Lake Sheridan Cottagers' Association



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LAKE SHERIDAN

LAKE AND WATERSHED ASSESSMENT STUDY

FINAL REPORT

August 2002

Presented to:

Lake Sheridan Cottagers’ Association

RR #2, Box 2223

Nicholson, PA 18446

Prepared by:

F. X. Browne, Inc.

1101 South Broad Street

Lansdale, Pennsylvania 19446

(800) 220-2022

LAKE SHERIDAN

LAKE AND WATERSHED ASSESSMENT STUDY

FINAL REPORT

August 2002

Presented to:

Lake Sheridan Cottagers’ Association

RR #2, Box 2223

Nicholson, PA 18446

Prepared by:

F. X. Browne, Inc.

1101 South Broad Street

Lansdale, Pennsylvania 19446

(800) 220-2022

FXB File No. PA1385-03

Table of Contents

Section Page

Executive Summary i

1.0 Project Description 1

1.1 Background 1

1.2 Project Objectives 1

2.0 Lake and Watershed Characteristics 4

2.1 Lake Morphology 4

2.2 Watershed Characteristics 4

2.2.1 Topography 5

2.2.2 Geology 5

2.2.3 Soils 5

2.2.4 Current and Future Land Use 5

2.3 Benefits and Recreational Use of Lake Sheridan 6

2.3.1 Present Uses 6

2.3.2 Impairment of Recreational Uses 8

2.4 Population and Socio-Economic Structure 8

3.0 Water Quality 10

3.1 Lake Ecology Primer 10

3.2 Study Design and Data Acquisition 11

3.3 Lake Water Quality 15

3.3.1 Temperature and Dissolved Oxygen 15

3.3.2 pH 18

3.3.3 Total Suspended Solids and Transparency 18

3.3.4 Phosphorus 19

3.3.5 Nitrogen 20

3.3.6 Limiting Nutrient 21

3.3.7 Phytoplankton 22

3.3.8 Chlorophyll a 22

3.3.9 Macrophytes 23

3.3.10 Trophic State Index 23

3.3.11 Sediment Analyses and Bathymetric Survey 26

3.4 Stream Water Quality 29

4.0 Pollutant Sources 31

4.1 Hydrologic Budget 31

4.2 Pollutant Budgets 33

4.3 Phosphorus Modeling 36

4.3.1 Evaluation of Models 37

4.3.2 Modeling Results 37

4.4 Phosphorus Reduction Requirements 38

5.0 Lake Sheridan Watershed Problem Areas 39

5.1 Identification of Nonpoint Source Pollution Problem Areas 39

5.1.1 Existing Studies 39

5.1.2 Watershed Evaluations 39

5.2 Nonpoint Source Pollution Problem Identification Map 39

6.0 Management Plan for Lake Sheridan 41

6.1 Existing Management and Restoration Programs 41

6.1.1 Grass Carp Stocking of Lake Sheridan 41

6.1.2 Chemical Herbicides and Algicides 41

6.1.3 Agricultural Programs 42

6.1.4 County Conservation Districts 43

6.1.5 Septic System Management Programs 43

6.1.6 The Countryside Conservancy 43

6.1.7 The Susquehanna River Basin Commission 44

6.2 In-Lake Management Recommendations 44

6.2.1 Alum Treatment 44

6.2.2 Spot Dredging 45

6.3 Watershed Management Recommendations 46

6.3.1 Agricultural Best Management Practices 47

6.3.2 Stormwater Management 47

6.3.3 Site Development Erosion and Sedimentation Pollution

Control 48

6.3.4 Streambank and Shoreline Stabilization 49

6.3.5 Dirt and Gravel Road Maintenance 50

6.3.6 Golf Course Management 50

6.3.7 Wastewater Treatment and Septic System Management 51

6.3.8 Waterfowl Control 52

6.4 Additional Watershed Management Recommendations 54

6.4.1 Riparian Stream Corridor Buffer Ordinance 54

6.4.2 Open Space Management 54

6.4.3 Public Education and Participation Program 54

6.4.4 Homeowner Practices 55

6.4.5 Water Quality Monitoring Program 55

7.0 Implementation of Lake and Watershed Management Programs 57

7.1 Implementation Programs, Costs, and Funding Sources 57

7.2 Existing Programs 57

7.2.1 Agricultural Best Management Practices 57

7.2.2 Sewage Facilities 57

7.3 Lake and Watershed Management Recommendations 57

7.3.1 In-Lake Management 57

7.3.2 Stormwater and Gravel Road Management 58

7.3.3 Open Space Planning and Zoning Ordinances 58

7.3.4 Water Quality Monitoring 59

7.3.5 Public Education and Participation 59

7.3.6 Golf Course Management 59

7.4 Prioritization of Lake and Watershed Management

Recommendations 60

8.0 Literature Cited 61

List of Tables

Table Page

2.1 Morphometric and Hydrologic Characteristics of Lake Sheridan 4

2.2 Current Land Use in the Lake Sheridan Watershed 6

2.3 Population Data for Lackawanna and Wyoming Counties and Townships

within the Lake Sheridan Watershed 9

3.1 Lake Sheridan Water Quality Monitoring Program Water

Quality Parameters 12

3.2 Mean Dissolved Reactive and Total Phosphorus Concentrations

in Lake Sheridan 20

3.3 Mean Ammonia, Nitrate/Nitrite, Total Kjeldahl Nitrogen, and Organic

Nitrogen Concentrations in Lake Sheridan 21

3.4 Mean Nitrogen to Phosphorus Ratios in Lake Sheridan 22

3.5 Carlson’s Trophic State Index Values for Lake Sheridan 25

3.6 Sediment Analyses Results for Lake Sheridan 26

3.7 Lake Sheridan Stream Station GPS Coordinates and Sub-Basin

Drainage Areas 29

3.8 Stream Water Quality Data for Major Sub-watersheds to Lake SheridanMean Concentrations 30

4.1 Hydrologic Characteristics of Major Sub-watersheds to Lake Sheridan 33

4.2 Annual Pollutant Budgets for Lake Sheridan and its Sub-watersheds 35

4.3 Areal Pollutant Loadings for Lake Sheridan and its Major Sub-watersheds 36

6.1 Potential Watershed Management and In-Lake Restoration Alternativesfor Lake Sheridan 42

List of Figures

Figure Page

1.1 Lake Sheridan Watershed Location Map 2

2.1 Lake Sheridan Watershed Land Use Map 7

3.1 Lake Sheridan Monitoring Station Location Map 14

3.2 Temperature profiles for the Upper Basin of Lake Sheridan during the

1998 growing season 15

3.3 Dissolved oxygen profiles for the Upper Basin of Lake Sheridan

during the 1998 growing season 15

3.4 Temperature Profiles for the Lower Basin of Lake Sheridan during the

1998 growing season 17

3.5 Dissolved oxygen profiles for the Lower Basin of Lake Sheridan

during the 1998 growing season 17

3.6 Lake Sheridan Macrophyte Map 24

3.7 Lake Sheridan Sediment Thickness Map 28

List of Appendices

A Glossary of Lake and Watershed Management Terms

B Lake Water Quality Data

C Dissolved Oxygen and Temperature Profile Data

D Phytoplankton Data

E Lake Sediment Data

F Stream Water Quality Data

G Nonpoint Source Pollution Area Map and Correlative Spread Sheets

I Model Riparian Corridor Ordinance

J South Branch Tunkhannock Creek Watershed Assessment Report

Executive Summary

Overview

Lake Sheridan is a 95-acre impoundment located in Lackawanna and Wyoming Counties in northeastern Pennsylvania. Lake Sheridan consists of two basins, a 64.5-acre northern basin and a 26.7-acre southern basin, that are joined by a narrow 875-foot-long, 4.2-acre channel. The northern basin was a shallow natural lake until the existing dam was constructed to deepen the northern basin and to create the smaller, shallower southern basin. The lake is privately owned and operated by the Lake Sheridan Cottagers’ Association. Lake Sheridan is located approximately 12 miles north of the City of Scranton. This scenic lake serves as a very important natural resource for the residents surrounding the lake who make up the Lake Sheridan Cottagers’ Association. Recreational activities include swimming, picnicking, fishing, power boating, water-skiing, sailing, hiking, wildlife observation, and other water related activities and sports.

