Bass Lake Rehabilitation District Summer Intern Report

Prepared by:

Nicole Gabriel

University- Wisconsin River Falls Intern

August 2007

Table of Contents Abstract……………………………………………………………….1

Purpose………………………………………………………………..1

Background……………………………………………………………2

Introduction…………………………………………………...2

Geology of Bass Lake and the surrounding watershed……….3

Topography…………………………………………………...3

Soils…………………………………………………………...3

Groundwater Hydrogeology…………………………………..7

Aquatic Vegetation……………………………………………9

Bass Lake Fish ………………………………………………..9

Population…………………………………………………….10

Development………………………………………………….11

Shoreland Zoning in St. Croix County………………………..11

Recreational Use………………………………………………11

Sampling………………………………………………………………13

Sampled Parameters…………………………………………...13

Phosphorus…………………………………………….13

Nitrogen………………………………………………..14

Dissolved Oxygen……………………………………..15

Temperature……………………………………………15

Clarity………………………………………………….17

pH………………………………………………………17

Macroinvertebrates……………………………………..18

Sampling Procedures……………………………………………18

Water Quality Results…………………………………………..20

Macroinvertebrate Results………………………………………24

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Discussion……………………………………………………….28

Shoreline Inventory……………………………………………………..29

Discussion……………………………………………………….29

Shoreline Runoff Survey………………………………………………..30

Conclusion………………………………………………………………31

Recommendations……………………………………………………….32

References……………………………………………………………….33

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Table of Figures

Figure 1………………………………………………………………….2

Figure 2………………………………………………………………….4

Figure 3………………………………………………………………….5

Figure 4………………………………………………………………….7

Figure 5………………………………………………………………….9

Figure 6…………………………………………………………………11

Figure 7…………………………………………………………………13

Figure 8…………………………………………………………………14

Figure 9…………………………………………………………………16

Figure 10………………………………………………………………..17

Figure 11………………………………………………………………..19

Figure 12………………………………………………………………..20

Figure 13………………………………………………………………..21

Figure 14………………………………………………………………..22

Figure 15………………………………………………………………..24

Figure 16………………………………………………………………..27

Abstract

Bass Lake has been studied for many years by the Wisconsin Department of Natural Resources

(WDNR). Water quality monitoring on Bass Lake started in 1986 as a part of the WDNR Long

Term Trends Monitoring program. This summer the Bass Lake Rehabilitation District (BLRD)

wanted to do some of their own testing and hired an intern from the University of Wisconsin –

River Falls. The intern was supervised by the St. Croix County Land & Water Conservation

Department (LWCD). The lake was tested for nitrate, phosphate, pH, dissolved oxygen,

temperature, clarity, and macroinvertebrates. The BLRD also asked that an individual shoreline

inventory be taken for every land parcel. The tests and shoreline inventory helped to determine

the water quality of Bass Lake. Everything that was tested confirmed that Bass Lake is an

Outstanding Water Resource, but the phosphate level is too high and needs some attention.

Some serious action needs to be taken in trying to keep phosphate levels down in the lake. This

is something that can be done with home and land owner participation and something that will

benefit the lake for years to come.

Purpose

The purpose of the summer internship was to work with the BLRD and the LWCD to determine

the water quality of Bass Lake by testing for nitrate, phosphate, pH, clarity, and dissolved

oxygen, to survey individual shorelines, and to survey for stormwater runoff. All of these things

relate to the quality of Bass Lake. Along with the results of this study, Bass Lake volunteers

were trained to monitor the lake for years to come. Keeping a record of readings for many years

will allow the BLRD to know about problems or improvements to the lake and what, if anything

needs to be done.

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Background Introduction

Bass Lake is located in northwestern Wisconsin, in St. Croix County. It is a thermally stratified,

groundwater seepage lake (Figure 1) that is 416 acres

and has a maximum depth of 45 feet, according to the

WDNR in 2006. The Bass Lake watershed is 1,398

acres, which is relatively small compared to the lake

size. This is a three to one ratio and is a contributing

factor that leads to the quality of the lake.

Figure 1

Currently, Bass Lake is named an Outstanding Water Resource by the WDNR. An Outstanding

Resource Water is a surface water which provides valuable fisheries, hydrologically or

geologically unique features, outstanding recreational opportunities, unique environmental

settings, and is not significantly impacted by human activities (Wisconsin Administrative Code

NR 102.11). The one thing that threatens that is the phosphate concentrations. They have been

on an increase for many years now and some serious considerations need to be taken. The rapid

development on and close to the lake is causing problems with the quality of the water. The

increase in recreational traffic also contributes to the rising problem.

There have been many studies done on Bass Lake, all of which give different numbers for

acreage, depth, and water level. In 1992 there was a study done by the WDNR and the West

Central Wisconsin Regional Planning Commission that stated the lake was 441 acres and had a

maximum depth of 38 feet. According to a 2006 WDNR study the lake was 416 acres with a

maximum depth of 45 feet, and the WDNR website has Bass Lake as a 293 acre lake with a

maximum depth of 37 feet. The water level has fluctuated a lot in the past several years. The

lowest recorded level was in 1963 at 876.37 feet and the highest level was 888.25 feet in 1995.

This is a difference of 11.91 feet in 32 years (Konkel and Borman 1996).

