Sturbridge Lakes 2008 Annual Data Report

1. Sturbridge Lakes 2008 Annual Data Report Presented by: David Mitchell Sturbridge Conservation Commission Sturbridge Town Hall June 18, 2008

2. Tonight’s Presentation • Introduction • Sturbridge Conservation Commission (SCC) Lake Policy and Lake Monitoring Program • Results from Summer 2007 Lake Sampling and Data Comparisons between Lakes • Planning for 2008 Lake Monitoring Program

3. SCC Lakes Policy The Town of Sturbridge is fortunate to have abundant water resources, including many lakes and ponds with significant scenic, ecological and recreational values. For the most part, these waterbodies exhibit good water quality and are largely unimpaired by nuisance algal blooms and excessive macrophyte growth. Future water quality in these lakes and ponds will be challenged by the continuinggrowth and development in the watersheds. It is therefore necessary to monitor the lakes regularly to detect undesirable trends at an early stage and to promote and develop appropriate and effective lake and watershed management

4. 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)

5. Great Ponds* of Sturbridge Currently Being Monitored • Big Alum Pond • Cedar Lake • Leadmine Pond • South (Quacumquasit) Pond • Walker Pond * Defined (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.

6. Sturbridge Great Ponds * WA = watershed surface area; SA = lake surface area

7. Other Lake and Ponds in Sturbridge Currently Not Monitored • East Brimfield/Long Pond (USACE) • Westville Lake (USACE) • Breakneck Pond • McKinstry Pond • Pistol Pond

8. Reasons for Lake Monitoring • Provides baseline data to compare with any future change • Basis for conducting informed lake management • Evaluate efficiency of various treatments • Economic incentives for protection of lake real estate values

9. 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

10. 2007 Lake Sampling Stations and Parameters

11. Thermal and Dissolved Oxygen Profiles and SDT Measurement

12. 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?

13. Epilimnion Thermocline Hypolimnion

15. Sturbridge Deep Lakes 2007Temperature and DO Depth Profiles

16. Sturbridge Shallow Lakes 2007Temperature and DO Depth Profiles)

17. Water Quality Sampling

18. Big Alum Pond BA-2 BA-1

19. Big Alum Pond BA-1 (8/11/2007)Nutrients and Secchi Disk Depth

20. CL-2 CL-1 Cedar Lake

21. Cedar Lake (8/11/07)Nutrients and Secchi Disk Depth

22. LP-1 LP-2

23. Leadmine Pond LP-1 (8/10/07)Nutrients and Secchi Disk Depth

24. SP-1 SP-2

25. South Pond SP-1 (8/11/07)Nutrients and Secchi Disk Depth

26. WP-1 WP-2

27. Walker Pond WP-2 (8/11/07)Nutrients and Secchi Disk Depth

28. Shallow Lakes Max. depth = 16 ft SDT = 6.2 ft (n=18) Alkalinity = 11.7 mg/L (n=31) Sp. Cond = 312 uS (n=36) Sodium = 45.5 mg/L (n=27) Chloride = 79.4 mg/L (n=26) Chl a = 8.1 ug/L (n=8) Deep Lakes Max. depth = 45-60+ ft SDT = 15.8 ft (n=36) Alkalinity = 11.9 mg/L (n=38) Sp. Cond = 90.9 uS (n=54) Sodium = 7.4 mg/L (n=39) Chloride = 15.3 mg/L (n=39) Chl a = 4.5 ug/L (n=12) Comparisons in Water Quality between Deep and Shallow Lakes – 2002-07 data

29. Biological Sampling

30. Zooplankton Sampling 2003-2007

31. Carlson’s Trophic State Indicators

32. Comparison of 2007 TSI scores for Sturbridge Lakes • Mean Carlson TSI Scores • Big Alum Pond = 40 • Cedar Lake = 52 • Leadmine Pond = 44 • South Pond = 42 • Walker Pond = 43

33. 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 – Mesotrophic Cedar Lake – Eutrophic Leadmine – Mesotrophic South – Mesotrophic Walker - Mesotrophic Trophic States of Sturbridge Lakes

34. 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 - Oligo-mesotrophic Cedar Lake – Eutrophic Leadmine – Mesotrophic South – Mesotrophic Walker - Mesotrophic Trophic States of Sturbridge Lakes(composite of 2004-2006 data)

35. Lake Stewardship for Watershed • Your watershed consists of the all the surface area and GW that supplies water to your lake • Look to manage land use in the watershed to reduce or mitigate future nutrient loading • Implement best practices for shoreline owners • Acquire key parcels in watershed • Consider lake protection districting • Support good lake management at the ballot box

36. Lake Stewardship for Lakeshore • Prevention of nutrients (phosphorus and nitrogen) from entering Great Ponds • Use low or no phosphorus fertilizer on lawns • Eliminate/mitigate direct stormwater discharge • Establishment of a natural vegetation buffer on the 20 feet nearest the lake • Don’t have lawn to waters edge • Provide overhanging vegetation (fish habitat) • Prevent erosion and sediment entering lake

37. Lake Stewardship for In-Lake • Boat Launch and Operation • Maintain adequate depth and angle for boat launch as it flattens out over time and creates delta • Keeps boat speed low near shallow depth as prop wash will re-suspend sediment material • Shoreline cleanup • Don’t dispose of leaves and organic materials in lake, it will lead to reduction in dissolved oxygen • Don’t ever dispose of unused bait fish or discard aquarium plants into lake • this is how non-indigenous species get into a lake !

38. Sturbridge Lakes Monitoring 2008 • SCC Lake Monitoring • We will conduct another round of physiochemical measurements and WQ sampling. • Sampling tentatively scheduled for Friday August 8th and Saturday 9th, 2008 • Exact scheduling of sampling will be finalized in mid-July • Many thanks to those who have already given generously of their time to make these events happen. • Volunteers and boats are alwaysappreciated !

39. Thanks to All the 2007 Lake Monitoring Volunteers • SCC – Donna Grehl, Kelly Kippenburger, Matt Mitchell, Dave Mitchell • Big Alum Pond – Scott Sanderson and kids • Cedar Lake – Pat Wondolowski • Leadmine Lake – Jim Dunn and Gary Craig • South Pond – Marita and Jeff Tasse • Walker Pond – Doug Smith

40. Photo credits • Big Alum Pond aerial – Lycott website • Leadmine Lake – Bill Kenyon • South Pond – Donna Grehl • Walker Pond – John Hoffman

41. QUESTIONS ?