Swan Lake Water Quality Investigation

Transcription

1 Swan Lake Water Quality Investigation 2011 Summary Report Prepared by: 635 Denver Street Whitefish, MT Prepared for: Swan Lakers; PO Box 399, Bigfork, MT Kootenai Lodge Estates; Sunburst Drive, Bigfork, MT Swan Ecosystem Center; 6887 Highway 83, Condon, MT May 15, 2012

2 Table of Contents 1.0 Introduction Project Goals and Objectives Project Site Description Water Quality Targets Methodology Results Discussion Literature Cited Appendix I Annual Trophic State Index (TSI) Calculations for North Basin and South Basin 11 Appendix II Hydrolab Data for all Sample Sites.. 14 Appendix III Temperature and Dissolved Oxygen Profiles 73 Appendix IV Water Chemistry Data.. 82 Swan Lake 2011 Water Quality Investigation Summary Report i

3 List of Tables & Figures Table 2.1. Swan Lake Sample Sites and GPS Coordinates... 4 Table 3.1 Minimum Dissolved Oxygen Concentrations (mg/l and % saturation) in the North and South Basins of Swan Lake, Table 3.3. Trophic State Index by Year and Parameter. 7 Table 3.4 Trophic State Index Average Figure 3.1. Minimum Dissolved Oxygen Concentrations (mg/l) in the North and South Basins of Swan Lake, Figure 3.2. Minimum Dissolved Oxygen Concentrations (% saturation) in the North and South Basins of Swan Lake, Figure Swan Lake Secchi Disc Depths 8 Figure Swan Lake Secchi Disc Depths... 8 Cite: Koopal, M. (2012). Swan Lake 2011 Water Quality Investigation Summary Report. Prepared for Swan Lakers, Kootenai Lodge Estates, and Swan Ecosystem Center. Whitefish Lake Institute, Whitefish, MT. Cover photo courtesy of gravityshots.com Swan Lake 2011 Water Quality Investigation Summary Report ii

4 1.0 Introduction 1.1 Project Goals and Objectives The goal of this project is to collect baseline water quality information for Swan Lake over a five year period to be used for trend analysis. The project was initiated in 2010 by a contract between Kootenai Lodge Estates, Swan Lakers and Whitefish Lake Institute (WLI). In 2011, the Swan Ecosystem Center expanded the scope of the project to include a late fall sample date and additional water chemistry analysis. The objective of this report is to provide a framework to display the water quality information for Swan Lake collected during this project and compare it to historical data where applicable. In particular, the focus of this 2011 annual report is to incorporate historical data relevant to the Swan Lake Total Maximum Daily Load (TMDL) Primary Targets. As the project moves forward, more of the budget will be available to provide specific analysis of other project parameters. 1.2 Project Site Descriptions The Swan Valley watershed in Northwest Montana is approximately 410,000 acres and has a stream network of nearly 1,300 miles. It is located in parts of Missoula, Lake and Flathead counties. The Swan River flows north from its headwaters in the Mission Mountains to Swan Lake, eventually emptying into Flathead Lake at Bigfork. The watershed includes the small communities of Condon, Salmon Prairie and Swan Lake. Most of the land is managed in a square-mile checkerboard pattern by the Flathead National Forest, Plum Creek Timber Company and to a lesser extent the Swan River State Forest. Private residences are scattered along the Swan River and State Highway 83, which parallels the river (PBS&J, 2008). Swan Lake is located between the Mission and Swan Ranges at an elevation of 3,199 feet within a basin area of 421,612 acres. The basin area is composed of alluvium (36%), and the Piegan group (30%), Missoula group (15%), Grinnel argillite (13%) and Appekunny argillite (4%) belt series. Swan Lake has a surface area of 3,276 acres and a maximum depth of 133 feet. Swan Lake is generally characterized by excellent water quality, with levels of nutrients, primary production, and chlorophyll (a) typical of an oligotrophic lake (low levels of nutrient inputs and low productivity). However, during late summer and early fall in the deepest parts of the lake, dissolved oxygen (DO) concentrations decline to unusually low levels. This is particularly evident in the south basin of the lake, where DO concentrations as low as 0.1% of saturation have been recorded. Low DO concentrations are a concern due to their potential to harm aquatic life, particularly bull trout, which are listed as a threatened species under the federal Endangered Species Act (PBS&J, 2008). According to Rosenthal (2011), the Swan Valley has been historically home to a stable, healthy bull trout population. However, in 1998 anglers began to occasionally catch adult sized (20-30 inch) lake trout from Swan Lake and the Swan River. This caused alarm because lake trout are not native and are notorious for rapidly expanding and dominating fish communities in lakes with Mysis shrimp, at the expense of bull trout and kokanee salmon. Since 2003, lake trout catch by anglers as well as during Montana Fish, Wildlife & Parks (FWP biological sampling has Swan Lake 2011 Water Quality Investigation Summary Report 1

