ASSESSMENT OF POTENTIAL HYDROLOGIC IMPACTS FROM …

ASSESSMENT OF POTENTIAL HYDROLOGIC IMPACTS FROM PROPOSED RESERVOIR(S) NEAR

FORT BAYARD, NEW MEXICO

prepared by

Steven T. Finch, Jr., CPG

JOHN SHOMAKER & ASSOCIATES, INC. Water-Resource and Environmental Consultants

2611 Broadbent Parkway NE Albuquerque, New Mexico 87107

505-345-3407 www.shomaker.com

prepared for

New Mexico Interstate Stream Commission Santa Fe, New Mexico

September 12, 2012

JSAI ii

JOHN SHOMAKER & ASSOCIATES, INC. WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS

CONTENTS

page

1.0 INTRODUCTION ................................................................................................................... 4

1.1 Objective .............................................................................................................................. 4

1.2 Background .......................................................................................................................... 4

1.3 Hydrogeologic Setting .......................................................................................................... 5

2.0 METHODS .............................................................................................................................. 8

2.1 Groundwater Model ............................................................................................................. 8

2.2 Tracer Velocity Calculations ................................................................................................ 9

2.3 Water-Quality Considerations ............................................................................................. 10

2.4 Change in Recharge Rate .................................................................................................... 10

2.5 Potential Drawdown at Bayard Well Field ......................................................................... 11

3.0 RESULTS .............................................................................................................................. 12

4.0 REFERENCES ...................................................................................................................... 13

JSAI iii


TABLES

page

Table 1. Summary of water supply wells in Twin Sister and Cameron creek drainages near Sasnta Clara, New Mexico............................................................................................... 6

Table 2. Estimates of calculated runoff for Twin Sister and Cameron Creek watersheds ........... 7

Table 3. Model simulated seepage from proposed reservoir in Twin Sisters Creek near Fort Bayard, New Mexico ....................................................................................................... 9

Table 4. Characteristics of alluvium in Twin Sisters and Cameron Creek drainages from proposed reservoir to the City of Bayard Well Field ..................................................... 10

Table 5. Summary of estimated reservoir size, stage elevation, volume, and lake evaporation rates for proposed Sites 2 .............................................................................................. 11

ILLUSTRATIONS

(follow text)

Figure 1. Map showing study area, Twin Sisters Creek and Cameron Creek alluvium, Lone Mountain aquifer system, and supply wells near Fort Bayard, New Mexico.

Figure 2. Geologic map of the study area near Fort Bayard, New Mexico. Figure 3. Map showing groundwater-level elevation contours, direction of groundwater flow,

and depth to water for the study area near Fort Bayard, New Mexico. Figure 4. Graph showing model simulated drawdown versus time for the City of Bayard Well

Field

JSAI


ASSESSMENT OF POTENTIAL HYDROLOGIC IMPACTS FROM PROPOSED RESERVOIR(S) NEAR FORT BAYARD, NEW MEXICO

1.0 INTRODUCTION

John Shomaker & Associates, Inc. (JSAI) was contracted by the New Mexico Interstate

Stream Commission (NMISC) to evaluate the potential hydrologic impacts associated with the

Grant County and City of Bayard proposals for the Arizona Water Settlement Act (AWSA)

related to the use of treated effluent for creating reservoirs and aquifer recharge near Fort

Bayard, New Mexico (Fig. 1). Each proposal contemplates the use of treated effluent from the

Tri-city wastewater treatment plant for landscape irrigation and creation of a multi-use reservoir.

Some of the places of proposed use are upstream of the Bayard Well Field, and pose a potential

for impacting the quantity and quality of water recharging the Bayard Well Field.

1.1 Objective

The project objective was to perform a hydrologic analysis of the Grant County Tier-2

ASWA proposal and quantify the potential hydrologic effects on downstream wells from the

creation of reservoirs, and from the infiltration of treated wastewater to the water table. The

analysis addresses potential effects from the proposed reservoirs on water availability, and the

effects of reservoir seepage on Twin Sisters and Cameron Creek drainages.

1.2 Background

Three locations were considered for the Grant County reservoirs (Fig. 1). A reservoir in

Twin Sisters Creek (Site 1 or 2) would be limited to approximately 130 acres and contain

3,300 acre-feet. The potential reservoir site in Cameron Creek (Site 3) would fill to the capacity of

53 ac-ft, have a 6-acre area, and evaporation rate of 26 acre-feet per year (Grant County Tier II

proposal). The reservoirs would be filled with some combination of stormwater and treated

effluent. Proposed releases of treated effluent to the stream alluvium downstream of the reservoirs

would be a minimum of 70 ac-ft/yr in Twin Sisters Creek and 26 ac-ft/yr in Cameron Creek.