In recent years, the water quality in Lake Sheridan has severely deteriorated. During the summer months, the lake is plagued by severe algal blooms, nuisance stands of aquatic weeds, extremely low dissolved oxygen levels, and the excessive accumulation of sediments. In order to improve and protect the water quality in Lake Sheridan, the Lake Sheridan Cottagers’ Association retained F. X. Browne, Inc. to perform an assessment of Lake Sheridan and its watershed. The study was initiated in1998, funded by the Lake Sheridan Cottage Owners Association, using the basic guidelines of a Phase I Diagnostic Feasibility Study. Pennsylvania Department of Environmental Protection Growing Greener funds were used to supplement the project and complete a lake and watershed management plan.

The Lake Sheridan Lake and Watershed Assessment Project includes the collection and analysis of lake and stream water quality data, evaluation of lake and watershed characteristics, performance of watershed tours to identify nonpoint sources of pollution, calculation of pollutant budgets for the lake, and development a lake and watershed management plan. This final report addresses the “ecological health” of the lake, identifies the major sources of nonpoint pollution to the lake, prioritizes the major sources of pollution to the lake, and provides a technically sound management plan to reduce nonpoint sources of pollution to the streams and to Lake Sheridan. A brief summary of the conclusions and recommendations of the Lake Sheridan Lake and Watershed Assessment Study are provided below.

Conclusions

As part of the Lake Sheridan Lake and Watershed Assessment Study, a lake and stream water quality monitoring program was conducted from July through September 1998. No significant or relevant past data were available for Lake Sheridan, and therefore, no trend analysis was completed. Based the 1998 study data, the following conclusions were made:

Lake, Stream, and Watershed Characteristics

• The average water depth in Lake Sheridan is approximately 10-12 feet in the northern basin and 3 feet in the southern basin. The maximum depth of 23 feet occurs in the northern basin. The total surface area of the lake is approximately 95 acres: 64.5 acres in the northern basin and 26.7 acres in the southern basin. The lake volume is estimated at 802.6 acre feet. The shoreline is approximately 2.9 miles. The watershed, or contributory drainage area to Lake Sheridan, is approximately 5.81 square miles.

• Four un-named streams feed directly into Lake Sheridan; three into the upper, northern basin and one into the lower, southern basin. The sub-watershed areas vary in size from 182 acres to 2,656 acres, the largest of which represents approximately 71% of the total watershed to Lake Sheridan (see Figure 3.1). There are approximately 331 acres of direct drainage to the lake.

• The watershed area to lake surface area ratio for Lake Sheridan is 39:1, and the mean hydraulic residence time has been calculated at 39 days. These statistics indicate that implementing watershed best management practices should have a measurable effect on the water quality in the lake.

• Soils within the watershed are slightly erodible with some areas listed as moderate erosion hazard. The topography in the Lake Sheridan watershed is variable with nearly level to extremely steep slopes throughout. Therefore, even though erosion hazards may be slight, erosion problems may be greatly accelerated by disturbance of the steeper sloped areas.

• The dominant existing land use within the watershed area is forested land (54%), followed by agricultural land (29.1%) wetland (10.6%), and open water (6.3%). Developed land within the watershed represents less than one percent of the land use (see Figure 2.1). It should be noted that these land use calculations were based on satellite imagery, and it is likely that some of the forested areas and areas around open waters that include homes did not show up as residential areas even though they do include residences. Current land use trends indicate low residential development; however, this is expected to change as the cleared land that is no longer farmed will likely be converted to residential and commercial development. The close proximity to the Scranton/Wilkes-Barre metropolitan area greatly increases the potential for development within the Lake Sheridan watershed area.

• The majority of the land immediately adjacent to the lake is either undeveloped, steeply sloped woodland or high density residential land. There are approximately 220 permanent and summer homes within the adjacent, direct drainage areas surrounding Lake Sheridan. These lots are currently all serviced by on-lot septic systems. Many of these septic systems are conventional drain fields that are poorly maintained or are malfunctioning. Also, many of these septic systems were designed for summer (second) homes that have since become permanent residences that over-burden the systems. The impact of nutrient and bacterial contamination to Lake Sheridan from these septic systems is documented but not well quantified. Central sewage wastewater treatment has been proposed and approved for these problems areas and will be implemented within the next few years.

• Lake Sheridan is “impaired” based on water quality standards presented in Chapter 93 of the Pennsylvania Code. The lake is classified in Chapter 93 as a Cold Water Fishery with a maximum water temperature of 66OF allowable in the epilimnion. Water temperatures in the epilimnion of both basins exceeded this standard during the study period, and was only slightly lower than 66OF during September. This standard was exceeded throughout the entire water column in the lower basin during July and August. During July and August, the dissolved oxygen concentrations in the metalimnion and hypolimnion of the upper, deeper northern basin were nearly 0 mg/L whenever water temperatures were below the 66OF standard.

• Lake Sheridan should be classified as “impaired” based on user definition. Dissolved oxygen levels in the epilimnions of both basins during the growing season dropped to dangerously low levels, threatening both cold and warm water fish species. In the cooler waters of the hypolimnion, the dissolved oxygen concentrations dropped to near 0 mg/L during the study period, inhibiting sustainable conditions for fish and many other aquatic organisms. The severe blue-green algae blooms that usually occur throughout the growing season make the lake unsafe and unusable for recreation. The dense algae also greatly reduces the aesthetic values of the lake. Sedimentation in the upper basin near the main inlet to the lake is also a problem threatening the benthic community and fish spawning, as well as reducing the navigable areas of the lake for boating.

Water Quality

• The upper, northern basin of Lake Sheridan essentially serves as a settling basin for the lower, southern basin, removing sediments and associated nutrients. Therefore, the upper basin has become increasingly filled in by sediment (larger and heavier particles such as silt, sand, and gravel). A sediment thickness map is provided in Figure 3.7. Finer particulate matter (smaller and lighter particles such as clay and silt) and organic matter is generally held in suspension until reaching the lower basin where much of this material precipitates to the lake bottom. Internal phosphorus loading from these sediments is suspected to contribute significantly to the available nutrients within the epilimnion.