5 continued to increase, indicating that wild reproduction is occurring. Based on case histories from nearby waters, long-term management alternatives for this increasing lake trout population are necessary in order to maintain the popular bull trout and kokanee fisheries. In addition to bull trout, lake trout, and kokanee salmon, Swan Lake fish distribution records from the FWP Montana Fisheries Information System (MFISH) database indicate a mix of both native and non-native species, including; brook stickleback, brook trout, largescale sucker, longnose sucker, mountain whitefish, northern pike, northern pike minnow, peamouth, pumpkinseed, pygmy whitefish, rainbow trout, redside shiner, westslope cutthroat trout and yellow perch. 1.3 Water Quality Targets The Swan Basin is listed as a high priority watershed by the Montana Department of Environmental Quality (DEQ), and Swan Lake is an A-1 classified waterbody. Based on the results of data collection efforts in the Swan TMDL, the Swan Basin appears to be recovering from past water quality impacts. Nevertheless, serious threats to water quality and beneficial use support remain throughout the basin and are likely to increase as land in the Swan Valley is converted from timber production to residential use (PBS&J, 2008). Swan Lake appears to be predisposed to DO problems by its own morphometry. According to the conclusions of the TMDL, this situation appears to have been exacerbated by excessive loading of particulate organic carbon (POC). Although POC source loading has decreased in recent decades, dissolved oxygen levels in Swan Lake have remained near zero, suggesting that DO recovery has not been concurrent with pollutant source reduction in the watershed. The cause and effect relationships between pollutant loading, lake morphometry, and DO levels within the lake remain poorly understood. In the Water Quality Protection Plan and TMDLs for the Swan Lake Watershed (DEQ 2004), no increase in loading of particulate organic carbon or nutrients to the lake from Swan River is required. Because the status of the lake appeared to be threatened, not impaired, DEQ determined that loading did not need to decrease from current levels. In order to verify that restoration and pollution source reduction efforts are effective in improving DO levels, and to ensure the continued health of both Swan and Flathead Lakes, the Swan Ecosystem Center (SEC) has taken the lead in implementing the monitoring plan recommended in the TMDL (PBS&J, 2008). To track progress towards ensuring beneficial use support in the lake, DEQ established two primary water quality targets and three secondary targets. According to the Swan TMDL (DEQ, 2004), primary targets are based on direct measures or direct indicators of beneficial uses within the lake. Secondary targets are based on loading conditions or surrogates for loading conditions with the watershed. The secondary targets help identify potential problems or progress towards resolving water quality concerns in the watershed. The scope of this study is limited to direct measurements in Swan Lake. As a result, data from this project can be used to determine if some of the primary targets for the Swan Lake TMDL are being met. The data in this report does not evaluate all of the primary targets or the secondary Swan Lake 2011 Water Quality Investigation Summary Report 2