Proposed irrigation projects include 58 acres of parks and fields in Bayard and 77 acres

of landscaping and cemetery in Fort Bayard. The City of Bayard is not in the Cameron Creek

watershed, although Fort Bayard is within the Cameron Creek watershed.

JSAI 5


The primary concern is the potential impacts to water-supply wells downstream of the

proposed Grant County reservoir in Twin Sister Creek. The location of the proposed reservoir

and downstream wells is shown on Figure 1. The City of Santa Clara has the Twin Sister

Infiltration Gallery located in Twin Sister creek directly north of Highway 152, and the City of

Bayard water supply well field is located in the Cameron Creek drainage southwest of town, in

Section 14, T18S, R13W (Fig. 1).

Information about the older, shallower City of Bayard wells (numbers 1-6) is incomplete

and contradictory. Available information for all wells is summarized in Table 1. Maximum

diversion from the Bayard Well Field was about 395 ac-ft/yr in 1995, and the average diversion

since 1995 has been approximately 300 ac-ft/yr. There are no available logs for the Bayard

supply wells. Based on logs from nearby wells, the City of Bayard wells are suspected to yield

groundwater from saturated alluvium along Cameron Creek and the underlying Gila

Conglomerate. Trauger (1972) documented seasonal water-level changes of 20 ft or more in the

City of Bayard wells.

1.3 Hydrogeologic Setting

There are three primary geologic units 1) alluvium along Twin Sisters and Cameron

Creek drainages, 2) Gila Conglomerate, and 3) low-permeability bedrock units. The distribution

of alluvium along Twin Sisters and Cameron Creek drainages and extent of Gila Conglomerate

are shown on Figure 1. The Gila Conglomerate in the vicinity southwest of Santa Clara is

referred to as the Lone Mountain aquifer system. The low-permeability bedrock includes

cemented sandstone, shale, and granodiorite (Fig. 2).

Twin Sisters and Cameron Creek channels contain stream alluvium from the proposed

reservoir sites, south, to the Lone Mountain Aquifer system. The stream alluvium width and

depth significantly vary along the channels. Stream alluvium at an exploratory well drilled near

the Village of Santa Clara infiltration Gallery is reported to be only 10 ft. In Cameron Creek, the

stream alluvium is 26 ft thick at the Fort Bayard Hospital Well (Fig. 1), and is reported to be up

to 50 ft in thickness downstream of the Village of Santa Clara. Several channel segments

between Fort Bayard and Santa Clara are barren of alluvium and have a low-permeability

bedrock streambed.

JSAI 6


Table 1. Summary of water supply wells in Twin Sister and Cameron creek drainages near Santa Clara, New Mexico

owner NMOSE File No.

location (T.R.S.qqq)

year drilled

casing diameter

reported yield

(gpm)

well depth

(ft)

depth to water when drilled

(ft)

City of Bayard M-2698 18.13.14.222 1942 8 45 300 65

City of Bayard M-2698-S 18.13.14.222 1948 12 45 220 65

City of Bayard M-2698-S-2 18.13.14.222 1950 12 85 250 65

City of Bayard M-2698-S-3 18.13.14.222 1950 8 5 80 65

City of Bayard M-2698-S-4 18.13.14.222 1950 8 40 300 65

City of Bayard M-2698-S-5 18.13.14.222 1956 8 30 650 65

City of Bayard M-2698-S-6 18.13.14.222 1965 10 60 700 65

City of Bayard M-2698-S-7 18.13.14.222 1965 12 90 982 65

City of Bayard M-2698-S-8 18.13.14.222 1970 8 115 500 70

City of Bayard M-2698-S-9 18.13.14.240 1954 10 116 274 46

City of Bayard M-2698-S-10 18.13.14.144 1985 10 140 380 52

Santa Clara SP-2677 17.13.35.330 na na na na 15

Santa Clara M-3127 17.31.35.330 na na na 15

JSAI 7


The Lone Mountain aquifer system is composed of stream alluvium and Upper Gila

Conglomerate as defined by Trauger (1972). The Upper Gila Conglomerate is composed of a

cemented sand and gravel with some intervals containing silt and clay. The aquifer system is

bound by low-permeability rocks (Fig. 2), and is no more than 300 ft in thickness. Well yield

can be several hundred gallons per minute, but varies significantly according to saturated

thickness.

