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Sturbridge Lakes 2009 Annual Data Report

Sturbridge Lakes 2009 Annual Data Report. Presented by: David Mitchell and Donna Grehl Sponsored by: Sturbridge Conservation Commission and Sturbridge Lakes Advisory Committee Sturbridge Senior Center June 24, 2009. Tonight’s Presentation.

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Sturbridge Lakes 2009 Annual Data Report

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  1. Sturbridge Lakes 2009 Annual Data Report Presented by: David Mitchell and Donna Grehl Sponsored by: Sturbridge Conservation Commission and Sturbridge Lakes Advisory Committee Sturbridge Senior Center June 24, 2009

  2. Tonight’s Presentation • Introduction to Sturbridge Conservation Commission (SCC) Lake Monitoring Program • Results from Summer 2008 Lake Sampling and Data Comparisons between Lakes • Planning for 2009 Lake Monitoring Program • Introduction to Sturbridge Lakes Advisory Committee (SLAC)

  3. SCC Lakes and Ponds Inventory, Monitoring, and Management Strategy • Conduct Annual Lake and Pond Monitoring • Develop Sturbridge Lake and Pond Water Quality Database • Watershed Delineation and Characterization • Coordinate with Lake Associations to define and develop long-term Lake Management and Watershed Protection Plans (LM/WPPs)

  4. Great Ponds* of Sturbridge Currently Being Monitored • Big Alum Pond • Cedar Lake • East Brimfield Reservoir/Long Pond • Leadmine Pond • South (Quacumquasit) Pond • Walker Pond * Defined by MGL Chapter 91.36 as ponds containing in their natural state more than ten acres of land, and subject to any rights in such ponds which have been granted by the Commonwealth.

  5. Reasons for Lake Monitoring • Provides baseline data to compare with future data to detect trends • Forms basis for conducting informed lake management • Allows evaluation of efficiency of various treatments • Economic incentives for protection of lake real estate values

  6. Lakes Monitoring Program • Lakes sampled during mid-summer (July-Aug.) • Central location (deep hole) and other location • Shallow (0.5 ft) and deep (2-3 ft off bottom) • Thermal and dissolved oxygen (DO) profiles • Secchi Disk Transparency (SDT) • Water Quality Samples taken: • Nutrients - nitrogen and phosphorus fractions • Other - alkalinity, hardness, TSS, iron, conductivity • Biological – chlorophyll a, zooplankton

  7. How deep is your lake? Is there a single water layer or a deeper colder layer where the big trout are lurking? • Average lake depth is important • Influences light availability for aquatic weeds • Lakes with >15-20 ft will usually seasonally stratify • Forms two layers with different temperature and water quality in summer • Algal blooms usually confined to upper layer • Bottom layer may provide coldwater fish habitat • Recycling of nutrients ... and even deeper?

  8. Sturbridge Great Ponds

  9. Thermal and Dissolved Oxygen Profiles and SDT Measurement

  10. Epilimnion Thermocline Hypolimnion

  11. DO % Saturation Profile Leadmine Pond (8/8/08) Thermocline

  12. Sturbridge Deep Lakes 2008Temperature and DO Depth Profiles

  13. Sturbridge Shallow Lakes 2008Temperature and DO Depth Profiles

  14. Water Quality Sampling

  15. Big Alum Pond BA-2 BA-1

  16. Big Alum Pond BA-1 (8/9/2008)Nutrients and Secchi Disk Depth

  17. CL-2 CL-1 Cedar Lake

  18. Cedar Lake (8/9/08)Nutrients and Secchi Disk Depth

  19. LP-1 LP-2

  20. Leadmine Pond LP-1 (8/8/08)Nutrients and Secchi Disk Depth

  21. SP-1 SP-2

  22. South Pond SP-1 (8/8/08)Nutrients and Secchi Disk Depth

  23. WP-1 WP-2

  24. Walker Pond WP-2 (8/08/08)Nutrients and Secchi Disk Depth

  25. East Brimfield Reservoir /Long Pond • Largest Great Pond in Sturbridge and last to be monitored • Only shoreline-based monitoring in 2008 • Initial water quality data indicates some influence of Route 20