6 targets that are generally associated with loading from the Swan River and other watershed loading. The primary targets specific to Swan Lake include: Primary Target 1 No decreasing percent saturation of dissolved oxygen (DO) in the bottom waters of Swan Lake and no increase in the spatial extent of the low DO area in the lake. According to DEQ (2004), the rationale for this TMDL target is as follows: This target addresses the primary reason for the listing of Swan Lake as a threatened waterbody on Montana s 303(d) list. In spite of the fact that the low DO in Swan Lake may not be unusual, it must be monitored for a period of time to ensure that conditions are not becoming worse due to human activities For Primary Target 1, project data is relevant to DO (percent saturation) at the benthic interface of Swan Lake at two long-term monitoring locations and is compared to historical data herein. However, the scope of work limits the extent of sampling locations and precludes an analysis of the spatial extent of low DO for the entire lake which is a component of the Target 1 analysis. Primary Target 2 No increasing trend of nutrient and chlorophyll (a) concentrations, no increasing trophic state index trends, and no decreasing trend in Secchi Depth values in Swan Lake. According to DEQ (2004) the rationale for this TMDL target is as follows: Meeting this target will prevent or minimize algae blooms within the lake and therefore provide protection for cold-water fish and aquatic life beneficial uses, and will further avoid potential POC loading associated with increased algal growth. It will also protect lake aesthetics ad help ensure that turbidity remains with the range of naturally occurring levels as defined under State Law. For Primary Target 2, project data collected by this study is comparable to historical data and is presented herein. 2.0 Methodology The project methodology follows objectives identified in the Swan Lakers Request for Proposal dated March 31, 2010 as responded to by WLI dated April 9, 2010 and is summarized below. Three (3) dates were sampled in 2010 (May, June, and August). For all three sample dates, eight (8) sites were sampled as represented in Table 1. North Basin and South Basin are historical water chemistry sites. The sample sites comprise a good spatial representation of the lake from the Swan River inlet at the southern end of the lake to the northern end of the lake to the Swan River outlet at the northern end of the lake. In 2011, as part of the Swan Ecosystem Center contract, an additional sample date was included in mid-october in attempt to describe the maximum extent of the DO depletion in the hypolimnion. In addition, the Swan Ecosystem Center contract expanded the water chemistry Swan Lake 2011 Water Quality Investigation Summary Report 3

7 sampling effort to include sulfate, dissolved iron, and dissolved manganese in an attempt to describe the phosphorus availability to primary productivity during any anoxic events at the benthic interface during lake stratification. Table 2.1. Swan Lake Sample Sites and GPS Coordinates. Sample Site GPS Coordinates (NAD 83) Bay South , Bay West , Bay East , Bug Creek , Rock House , South Basin* , North Basin* , North Lake/River , *North Basin and South Basin are historic sample sites At each sample site, a Hydrolab DS5 Sonde was deployed to collect the following parameters at roughly 1 meter depths; depth, dissolved oxygen (%), dissolved oxygen (mg/l), ph, total dissolved solids (TDS), specific conductance, oxidation reduction potential (ORP), photosynthetically active radiation (PAR) (in-situ and boat mounted), salinity, resistivity, and relative chlorophyll (a) concentrations. In addition, at each sample site, a Secchi disc measurement was recorded. Based on the collected Hydrolab data, the lake was classified as stratified with a defined epilimnion, metalimnion and hypolimnion, or mixed. Water chemistry samples (Total Phosphorus, Soluble Reactive Phosphorus, Total Nitrogen, Nitrate + Nitrite, Total Organic Carbon, Dissolved Organic Carbon, and Total Dissolved Solids) were then collected at the South Basin and North Basin sites at the mid-point of each stratified layer using a Van Dorn vertical water sampler. In addition, an integrated 0-30m sample was taken from a compilation of discrete samples from the surface, 5m,10m, 15m, 20m, 25m and 30m that were composted and mixed in a sampling container. For sample dates where the lake was not stratified, water chemistry samples were collected at a 1/3 and 2/3 depth of the water column in addition to the 0-30m integrated sample. Chlorophyll (a) samples were collected at the mid-point of the epilimnion if the lake was stratified or the center of the photic zone (as determined by 3 times the Secchi disc depth) if mixed. In 2010, chlorophyll (a) samples were vacuum pumped below 9.0 inches of mercury over a glass fiber filter, placed in a sample vial and immediately wrapped in aluminum foil and placed on dry ice. In 2011, chlorophyll (a) samples were not field prepared but rather sent directly to the laboratory for processing and analysis. Water chemistry samples were preserved according to laboratory specifications and placed on ice or dry ice and shipped next day along with a Chain of Custody form to Energy Laboratories in Helena for analysis. Swan Lake 2011 Water Quality Investigation Summary Report 4

