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Second Annual State of Deep Creek Lake, 2012

Second Annual State of Deep Creek Lake, 2012. 14 November 2012. John R. Griffin, Secretary Maryland Department of Natural Resources. Introduction Secretary John R. Griffin MD Department of Natural Resources. Goals for Deep Creek Lake. to protect the lake as a man-made resource,

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Second Annual State of Deep Creek Lake, 2012

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  1. Second AnnualState ofDeep Creek Lake, 2012 14 November 2012 John R. Griffin, SecretaryMaryland Department of Natural Resources

  2. Introduction Secretary John R. Griffin MD Department of Natural Resources

  3. Goals for Deep Creek Lake • to protect the lake as a man-made resource, • preserve its ecological balance, and • maintain its use as a recreational and economic asset.

  4. The state of Deep Creek Lake today is that of a healthy reservoir that meets most users needs under the federal Clean Water Act… • Good water quality • Diverse plant and animal life • Moderate levels of nutrients to support aquatic life Even so… the lake has its share of issues…

  5. Water Quality Bruce Michael Director, Resource Assessment Service MD Department of Natural Resources

  6. Water quality monitoring goals: • characterize existing water quality conditions in the lake and its tributary coves – physical and chemical characteristics, levels of nutrients and primary productivity • establish baseline conditions to evaluate trends in water quality conditions • monitor water quality conditions at tributary stream gage sites to eventually determine nutrients and sediment loads entering the lake from the watershed

  7. Monitoring Summary • The current monitoring program has defined seasonal and spatial variations and established a baseline of conditions to evaluate how changes in population/land use in the watershed affect Deep Creek Lake. • Deep Creek Lake has a diverse aquatic plant community with a wide range of species ranging from microscopic phytoplankton species to vascular aquatic plants, including invasive species. • Weather conditions (temperatures/precipitation) have varied each year during the summer, which can affect some measures… 2009 - cool, moderately dry summer 2010 – very warm, dry summer 2011 - very warm, wet summer 2012 - hot, moderately dry summer

  8. 2012 Monitoring Results • Water temperatures in summer 2012 were highestrecorded during this monitoring period (2009-2012). • Oxygen levels in the upper waters of the lake, pH, conductivity, and nutrients (nitrogen and phosphorus) are at levels that support a diverse biological community (plankton, aquatic plants, fish and wildlife). • Algal levels are limited by the low concentrations of phosphorus in the lake. • Open waters are very clear and support swimming, boating and growth of aquatic plants in deeper waters

  9. Water Quality Issues • Health advisory to limit consumption of bass and walleye caught in the lake due to elevated mercury. This is a Statewide concern in many lakes. • Summer oxygen levels in the cool, deep portions of the lake (greater than 21-34 feet) are too low(< 2 ppm; hypoxic) to support aquatic life. This is naturally occurring but increases in nutrients to the lake = increases in algae = longer hypoxic periods and occurrences in more shallow areas of the lake.

  10. Water Quality Trends, 1970-2012 Long-term trends in lake productivity (measured as the amount of chlorophyll in microscopic phytoplankton) show little change and indicates that phosphorus levels have not appreciably increased. nutrient polluted nutrient enriched moderate nutrients supports diverse aquatic life nutrient poor

  11. Water Quality Trends, 1970-2012 Long term trends in electrical conductivity in the lake (a measure of input of dissolved salts in fertilizers, septage, and deicer chemicals from the watershed) have doubled but are not yet at levels that impact aquatic life.

  12. Aquatic Vegetation

  13. Locations of DNR’s Aquatic Vegetation survey transects,2010-2012

  14. 2012 EWM shoreline survey summary – I 86 acres of Eurasian water milfoil (EWM) were mapped in a complete shoreline survey conducted July 9-10, 2012 • 2.3% of the lake surface • 5.8% of shallow (less than 6m deep) water • EWM co-occurred with other SAV species Northwest half of Deep Creek Lake

  15. 2012 EWM shoreline survey summary - II Transect data indicate no significant difference in percent cover of EWM between 2010, 2011 and/or 2012 Seen from the surface, other native submerged grasses are far more common, specificallyPotamogetons andVallisneria, which occupy virtually all of the lake shallows Southeast half of Deep Creek Lake

  16. Control options for EWM Most effective / lowest impact large scale (acres) control option is the use of herbicide 2,4-D (repeated application necessary over years) • Cost of $500 to $1000/acre • Can be used in “spot” treatments • Low toxicity to most fish (some salts are highly toxic to trout), but might be an endocrine disruptor to aquatic vertebrates Localized control measures include benthic barriers or hand removal • Care must be used to capture all hand-harvested removal to minimize spread • Benthic barriers are expensive per unit area (4 installations in 2012; $300-500/mat – cost, install, removal), but very effective • Hand removal is inexpensive and very low impact, but is inefficient Mechanical harvesting • Expensive ($8-10,000 for two days) • Risk of spreading EWM from fragments or introducing other SAV species carried in on equipment from other water bodies

