storm events evaluated.


Lstd Ustd n

Stephenville

TP040 (Date of first sample: 10Oct95)

DO (mg/L) 8.4 7.4 9.4 69

Water Temp. (ºC) 19.8 14.7 24.9 69



NH3-N (mg/L) 0.1 0.03 0.28 56

NO2-N (mg/L) 0.005 0.001 0.028 69

NO3-N (mg/L) 6.31 3.44 11.57 69

TKN (mg/L) 1.25 0.7 2.23 56

Inorganic-N (mg/L) 7.51 4.87 11.59 56

Organic-N (mg/L) 1.1 0.65 1.87 55

Total-N (mg/L) 8.87 5.94 13.23 56

PO4-P (mg/L) 2.08 0.8 5.43 68

Total-P (mg/L) 2.72 1.45 5.12 57

COD (mg/L) 11 6 19 57

TSS (mg/L) 5 3 8 68


Hico


DO (mg/L) 5.7 3.9 7.4 60

Water Temp. (ºC) 19.1 12.8 25.4 60



Lstd Ustd n



NH3-N (mg/L) 0.08 0.02 0.24 49

NO2-N (mg/L) 0.004 0.001 0.013 61

NO3-N (mg/L) 4.43 1.03 19.02 61

TKN (mg/L) 1.07 0.62 1.86 48

Inorganic-N (mg/L) 4.19 1.01 17.42 49

Organic-N (mg/L) 0.9 0.51 1.6 48

Total-N (mg/L) 6.17 2.26 16.8 48

PO4-P (mg/L) 2.38 1.2 4.71 60

Total-P (mg/L) 3.17 2.11 4.76 49

COD (mg/L) 8 4 14 49

TSS (mg/L) 5 3 8 60


Iredell


DO (mg/L) 8.7 7.3 10.1 58

Water Temp. (ºC) 19.1 12.8 25.4 60



NH3-N (mg/L) 0.11 0.03 0.38 49

NO2-N (mg/L) 0.005 0.001 0.025 60

NO3-N (mg/L) 12.94 5.89 28.39 60

TKN (mg/L) 0.95 0.39 2.3 48

Inorganic-N (mg/L) 13.11 6.36 27.03 49

Organic-N (mg/L) 0.68 0.19 2.43 48

Total-N (mg/L) 14.83 8.77 25.07 48

PO4-P (mg/L) 2.07 1.29 3.33 58

Total-P (mg/L) 2.28 1.22 4.27 49

COD (mg/L) 7 3 18 49

TSS (mg/L) 7 3 13 59


Meridian


DO (mg/L) 7.8 6.3 9.2 59



Lstd Ustd n

Water Temp. (ºC) 18.6 12.4 24.9 60



NH3-N (mg/L) 0.12 0.03 0.5 34

NO2-N (mg/L) 0.008 0.001 0.041 57

NO3-N (mg/L) 7.25 0.84 62.37 57

TKN (mg/L) 1.39 0.68 2.83 33

Inorganic-N (mg/L) 15.4 9.31 25.5 34

Organic-N (mg/L) 1.12 0.62 2.02 33

Total-N (mg/L) 16.66 10.79 25.72 33

PO4-P (mg/L) 2.43 1.27 4.63 55

Total-P (mg/L) 2.98 1.92 4.62 34

COD (mg/L) 11 6 24 34

TSS (mg/L) 8 4 16 59


Clifton


DO (mg/L) 6.7 5.1 8.2 61

Water Temp. (ºC) 21.3 15.6 27.0 61



NH3-N (mg/L) 0.48 0.08 2.81 31

NO2-N (mg/L) 0.021 0.003 0.153 56

NO3-N (mg/L) 1.63 0.26 10.41 60

TKN (mg/L) 3.46 1.47 8.17 30

Inorganic-N (mg/L) 4.05 1.71 9.59 31

Organic-N (mg/L) 2.5 1.25 5.01 30

Total-N (mg/L) 7.14 3.73 13.65 30

PO4-P (mg/L) 1.52 0.46 5.03 58

Total-P (mg/L) 2.01 0.92 4.37 31

COD (mg/L) 29 13 63 31

TSS (mg/L) 9 3 27 56


Valley Mills




Lstd Ustd n

DO (mg/L) 6.2 4.2 8.2 60

Water Temp. (ºC) 19.2 12.8 25.7 60



NH3-N (mg/L) 0.08 0.02 0.29 31

NO2-N (mg/L) 0.006 0.002 0.021 58

NO3-N (mg/L) 4.83 0.41 57.66 60

TKN (mg/L) 1.27 0.65 2.5 30

Inorganic-N (mg/L) 14.11 9.06 21.97 31

Organic-N (mg/L) 1.13 0.62 2.06 30

Total-N (mg/L) 15.39 10.33 22.93 30

PO4-P (mg/L) 2.24 0.84 6 56

Total-P (mg/L) 2.68 1.87 3.83 31

COD (mg/L) 11 5 26 31

TSS (mg/L) 7 3 15 58


Crawford (1)

LB060a (Date of first sample: 02Jan96; Date of last sample:30Apr96- Old wastewater treatment system)

DO (mg/L) 10.8 6.9 14.7 15

Water Temp. (ºC) 14.0 8.8 19.1 17



NH3-N (mg/L) 1.37 0.17 11.29 8

NO2-N (mg/L) 0.015 0.003 0.082 17

NO3-N (mg/L) 0.63 0.11 3.58 17

TKN (mg/L) 11.9 4.35 32.55 8

Inorganic-N (mg/L) 3.91 1.67 9.17 8

Organic-N (mg/L) 9.18 3.62 23.3 8

Total-N (mg/L) 15.75 11.28 21.99 8

PO4-P (mg/L) 3.64 1.89 7 14

Total-P (mg/L) 3.62 2.08 6.29 8

COD (mg/L) 101 29 351 8

TSS (mg/L) 77 24 247 13




Lstd Ustd n

Crawford (2)