  26. East Brimfield Reservoir (8/9/08)Nutrients and Secchi Disk Depth

  27. Shallow Lakes Max. depth = 16 ft SDT = 6.2 ft (n=22) Alkalinity = 10.3 mg/L (n=39) Sp. Cond = 299 uS (n=44) Sodium = 43.2 mg/L (n=35) Chloride = 73.2 mg/L (n=34) Chl a = 8.7 ug/L (n=10) Deep Lakes Max. depth = 45-60+ ft SDT = 15.5 ft (n=42) Alkalinity = 10.5 mg/L (n=49) Sp. Cond = 90.5 uS (n=63) Sodium = 7.5 mg/L (n=50) Chloride = 15.3 mg/L (n=50) Chl a = 5.75 ug/L (n=15) Comparisons in Water Quality between Deep and Shallow Lakes: 2002-08 data

  28. Carlson’s Trophic State Indicators

  29. Comparison of 2008 TSI scores for Sturbridge Lakes • Mean Carlson TSI Scores • Big Alum Pond = 37 • Cedar Lake = 51 • Leadmine Pond = 38 • South Pond = 41 • Walker Pond = 39

  30. TSI Score & Trophic Classifications Oligotrophic= < 38 (poorly fertilized) Mesotrophic = 38-47 (moderately fertilized) Eutrophic = 48-66 (well fertilized) Hypereutrophic = > 66 (extremely fertilized) Sturbridge Lakes Big Alum: Oligotrophic Cedar Lake: Eutrophic Leadmine: Oligo-Mesotrophic South: Mesotrophic Walker: Mesotrophic Trophic States of Sturbridge Lakes

  31. Biological Sampling

  32. Chlorophyll trends 2004-2008 Chlorophyll values in ug/L

  33. Zooplankton Sampling 2003-2008 (average cladoceran length in mm)

  34. Comments on 2008 Monitoring Program Results • Lake water quality indicates generally good conditions, but some mixed signals • Higher chlorophyll levels and lowered SDT values in some lakes, generally less TP observed this year • Water clarity values well within seasonal ranges previously recorded • South Pond continues to have smaller zooplankton species, which may limit grazing. • The fight against non-native aquatic invasive species continues

  35. Common species: Chara / Nitella Elodea canadensis Myriophyllum heterophyllum Najas flexilis Potomogeton (10 species) Utricularia Vallisneria americana Non-indigenous invasive species: Cabomba caroliniana (South Pond) Myriophyllum spicatum (South Pond) Potomogeton crispus (Big Alum Pond, Cedar Lake) Common and non-native invasive aquatic macrophytes in Sturbridge Lakes

  36. Thanks to All the 2008 Lake Monitoring Volunteers • SCC – Dave Barnicle, Matt Mitchell, Dave Mitchell, Erin Jacque • Big Alum Pond – Bruce Gran • Cedar Lake – Pat Wondolowski • Leadmine Lake – Bill Kenyon • South Pond – Marita and Jeff Tasse • Walker Pond – John O’Brien and Zack

  37. Sturbridge Lakes Monitoring 2009 • SCC Lake Monitoring • We will conduct another round of physiochemical measurements and WQ sampling. • Sampling tentatively scheduled for Friday August 14th and Saturday 15th, 2009 • Exact schedule of lake sampling to be finalized in July • Many thanks to those who have already given generously of their time to make these events happen and the monitoring successful. • Volunteers and boats are alwaysappreciated !

  38. Photo credits • Big Alum Pond aerial – Lycott website • Cedar Lake – Pat Wondolowski • East Brimfield Reservoir – USACE website • Leadmine Lake – Bill Kenyon • South Pond – Donna Grehl • Walker Pond – John Hoffman

  39. QUESTIONS ?

  40. 2008 Lake Sampling Stations and Parameters

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