2

Geology of Bass Lake and the surrounding watershed

The rocks and soils that control movement and storage of groundwater in St. Croix County range

from the bedrock of Precambrian age to the glacial deposits, alluvium and soils of the Quaternary

age. Throughout most of the county the bedrock is overlain by glacial drift. The Bass Lake

watershed is overtop of a bedrock fault that runs from the northeast to the southwest through the

center of the lake (Figure 2). The bedrock that lies north and west of the fault is Cambrian

sandstone, the Trempealeau formation. This bedrock consists mostly of sandstone, shale,

siltstone, and dolomite. The bedrock that lies to the south and east of the fault is Ordovician.

The thickness of the glacial drift varies greatly, from 0’ on hilltops and road cuts to more than

450’ west of Bass Lake. The depth to the surface of the Bass Lake watershed varies from 0-200

feet (Figure 3).

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Figure 2

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Figure 3

Topography

The Bass Lake watershed has the characteristics of a typical end moraine of a glaciated area.

The watershed mostly is a rolling landscape with approximately 20% of the landscape as a C

slope (6%- 12%). Some of the gentler slopes in this category can be developed on with care, but

development of slopes approaching 12% can pose a serious problem with erosion and runoff.

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Steeper slopes in the D (12%- 25%) and E (20%- 35%) categories tend to ring the lake. About

266.8 acres of the watershed has a D slope and development is likely to cause major erosion and

runoff problems. Only about 62.9 acres of the Bass Lake watershed have E slopes, which many

of these are located on the heavily developed east bank of the lake (WDNR and West Central

Wisconsin Regional Planning Commission, 1992).

Soils

According to the St. Croix County Land Information Plan, an updated soil survey has not been

done since 1978 and will be done only when the NRCS schedule allows. There are three main

soil series that are within the Bass Lake watershed: Onamia, Chetek, and Burkhardt (Figure 4).

The Onamia series covers 12,818 acres of St. Croix County. This series also consists of gently

sloping to steep, well drained soils on outwash plains and areas of pitted outwash plains. It is a

fine loamy soil that lies overtop of sandy gravel. Native vegetation that is normally found

around this type of soil is white pine, sugar maple, and red oak. It has a moderate ability to hold

water and permeability is moderate in the subsoil and rapid in the sand and gravel.

The Chetek series covers 6,941 acres of St. Croix County. This series consists of sloping to

steep, somewhat excessively drained soils on knolls of pitted outwash plains. It is a course

loamy material that is overtop of sand and gravel. The native vegetation that is normally found

around this type of soil is red oak and white pine. The water holding capacity is relatively low

and permeability is moderately rapid in the subsoil and rapid in the substratum.

The Burkhardt series covers 16,936 acres of St. Croix County. This series consists of very deep,

somewhat excessively drained soils formed in 25 to 50 cm of loamy alluvium and in the

underlying sandy outwash. The native vegetation that is present in this series is mainly oak

savanna or native prairie grasses. The water holding capacity is low and permeability ranges

from moderately rapid in the loamy upper part to rapid in the underlying sand and gravel.

There are various individual soil types that are within these three groups. The most dominant

individual soil type in the Bass Lake watershed is OnD2, the Onamia-Antigo complex. The

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surface layer is mainly silt loam and loam, but is sandy loam on steep parts of the complex.

With this composition and with the typical slope (12%- 25%) runoff is rapid and the hazard of

erosion is severe. This is bad for agriculture and the absorption for septic tank fields is limited.

The next dominant soils type in the watershed is CoC2, the Chetek-Onamia complex. This has a

surface layer that is mainly sandy loam and loam, but with some small areas of silt loam and

loamy sand. This soil type is mostly found on the crests of knolls and has the tendency to be

more eroded than the Onamia soils. With the composition and slopes (6%- 12%) runoff is

medium and the hazard of erosion is moderate. There is some of this soil that is present on the

east side of the lake where there are slopes of 12%- 20% and this has very high potential for

rapid runoff and severe erosion.

The other soil type is found in the southern part of the watershed, which is BxD2, Burkhardt-

Sattre complex. This complex also is found near the crest of knolls and on steeper slopes. These

have a slope of 12%- 30%, which makes runoff and erosion rapid and severe.

The Emmert soil series is found in lesser amounts throughout the watershed. But is one to pay

attention to. This series occurs mostly on the eastern lakeshore and along the southwestern

shoreline. The eastern shoreline makes up the earliest and more densely developed areas. The

sandy makeup of the soil and the steep slopes limit road and septic tank absorption development

(WDNR and West Central Wisconsin Regional Planning Commission, 1992).

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Groundwater Hydrogeology

Bass Lake is a groundwater seepage lake that has no inlets or outlets and has little overland flow.

The only recharge that the lake gets is from groundwater inflow and precipitation. Evaporation

and groundwater outflow account for the loss of water from the lake. In the last four decades the

lake level has fluctuated by more than ten feet. In the early 1970’s high water levels flooded

many homes and roads. This lead to a study done by Rinaldo-Lee in 1978. The study used 32

wells to determine that groundwater flows to the west and ends up discharging into the St. Croix

River. The immediate area of Bass Lake has a more complex flow system tied to it. The

northern half of the lake is located in the regional flow through system; the southern half has

both the regional flow through system and a local recharge system to the upper glacial aquifer

(Figure 5). Most of the wells that were installed were destroyed or are now unstable, but in 1992

five wells on the south end of the lake remained useable and four wells were installed in

September of 1990 on the east side of the lake to determine groundwater inflow gradients

(WDNR and WCWRPC, 1992).