• Lake Sheridan is well-suited for warm water fish species; however, due to severe dissolved oxygen depletions in the bottom waters and increased temperatures in the top waters throughout the entire growing season, cold water fish species would likely not survive.

• Phosphorus appeared to be the "limiting nutrient” in Lake Sheridan throughout the growing season; however, the control of both phosphorus and nitrogen inputs to the lakes is important.

• The Carlson’s Trophic State Index (TSI) values for Lake Sheridan, based on total phosphorus, chlorophyll a, and Secchi disk transparency were 55, 64, and 54 for the upper northern basin and 75, 70, and 66 for the lower southern basin, respectively. Based on Carlson’s TSI values, the upper basin of Lake Sheridan is considered eutrophic, while the lower basin is considered hyper-eutrophic. See Appendix A for a glossary of Lake and Watershed Management Terms.

• Stormflows in the influent streams transported much higher concentrations of sediments, nutrients, and bacteria to Lake Sheridan than did baseflows.

• Phosphorus, nitrogen, suspended solids, and fecal bacteria concentrations increased one order of magnitude higher during stormwater conditions than under baseflow conditions.

• Based on stream water quality and quantity information obtained as part of this study, the following hydrologic and pollutant budgets were calculated for Lake Sheridan:

Surface Water Inputs 2,626 Million gal/yr

Phosphorus Load (Total Phosphorus) 862 lbs/yr

Nitrogen Load (Total Nitrogen) 11,126 lbs/yr

Total Suspended Solids Load 67,952 lbs/yr

Percent Phosphorus Reduction

Required 36%

Phosphorus Reduction Needed to

Achieve Mesotrophic Phosphorus levels 312 lbs/yr

Watershed Management Plan Recommendations

Based on the diagnostic and feasibility portions of the Lake Sheridan Watershed Assessment Study, the following recommendations were developed as part of the Lake and Watershed Management Plan. The Lake Sheridan Lake and Watershed Management Plan focuses primarily on reducing nonpoint source pollution from identified agricultural, residential, and commercial problem areas. The plan recommends specific in-lake restoration and watershed management techniques designed to further reduce nonpoint source pollution to Lake Sheridan and to manage in-lake water quality.

Each element of the recommended Lake and Watershed Management Plan for Lake Sheridan is described below.

Continuation of Existing Programs

• The Lake Sheridan Cottagers’ Association currently uses algicides to control nuisance levels of algae. A modified lake monitoring program should be implemented to best detect algae populations during the growing season. Limited monitoring would sufficiently identify the applicability of algicide use with respect to algal biomass and algal species. Effective use of algicides is greatly dependent on algal species, as certain species are very tolerant and may not respond to available treatments.

• Triploid Grass Carp should continue to be stocked in the lake as planned to help reduce nuisance stands of aquatic plants, or macrophytes. Additional stocking may be required in the event that an adequate level of treatment cannot be accomplished, or at such time when the level of treatment naturally declines. Ongoing monitoring of the aquatic macrophyte coverage and densities is recommended to document the long-term success of the grass carp stocking and to determine additional management requirements. A macrophyte map is provided in Figure 3.6. Annual vegetation monitoring and mapping should be performed by the Cottagers’ Association or a consultant to track changes in species specific coverage resulting from the grass carp program. Macrophyte sampling should be conducted throughout all shallow areas (less than 12 feet) in each basin, sufficient to produce species specific, macrophyte coverage maps for each year, allowing for comparisons with prior years’ mapping.

• The Lackawanna and Wyoming County Conservation Districts and the Natural Resource Conservation Service are currently working with active farms within the watershed to implement nutrient management plans and other agricultural best management practices. Currently, only two farms in the watershed have nutrient management plans, but only two other farms have livestock. This work should be continued and expanded to incorporate as many active farms as possible. Agricultural nonpoint source pollution reduction strategies include construction of loafing pads, stream-side fencing, stream crossings, streambank stabilization, manure storage/handling facilities, constructed wetlands, and conservation crop farming practices. Each farm operation within the watershed should be evaluated to determine additional best management practices necessary to correct and minimize nonpoint source pollution. A prioritized action plan should be developed for each operation, and should include cost estimates, project partners, and viable sources of funding.

• The Chesapeake Bay Program has funded past studies of the South Branch Tunkhannock Creek which includes the Lake Sheridan Watershed. Additional funding from the Chesapeake Bay Program for watershed restoration and protection projects should be pursued to correct nonpoint source pollution problem areas and to protect the water resources from future degradation.

• The Countryside Conservancy was founded to preserve and protect the natural resources within Northeastern Pennsylvania. To accomplish these goals, the Conservancy works with large and small land owners to acquire land and to place environmentally sensitive areas under management programs such as conservation easements and deed restrictions. The protection of streams, wetlands, and riparian corridors receive top priority. The Conservancy should be contacted to see if any areas within the Lake Sheridan watershed are eligible for their programs.

• The Susquehanna River Basin Commission has conducted past studies throughout the Susquehanna River Basin in Pennsylvania which included Lake Sheridan. Regulatory and research information should be pursued to assist with watershed protection within the Lake Sheridan Watershed.

In-Lake Management Recommendations

• Spot dredging should be implemented as needed only where necessary boat trafficking is impeded near lake inlets. Mechanical dredging could be completed by temporarily lowering the lake water elevation and using equipment from the shoreline to mechanically remove accumulated sediments. Such dredging would improve recreational values and would remove the accumulated sediments and their associated nutrients that contribute to eutrophic lake conditions. A detailed bathymetric survey and dredging feasibility study should be conducted prior to any lake dredging activities. All dredging activities require federal, state, and local regulatory approvals and permits. Spot dredging of less than one acre in a reservoir with a registered dam is considered a maintenance activity that generally only requires an approval of a formal erosion and sedimentation pollution control plan by the county conservation district and an approval by the Pennsylvania Department of Environmental Protection Office of Dam Safety. As part of this approval process, Dam Safety will also issue the federal approvals in the form of a State Programmatic General Permit No. 2 (SPGP-2) and the federal 401 Water Quality Certification. Wetlands mitigation may be required for the project, depending on the dredging location.

• Alum treatment implemented at the main tributary inlet to the lake would help to remove incoming nutrients. Periodic “batch” alum treatments may be required to prevent or reduce internal nutrient loading in the upper basin where the deeper, hypolimnetic waters become anoxic and allow phosphorus release from the sediments. Additional water monitoring should be conducted before alum treatment is initiated, including bench-scale laboratory tests to determine the application rate of the alum, and in-lake testing of pH and alkalinity. Flow monitoring should also be conducted in Lake Sheridan before initiation of alum treatment in order to document the flushing rate and determine the necessary frequency of alum application.

Watershed Management Recommendations

• Stream channels with severe erosion should be stabilized through the combined or exclusive use of bioengineering techniques (e.g., vegetative measures) and structural methods (e.g., rip-rap) to reduce erosion and sedimentation. Streambank stabilization is an effective method for the removal and prevention of nonpoint source pollution including total suspended solids, phosphorus, and nitrogen.

• Agricultural waste handling facilities should be installed at all active, large and small livestock operations within the watershed to reduce nutrient and bacteria inputs to streams and to Lake Sheridan.