Water-level elevation contours are shown on Figure 3, and the direction of groundwater

flow is generally from north to south. Depth to water across the study area varies significantly

and can range from 10 to over 50 ft bgl along the Twin Sisters and Cameron Creek drainages

(Fig. 3).

Twin Sisters and Cameron Creeks are ephemeral drainages, but during seasons with

above-average precipitation can be perennial to intermittent drainages. Estimates of calculated

runoff are listed in Table 2.

Table 2. Estimates of calculated runoff for

Twin Sister and Cameron Creek watersheds

watershed area

(acres) range in estimate runoff

(ac-ft/yr)

Twin Sisters 7,380 70 to 178

Cameron 11,550 110 to 278

ac-ft/yr - acre-feet per year

JSAI 8


2.0 METHODS

The methods of analysis needed to address potential changes in availability of water to

downstream wells and the potential for impacting groundwater with infiltration of treated

effluent. The potential reservoir site 2 was considered for the analysis because it would be the

largest of the three possibilities proposed by Grant County Tier-2 AWSA proposal. A

groundwater model was used to calculate potential reservoir seepage and hydraulic response of

the aquifer to infiltrated treated effluent, and Darcy’s Law was used to calculate travel velocity

of treated effluent in the groundwater system. This would tell us how much water is introduced

to the system, when it will get to a specific point, and the hydrologic effects.

2.1 Groundwater Model

Numerous groundwater models have been developed for the Mimbres Basin, some

examples include Hanson et al. (1994), Johnson et al. (2002), JSAI (2006), Keyes and Cuddy

(2011), and Balleau (2011). Only the groundwater models by JSAI (2006) and Balleau (2011)

simulate the aquifer system near Fort Bayard, New Mexico. The eastern limit of the Balleau

Model does not include parts of Cameron Creek drainage and the Lone Mountain Aquifer system.

The JSAI Mimbres Basin model best represents the aquifer conditions in the vicinity of the

proposed reservoir(s), and was used to simulate reservoir seepage and to simulate hydrologic

responses to pumping and changes in recharge. The River Package was used to simulate the

proposed reservoir. Input parameters included a stage elevation of 6,100 ft amsl, and lake bed

conductance of 0.007 ft/day.

The bedrock at the proposed reservoir site(s) has a model-assigned hydraulic conductivity

of 0.1 ft/day. Trauger (1972) reports a hydraulic conductivity range of 0.01 to 0.5 ft/day, therefore

the model simulated seepage rate could be less if the reservoir footprint is less than 130 acres and

the underlying bedrock have a lower hydraulic conductivity.

JSAI 9


Table 3. Model simulated seepage from proposed reservoir in Twin Sisters Creek near Fort Bayard, New Mexico

time (years)

simulated seepage for 130 acre

reservoir (ac-ft/yr)

10 55

20 58

40 61

2.2 Tracer Velocity Calculations

The regional groundwater-flow model does not consider the saturated alluvium and Lone

Mountain aquifer system in enough detail for evaluation of travel time in the saturated alluvium.

Darcy’s Law is a reasonable method for estimating groundwater velocity. Estimates of the tracer

velocity (Vx) can be used to provide some indication of the average horizontal rate of treated

effluent migration in the groundwater system. The tracer velocity can be calculated using the

following equation:

Vx = KI/ne

where,

Vx = tracer velocity in feet per day (ft/day)

K = horizontal hydraulic conductivity (ft/day)

I = hydraulic gradient (ft/ft)

ne = effective porosity (dimensionless)

Characteristics of the alluvium are listed in Table 4. Using a horizontal hydraulic

conductivity (K) of 200 ft/day and hydraulic gradient (I) of 0.0108 ft/ft, and keeping effective

porosity (ne) fixed at 0.2, the tracer velocity equals 11 ft/day. Using an average expected tracer

velocity range of 11 ft/day, the groundwater travel time from the proposed reservoir in Twin

Sisters Creek to the closest City of Bayard well would be approximately 3 years. These are over-

simplified estimates that provide a hypothetical rate of groundwater velocity in the saturated

alluvium.