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Figure 5 (WDNR and WCWRPC, 1992)

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Aquatic Vegetation

An aquatic vegetation study of Bass Lake has been preformed annualy by Deb Konkel of the

WDNR. The results from the 1987-2006 study are attached as Appendix A. These results

indicate that there is a good species diversity. It also states that phosphorus levles have been on

the rise in the past few years.

Bass Lake Fish

Fish population surveys done by the WDNR have found a quality self-sustaining large mouth

bass and panfish fishery, which is supplemented by alternate year stocking of walleye

fingerlings. A copy of the DNR stocking report has been attached as Appendix B. The panfish

population that has been found includes bluegills, black crappies, yellow perch, and

pumpkinseeds. There are also northern pike, yellow and black bullheads, white suckers and carp

present (Engel, 1986). Bass Lake has had fish populations documented since 1953 with little

change occuring. Most years have shown a good populaiton of largemouth bass, walleye, and

panfish.

Mercury testing in fish has been done on Bass Lake. The WDNR focused their sampling efforts

on lakes that are popular with anglers, lakes that have a low pH or low alkalinity, areas where

mercury contaminated wastes have been dumped, or where long-term contaminant trends in fish

are being studied. With the size and different fish species present in Bass Lake, the WDNR

gives the following health advisories to the public:

• Women beyond their childbearing years and men may eat:

o Unrestricted- Bluegill, crappies, yellow perch, sunfish, bullheads and inland trout; o 1 meal per week- Walleye, pike, bass, catfish and all other species o 1 meal per month - Muskies.

• Women of childbearing years, nursing mothers and all children under 15 may eat:

o 1 meal per week - Bluegill, crappies, yellow perch, sunfish, bullheads and inland trout

o 1 meal per month - Walleye, pike, bass, catfish and all other species. o Do not eat - Muskies.

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Population

The number of people that now inhabit the Bass Lake area is greater than ever. In 1982 the West

Central Wisconsin Regional Planning Commission prepared a population projection for three

different places affecting Bass Lake (Figure 6) and the population from the U.S. Census Bureau

in 2000 was: St. Joseph- 3,436; Somerset- 2,644; St. Croix County- 63,155. The projection was

done again in 2004. According to the Wisconsin Department of Natural Resources Statewide

Comprehensive Outdoor Recreation Plan, St. Croix County has grown the most rapid at 44%

from 1990- 2004 and is projected to gain 22,680 residents between 2004-2020. This increase

will affect the amount of people living and recreating on Bass Lake.

Figure 6

POPULATION PROJECTIONS

1980 1990 2000 2010St. Joseph 2,180 2,657 3,150 3,760 Somerset 1,833 1,975 3,056 3,947 St. Croix County 43,260 50,251 64,853 79,093 (WCWPC, 1982)

POPULATION PROJECTIONS

2010 2015 2020 2025St. Joseph 4,172 4,456 4,746 4,957 Somerset 3,478 3,824 4,171 4,446 St. Croix County 80,779 87,967 95,202 100,806 (WCWPC, 2004)

Development

Most of the development on the east shoreline occurred during the 1950s. Building permits have

not been systematically collected or maintained by townships in the past and less than adequate

records have been updated by the Township of St. Joseph since 1979. According to St. Joseph

Township on August 27, 2007 there have only been about 3 new construction building permits

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and 5-10 major remodel building permits within the past ten years. The west side of the lake

contains most of the larger more wooded lots. These homes also tend to be year round homes

and the ones on the east side are more seasonal homes.

Shoreland Zoning in St. Croix County

The WDNR wrote NR 115 to meet the responsibilities of the Water Resources Act of 1966.

They did this to establish standards and criteria that must be met by county shoreland zoning

ordinances. St. Croix County defines a shoreland as all lands that fall within 300’ of a river or

stream or to the landward edge of the floodplain or within 1000’ of a lake, pond or flowage or

the St. Croix River. Appendix C has a copy of the St. Croix County Code of Ordinances as it

relates to shoreland zoning. Bass Lake and its watershed fall mostly within St. Joseph Township

and the northern half falls in Somerset Township. These two townships don’t have their own

shoreland regulations, so they must follow the county regulations. St. Joseph Township does

have regulations regarding lot size and number of residences on one given lot.

Recreational Use

Bass Lake is a heavily used recreation lake. It is located in the Mississippi River Corridor and

urban influences impact the region as visitors from the nearby Twin Cities metropolitan area

make use of the region’s recreational resources. Suburban development associated with the

greater Twin Cities metropolitan area in St. Croix and Pierce Counties continues to impact

recreation supply and demand across the region (WDNR Statewide Comprehensive Outdoor

Recreation Plan, 2005-2010). Both residents and non-residents use the lake for fishing, skiing,

and boating. Marty Engel of the WDNR has said that Bass Lake is felt to be a heavily used lake

in the area by local fish and game managers. This year a boat patrolman was hired to watch the

lake for people disobeying the law for the summer.

Sampling

Sampled Parameters

Phosphorus

Phosphorus occurs naturally in rocks and other mineral deposits. Figure 7 shows what the

phosphorus cycle looks like. During the natural process of weathering, rocks gradually release

phosphorus as phosphate ions which are soluble in water and the mineralized phosphate

compounds breakdown. In freshwater lakes it is considered the growth-limiting nutrient. When

levels are too high it causes algae blooms and this is what makes lakes eutrophic. Storm events

can cause the vertical infiltration of the phosphates into the groundwater system, but because of

soils affinity for phosphate, the soil mantle acts as a storage media. The non-point sources of

phosphates include: natural decomposition of rocks and minerals, stormwater runoff, agricultural

runoff, erosion and sedimentation, atmospheric deposition, and direct input by animals/wildlife.