• Nutrient management plans have been developed for two of the farms in the Lake Sheridan watershed. Nutrient management plans should be developed for all additional active livestock and crop farming operations in the Lake Sheridan Watershed with the assistance of the Lackawanna and Wyoming County Conservation Districts.

• Conservation crop farming practices should be encouraged for all crop farming operations within the watershed to reduce nutrient and sediment inputs to streams and to Lake Sheridan. Many of the crop farmed areas of the watershed are located on moderate to steep slopes where soil erosion can be very severe.

• The proposed central wastewater treatment plan for Lake Sheridan, Baylors Pond, and other surrounding areas should be implemented to replace the malfunctioning and sub-standard on-lot disposal systems. The outlet of this centralized facility should be below Lake Sheridan in the outlet stream channel. Implementation of individual residential and community spray irrigation systems should be investigated as an alternative method of wastewater disposal in the areas that are not serviced with the central wastewater system. Properly designed, maintained, and operated spray irrigation systems provide highly effective treatment of residential wastewater and allow for maximum recharge of groundwater, a benefit that is completely lost by small package and large community wastewater treatment facilities that use stream discharge for treated effluent.

• Erosion and Sedimentation Control Plans should be developed for all new construction sites within the watershed to limit the amount of sediment entering streams and drainage ditches, and eventually Lake Sheridan. Site development or any earthmoving activities that lack or have inadequate erosion and sedimentation pollution controls should be immediately reported to the County Conservation Districts so that timely correction may ensue.

• Township ordinances should be revised or adopted for stormwater management, riparian stream corridor buffer establishment and restoration, wetlands protection, subdivision and land development, and natural features conservation.

• Dirt and gravel roadways should be better managed to control stormwater runoff and erosion, or they should be resurfaced with a more erosion resistant top course. Many existing gravel roadways follow steep slopes and experience extreme erosion conditions. The Dirt and Gravel Roads Program through the State Conservation Commission, as executed by the Lackawanna and Wyoming County Conservation Districts, should be pursued to address severe erosion problems associated with construction and maintenance of existing and proposed gravel roadways within the Lake Sheridan Watershed. The moderate and steep slopes throughout the watershed present a challenging management problem in certain areas, specifically along Farnham Road north of Baylor’s Pond, and along the north and south shores of Lake Sheridan.

• Watershed investigations should be conducted on a continual basis by the Lake Sheridan Cottagers’ Association. The initial efforts as part of this project focused on locating roadside and streambank erosion problems in the watershed. Additional watershed investigations should be performed to document the location and magnitude of additional streambank erosion problems within the watershed. Areas and reaches of stream channels that are not accessible by roads should be evaluated by walking the channels with landowner permission. The focus should then be expanded to identify all other nonpoint source problem areas.

• An inventory of all drainage facilities along state highways within the Lake Sheridan Watershed should be conducted to document the condition of all drainage facilities and erosion problems. The results of this survey should be presented to the Pennsylvania Department of Transportation with a request for assistance.

• Riparian buffers should be re-established throughout developed and farmed areas within the Lake Sheridan Watershed. A permanent wooded buffer along all streambanks is the most desirable buffer to provide stable ground cover and shading of the stream channels. Native warm season grasses should be planted to establish an effective temporary buffer until the more permanent shrubby and woody buffer can become established. A narrow strip of warm season grasses should be maintained between the wooded buffer and the tilled or grazing fields to provide maximum filtration for agricultural runoff.

* The Lake Sheridan Cottagers’ Association should approach the Lakeland Golf Course to discuss ways to improve golf course maintenance and reduce the nonpoint source pollution from entering the waterways. Planting vegetative buffer strips around all water bodies, managing fertilizer application such that application rates can be reduced, and maintaining gravel driveways, paths, and drainage structures on the golf course so that sediment loadings are reduced are all possible BMPs for the golf course. If possible, the Lake Sheridan Cottagers’ Association should apply for a Growing Greener grant in conjunction with the golf course that would specifically address these nonpoint source pollution issues.

• A riparian stream corridor buffer ordinance should be adopted by Benton Township, Lackawanna County and Nicholson Township, Wyoming County to help protect streams and Lake Sheridan from the impacts of development within the watershed. The ordinance should also incorporate enhancement and restoration of stream corridor buffers.

* Canada geese populations in the Lake Sheridan watershed are excessive and should be controlled by landscaping, egg inactivation, chemical deterrents, scare tactics, and culling during summer molt. Residents should be discouraged from feeding the geese and other waterfowl. Signs should be posted at strategic locations in the watershed to inform people about not feeding the waterfowl. An ordinance prohibiting feeding and subsequent enforcement is recommended.

* Since Edwards’ Pond (also known as Beaver Pond) and the pond outlet show signs of significant eutrophication, and are directly upstream of Lake Sheridan, the source of nutrient loading should be further investigated.

• Benton Township in Lackawanna County and Nicholson Township in Wyoming County should re-evaluate existing zoning and land development ordinances to ensure that open space planning is encouraged. Open space provisions in all new site developments should be required.

• A comprehensive watershed education program should be developed for implementation in local public schools. Also, fact sheets and brochures should be developed and presented to the Lake Sheridan Cottagers’ Association members, as well as other associations and residents within the Lake Sheridan Watershed. Homeowner seminars should be conducted to educate local citizens about the benefits of reducing nonpoint source pollution.

• Water quality monitoring of Lake Sheridan should continue in order to develop baseline environmental information and to illustrate the benefits of implemented lake and watershed management recommendations. Annual monitoring of selected parameters (i.e. dissolved oxygen/temperature, pH, total nitrogen, total phosphorus, chlorophyll a, and Secchi disk transparency) should be conducted to document water quality changes in the lake. Monitoring should take place once per month during the growing season in order to account for climatic influences.

• Funds available through the Pennsylvania Section 319 Nonpoint Source Management Program and the Pennsylvania Department of Environmental Protection Growing Greener Grant Program should be pursued to conduct further watershed studies and to correct nonpoint source pollution problem areas in the Lake Sheridan Watershed. The Lake Sheridan Cottagers’ Association should apply for a Growing Greener grant during the next round of funding to help defray the costs of the in-lake diagnostic studies and stormwater management activities in the watershed. The PA DEP gives priority to projects that implement recommendations from existing watershed management plans. A Growing Greener grant application should also be submitted to help defray costs of BMPs and stormwater management at the Lakeland Golf Course.

1.0 Project Description

1.1 Background

The Lake Sheridan Lake and Watershed Assessment Study was initiated in 1998, funded by the Lake Sheridan Cottage Owners Association, and conducted using the basic guidelines of a Phase I Diagnostic Feasibility Study. Pennsylvania Department of Environmental Protection Growing Greener funds were used to supplement the project and complete a lake and watershed management plan.

Lake Sheridan is a 95-acre impoundment located in in Lackawanna and Wyoming Counties in northeastern Pennsylvania. Lake Sheridan was created as a multi-purpose impoundment for land development improvement and recreation. The lake is privately owned and operated by the Lake Sheridan Cottagers’ Association. Lake Sheridan is located approximately 12 miles north of the City of Scranton, as shown in Figure 1.1. This scenic lake serves as a very important natural resource for the residents surrounding the lake who make up the Lake Sheridan Cottagers’ Association.