8 3.0 Results Where applicable, project results from 2010 and 2011 have been compared to historical data for Swan Lake and are found below. Annual Trophic State Index (TSI) calculations can be found in Appendix I and 2011 Hydrolab data for all parameters can be found in Appendix II and 2011 Hydrolab depth profile representations for temperature and dissolved oxygen can be found in Appendix III water chemistry data can be found in Appendix IV. Primary Target 1 No decreasing percent saturation of dissolved oxygen (DO) in the bottom waters of Swan Lake and no increase in the spatial extent of the low DO area in the lake. Table 3.1 and Figures 3.1 and 3.2 display project DO values near the benthic interface at the Swan Lake North Basin and South Basin Sample Sites as compared to historical data. According to PBS&J (2008) the lowest DO concentrations and percent saturation in Swan Lake typically occur in the deepest portions of the lake in the early fall, prior to turnover. PBS&J (2008) uses the window of September 21 st to fall turnover for sample dates that qualify for long-term trend analysis. Table 3.1 Minimum Dissolved Oxygen Concentrations (mg/l and % saturation) in the North and South Basins of Swan Lake, Date North Basin (mg/l) North Basin (% Sat) South Basin (mg/l) South Basin (% Sat) 10/18/1990 NA NA 0.5 NA 10/21/1992 NA NA 7 NA 10/16/ NA 0.4 NA 9/30/ NA 1.42 NA 10/19/ /22/ /6/ /28/ /27/ NC NC 10/18/ NC: Not collected; NA: Not Available Status of Primary Target 1 The North Basin shows a range of DO concentrations from a low of 2.43 mg/l in 2004 to a high of 5.2 mg/l in Since 2004, DO concentrations have shown steady improvement. The South Basin displays much lower values with a range of DO concentrations from a low of 7 mg/l in 1992 to a high of 1.42 mg/l in No trend is apparent, but DO concentrations in the South Basin, which was the main area of concern in the TMDL, showed no obvious signs of decline, and when coupled with the increased trend of DO concentrations in the North Basin suggests that Primary Target 1 for Swan Lake is being met. Swan Lake 2011 Water Quality Investigation Summary Report 5

9 Figure 3.1. Minimum Dissolved Oxygen Concentrations (mg/l) in the North and South Basins of Swan Lake, Figure 3.2. Minimum Dissolved Oxygen Concentrations (% saturation) in the North and South Basins of Swan Lake, Swan Lake 2011 Water Quality Investigation Summary Report 6

10 Primary Target 2 No increasing trend of nutrient and chlorophyll (a) concentrations, no increasing trophic state index trends, and no decreasing trend in Secchi Depth values in Swan Lake. Table 3.3 displays the Trophic State Index (TSI) by year and parameter. Some of the historical data is missing and is noted. PBS&J (2008) documents that a TSI value of less than 40 indicates an oligotrophic (nutrient poor) lake; while a value between 40 and 60 indicates a mesotrophic (moderately enriched) lake; values above 60 would indicate a eutrophic (nutrient rich) lake. The yearly TSI calculations from can be found in Appendix I. Table 3.4 displays an average of the TSI values from to account for inter-annual variation. Table 3.4 values were obtained from averaging all values for each parameter through the years; chlorophyll (a) (N=30), Secchi disk (N=7) and total phosphorus (N=30). Table 3.3. Trophic State Index by Year and Parameter. Trophic State Chlorophyll (a) (mg/ cu.m ) Secchi Disk Depth (m) Total Phosphorus (ug/l) Index North Basin South Basin North Basin South Basin North Basin South Basin 2004 Oligotrophic Oligotrophic NA NA Mesotrophic Oligotrophic 2007 Mesotrophic Mesotrophic NA NA Oligotrophic Oligotrophic 2008 Mesotrophic Mesotrophic NA NA Oligotrophic Oligotrophic 2009 Oligotrophic Oligotrophic NA NA Oligotrophic Oligotrophic 2010 Mesotrophic Mesotrophic Oligotrophic Oligotrophic Oligotrophic Oligotrophic 2011 Oligotrophic Oligotrophic Oligotrophic Oligotrophic Oligotrophic Oligotrophic Table 3.4 Trophic State Index Average Trophic Chlorophyll (a) (mg/ cu.m ) Secchi Disk Depth (m) Total Phosphorus (ug/l) State North Basin South Basin North Basin South Basin North Basin South Basin Index Average Mesotrophic Mesotrophic Oligotrophic Oligotrophic Oligotrophic Oligotrophic Figures 3.3 and 3.4 display the range and means of Secchi disc depths at seven of the eight sample locations for Swan Lake in 2010 and The eighth site (North Lake/River) is too shallow to allow for a Secchi disc reading. Water chemistry data from 2010 and 2011 can be found in Appendix IV. As the project proceeds, more time can be devoted to interpreting the data for trends. Status of Primary Target 2 TSI values show Swan Lake within the oligotrophic classification for Secchi disc and total phosphorus while chlorophyll (a) values fall within the Mesotrophic range. Based on the TSI, Swan Lake is described as an oligo-mesotrophic lake. Chlorophyll (a) results show no significant trend and appear to be influenced by yearly specific conditions and sample timing. Correlating water chemistry trend data to chlorophyll (a) values in future project annual reports might aid in interpreting the data. Secchi discs values show no apparent trend at this time but do indicate good transparency. At this time, without further data and analysis, it is not apparent if Primary Target 2 is being met. Swan Lake 2011 Water Quality Investigation Summary Report 7