Just one pound of phosphorus in runoff can result in 500 pounds of algae growth. Phosphates are

not toxic to people or animals unless they are present in very high levels. Digestive problems

could occur from extremely high levels of phosphate (Wilkes University).

Figure 7

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Ortho phosphate (PO4) is one of the types of inorganic phosphorus and is the most stable type of

phosphate. It is usually referred to as reactive phosphorus. This means that it is used by plants

and is produced by natural processes. This differs from total phosphorus (P), which entails all

three forms of phosphates in the environment: ortho phosphate, metaphosphate, and organically

bound phosphate. Phosphorus readings are taken in mg/L of phosphate. Since our readings were

in ortho phosphate, they had to be converted into phosphate. According to the EPA, in order to

convert ortho phosphate into phosphate, the PO4 needs to be divided by three.

Nitrogen

The nitrogen cycle in one of the most important processes in nature for living organisms (Figure

8). It makes up 78% of the Earth’s air and is an essential part of amino acids. Nitrate (NO3) is a

common inorganic form of nitrogen. Plants normally use nitrate as their source of the nitrogen

and so, nitrate is considered a nutrient for plants. Excessive concentrations of nitrate in lakes and

streams greater than about 5 milligrams per liter, depending on the water body, can cause

excessive growth of algae and other plants, leading to accelerated eutrophication or "aging" of

lakes, and occasional loss of dissolved oxygen. In most cases of excess nitrate concentrations,

the principle pathway of entering aquatic systems is through surface runoff from agricultural or

landscaped areas which have received excess nitrate fertilizer (USGS, 2007).

Figure 8

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Dissolved Oxygen

Dissolved oxygen is one of the best indicators of water quality. It can range from 0-18 mg/L and

it takes about 5-6 mg/L to support a diverse aquatic population. Oxygen enters the water by

direct absorption from the atmosphere or plant photosynthesis. The oxygen is used by plants and

animals for respiration and by aerobic bacteria which consume oxygen during the process of

decomposition. The oxygen reading tends to be lower in the early morning because

photosynthesis stops at night, stopping the production of oxygen, while animal/plant activity and

respiration continue. The level should increase during a normal sunny day, reaching a maximum

late in the afternoon. There are three main reasons why dissolved oxygen would decrease:

1. Increase in temperature, decreasing the amount of any gas that water can hold.

2. Respiration - All aquatic plants and animals use oxygen to respire, to break down food to

release the energy required for cellular activity. Even though plants photosynthesize and

produce oxygen during daylight hours, they, like animals, carry on respiration at night.

3. Decomposition - After death, all organisms decompose, and in this process the bacteria

use oxygen to break down the material. At times this can seriously deplete aquatic

oxygen, especially at night when the oxygen cannot be replaced.

(Chase, 1988)

Temperature

The rates of biological and chemical processes depend on temperature. Aquatic

organisms from microbes to fish are dependent on certain temperature ranges for their

optimal health. Optimal temperatures for fish depend on the species: some survive best in

colder water, whereas others prefer warmer water. Figure 9 shows just what temperatures warm

water fish prefer for different life stages. There are six main things that cause changes in

temperatures:

1. Weather

2. Removal of shoreline vegetation

3. Impoundments

4. Discharge of cooling water

5. Stormwater Runoff

6. Groundwater inflows

Figure 9

Species Life Stage Degrees (C°) Catfish Spawning 24 Incubate 29 Juvenile 32 Adult 32 Smallmouth Bass Spawning 18 Incubate 23 Juvenile 29 Adult 29 Largemouth Bass Spawning 21 Incubate 23 Juvenile None Given Adult 32 Bluegill Spawning 25 Incubate 34 Juvenile None Given Adult 32 Black Crappies Spawning 17 Incubate 20 Juvenile None Given Adult 27 Striped Bass Spawning 18 Incubate 24 Juvenile None Given Adult None Given White Bass Spawning 17 Incubate 26 Juvenile None Given Adult None Given Walleye Spawning 11 Incubate None Given Juvenile None Given Adult 28 (http://ndep.nv.gov/bwqp/file/recommended_temp_criteria06.pdf, 2006)

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Clarity

Water clarity is a measure of water quality related to chemical and physical properties. There are

two main parts related to clarity: true color (materials dissolved in water) and transparency

(materials suspended in water). The transparency is a good indicator of a lake’s algae presence.

Algae is natural and essential in water, but too much of it can cause some major problems. The

best times to test for water clarity with the secchi disc is between the months of June and August.

pH

The pH of water is a measure of the lake’s acid level. Hydrogen and hydroxide ions are what

make up water. The separation of these two ions allows water to be acidic, neutral, or alkaline.

The pH scale ranges from 0-14 making each range either an acid, neutral, or alkaline (Figure 10).

The largest variety of aquatic animals prefers a pH range of 6.5-8.0. pH outside this range

reduces the diversity in the lake, because it stresses the physiological systems of most organisms

and can reduce reproduction. Natural rainfall, exposed to C02 in the atmosphere, maintains a pH

of 5.6 in northwestern WI. Most fish could not reproduce in even the best rainfall if rainwater

pH were not raised by the chemical buffering of the carbonate system in streams, lakes and the

surrounding watershed.