In recent years, the water quality in Lake Sheridan has severely deteriorated. During the summer months, the lake is plagued by severe algal blooms, nuisance stands of aquatic weeds, extremely low dissolved oxygen levels, and the excessive accumulation of sediments. In order to improve and protect the water quality in Lake Sheridan, the Lake Sheridan Cottagers’ Association retained F. X. Browne, Inc. to perform an assessment of Lake Sheridan Lake and its watershed and to develop a lake and watershed management plan.

1.2 Project Objectives

The primary objective of the Lake Sheridan Lake and Watershed Assessment Study was to develop a lake and watershed management program based on past and current water quality data. The project included the collection and analysis of lake and stream water quality data, evaluation of lake and watershed characteristics, performance of watershed tours to identify nonpoint sources of pollution, calculation of pollutant budgets for the lake, and development a lake and watershed management plan. This final report addresses the “ecological health” of the lake, identifies the major sources of nonpoint source pollution to the lake, prioritizes the major sources of pollution to the lake, and provides a technically sound management plan to reduce nonpoint sources of pollution to the streams and to Lake Sheridan. Both wet and dry weather water quality data were collected for this study to develop pollutant loadings for the four major sub-watersheds to Lake Sheridan. Average nutrient and sediment concentrations for baseflow conditions were taken from stream water quality data collected from four representative streams in the adjacent Lackawanna Lake Watershed. These data were collected during the growing season of 1997 which exhibited similar rainfall and climactic conditions to the growing season of 1998. The land uses, soils, and topography of the Lackawanna Lake Watershed are very similar to those of the Lake Sheridan Watershed.

Figure 1.1 Lake Sheridan Watershed Location Map

The ultimate goal of this study is to implement prioritized restoration recommendations or Best Management Practices (BMPs). A detailed watershed evaluation was conducted to identify and locate nonpoint sources of pollution including agriculture, silviculture, on-lot wastewater disposal, stormwater runoff, streambank and shoreline erosion, and other sources. The study approach combined water quality data and watershed assessments to develop a lake and watershed management plan that includes prioritized lake and watershed best management practices (BMPs). The implementation of the BMPs included in the study is intended to improve the water quality of Lake Sheridan and to protect and preserve the recreational, educational, and wildlife values of this valuable resource.

To attain the goals of the study, the following tasks were completed for the Lake Sheridan Watershed Assessment:

• Development of a work plan to provide a comprehensive framework for a sound lake and watershed study with measurable results,

• Implementation of a Quality Assurance and Quality Control Plan to assure accurate water quality sampling procedures, testing methods, and laboratory results,

• Study and analysis of pertinent environmental watershed characteristics within the watershed including: topography, geology, hydrology, groundwater, and soils, including the collection and analysis of current and projected land use information, and the estimated proportion of pollution originating from each type of land use,

• Identification and mapping of nonpoint source problem areas through a complete investigation of the watershed, and

• Development of a Lake and Watershed Management Plan which includes structural and non-structural best management practices (BMPs), and a determination of the most effective BMPs for the Lake Sheridan watershed.

2.0 Lake and Watershed Characteristics

2.1 Lake Morphology

Lake Sheridan is a 95-acre impoundment located in Lackawanna and Wyoming Counties in Northeastern Pennsylvania. Lake Sheridan consists of a 64.5-acre northern basin and a 26.7-acre southern basin that are joined by a narrow 875-feet long, 4.2-acre channel, as shown in Figure 1.1. The northern basin was a shallow natural lake until the existing dam was constructed to deepen the northern basin and to create the smaller, shallower southern basin. The dam is concrete with a broad crested weir spillway. A gate valve allows complete drawdown of the lower basin. The average lake water surface elevation is 998 feet above mean sea level. A complete listing of the Lake Sheridan morphometric and hydrologic characteristics is summarized in Table 2.1.

| |

|Table 2.1 |

|Morphometric and Hydrologic Characteristics of Lake Sheridan |

| | |

|Watershed Area |3,720 Acres (5.81 Square Miles) |

| | |

|Lake Surface Area |95 Acres |

| | |

|Lake Volume |261 Million Gallons |

| | |

|Average Depth |11 Feet (3.35 Meters) - Northern Basin |

| |3 Feet (0.91 Meters) - Southern Basin |

| | |

|Maximum Depth |23 Feet (7.01 Meters) |

| | |

|Drainage Basin Area: Lake Surface Area Ratio |39:1 |

2.2 Watershed Characteristics

The watershed area draining to Lake Sheridan is approximately 3,720 acres, or 5.81 square miles. There are four main tributaries to the lake. Three of the tributaries feed into the upper, northern basin and one tributary feeds into the lower, southern basin. The sub-watershed areas vary in size from 182 acres to 2,656 acres; the largest of which represents approximately 71% of the total watershed to Lake Sheridan. There are approximately 331 acres of direct drainage to the lake (see Figure 3.1). The discharge from Lake Sheridan flows into the South Branch Tunkhannock Creek to the southwest. The South Branch Tunkhannock Creek discharges directly to the Tunkhannock Creek which discharges to the Susquehanna River at the Town of Tunkhannock, Pennsylvania. The Susquehanna River is a major tributary to the Chesapeake Bay. Additional watershed characteristic information is presented in the following subsections.

2.2.1 Topography

The entire Lake Sheridan Watershed is located on the Appalachian Plateau, an area glaciated during the last ice age, Wisconsin Stage, by the advance and retreat of the Wisconsin glaciers which greatly influenced the local topography. Several smaller impoundments are located in the watershed, including Baylors Pond, the watershed for which accounts for 39% of the total watershed to Lake Sheridan. Some larger wetland areas are also located primarily in the headwater areas along the watershed divide. Slopes throughout the watershed typically range from 0-75%, many of which are very steep and quite prone to erosion. Sediment and nutrients are eroding from the steep slopes and eventually are deposited in Lake Sheridan, especially from agricultural lands.

2.2.2 Geology

Glacial activity has greatly influenced the subsurface geology throughout all of Northeastern Pennsylvania. The entire watershed is composed of the Catskill formation (undivided) of the Upper Devonian period which are primarily a succession of grayish-red sandstone, siltstone, and shale, generally in fining-upward cycles. Also typical are some gray sandstone and conglomerate (Pennsylvania DER, 1980).

2.2.3 Soils

The soils in the Lake Sheridan Watershed include Wellsboro-Morris-Oquaga, Mardin-Lordstown-Volusia, and Rock outcrop-Arnot-Dystrochrepts associations. They are derived from shale and sandstone which make up most of Lackawanna County. The major soil series of the Lake Sheridan Watershed area are too varied to list; however, the predominant soil series in proximity to the lake include Arnot, Lordstown, Mardin, Morris, Oquaga, Wellsboro, Wyoming silt loams and channery silt loams. These soils have a slight to moderate erosion potential and severe erosion potential for steeply sloped agricultural lands, which makes Lake Sheridan vulnerable to sediment and nutrient pollution (USDA, 1982).

2.2.4 Current and Future Land Use

Land use in the Lake Sheridan watershed is presented in Table 2.2. A map of land use in the watershed is shown in Figure 2.1. Land use data were determined from available mapping and field reconnaissance from a thorough watershed investigation.