JSAI 10


Table 4. Characteristics of alluvium in Twin Sisters and Cameron Creek drainages

from proposed reservoir to the City of Bayard Well Field

characteristic unit value

length of channel ft 18,480

area of alluvial channel acres 800

volume of alluvium ac-ft 19,800

specific yield fraction 0.20

groundwater storage capacity ac-ft 3,960

2.3 Water-Quality Considerations

The treated effluent will need to meet NMED water quality standards for the proposed

use, and is expected to be suitable for recharge. Comingling stormwater runoff with seepage will

reduce the effluent concentration, regardless if the stormwater is mixed in the reservoir or

downstream of the reservoir. The mixing ratio of stormwater to treated effluent downstream of

the reservoir is approximately 1 part effluent to 3 parts stormwater. The mixed water would

travel downstream in the alluvium in Twin Sisters Creek drainage and then infiltrate where the

alluvium thickens in the Cameron Creek drainage (Fig. 1). Once infiltrated, the mixed water will

commingle with groundwater in the Lone Mountain Aquifer system. No significant water

quality effects are expected given the dilution effects and distance to travel through alluvium and

other geologic units.

2.4 Change in Recharge Rate

Filling of the proposed reservoir site in Twin Sisters Creek drainage could temporarily

reduce downstream recharge in Cameron Creek by collection of stormwater flows that would

otherwise infiltrate downstream. The effect would be temporary until the reservoir filled to the

designed spill level. Table 5 is a fill schedule for proposed reservoir site 2. Approximately 400

ac-ft/yr of treated effluent would be available for reservoir filling (Grant County Tier-2

proposal). All of the available treated effluent and stormwater runoff in Twin Sisters Creek

would be needed to build and fill to maximum stage.

JSAI 11


Table 5. Summary of estimated reservoir size, stage elevation, volume, and lake

evaporation rates for proposed Site 2

interval Acres stage stage area

(acres)

incremental volume (ac-ft)

stage volume (ac-ft)

lake evaporation

(ac-ft/yr)

Lower Twin Sisters Creek Reservoir (Site 2)

6090-6080 44.0 6,090 132.5 1,105 3,297 552

6080-6070 26.2 6,080 88.5 754 2,192 369

6070-6060 16.2 6,070 62.3 542 1,438 260

6060-6050 14.6 6,060 46.2 388 896 192

6050-6040 12.7 6,050 31.5 252 507 131

6040-6030 8.3 6,040 18.8 146 256 78

6030-6020 5.4 6,030 10.5 77 109 44

6020-6010 3.8 6,020 5.0 31 32 21

<6010 1.3 6,010 1.3 1 1 5

Total 132.5 ac-ft/yr - acre-feet per year

Recharge in Twin Sisters Creek below the reservoir will be limited to reservoir seepage

losses and stormwater inflow below the reservoir if all of the stormwater originating upstream of

proposed reservoir site 2 is captured. The change in potential recharge downstream would be

equal to the calculated stormwater inflow of approximately 120 ac-ft/yr (average of 70 to 178 ac-

ft/yr in Table 2) from Twin Sisters Creek to the proposed reservoir less the calculated seepage of

60 ac-ft/yr.

2.5 Potential Drawdown at Bayard Well Field

The groundwater flow model was used to simulate drawdown resulting from pumping the

Bayard well field at 300 ac-ft/yr and changes in recharge (60 ac-ft/yr). The model simulations

also included pumping from other users such as from Santa Clara’s Lone mountain Well field.

Results are shown on Figure 4. The decrease in 60 ac-ft/yr of recharge to the Bayard Well Field

results in approximately 20 ft of drawdown over a 40 year period. The recharge will increase

downstream of the proposed reservoir if stormwater is bypassed.

JSAI 12


3.0 RESULTS

The Grant County Tier-2 AWSA proposal contemplates proposed reservoirs near Fort

Bayard, New Mexico that would be filled with treated effluent from the Tri-City Wastewater

Treatment Plant and possibly stormwater runoff (Fig. 1). The hydrologic analysis considered the

largest of the proposed reservoirs, which is potential reservoir site 2 in Twin Sisters creek

drainage. The following conclusions were made from the hydrologic analysis:

1. Estimates of stormwater runoff above potential reservoir site 2 ranges between 70

and 178 ac-ft/yr.

2. Model calculated seepage, considering maximum stage, is 60 ac-ft/yr. The

seepage rate will depend on footprint area and reservoir stage. Model simulated

seepage rate is 0.46 ft/yr.

3. Groundwater travel time from potential reservoir site 2 to the Bayard Well Field

is 3 years. Treated effluent will mix with larger portions of stormwater and

groundwater before arriving at the Bayard Well Field. Groundwater quality at the

Bayard well field is not expected to change.