Figure 10

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Macroinvertebrates

A macroinvertebrate is any insect without a backbone that can be seen by the naked eye. One

way to find out the water quality of Bass Lake was to look for indicator species. According to

the Merriam Webster dictionary an indicator species is defined as; an organism or ecological

community so strictly associated with particular environmental conditions that its presence is

indicative of the existence of these conditions. Macroinvertebrates are used in streams to

indicate good or bad water quality. The science isn’t as accurate for lakes. Macroinvertebrates

that indicate good water quality are those that need higher levels of dissolved oxygen and are not

tolerant of pollution. Macroinvertebrates that indicate bad water quality are those that can live in

lower levels of dissolved oxygen. The presences of macroinvertebrates that indicate bad water

quality only indicate bad water quality if they are the only types of macroinvertebrates found.

These “bad water” macroinvertebrates will live in high levels of dissolved oxygen as well as low

levels of dissolved oxygen.

Sampling Procedures

Water quality samples and readings were collected biweekly and weekly at four randomly

chosen sites from June 2007 to August 2007 (Figure 11). Phosphorus, nitrogen, dissolved

oxygen, temperature, clarity, and pH were sampled at these sites.

Water chemistry samples for phosphorus and nitrogen were collected every other week at each of

the four locations. They were collected in plastic containers and stored in a cooler with ice packs

for no longer than 24 hours. The samples were then taken to the UWRF chemistry lab and tested

for nitrate and ortho phosphate with a Hach DR/2400 meter. Each sample was tested following

the manual instructions (Appendix D). A 10ml sample was used for each test. The glass testing

tubes were washed out with distilled water after every use. A sample site was chosen randomly

for running duplicate tests. This helps ensure the accuracy of the results. The results were then

entered into an Excel spreadsheet and graphs were charted. Since the phosphorus was read in

ortho phosphate, it had to be converted into phosphate. According to the EPA, in order to

convert ortho phosphate into phosphate, the PO4 needs to be divided by three.

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Figure 11

19

Dissolved oxygen, temperature, clarity and pH were sampled weekly at these sites. A YSI-55

meter was used at the lake’s surface for measuring dissolved oxygen and temperature. The meter

was calibrated and samples taken according to the manual instructions. Clarity depth was

measured using a secchi disc. The procedures outlined in the WDNR Citizen Lake Monitoring

Training Manual were followed for taking secchi disc readings. Transparency readings weren’t

taken every week due to bad weather and equipment problems. The pH was measured using an

Oakton double junction waterproof pHtestr 1. The meter was calibrated and samples taken

according to the manual instructions.

Macroinvertebrates were also collected to give an idea of just what was living in Bass Lake.

Sixteen traps were built out of plastic mesh and then filled with basalt rock (Figure 12). a long

string was then connected to each trap which was used to secure the trap to the shoreline. Eight

traps were put out at a time at four different locations (Figure 13). They were left for a week at a

time and then collected and sorted.

Figure 12

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Figure 13

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Water Quality Results

Eleven weeks of water quality data were taken at Bass Lake this summer (Figure 15). Appendix

E has a list of all the graphs associated with those results. These results are what determine the

lake to be Oligotrophic, Mesotrophic, or Eutrophic (Figure 14). The Merriam Webster

Dictionary defines these three terms as:

• Oligotrophic- having a deficiency of plant nutrients that is usually accompanied by an

abundance of dissolved oxygen

• Mesotrophic- having a moderate amount of dissolved nutrients

• Eutrophic- a body of water that becomes enriched in dissolved nutrients (as phosphates)

that stimulate the growth of aquatic plant life usually resulting in the depletion of

dissolved oxygen

Figure 14

Quality Phosphorus ChlorophyllSecchi Disc

Index ug/L ug/L ft. Oligotrophic Excellent <1 <1 >19 Very Good 1-10 1-5 8-19 Mesotrophic Good 10-30 5-10 6-8 Fair 30-50 10-15 5-6 Eutrophic Poor 50-150 15-30 3-4

(Konkel, 2006)

The phosphate readings that were found are the ones that show some concern. Just about every

time that ortho phosphate was tested, the readings were over the DNR recommended levels. Past

studies have shown that phosphorus has been on the rise since 1998. The highest ortho

phosphate concentration was over the HACH scale, which is 10.0 mg/L, the lowest was 0.05

mg/L, and the mean was 0.54 mg/L. These levels show Bass Lake to be in the Eutrophic status.

The concentrations of nitrate are all under DNR recommendations, 5 mg/L, and don’t show to be

a threat to the lake. The highest concentration was 4.91 mg/L, the lowest was 0.78 mg/L, and the

mean was 3.09 mg/L.

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Dissolved Oxygen levels are higher than the needed amount for living organisms to survive. The

highest reading was 9.63 mg/L, the lowest was 7.38 mg/L, and the mean was 8.52 mg/L. There

isn’t 11 weeks worth of dissolved oxygen readings due to a problem with equipment. The last

sampling day, 8/22/07, the DO meter was used to find the hypolimnon. It was found it to be

around 26-30 feet.

The secchi depth results are in the good range according to the Trophic Status table. All of the

secchi disc depths fall in the Oligotrophic or Mesotrophic status. The majority of these readings

fall into the Mesotrophic category. The highest reading was 13.25 feet, the lowest was 4.5 feet,

and the mean was 7.4 feet.

pH stayed around the same almost all summer. Theses results also match previous studies that

have been done and they show Bass Lake to be on the alkaline side. This puts Bass Lake in the

hard water category and these lakes tend to have more abundant aquatic plant growth.