The dominant existing land use within the watershed area is forested land (54%), followed by agricultural land (29.1%) wetland (10.6%), and open water (6.3%). Developed land within the watershed represents less than one percent of the land use. It should be noted that these land use calculations were based on satellite imagery, and it is likely that some of the forested areas and areas around open waters that include homes did not show up as residential areas even though they do include residences. Current land use trends indicate low residential development; however, this is expected to change as the cleared land that is no longer farmed will likely be converted for residential and commercial development. The close proximity to the Scranton/Wilkes-Barre metropolitan area greatly increases the potential for development within the Lake Sheridan watershed area. Nearly the entire watershed was cleared and farmed where slopes and soil conditions permitted. Most of the population within the watershed is located in scattered rural developments or within the communities of Fleetville, Baylors Pond, and Lake Sheridan.

| |

|Table 2.2 |

|Current Land Use in the Lake Sheridan Watershed |

| | |

|Land Use Category |Percent (%) of Watershed Area |

| | |

|Wooded |54% |

| | |

|Agricultural |29.1% |

| | |

|Developed Areas (Residential and Commercial) |< 1% |

| | |

|Wetlands |10.6% |

| | |

|Water |6.3% |

| | |

|Total |100% |

The Lake Sheridan Watershed is quite rural, and comprehensive planning and municipal zoning are not yet practiced. Therefore, most of the information gathered on projected land use was informal. For instance, several local and regional agency sources felt that significant land use changes would probably not occur in the next few years, unless the depressed economy of the Scranton/Wilkes-Barre metropolitan area improves significantly. In that case, the existing small farms, many of which have stopped or decreased production, would likely be converted for residential development. Increased commercial development would also be likely near the three Interstate 81 interchanges. The rural nature of the watershed offers attractive building sites within a few miles of the Scranton/Wilkes-Barre metropolitain area. Agricultural lands are extremely attractive to developers since land preparation costs such as clearing and grubbing are minimal.

2.3 Benefits and Recreational Use of Lake Sheridan

2.3.1 Present Uses

Lake Sheridan is located in Benton Township, Lackawanna County and Nicholson Township, Wyoming County, Pennsylvania. The lake was created primarily for recreational use. At present, the lake serves as the focal point for the Lake Sheridan Cottagers’ Association and provides activities including swimming, picnicking, fishing, power boating, water-skiing, sailing, hiking, wildlife observation, and other water related activities and sports. The lake is a heavily used warm water fishery. The large mouth bass population in the lake is self supporting. Power boating is currently permitted throughout the entire lake.

Figure 2.1 Lake Sheridan Watershed Land Use Map

2.3.2 Impairment of Recreational Uses

As stated in previous sections, Lake Sheridan was once a natural lake. It was enhanced by constructing a dam on the outlet stream to raise the water elevation and increase the areal extent of the water surface in order to create a larger lake for development and recreational purposes. In addition, the entire area surrounding the lake is quite picturesque, and provides many forms of popular passive recreation (e.g. photography, bird watching, environmental education).

Phosphorus and nitrogen, which are present in fertilizers, animal waste, sediment, sewage, and stormwater runoff, have caused Lake Sheridan to become eutrophic. Excessive growth of algae and aquatic weeds (macrophytes) plague the lake during the growing season when the lake receives its highest recreational use. Higher water temperatures and lower dissolved oxygen concentrations during this time threaten the health of the lake’s aquatic organisms. Many desirable fish species including large mouth bass and bluegill are particularly sensitive to such stressful conditions. A eutrophic lake is not aesthetically pleasing, which is extremely important to the Lake Sheridan Cottagers’ Association. Extensive and severe algal blooms throughout the entire growing season make the lake unsightly, unhealthy (for aquatic organisms and humans), and unusable for certain activities.

2.4 Population and Socio-Economic Structure

The Lake Sheridan watershed is located approximately twelve miles north of the City of Scranton and the Scranton/Wilkes-Barre metropolitan area, which is the third largest metropolitan area in the Commonwealth of Pennsylvania. The lower basin and a small portion of the total watershed area to Lake Sheridan lies within Wyoming County, while the upper basin and the majority of the watershed lie within Lackawanna County.

Lackawanna County consists of 40 municipalities (21 townships, 19 boroughs/cities) and Wyoming County consists of 23 municipalities (18 townships, 5 boroughs/cities). According to the available data from the Center for Rural Pennsylvania, the populations of both counties are steady or slowly declining and will likely maintain this trend barring an improvement in the localized economy of the Scranton\Wilkes-Barre metropolitan area. The Lackawanna County population has slowly declined at an estimated annual average rate of 2.6 percent and the Wyoming County population has remained virtually unchanged from 1990 to 2000.

The total population for Benton Township, Lackawanna County was 1,881 according to the 2000 Census. The total population for Nicholson Township, Wyoming County was 1,361 according to the 2000 Census. The majority of the population within the watershed resides along the PA Route 407 corridor, at Baylors Lake, and at Lake Sheridan. The remaining population resides on farms and in rural residences sparsely scattered along local roadways. Present and projected population data for Lackawanna and Wyoming Counties and the townships in the Lake Sheridan Watershed are presented in Table 2.3.

Personal income in the watershed is strongly related to the economic conditions of the Scranton/Wilkes-Barre metropolitain area. The estimated 1997 median household income for Lackawanna County was $32,536, while the median income for Wyoming County was $35,110. The estimated 1997 statewide median household income based on all municipalities was $37,267 (Center for Rural Pennsylvania).

| |

|Table 2.3 |

|Population Data for Lackawanna and Wyoming Counties and Townships within the Lake Sheridan Watershed, Commonwealth of Pennsylvania |

| | |

| |Population |

|County | |

| | | | | |

| |1980 |1990 |2000 |2010 |

| | | | | |

|Lackawanna County |227,908 |219,097 |213,295 |211,356 |

|BentonTownship |1,670 |1,837 |1,881 | |

| | | | | |

|Wyoming County |26,433 |28,076 |28,080 |35,187 |

|Nicholson Township |1,244 |1,279 |1,361 | |

Source: Lackawanna County Planning Commission, 1980 and 1990 census. Wyoming County Planning Commission, 1980 and 1990 census The 2000 population and 2010 population estimate was provided by the Center for Rural Pennsylvania.

3.0 Water Quality

As part of this watershed assessment, both lake and stream water quality samples were collected. All water quality testing was conducted by F. X. Browne, Inc. with assistance from Lake Sheridan Cottagers’ Association. The monitoring program began in July 1998 and was completed in September 1998.

A glossary of lake and watershed terms is provided in Appendix A as an aid to understanding the following discussion.

3.1 Lake Ecology Primer

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The ecological condition of any lake is the summation of the physical, chemical, and biological processes that occur within it. Temperature and dissolved oxygen measurements are usually reliable means of evaluating the ecological condition of a lake. Life processes in the upper, well-lit waters result in the uptake of nutrients by algae and in the resultant production of oxygen and organic material. At the lake bottom, the absence of light results in an environment which is colder than the surface and often reduced or devoid of dissolved oxygen. Photosynthetic production by green plants is the predominant life process at the surface while bacterial decomposition of organic matter is the predominant process at the bottom. The supply of dissolved oxygen at the bottom may be depleted by bacterial decomposition and by various chemical processes associated with nutrient cycling.