LB060b (Date of first sample: 15Jan97 - New wastewatertreatment system)

DO (mg/L) 10.8 8.7 12.9 7

Water Temp. (ºC) 12.2 7.4 17.0 7



NH3-N (mg/L) 0.11 0.04 0.27 5

NO2-N (mg/L) 0.01 0.002 0.054 7

NO3-N (mg/L) 0.2 0.04 1.03 7

TKN (mg/L) 2.63 2.09 3.32 5

Inorganic-N (mg/L) 0.48 0.18 1.27 5

Organic-N (mg/L) 2.44 1.84 3.25 5

Total-N (mg/L) 3.14 2.5 3.94 5

PO4-P (mg/L) 0.02 0.01 0.08 7

Total-P (mg/L) 0.28 0.16 0.47 5

COD (mg/L) 44 36 52 5

TSS (mg/L) 23 14 37 7


McGregor


DO (mg/L) 5.7 4.7 6.8 60

Water Temp. (ºC) 20.5 15.0 26.1 60



NH3-N (mg/L) 0.37 0.06 2.1 31

NO2-N (mg/L) 0.006 0.002 0.023 59

NO3-N (mg/L) 1.65 0.19 14 60

TKN (mg/L) 2.63 1.02 6.81 30

Inorganic-N (mg/L) 4.41 1.57 12.42 31

Organic-N (mg/L) 1.96 0.87 4.39 30

Total-N (mg/L) 7.34 3.6 14.96 30

PO4-P (mg/L) 0.69 0.18 2.64 57

Total-P (mg/L) 1.42 0.82 2.47 31

COD (mg/L) 21 9 45 31



Lstd Ustd n

TSS (mg/L) 10 4 25 59



APPENDIX D.

Average Monthly Effluent Discharge from MunicipalWastewater Treatment PlantsTable D- 2. Average monthly effluent discharge in cubic feet per second (cfs) for November 1995 through

March 1997.

Site

Stephenville Hico Iredell Meridian Clifton Valley Mills Crawford McGregorYear Month TP040 LB010 LB020 LB030 LB040 LB050 LB060† LB070

1995 Nov 1.835 0.122 0.040 0.274 0.423 0.122 0.023 0.738

1995 Dec 1.691 0.116 0.043 0.302 0.420 0.001 0.026 0.777

1996 Jan 1.902 0.105 0.040 0.298 0.395 0.100 0.025 0.825

1996 Feb 2.161 0.088 0.042 0.313 0.400 0.120 0.026 0.808

1996 Mar 2.258 0.084 0.043 0.302 0.307 0.107 0.012 0.784

1996 Apr 2.438 0.082 0.040 0.319 0.419 0.002 . 0.966

1996 May 2.089 0.057 0.042 0.307 0.427 0.002 . 0.736

1996 Jun 2.162 0.082 0.040 0.344 0.437 0.159 . 0.702

1996 Jul 2.170 0.073 0.043 0.364 0.439 0.170 . 0.684

1996 Aug 2.719 0.090 0.040 0.207 0.482 0.232 . 0.947

1996 Sep 2.604 0.081 0.042 0.477 0.484 0.222 . 1.818

1996 Oct 2.544 0.079 0.042 0.248 0.448 0.110 . 0.950

1996 Nov 2.922 0.085 0.042 0.273 0.498 0.147 . 1.215

1996 Dec 2.589 0.087 0.045 0.279 0.488 0.002 . 1.783

1997 Jan 2.451 0.091 0.039 0.301 0.496 0.172 . 1.426

1997 Feb 4.661 0.254 0.039 0.515 0.431 0.372 0.017 2.161

1997 Mar 4.687 0.285 0.039 0.380 1.006 0.299 0.040 1.796



APPENDIX E.

Acronyms and AbbreviationsAMS Agricultural Marketing ServiceANOVA analysis of varianceAPHA American Public Health AssociationBOD5 five-day biochemical oxygen demandBRA Brazos River AuthorityCAFO confined animal feeding operationCBMS Computer Based Mapping SystemCHLA chlorophyll-αCOD chemical oxygen demandCR county roadDO dissolved oxygenEPA Environmental Protection AgencyFM farm-to-marketGRASS Geographic Resources Analysis Support Systeminorg.-N inorganic nitrogenln natural logLSD least significant differenceMDL method detection limitMGD million gallons per dayNH3-N ammonia-nitrogenNO2-N nitrite-nitrogenNO3-N nitrate-nitrogenNRCS Natural Resources Conservation ServiceNWS National Weather Serviceorg.-N organic nitrogenPL-566 Public Law 566PO4-P orthophosphate-phosphorusQAPP Quality Assurance Project Planstd standard deviationTIAER Texas Institute for Applied Environmental ResearchTKN total Kjeldahl nitrogenTM thematic mapperTMDL total maximum daily loadTNRCC Texas Natural Resource Conservation Commissiontotal-N total nitrogentotal-P total phosphorusTSS total suspended solidsTSSWCB Texas State Soil and Water Conservation BoardTWC Texas Water CommissionUSDA United States Department of AgricultureUSGS United States Geological SurveyWWTP wastewater treatment plant


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