Bass Lake water quality samples June - August 2007

Sample Locations Kelly's Swamp Site

1. Elevation 891 ft N 45° 04.664' W092° 38.818

3. Elevation 893 ft 45° 03.441'

W092° 38.807'

5. Elevation 891 ft 45° 03.712'

W092° 38.623' 2. Elevation 892 ft

45° 03.785' W092° 39.156'

4. Elevation 885 ft 45° 03.290'

W092° 38.803' Recommended phosphorus concentration from DNR for lake quality = .01mg/L Recommended nitrate concentration from DNR for lake quality= 5mg/L Nitrogen Equation: y= -0.39000806x + 38.6077357 *Used to convert the absorbancy number given by the Hach DR/2400 to mg/L Temperature Conversion: F°= 1.8(C°)+ 32 pH in Wisconsin lakes usually between 4.5-8.4

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Figure 15

Date Sample Location Time

Dissolved Oxygen (mg/L)

Temp (C°) Transparency (in)

Nitrate (ABS)

Ortho Phosphate

(mg/L)

Phosphate (mg/L)

Sample 1 10:08 NA NA 77 38.59 0.07 0.02 Sample 2 9:55 NA NA 90 38.49 0.55 0.18 Sample 3 9:40 NA NA 74 38.6 0.07 0.02

6/12/2007

Sample 4 9:30 NA NA 72 38.59 0.05 0.02

Date Sample

Location TimeDissolved Oxygen (mg/L)

Temp (C°) Transparency (in)

Nitrate (mg/L)

Ortho Phosphate

(mg/L)

Phosphate (mg/L)

Sample 1 1:07 NA NA 6/24 69 4.91 0.12 0.04 Sample 2 1:14 NA NA 6/24 81 1.32 0.3 0.1 Sample 3 1:27 NA NA 6/24 66 3.47 2.07 0.69

6/19/2007

Sample 4 1:35 NA NA 6/24 63 3.59 0.98 0.33

Date Sample

Location TimeDissolved Oxygen (mg/L)

Temp (C°) Transparency (in)

Nitrate (mg/L)

Ortho Phosphate

(mg/L)

Phosphate (mg/L)

Sample 1 8:25 NA 25.4 63 2.22 0.28 0.09 Sample 2 8:41 NA 25.5 69 3.23 0.07 0.02 Sample 3 8:50 NA 24.8 54 4.64 1.04 0.35 Sample 4 9:00 NA 24.7 63 3.55 1.48 0.49

6/26/07

Duplicate #4 9:01 2.02 1.04 0.35

Date Sample

Location TimeDissolved Oxygen (mg/L)

Temp (C°) Transparency (in)

pH

Sample 1 8:19 NA 23.4 78 9.4 Sample 2 8:31 NA 24.4 69 9.1 Sample 3 9:07 NA 24.3 69 9.1

7/5/07

Sample 4 9:16 NA 24.6 69 9

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Date Sample Location Time

Dissolved Oxygen (mg/L)

Temp (C°) Transparency (in)

pH Nitrate (mg/L)

Ortho Phosphate

(mg/L)

Phosphate (mg/L)

Sample 1 10:33 NA N/A 102 9.2 3.78 0.5 0.17 Sample 2 10:39 NA N/A 120 9.1 1.79 0.32 0.11 Sample 3 10:44 NA N/A 153 9.1 2.65 0.07 0.02 Sample 4 10:51 NA N/A 159 9.1 2.14 1.4 0.47

7/10/2007

Duplicate #2 10:40 2.84 0.1 0.7

Date Sample

Location TimeDissolved Oxygen (mg/L)

Temp (C°) Transparency (in)

pH

Sample 1 10:11 8.84 24.6 N/A 9.4 Sample 2 10:25 8.77 25.1 N/A 9.2 Sample 3 10:33 8.51 25.1 N/A 9.2

7/20/2007

Sample 4 10:35 8.44 25.4 N/A 9.1

Date Sample Location Time

Dissolved Oxygen (mg/L)

Temp (C°) Transparency (in)

pH Nitrate (mg/L)

Ortho Phosphate

(mg/L)

Phosphate (mg/L)

Sample 1 9:30 8.88 25.7 126 9.2 1.4 0.11 0.04 Sample 2 9:54 8.55 25.2 138 9.1 4.44 0.48 0.16 Sample 3 10:06 8.57 25.1 123 9.1 2.1 0.74 0.25 Sample 4 10:17 8.63 25.2 123 9.1 3.08 0.26 0.09

7/25/2007

Duplicate #4 10:17 2.69 0.39 0.13

Date Sample

Location TimeDissolved Oxygen (mg/L)

Temp (C°) Transparency (in)

pH

Sample 1 11:20 9.22 26.5 N/A 9.4 Sample 2 11:30 9.63 26.7 N/A 9.3 Sample 3 11:42 8.87 26.7 N/A 9.2

8/4/2007

Sample 4 11:50 8.67 26.7 N/A 9.2

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Date Sample Location Time

Dissolved Oxygen (mg/L)

Temp (C°) Transparency (in)

pH Nitrate (mg/L)

Ortho Phosphate

(mg/L)

Phosphate (mg/L)