11 Figure Swan Lake Secchi Disc Depths Swan Lake Secchi Depths -7.5 Depth Bay_E Bay_W Bay_S S_Basin Rock_H Bug_Cr N_Basin Site Figure Swan Lake Secchi Disc Depths Swan Lake Secchi Depths -7.5 Secchi Depth (ft) Bay E Bay W Bay S S Basin RH BC N Basin Site Swan Lake 2011 Water Quality Investigation Summary Report 8

12 4.0 Discussion Nutrient concentrations generally show a flow through gradient (higher in the South Basin than in the North Basin) with the highest concentrations shown during the freshet in June. The higher concentrations in the South Basin are due to allocthonous nutrient input from the Swan River. As water flows through Swan Lake, these nutrients are either used by primary producers or precipitate to the lake bottom and are stored in the sediments. Mean secchi disc data also show no significant trends between 2010 and Swan Lake displays low dissolved oxygen concentrations in the hypolimnion in the fall. The low dissolved oxygen concentrations probably deteriorate until the stratified layers in the lake circulate again via overturn in late fall or early winter. High dissolved organic carbon concentrations can decrease dissolved oxygen levels. However, dissolved organic carbon levels for Swan Lake in 2010 suggest that this influence is minimal, the lake is not dystrophic, and other factors are present. When dissolved oxygen levels decline to anoxic levels at the benthic interface, an oxidation/reduction potential exists where nutrients stored in the sediments could be liberated, dramatically affecting lake water quality and altering food web dynamics. The focus of this report was to incorporate historic data related to TMDL target parameters and provide the reader with a trend analysis of target status. As this project moves forward, future annual reports will provide more in-depth water chemistry analysis that will provide secondary support for the target status justifications. Swan Lake 2011 Water Quality Investigation Summary Report 9

13 5.0 Literature Cited Montana Department of Environmental Quality Water Quality Protection Plan and TMDLs for the Swan Lake Watershed. June Helena, MT. PBS&J, Swan Lake Watershed TMDL Implementation Program- Target Status Report. Prepared for Swan Ecosystem Center and Montana Department of Environmental Quality. Project No. B Missoula, MT. Rosenthal, L Experimental Removal of Lake Trout in Swan Lake, Montana: 2010 Annual Report. Prepared for the Swan Valley Bull Trout Working Group. Montana Fish, Wildlife & Parks. Kalispell, MT. Swan Lake 2011 Water Quality Investigation Summary Report 10

14 Appendix I (Annual Trophic State Index (TSI) Calculations for North Basin and South Basin) Swan Lake 2011 Water Quality Investigation Summary Report 11