Dissolved oxygen is necessary to support most forms of aquatic life. A minimum dissolved oxygen concentration of 5.0 milligrams per liter is required to support most fish. Warm water fish, such as bass and perch, often survive at lower oxygen levels. Oxygen levels in a lake are directly related to the physical, chemical and biological activities occurring in the lake water. Dissolved oxygen measurement is therefore an excellent indicator of the overall water quality of a lake. Additional information about a lake is gained by monitoring for nutrient levels, transparency, and the amount and types of algae present.

Although a lake may appear to be in equilibrium, two types of natural long-term successional changes occur: (1) the lake gradually fills in with sediment from the erosion of streams and surrounding land areas; and (2) eroded sediments deposited into the lake are usually rich in nutrients which stimulate increased plant growth. The process is further accelerated by the increase of organic nutrients derived from dead plants and animals as the number of organisms increase within the lake. This process, called succession or aging, causes the lake to fill in and become shallower. As it continues, the types of animals and plants within the lake's ecosystem also begin to change. Game fish such as bass, pike, and pan fish may be replaced by rough species such as carp, suckers, and bullheads. Rough fish are better adapted to live in a lake which is relatively old on the time scale of succession. As the process of filling in continues, eventually the lake or pond becomes a herbaceous and shrub/scrub wetland. If conditions are right, a forested wetland takes over. Depending on environmental conditions, the process of natural succession may take hundreds or even thousands of years. The actions of man, however, can considerably accelerate this aging process.

Lake water quality is a direct reflection of the water quality of the watershed area. The term “watershed” is defined as all lands that eventually drain or flow into a lake (...“all waters that are shed to a lake”). Potential sources of water to lakes are streams (tributaries), surface runoff (overland flow from lakeside properties), groundwater (interflow), and precipitation. The water quality of these water sources are greatly influenced by watershed characteristics including soils, geology, vegetation, topography, climate, and land use. Typical land uses encountered in watershed areas are wetlands, forests, agriculture, residential, commercial, and industrial. With regards to water quantity, larger watershed areas contribute larger volumes of water to lakes and vice versa.

The water quality of Lake Sheridan is the result of chemical, physical, and biological interactions of the aquatic system within the lake. Nutrients such as nitrogen and phosphorus, as well as suspended solids, are present in the stormwater runoff from the forested and agricultural land throughout the entire watershed. Eventually, the sediment and nutrient-laden stormwater enters the tributaries and is ultimately deposited in Lake Sheridan. Nutrients and sediments are also present in overland flow, which is deposited directly from the lands adjacent to the lake.

3.2 Study Design and Data Acquisition

The lake and watershed monitoring program for Lake Sheridan was designed and coordinated by F. X. Browne, Inc., in accordance with Title 40 CFR Part 35, Subpart H entitled “Cooperative Agreements for Protecting and Restoring Publicly Owned Freshwater Lakes” (U. S. Environmental Protection Agency, 1980). The monitoring program followed standard Quality Assurance/Quality Control (QA/QC) guidelines, in accordance with DEP and EPA requirements.

Two lake monitoring stations were established, Station #1 near the center of the lower basin (N 41º35.780', W 75º45.714') and Station #2 near the center of the upper basin (N 41º35.883', W 75º45.146'), as shown in Figure 3.1. The lake water quality sampling locations were selected to provide the most representative overall results for both chemical and physical parameters. Water quality samples were collected at two discrete depths (surface and bottom) and analyzed for key water quality parameters. Surface samples were collected 0.5 meters below the water surface, and bottom samples were collected approximately 0.5 meters above the lake bottom.

The stream water quality sampling locations were selected at each of the four tributaries of Lake Sheridan to provide thorough and complete coverage of the entire contributory drainage from the Lake Sheridan Watershed (see Figure 3.1 for a map of the drainage basins, and Table 3.7 for station GPS coordinates). The stream and lake samples were analyzed for the parameters listed in Table 3.1. Direct drainage to the lake comprises only 8.9 percent of the total watershed area. A large portion of the total population within the watershed does reside in this direct drainage area, allowing for potentially significant nonpoint source pollution inputs from homes and development.

| |

|Table 3.1 |

|Lake Sheridan Water Quality Monitoring Program |

|Water Quality Parameters |

| |

|STREAM WATER QUALITY MONITORING: |

| | |

|Total Phosphorus |Total Suspended Solids |

| | |

|Dissolved Reactive Phosphorus |Fecal Coliform |

| | |

|Nitrate/Nitrite Nitrogen |Fecal Streptococcus |

| | |

|Total Kjeldahl Nitrogen |pH |

| | |

|Ammonia Nitrogen | |

| |

|LAKE WATER QUALITY MONITORING: |

| | |

|Total Phosphorus |Dissolved Reactive Phosphorus |

| | |

|Nitrate/Nitrite |Ammonia |

| | |

|Total Kjeldahl Nitrogen |Total Suspended Solids |

| | |

|pH |Transparency |

| | |

|Temperature (vertical profile) |Dissolved Oxygen (vertical profile) |

| | |

|Chlorophyll a * |Fecal Coliform * |

| | |

|Phytoplankton * | |

* Surface samples only

Lake water quality data were collected for this study once per month from July through September of 1998. Stream stormwater quality data were collected during September 1998 on each of the four major tributaries. Baseflow water quality data were assumed to be similar to data collected for tributaries of Lackawanna Lake (Lackawanna Lake Watershed Assessment Study, 1997, F. X. Browne, Inc.), and were used to calculate nutrient and sediment loads to Lake Sheridan.

Three samples were collected from each stream station during the storm, or wet-weather, monitoring event and composited to create one sample for each stream station. The monitoring of wet weather events for this study was performed jointly by F. X. Browne, Inc. and the Lake Sheridan Cottagers’ Association. The monitoring data collected were used to develop an annual nonpoint source loading budget for phosphorus, nitrogen, and suspended solids for Lake Sheridan. Annual nonpoint source loads from tributaries were calculated using the measured pollutant loads during stormflow conditions by the Simple Method (Scheuler, 1987). The pollutant budgets for each subwatershed, along with estimates of atmospheric deposition and groundwater contribution, are presented in Section 4.0. The pollutant budgets were used to target areas for the most effective implementation of best management practices, and later used to develop the restoration alternatives and the management recommendations contained in Sections 5.0 and 6.0 of this study. Applicable data for all water quality parameters are presented in the following sections.

Figure 3.1 Lake Sheridan Monitoring Station Location Map

3.3 Lake Water Quality

The lake water quality monitoring program was designed to assess the existing water quality conditions in Lake Sheridan. Lake water quality data are provided in Appendix B and discussed in the following sections.

3.3.1 Temperature and Dissolved Oxygen

As illustrated in Figure 3.2, Lake Sheridan was thermally stratified during all sampling events from July through September. In July, the thermocline occurred at approximately 2.25 meters in the upper, deeper basin, and dissolved oxygen depletion was already noticeable in the bottom waters (Figure 3.3). Epilimnetic (surface) waters were well oxygenated at both stations during all sampling events from July through September. The greatest degree of thermal stratification occurred in July and August. Lake temperatures ranged from 9 to 26.5 degrees Celsius in the upper basin and 1.7 to 27.2 degrees Celsius in the lower basin. Complete temperature and dissolved oxygen profile data are provided in Appendix C. Temperature and dissolved oxygen profiles were measured at that same location (Figure 3.1) each time they were measured.