  17. EWM Control options rejected / reasons Herbicides other than 2,4-D • Some impacts to other SAV species and/or fish • Less effective in DCL – due to the large lake volume ($300-500/acre) Biological controls • Grass carp are illegal in Maryland • Milfoil weevils haven’t been approved for importation into the state by Invasive Species Matrix Team • Risk of escape into Chesapeake / other waterbodies • Very expensive ($1,000s per acre) • Efficacy uncertain in Deep Creek Lake • In other regions, EWM control is very slow • Controls are vulnerable to sunfish predation - DCL has a lot of sunfish

  18. Going forward… • Continue transect surveys at 6 locations in the lake (3 times per year) • Monitor / assess Eurasian water milfoil • Complete statistical analyses • Conduct 2nd targeted EWM survey in June 2013 • Implement pilot control actions • Monitor results to guide future actions

  19. Pilot project proposed to evaluate effectiveness of EWM control measures in selected Deep Creek Lake sites • Herbicide (2,4-D) control – location TBD • Harvest of limited areas – location TBD

  20. Sedimentation Phase II – DCL Sediment Plan

  21. Lake Sediments - Completed Field Work • April 2012 - Field Work • Sub-bottom seismic survey and bathymetry collected along transects throughout the lake. • Complete sidescan sonar imagery of the lake and GPS-referenced shoreline video inventory • May-September 2012 - Data processing / analysis • QA/QC and processing/correcting and interpretation of data results • Identify areas of sedimentation / no sedimentation using sidescan imagery, bathymetric comparisons, and sub-bottom seismic data. • October 2012 – Field Work • Collected 42 sediment cores throughout lake and analyzed selected cores and deposited sediment for chemicals and pollutants. All samples were determined and documented to have no pollutants at detectable and reportable levels. • Alternatives Analysis and Sediment Reduction contracts have been written and are awaiting the bidding process.

  22. Sub-Bottom Seismic/Bathymetry Survey Coverage

  23. Sediment Cores • 42 Cores collected throughout lake • Core lengths ranged from 0 (Rock confirmation) to 7 feet in length. The average collected length of each core was 3 feet. • Cores were described, photographed, and sampled. Select samples are being analyzed for pollutants, chemical properties, and physical properties.

  24. Future Plan • November 2012 – May 2013 • Complete analysis of sedimentation within the Lake and publish a comprehensive report (February 2013) • Contractors will develop a sediment reduction plan to be provided to state and local governments and landowners. (May 2013) • Contractors will develop an alternatives analysis determining if dredging is recommended. If so, they will identify costs, methods, and impacts.

  25. Fisheries

  26. Status of the Fishery Remember that:in summer 2010, about 10,000 fish died in the lake from a bacterial infection. Yellow perch, Walleye, and Smallmouth bass were most affected.

  27. Spring 2012 Walleye Survey Walleye are the most abundant game fish species in the Deep Creek Lake with diverse size classes including trophy-sized fish over 20 inches long. The 2012 adult walleye abundance value was one of the highest recorded to date in Deep Creek Lake.

  28. Also in Spring 2012…Maryland DNR Fisheries Service conducted a corrective stocking of 10,000 fingerlingLargemouth Bass. These were stocked at several locations in Deep Creek Lake in response to losses from the 2010 fish kill event.

  29. Summer 2012 – Conducted seining surveys to monitor reproductive success for Largemouth Bass, Smallmouth Bass, and Yellow Perch. Reproductive success in 2012 was rated as: - “Good” for Largemouth Bass; - “Excellent” for Smallmouth Bass; and - “Excellent” for Yellow Perch

  30. Summer – Fall 2012:MD DNR Fisheries Service obtained length, weight, and angler catch data during bass tournaments held on Deep Creek Lake. Analysis of these data have not been completed, but size of fish and catch rates among anglers appear to have improved since the 2010 fish kill event.

  31. Fall 2012 – Comprehensive Fish Population Survey - scheduled for Oct. 31, but delayed by some snow on the ground…

  32. Lake Water Levels John GraceWater Management Administration MD Department of the Environment

  33. Uses of the Lake Deputy Secretary Joe Gill MD Department of Natural Resources

  34. Boating Boating

  35. Boating • 5,300 boats, including 600 PWCs • Trend - bigger boats, e.g., 26-foot boat with molded platform • Trend – wider, longer piers • Wake-boarding • Recent regulatory changes • Limits on powerboats • Limits on wakeboarding

  36. Boating • Carrying capacity • 2003 study – tolerance to crowding on the surface of the Lake by various types of recreational boating activity • No study on maximum “build-out” of dock slips on the Lake

  37. Marinas

  38. Marinas • Mini-marina requirements • Impact to Deep Creek Lake - Town Center - Town Residential - Assessment • Illustrates need to manage shoreline in concert with the Lake • Illustrates larger need to manage watershed

  39. Lake / Watershed Management Secretary John R. Griffin MD Department of Natural Resources

  40. “A lake is a reflection of its watershed”… DNR manages only a small portion of the Deep Creek Lake watershed - mostly the lake and buffer areas at the end of each sub-watershed.Private holdings make up most of the watershed. As land use changes occur in the watershed, characteristics of the lake also will change. Addressing stresses in the watershed will slow changes in the quality of the lake and will maintain current conditions for this important asset for the county and State. Image source: Chesapeake EcoCheck. 2011. Deep Creek Lake baseline condition assessment”. 4p. Online at: http://www.eco-check.org

  41. Our greatest collective challenge… To take a watershed approach to future lake management.

  42. Individual Testimony

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