Sample 1 12:05 9.46 26.6 84 9.4 0.78 0.12 0.04 Sample 2 12:16 9.21 26.4 87 9.3 3.23 1.01 0.34 Sample 3 12:31 9.18 26.3 96 9.3 3.43 over over Sample 4 12:46 8.93 26.3 93 9.3 3.27 0.63 0.21

8/9/2007

Duplicate #2 12:16 2.69 0.96 0.32

Date Sample

Location TimeDissolved Oxygen (mg/L)

Temp (C°) Transparency (in)

pH

Sample 1 10:52 7.86 24.8 78 9.3 Sample 2 11:15 8.1 25.1 75 9.2 Sample 3 11:27 7.85 25.3 87 9.2

8/17/2007

Sample 4 11:19 7.86 25.3 87 9.2

Date Sample Location Time

Dissolved Oxygen (mg/L)

Temp (C°) Transparency (in)

pH Nitrate (mg/L)

Ortho Phosphate

(mg/L)

Phosphate (mg/L)

Sample 1 12:17 7.38 22.2 N/A 9.4 3.08 0.09 0.03 Sample 2 11:54 7.74 22.5 N/A 9.3 4.21 0.16 0.05 Sample 3 11:40 7.85 22.4 N/A 9.3 2.96 1.03 0.34 Sample 4 11:45 7.5 22.6 N/A 9.3 3.96 0.79 0.26

8/22/2007

Duplicate #1 12:17 3.27 1.01 0.34

Macroinvertebrate results

Almost all of the macroinvertebrates found were indicators of good water quality. All of the

other macroinvertebrates that were found didn’t really have an effect on the water quality status

in terms of indicator role. Figure 16 will show macroinvertebrates that were found and if they

were indicators of good water quality. Appendix F has all of the numbers at each site that was

found.

Figure 16

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Discussion

All of the following testing results were good: pH, nitrate concentration, transparency, dissolved

oxygen, and temperature. Temperature plays a important role on a lot of the things that were

tested. The last day of testing, 8/22/07, the temperature dropped more than it had all summer.

This has to do with all of the rain storms that St. Croix County had endured. All of the

stormwater runoff caused the lake’s normal temperature to decrease. The storms also caused a

drop in secchi depth clarity. The dissolved oxygen dropped due to the storms because there had

been fewer sunny days compared to the rest of the summer. The aquatic plant life had not been

getting as much light as before. This reduced the amount of photosynthesis while reparation

stayed the same.

The high levels of phosphorus can be linked to the amount of aquatic plant life that exists in Bass

Lake. Phosphorus clings tightly to soil particles and vegetation. With the water level of Bass

Lake being low and the boater use being high, boat motors will stir up more sediment and soil

from the bottom of the lake and cause spiked levels of phosphate. There were a lot of very

windy days on the lake this summer and all the wind and wave action stirs up sediment. Not

allowing your land to have an adequate buffer zone allows for soil erosion, stormwater runoff,

and a greater amount of fertilizer, which in return adds more phosphorus to the lake. Any type of

building or road causes impervious surfaces. The percent of these items compared to your lot

size gives your impervious surface percent and it should not exceed 10%. In all actuality it

should stay around 1%-3%. Any time you can reduce this percent, you should. This can be done

by removing unneeded buildings or roads that are not in use.

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Shoreline Inventory In order to start this inventory, a master inventory sheet had to put in place. This inventory sheet

was made through research of other shoreline inventories that had been done at other places.

After this sheet was made a point system had to be developed for it. This delegated a certain

amount of points for each item according to the benefit of shoreline conservation.

There were 105 parcels of land that were inventoried this summer. Each parcel was given a

score based on how they rated on the monitoring sheet guidelines (Appendix G). This inventory

was done during the last week in June 2007 and the first week in July 2007. It was a visual

survey that was done by boat and some of the information was provided by home owners. The

inventory was also based off of studies done in the past and some guidelines put in force by the

WDNR. Lots were scored on the following:

• Shoreland buffer extending 35’ back from the Ordinary High Water Mark

• A viewing corridor of 35’

• Critical sites that were tested in 2005 by St. Croix County

• DNR regulations

o Structures in water per 50’ of shoreline

o Objects below Ordinary High Water Mark

There was a possible 98 points that could be earned. Nine lots scored 78 or above, forty nine lots

scored 77-58, twenty six lots scored 57-38, and twenty one lots scored 37 or below. A copy of

the individual surveys is located with the BLRD and LWCD.

Discussion

This survey ultimately told us that the majority of shoreline owners are keeping their shorelines

as natural as possible. There were some land owners that don’t seem to be very concerned about

the effects that they have on the lake quality due to things like; mowing all the way to the

shoreline, no natural vegetation between lake and home, allowing erosion to go into the lake, and

disobeying the DNR regulations for shoreline properties. This survey proved to be a good thing

for the BLRD to ask for this summer. We have received calls from people asking what they can

do to improve their score and future things that they could do. Neighbors have also been talking

to each other to compare scores and talking about what they can do to improve.

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Shoreline Runoff Survey On August 22, 2007 a visual survey was done to see just where runoff problems might be

occurring around the lake. These places were ones that might cause major runoff from storms.

They were evaluated and recommendations were given.

The first sight was at the east entrance of Awatukee Trail. There is a culvert that runs under the

road and over towards the lake. This was put there a long time ago when there was farmland on

the upper half of that road. It was assessed and the conclusion was that the drainage basin that

was on the other side of the culvert was deep enough to hold approximately 5 feet of water. This

basin would have to become very full, very fast before any overflow would occur.

