State of the Lake Conesus Lake Watershed Characterization Report Update Prepared by EcoLogic LLC and Livingston County Planning Department May 2013 Conesus Lake Watershed Characterization Report Update Conesus Lake Characterization Report Update 1. Executive Summary ............................................................................................................................ 10 2. Introduction ......................................................................................................................................... 18 3. Institutional Framework ...................................................................................................................... 19 3.1. Conesus Lake Watershed Management Council ......................................................................... 19 3.2. Monitoring Consortium............................................................................................................... 20 3.3. Communications and Outreach ................................................................................................... 21 3.4. Investment in Watershed Restoration and Protection ................................................................. 22 4. The State of the Watershed 2012: Status and Trends ......................................................................... 24 4.1. Population and Land Cover ......................................................................................................... 24 4.2. Agricultural Practices .................................................................................................................. 30 4.3. Effectiveness of agricultural BMPs on tributary water quality and loading ............................... 32 4.4. The Stream Water Quality Index ................................................................................................ 33 4.4.1. Cottonwood Gully ............................................................................................................... 35 4.4.2. North McMillan Creek ........................................................................................................ 36 4.4.3. Graywood Gully .................................................................................................................. 36 4.4.4. Long Point Gully ................................................................................................................. 36 4.4.5. Sutton Point Gully ............................................................................................................... 37 4.4.6. Sand Point Gully ................................................................................................................. 37 4.4.7. Outlook for Using the Stream Water Quality Assessment Index ........................................ 37 4.5. Streambank Remediation and Road Ditch Remediation ............................................................. 38 4.5.1. Streambank Remediation .................................................................................................... 38 4.5.2. Road Ditch Remediation ..................................................................................................... 41 4.6. Town and Village Initiatives: Local Regulations and Programs ................................................ 44 4.6.1 Zoning ................................................................................................................................. 46 4.6.2 Comprehensive Plans .......................................................................................................... 48 4.6.3 Docks and Moorings Laws ................................................................................................. 49 4.6.4 Subdivision Regulations ..................................................................................................... 49 4.7. New York State Initiatives .......................................................................................................... 50 5. The State of the Lake 2012: Status and Trends................................................................................... 51 1 Conesus Lake Watershed Characterization Report Update 5.1 Regulatory status ......................................................................................................................... 51 5.2 Physical Characteristics .............................................................................................................. 53 5.2.1 Bathymetry .......................................................................................................................... 53 5.2.2 Ice cover .............................................................................................................................. 55 5.3 Chemical Characteristics and Trophic State ............................................................................... 56 5.3.1 Total phosphorus, Secchi disk transparency, chlorophyll-α ............................................... 56 5.3.2 Deep water dissolved oxygen ............................................................................................. 61 5.3.3 Sediment flux estimates ...................................................................................................... 61 5.3.4 Inorganic water quality conditions ...................................................................................... 62 5.4 Biological Characteristics ........................................................................................................... 63 5.4.1 Macrophytes and macroalgae .............................................................................................. 63 5.4.2 Cyanobacteria...................................................................................................................... 67 5.4.3 Benthic macroinvertebrates ................................................................................................. 67 5.4.4 Zooplankton ........................................................................................................................ 68 5.4.5 Fish Community .................................................................................................................. 71 6. Assessment: Factors Affecting Lake and Watershed Management .................................................... 75 6.1. Population and land use changes ................................................................................................ 75 6.2. Water and sewer infrastructure improvements ........................................................................... 75 6.3. Public education and outreach efforts ......................................................................................... 77 6.4. Institutional framework and collaborations ................................................................................ 77 6.5. Effectiveness of remedial measures ............................................................................................ 77 6.5.1. Loading reductions from BMP implementation ................................................................. 77 6.5.2. Biological control of Eurasian watermilfoil using aquatic weevils .................................... 78 6.5.3. SolarBee® pilot test ............................................................................................................ 78 6.5.4. Diversion of North Gully Creek .......................................................................................... 79 6.5.5. Feasibility of an alum treatment program to control internal phosphorus loading ............. 79 7. Emerging issues .................................................................................................................................. 81 7.1. Climate change ............................................................................................................................ 81 7.2. Invasive species .......................................................................................................................... 83 7.2.1. Eurasian watermilfoil .......................................................................................................... 83 2 Conesus Lake Watershed Characterization Report Update 7.2.2. Water chestnut .................................................................................................................... 83 7.2.3. Dreissenid mussels .............................................................................................................. 83 7.3. Invasive Species to Watch .......................................................................................................... 84 7.3.1. Asian clams ......................................................................................................................... 84 7.3.2. Emerald Ash Borer .............................................................................................................. 84 7.3.3. Feral swine .......................................................................................................................... 85 7.3.4. Hydrilla ............................................................................................................................... 86 7.4. Conesus Lake’s status on the state’s 305 (b) and 303 (d) lists .................................................... 86 8. Conclusions ......................................................................................................................................... 87