15 2004 Chlorophyll (a) (mg/l) Total Phosphorus (ug/l) Date North Basin South Basin North Basin South Basin 5/28/ /21/ /27/ /27/ /16/ Average TSI Trophic State Oligotrophic Oligotrophic Mesotrophic Oligotrophic 2007 Chlorophyll (a) (mg/l) Total Phosphorus (ug/l) Date North Basin South Basin North Basin South Basin 5/24/ /11/ /26/ /16/ /30/ /28/ /10/ /27/ Average TSI Trophic State Mesotrophic Mesotrophic Oligotrophic Oligotrophic 2008 Chlorophyll (a) (mg/l) Total Phosphorus (ug/l) Date North Basin South Basin North Basin South Basin 5/5/ /22/ /12/ /25/ /15/ /1/ /26/ /23/ Average TSI Trophic State Mesotrophic Mesotrophic Oligotrophic Oligotrophic Swan Lake 2011 Water Quality Investigation Summary Report 12

16 2009 Chlorophyll (a) (mg/l) Total Phosphorus (ug/l) Date North Basin South Basin North Basin South Basin 6/24/ /19/2009 ND ND Average TSI Trophic State Oligotrophic Oligotrophic Oligotrophic Oligotrophic 2010 Chlorophyll (a) (mg/ cu.m ) Secchi Disk Depth (m) Total Phosphorus (ug/l) Date North Basin South Basin North Basin South Basin North Basin South Basin 5/10/ /14/ /2/ Average TSI Trophic State Mesotrophic Mesotrophic Oligotrophic Oligotrophic Oligotrophic Oligotrophic ND (not detected) ND samples were assigned a 0 value for averaging 2011 Chlorophyll (a) (mg/ cu.m ) Secchi Disk Depth (m) Total Phosphorus (ug/l) Date North Basin South Basin North Basin South Basin North Basin South Basin 5/25/ /13/ /25/ ND ND 10/18/ Average TSI Trophic State Oligitrophic Oligotrophic Oligotrophic Oligotrophic Oligotrophic Oligotrophic ND (not detected) ND samples were assigned a 0 value for averaging Swan Lake 2011 Water Quality Investigation Summary Report 13

17 Appendix II ( Hydrolab Data for all Sample Sites) Swan Lake 2011 Water Quality Investigation Summary Report 14

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76 Appendix III ( Temperature and Dissolved Oxygen Profiles) Swan Lake 2011 Water Quality Investigation Summary Report 73

77 Swan Lake (Bay East) 2009 Temperature Profiles (F) Variables June 24 August Swan Lake (Bay East) 2009 Dissolved Oxygen Profiles (% Sat) Variables June 24 August Depth (m) Depth (m) Swan Lake (Bay East) 2010 Temperature Profiles (F) Variables May 10 June August 2 Swan Lake (Bay East) 2010 Dissolved Oxygen Profiles (% Sat) Variables May 10 June August 2 Depth (m) Depth (m) Swan Lake (Bay East) 2011 Temperature Profiles (F) Variables May 25 June August 25 October 18 Swan Lake (Bay East) 2011 Dissolved Oxygen Profiles (% Sat) Variables May 25 June August 25 October 18 Depth (m) Depth (m) Swan Lake 2011 Water Quality Investigation Summary Report 74

78 Swan Lake (Bay South) 2009 Temperature Profiles (F) Variables June 24 August Swan Lake (Bay South) 2009 Dissolved Oxygen Profiles (% Sat) Variables June 24 August Depth (m) Depth (m) Swan Lake (Bay South) 2010 Temperature Profiles (F) Variables May 10 June August 2 Swan Lake (Bay South) 2010 Dissolved Oxygen Profiles (% Sat) Variables May 10 June August 2 Depth (m) Depth (m) Swan Lake (Bay South) 2011 Temperature Profiles (F) Variables May 25 June August 25 October 18 Swan Lake (Bay South) 2011 Dissolved Oxygen Profiles (% Sat) Variables May 25 June August 25 October 18 Depth (m) Depth (m) Swan Lake 2011 Water Quality Investigation Summary Report 75

79 Swan Lake (Bay West) 2009 Temperature Profiles (F) Variables June 24 August Swan Lake (Bay West) 2009 Dissolved Oxygen Profiles (% Sat) Variables June 24 August Depth (m) Depth (m) Swan Lake (Bay West) 2010 Temperature Profiles (F) Variables May 10 June August 2 Swan Lake (Bay West) 2010 Dissolved Oxygen Profiles (% Sat) Variables May 10 June August 2 Depth (m) Depth (m) Swan Lake (Bay West) 2011 Temperature Profiles (F) Variables May 25 June August 25 October 18 Swan Lake (Bay West) 2011 Dissolved Oxygen Profiles (% Sat) Variables May 25 June August 25 October 18 Depth (m) Depth (m) Swan Lake 2011 Water Quality Investigation Summary Report 76