4. Changes in the potential recharge rate along Cameron Creek near the Bayard Well

Field may occur from the proposed reservoir in Twin Sisters Creek drainage. An

increase in recharge (60 ac-ft/yr) will occur if stormwater runoff is routed around

the proposed reservoir. A 60 ac-ft/yr decrease in recharge will occur if

stormwater is impounded in the proposed reservoir.

5. A 60 ac-ft/yr decrease in recharge at the Bayard Well Field results in 20 ft of

model-simulated drawdown over a 40 year time period (Fig. 4). Adding treated

effluent to Twin Sisters Creek or Cameron Creek without capture of stormwater

runoff for reservoir filling would recharge the Lone Mountain Aquifer and

significantly reduce aquifer dewatering and drawdown.

JSAI 13


4.0 REFERENCES

Balleau, 2011, Preliminary description of Town of sliver City aquifer model: Technical memorandum prepared by D. M. Romero to file Balleau Groundwater, Inc.

Cuddy, A. S., Keyes, E., 2001, Groundwater model of the Mimbres Basin, Luna, Grant, sierra

and Dona Ana Counties, New Mexico: New Mexico Office of the State Engineer, Hydrology Bureau Report 11-1.

Hanson, R.T., McLean, J.S., and Miller, R.S., 1994, Hydrogeologic framework and preliminary

simulation of ground-water flow in the Mimbres Basin, Southwestern New Mexico: U.S. Geological Survey Water-Resources Investigations Report 94-4011, 118 p. plus maps.

Johnson, M. S., Logan, L. M., and Rappuhn, D. H., 2002, Analysis of effects of groundwater

development to meet project demands in regional planning District 4 southwest New Mexico: New Mexico Office of the State Engineer, Hydrology Bureau Report 02-04.

Jones, W.R., Moore, S.L., and Pratt, W.P., 1970, Geologic Map of the Fort Bayard Quadrangle,

Grant County, New Mexico: U.S. Geological Survey Geologic Quadrangle Map GQ-865, scale 1:24,000.

JSAI, 2006, Report on water treatment system sustainability, Chino Mines Company, DP-1340,

Condition 86: consultants report prepared by John Shomaker & Associates, Inc. for Chino Mines Company.

Pratt, W. P., 1967, Geology of the Hurley West Quadrangle, Grant County, New Mexico: U. S.

Geological Survey Bulletin 1241-E. Skotnicki, S.J., and Ferguson, C.A., 2007, Preliminary Geologic Map of the Fort Bayard

Quadrangle, Grant County, New Mexico: New Mexico Bureau of Geology and Mineral Resources Open-File Geologic Map 152, scale 1:24,000.

Trauger, F. D., 1972, Water Resources and General Geology of Grant County, Hydrologic

Report 2, New Mexico: New Mexico Bureau of Mines and Mineral Resources, 211 p.

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Village of Santa Clara wellLone Mountain Well FieldCron Ranch industrial well

"¬! Bayard Wastewater Treatment PlantLone Mountain aquifer system

alluvial thickness<30 ft>30 ft

JOHN SHOMAKER & ASSOCIATES, INC.

Figure 1. Map showing study area, Twin Sisters Creek and Cameron Creek alluvium, Lone Mountain aquifer system, and supply wells near Fort Bayard, New Mexico.

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Geologic map source: USGS OFR97-0052

Figure 2. Geologic map of the study area near Fort Bayard, New Mexico.

ExplanationXY Ft. Bayard Hospital well") Bayard municipal supply well#* Santa Clara infiltration gallery

Santa Clara well(Lone Mountain Well Field)Cron Ranch industrial well

"¬! Bayard Wastewater Treatment PlantfaultdikeLone Mountain aquifer systemwatershed

Geologic UnitsQuaternary

Qp piedmont alluvial depositsQuaternary and Tertiary

QTg Gila Group

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water-level elevation contour, ft amsl

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Figure 3. Map showing groundwater-level elevation contours, direction of groundwater flow, and depth to water for the study area near Fort Bayard, New Mexico.

Lone Mountain Aquifer0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

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200.0

0 5 10 15 20 25 30 35 40 45

model simulated time (years)

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(ft)

Bayard and others no recharge

Bayard and others with recharge

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Bayard only with recharge

City of Bayard Well Field pumping = 300 ac-ft/yrother (Santa Clara) pumping = 272 ac-ft/yrrecharge = 60 ac-ft/yr in Cameron Creek

Figure 4. Graph showing model simulated drawdown versus time for the City of Bayard Well Field


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ASSESSMENT OF POTENTIAL HYDROLOGIC IMPACTS FROM …