Don River Watershed Plan Aquatic System – Report on Current Conditions 2009 Prepared by: Toronto and Region Conservation Don River Watershed Plan: Aquatic System – Report on Current Conditions Table of Contents Table of Contents............................................................................................................................ 2 List of Tables................................................................................................................................... 3 List of Figures ................................................................................................................................. 4 1.0 Introduction............................................................................................................................... 5 2.0 Understanding the Aquatic System ......................................................................................... 6 2.1 An Urban Ecosystem........................................................................................................... 8 3.0 Data Sources and Methods...................................................................................................... 8 3.1 Current Conditions Fish Data ............................................................................................... 9 3.1.1 Regional Watershed Monitoring Program..................................................................... 9 3.1.2 Fish Management Plan Data Collection........................................................................ 9 3.1.3 Lakefront Environmental Monitoring Program.............................................................. 9 3.1.4 Richmond Hill East Data Collection ............................................................................ 11 3.2 Past Conditions Fish Data .................................................................................................. 11 3.3 Benthic Invertebrate Sampling ........................................................................................... 13 3.4 Stream Temperature Methods 1 and 2 .............................................................................. 13 3.4.1 OSAP Method .............................................................................................................. 13 3.4.2 Wehrly Method.............................................................................................................14 3.5 BFI Calculation Methods .................................................................................................... 14 3.6 Surface Water Quality......................................................................................................... 14 3.7 Percent Impervious Cover .................................................................................................. 14 3.8 Riparian Vegetation and Wetlands..................................................................................... 14 3.9 Instream Barriers................................................................................................................. 15 3.10 Stream Length .................................................................................................................. 16 3.11 Aquatic Invasive Species (AIS)......................................................................................... 16 3.12 Human Use ....................................................................................................................... 16 4.0 Current Conditions in the Don River Watershed – Aquatic Communities............................. 16 4.1 Fish Community at the Watershed Scale........................................................................... 16 4.1.1 Species of Local Concern ........................................................................................... 20 4.1.2 Introduced Species (Stocking).................................................................................... 22 4.1.3 Aquatic Invasive Species............................................................................................. 22 4.2 Fish Community at the Subwatershed Scale.................................................................... 24 4.2.1 Upper West Don River Subwatershed ........................................................................ 24 4.2.2 Upper East Don River Subwatershed ......................................................................... 26 4.2.3 German Mills Creek Subwatershed ............................................................................ 29 4.2.4 Lower West Don River Subwatershed ........................................................................ 30 4.2.5 Lower East Don River Subwatershed.......................................................................... 31 4.2.6 Taylor/Massey Creek Subwatershed .......................................................................... 32 4.2.7 Lower Don River Subwatershed.................................................................................. 33 4.3 Other Aquatic Communities ............................................................................................... 35 4.3.1 Freshwater Mussels..................................................................................................... 35 4.3.2 Crayfish ........................................................................................................................ 36 4.4 Aquatic Ecosystem Health ................................................................................................. 36 4.4.1 Fish Index of Biotic Integrity ........................................................................................ 36 4.4.2 Fish IBI Results – RWMP Stations ............................................................................... 36 4.4.3 Benthic Aggregate Assessment .................................................................................. 41 4.4.4 Ratings for Current Conditions of Benthic Invertebrates and Fish Communities ...... 44 Toronto Region Conservation CFN: 37590 2 2009 Don River Watershed Plan: Aquatic System – Report on Current Conditions 5.0 Current Conditions in the Don River Watershed – Stream Conditions and Aquatic Ecosystem Health......................................................................................................................... 51 5.1 Groundwater ....................................................................................................................... 51 5.2 Baseflow and Total Flow Conditions.................................................................................. 51 5.3 Temperature Regime and Stability..................................................................................... 52 5.3.1 Temperature Regime Results...................................................................................... 52 5.3.2 Temperature Stability Results...................................................................................... 53 5.3.3 Discussion of Thermal Results .................................................................................... 57 5.4 Riparian Wetlands............................................................................................................... 58 5.5 Riparian Zone Vegetation ................................................................................................... 59 5.6 In-stream Barriers and Watercourse Crossings................................................................. 60 5.7 Water Quality ...................................................................................................................... 64 5.7.1 TSS............................................................................................................................... 64 5.7.2 Chloride........................................................................................................................ 65 5.7.3 Un-ionized Ammonia ................................................................................................... 65 5.7.4 PAHs ............................................................................................................................ 65 5.7.5 PCBs ............................................................................................................................ 66 5.7.6 Copper ......................................................................................................................... 66 5.7.7 Iron ............................................................................................................................... 66 5.7.8 Lead ............................................................................................................................. 66 5.7.9 Zinc .............................................................................................................................. 67 5.8 Percent Impervious Cover .................................................................................................. 67 5.9 Angling in the Don River..................................................................................................... 72 5.10 Ratings for Stream Conditions ......................................................................................... 72 5.10.1 Thermal Regime and Thermal Stability..................................................................... 74 5.10.2 In-Stream Barriers...................................................................................................... 74 5.10.3 Percent of Total Potential Riparian Zone with Natural Cover