80 Swan Lake (Bug Creek) 2009 Temperature Profiles (F) Variables June 24 August Swan Lake (Bug Creek) 2009 Dissolved Oxygen Profiles (% Sat) Variables June 24 August Depth (m) Depth (m) Swan Lake (Bug Creek) 2010 Temperature Profiles (F) Variables May 10 June August 2 Swan Lake (Bug Creek) 2010 Dissolved Oxygen Profiles (% Sat) Variables May 10 June August 2 Depth (m) Depth (m) Swan Lake (Bug Creek) 2011 Temperature Profiles (F) Variables May 25 June August 25 October 18 Swan Lake (Bug Creek) 2011 Dissolved Oxygen Profiles (% Sat) Variables May 25 June August 25 October 18 Depth (m) Depth (m) Swan Lake 2011 Water Quality Investigation Summary Report 77

81 Swan Lake (North Basin) 2008 Temperature Profile (F) Variables August 26 Swan Lake (North Basin) 2008 Dissolved Oxygen Profile (% Sat) Variables August Depth (m) Depth (m) Swan Lake (North Basin) 2009 Temperature Profiles (F) Variables June 24 August 19-1 Swan Lake (North Basin) 2009 Dissolved Oxygen Profiles (% Sat) Variables June 24 August 19-1 Depth (m) -2-3 Depth (m) Swan Lake (North Basin) 2010 Temperature Profiles (F) Variables May 10 June 14-1 August 2 Swan Lake (North Basin) 2010 Dissolved Oxygen Profiles (% Sat) Variables May 10 June 14-1 August 2 Depth (m) -2-3 Depth (m) Swan Lake 2011 Water Quality Investigation Summary Report 78

82 Swan Lake (North Basin) 2011 Temperature Profiles (F) Variables May 25 June 13-1 August 25 October 18 Swan Lake (North Basin) 2011 Dissolved Oxygen Profiles (% Sat) Variables May 25 June 13-1 August 25 October 18 Depth (m) -2-3 Depth (m) Swan Lake 2011 Water Quality Investigation Summary Report 79

83 Swan Lake (Rock House) 2009 Temperature Profiles (F) Variables June 24 August Swan Lake (Rock House) 2009 Dissolved Oxygen Profiles (% Sat) Variables June 24 August Depth (m) Depth (m) Swan Lake (Rock House) 2010 Temperature Profiles (F) Variables May 10 June August 2 Swan Lake (Rock House) 2010 Dissolved Oxygen Profiles (% Sat) Variables May 10 June August 2 Depth (m) Depth (m) Swan Lake (Rock House) 2011 Temperature Profiles (F) Variables May 25 June August 25 October 18 Swan Lake (Rock House) 2011 Dissolved Oxygen Profiles (%Sat) Variables May 25 June August 25 October 18 Depth (m) Depth (m) Swan Lake 2011 Water Quality Investigation Summary Report 80

84 Swan Lake (South Basin) 2009 Temperature Profiles (F) Variables June 24 August Swan Lake (South Basin) 2009 Dissolved Oxygen Profiles (% Sat) Variables June 24 August Depth (m) Depth (m) Swan Lake (South Basin) 2010 Temperature Profiles (F) Variables May 10 June August 2-4 Swan Lake (South Basin) 2010 Dissolved Oxygen Profiles (% Sat) Variables May 10 June August 2 Depth (m) Depth (m) Swan Lake (South Basin) 2011 Temperature Profiles (F) Variables May 25 June August 25 October 18 Swan Lake (South Basin) 2011 Dissolved Oxygen Profiles (%Sat) Variables May 25 June August 25 October 18 Depth (m) Depth (m) Swan Lake 2011 Water Quality Investigation Summary Report 81

85 Appendix IV ( Water Chemistry Data) Swan Lake 2011 Water Quality Investigation Summary Report 82

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