Dissolved oxygen concentrations in the upper basin of Lake Sheridan were below 5.0 mg/L (Figure 3.3) in water depths exceeding 2.5 to 3.0 meters during all sampling dates. Therefore, most fish and other aquatic life requiring oxygen are confined to the upper 2.5 to 3.0 meters throughout the growing season. With such a shallow depth of oxygenated water, complete depletion of life sustainable oxygen may occur during the non-daylight hours when decomposition which uses oxygen exceeds photosynthetic production which produces oxygen.

The lower basin of Lake Sheridan is very shallow with respect to the upper basin and exhibits a maximum depth of approximately 3 meters (9.1 feet). Therefore, the lower basin does not thermally stratify or experience oxygen depletion during the growing season (Figures 3.4 and 3.5).

Based on the data collected, Lake Sheridan is fairly well-suited for warmwater fish species. However, the hypolimnetic waters provide little habitat for cold water fish species due to severe dissolved oxygen depletions during the late summer months. In general, the optimal water temperature for trout is 55 oF to 60 o F (12.8 oC to 15.6 oC). Trout may withstand water temperatures above 80 oF (26.7 oC) for several hours, but if the temperatures exceed 75 oF (23.9 oC) for extended periods, trout mortality is expected. A safe minimum dissolved oxygen concentration for trout is 5.0 mg/L. Warmwater species grow well when water temperatures exceed 80 oF (26.7 oC). Most warm water fish species will tolerate a minimum dissolved oxygen concentration of approximately 3.0 mg/L. However, as noted above, such low concentrations are generally precursors to complete oxygen depletion which may stress fish populations and ultimately lead to fishkills. Also, the area of lake bottom that maintains safe oxygen concentrations is reduced as the thickness of the oxygenated water column (from the lake surface) decreases, providing additional stress for bottom dwelling species such as catfish or bullhead.

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The warm water fishery of Lake Sheridan is reported to be healthy in recent years despite lower oxygen conditions. The lake offers excellent fish habitat with diverse bathymetry and subsurface structure. Also, there are expansive emergent wetland areas at the primary inlets at the northeastern end of the upper basin which provide protective cover and excellent spawning habitat.

3.3.2 pH

The pH values in Lake Sheridan were very reflective of the phytoplankton populations observed during all monitoring events, which typically lead to basic conditions. The pH values in the surface waters of the upper basin were basic and ranged from 8.2 to 8.7 standard units. In the lower basin where phytoplankton populations were significantly higher, pH values ranged from 8.2 to 9.6 standard units. A pH value of 6.8 standard units was recorded for the bottom waters of the upper, deeper basin during the September monitoring event. Higher pH values in the surface waters were likely attributed to high levels of algal photosynthetic activity in the surface waters which depletes carbon dioxide that would normally create a weak carbonic acid. The measured pH values are typical for productive lakes in the Northeastern United States and impose no negative impacts to the aquatic biota.

3.3.3 Total Suspended Solids and Transparency

The total suspended solids concentrations for the surface waters in Lake Sheridan were relatively low during all monitoring events. However, the August and September total suspended solids concentrations were slightly higher as a result of severe blooms of blue-green algae. Algicide treatments were implemented throughout the growing season to help control the nuisance algal blooms. However, these treatments were relatively unsuccessful since the majority of the algal biomass was composed of copper tolerant blue-green species. In fact, the growth potential of the blue-green algae in Lake Sheridan may have been increased by the treatments, as the copper-sulfate treatments likely killed other algal species that were competing with the blue-greens for available nutrients.

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The transparency of a lake’s surface waters is typically measured with a Secchi disk. The mean Secchi disk transparency in the upper basin of Lake Sheridan during the study period ranged from 1.7 meters (5.6 feet) in September to 1.3 meters (4.3 feet) in August, with a mean transparency of 1.5 meters (4.9 feet). Secchi disk transparency in the lower basin of Lake Sheridan ranged from 0.85 meters (2.8 feet) in September to 0.45 meters (1.5 feet) in August, with a mean transparency of 0.7 meters (2.3 feet). Based on Secchi disk transparency, Lake Sheridan is categorized as hyper-eutrophic (see Section 3.3.10).

3.3.4 Phosphorus

Total phosphorus represents the sum of all phosphorus forms, and includes dissolved and particulate organic phosphorus from algae and other organisms, inorganic particulate phosphorus from soil particles and other solids, polyphosphates from detergents, and dissolved orthophosphates. Soluble orthophosphate is the phosphorus form that is most readily available for algal uptake and is usually reported as dissolved reactive phosphorus, because the analysis takes place under acid conditions which can result in some hydrolysis of other phosphorus forms. Total phosphorus levels are strongly affected by the daily phosphorus loads that enter the lake. Soluble orthophosphate levels, however, are more affected by algal consumption during the growing season.

The total phosphorus concentrations in the surface and bottom waters of Lake Sheridan are presented in Table 3.2. The dissolved reactive phosphorus concentrations in the surface waters were low, as expected, due to rapid algal uptake. However, the total phosphorus concentrations in the surface waters increased throughout the growing season as the algal biomass increased, accumulating phosphorus within the plant material. This correlation of increased total phosphorus with increased algal biomass is especially well illustrated during the August monitoring event when algal biomass increased from 7,583 to 15,829 ug/L between the upper and lower basins and total phosphorus increased from 0.031 to 0.195 mg/L. The total phosphorus concentrations in the bottom waters were greatly elevated throughout the growing season when the lake was stratified. This increase is the result of a release of phosphorus from the lake sediments caused by anoxic conditions (near zero dissolved oxygen levels) in the bottom waters during thermal stratification. Under anoxic conditions, dissolved reactive phosphorus is released at the sediment-water interface.

The trophic status of lakes and reservoirs is often correlated to the total phosphorus concentrations in surface waters. Based on criteria established by the U.S. EPA (1990), a lake is classified as oligotrophic when total phosphorus concentrations are less than or equal to 0.005 mg/L, mesotrophic when total phosphorus concentrations are between 0.005 mg/L to 0.025 mg/L, eutrophic when total phosphorus concentrations are between 0.025 mg/L to 0.100 mg/L, and hyper-eutrophic when total phosphorus concentrations are greater than 0.100 mg/L. The mean total phosphorus concentrations in the surface waters of Lake Sheridan were 0.035 mg/L in the upper basin and 0.139 mg/L as P in the lower basin. Based on these criteria, Lake Sheridan is classified as eutrophic to hyper-eutrophic (see Section 3.3.10).

| |

|Table 3.2 |

|Mean Dissolved Reactive and Total Phosphorus |

|Concentrations in Lake Sheridan |

| | | |

| |Dissolved Reactive Phosphorus |Total Phosphorus |

|Depth |(mg/L as P) |(mg/L as P) |

| | | |

|Surface | | |

|Station 1 - Upper Basin |0.003 [ ................
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