The second sight was Bass Lake Trail. This runoff occurred form the gravel road that lead back

to a few homes. This gravel washout ran along the north side of 132nd Ave., but then started to

cut back to the other side of the road towards the woods. The topography of the road at the south

end of the lake allows for the gravel to run away from the lake.

The third sight was the ditch that runs along the Wilson property. This used to be where 132nd

Ave. connected to the east side of the lake. This ditch did show signs of runoff, but it is a

problem that could be fixed. Recommendations were made at that point in time and are listed at

the end of this report.

The last runoff sight that was observed was the detention basin at the boat launch. This basin

was in good working order. This could be seen, because it had caught a lot of water from the

previous storms that week. The concrete lip that is in place between the parking lot and slope of

the boat launch it raised enough to keep the flow of water heading towards the detention basin.

30

Conclusion Bass Lake is a thermally stratified groundwater seepage lake that has had fluctuating lake levels

for many, many years. With the watershed to lake ratio, residents need to be careful of their

daily activities. Encouraging conservation and best management practices will educate the

public on what they can do to help. The BLRD would like to keep the lake as an Outstanding

Water Resource, so they looked into what they could do as a community. They have purchased

their own testing equipment and they will be using it to test the water quality for summers to

come. They are also going to be working with the WDNR, through the Self-Help Monitoring

Program, to have water chemistry samples tested and secchi disc readings recorded. The work

that was done this summer will give the BLRD a step in the right direction to maintaining the

water quality. The residents of Bass Lake have shown an interest in protecting the water and this

will help for future generations.

31

32

Recommendations Bass Lake already has good water quality and the thing to do now is to keep it that way and work

on reducing phosphate levels. In order for Bass Lake to stay an Outstanding Water Resource, I

recommend:

1. Continue monitoring and chemical testing of the water. This can be done through the

WDNR Self-Help Lake Monitoring Program.

http://dnr.wi.gov/org/water/fhp/lakes/selfhelp/

2. Plant some vegetation in the road ditch at the south end of the lake. This will help with

stormwater runoff. Some guidelines to follow are:

a. Seed in Spring (4/15-6/1) or Fall (8/1-8/21) b. Seed mix for that area:

i. Smooth Bromegrass (Bromus inermis), 0.5lbs ii. Creeping Red Fescue (Cestuca rubra), 0.14lbs iii. Alfalfa (Medicago sativa), 0.14lbs iv. Red Clover (Trifolium pretense), 0.14lbs

c. Install one erosion logs

3. Properly maintain all private roads around Bass Lake to ensure no gravel runoff.

4. Participate in St. Croix County’s program for soil testing. Encourage all lake

residents to have their soil nutrient levels tested.

5. Keep in contact with the parks department to make sure the boat landing is being

maintained so that stormwater runoff filters into the detention pond.

6. Encourage residents to join WAL (Wisconsin Association of Lakes) and sign up for

their e-mail newsletter. www.wisconsinlakes.org

7. Remind residents and boaters to participate in Clean Boats, Clean Waters Program.

http://www.uwsp.edu/cnr/uwexlakes/CBCW/

8. Encourage residents to maintain a natural shoreline.

9. Encourage residents to attend meetings and picnics to keep themselves informed on

what is happening around the lake.

10. Impact on lake quality occurs when the watershed has 7% impervious surface. Contact

Town and County representatives about keeping impervious surface low within Bass

Lake’s Watershed. Encourage conservation development.

11. Update the signs that are posted at the boat launch. The better people can read them, the

better they will be at obeying the rules and regulations.

12. Contact the Bureau of Water Resources Management Groundwater Section and try to

have a study conducted to determine the nutrient contribution of septic systems.

References Chase, Valerie. Dissolved Oxygen, Carolina Tips, May 1, 1988.

"Dissolved Oxygen", LaMotte Company brochure, 8/24

Engel, M.P. Basic Fish Survey of Bass Lake- St. Croix County. Wisconsin Department of Natural Resources Project FM02BAL FM687. September 1988.

Konkel, Deborah and Susan Borman. 1996. Changes in the Aquatic Plant Community of Bass

Lake, St. Croix County, 1987-1996. Wisconsin Department of Natural Resources. Murphy, Sheila. General Information on Phosphorus. 2007. 24 Aug. 2007 < http://bcn.

boulder.co.us/basin/data/BACT/info/TP.html> St. Croix County Planning and Zoning Department. St. Croix County Code of Ordinances Land

Use Development.2003. 27 Aug. 2007 < http://www.co.saint-croix.wi.us/Ordinances/Ch%2017%20SUBCHAPTER%20III%20Shoreland.pdf>

U.S. Environmental Protection Agency. 2007. 23 Aug. 2007 <http://www.epa.gov/owow/

monitoring/volunteer/stream/vms54.html>

U.S. Environmental Protection Agency. 1997. 23 Aug. 2007 < http://www.epa.gov/ volunteer/stream/stream.pdf>

USGS: Science for a Changing World. 2007. 24 Aug. 2007 <http://interactive2.usgs.

gov/faq/list_faq_by_category/get_answer.asp?id=641> Wilkes University Center for Environmental Quality Environmental Engineering and Earth

Sciences Phosphates and Water Quality. 24 Aug. 2007 < http://www.water-research.net/phosphate.htm>

Wisconsin Department of Natural Resources, West Central Wisconsin Regional Planning

Commission. Phase I Diagnostic and Feasibility Study for Bass Lake St. Croix County, Wisconsin. 1992.

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