Etobicoke and Mimico Creeks Watersheds Technical Update Report

2010

Prepared by: Toronto and Region Conservation Authority Acknowledgements

The Etobicoke and Mimico Creeks Watersheds Technical Update Report was prepared by staff of the Toronto and Region Conservation Authority. Appreciation and thanks are extended to members of the Etobicoke and Mimico Watersheds Coalition, staff from watershed municipalities and government partners who provided input at various stages of the study.

©Copyright Toronto and Region Conservation 5 Shoreham Drive ,Downsview, Ontario, M3N 1S4, Canada Ph: (416) 661-6600 www.trca.on.ca ISBN 978-0-9811107-6-9 TABLE OF CONTENTS

EXECUTIVE SUMMARY...... i

1.0 INTRODUCTION ...... 1-1 1.1 Technical Update Approach...... 1-1 1.2 Report Scope and Organization...... 1-2 1.3 Watershed Vision...... 1-2 1.4 Watershed Objectives, Indicators and Targets...... 1-3

2.0 STUDY AREA AND PHYSICAL SETTING ...... 2-1 2.1 Study Area and Location ...... 2-1 2.2 Watershed and Subwatershed Boundaries ...... 2-1 2.3 Land Use and Population ...... 2-3 2.3.1 Current Land Use and Population...... 2-4 2.3.2 Planned Development ...... 2-6 2.4 Climate ...... 2-8 2.5 Physiographic Regions...... 2-10 2.6 Surficial Geology and Geology ...... 2-11 2.6.1 Scarborough Formation ...... 2-11 2.6.2 Sunnybrook Diamict ...... 2-17 2.6.3 Thorncliffe Formation...... 2-17 2.6.4 Newmarket Till ...... 2-17 2.6.5 Oak Ridges Moraine and Mackinaw Interstadial Deposits ...... 2-17 2.6.6 Halton Till ...... 2-17 2.6.7 Recent Deposits...... 2-18 2.7 References…...... 2-21

3.0 GROUNDWATER QUANTITY AND QUALITY ...... 3-1 3.1 Watershed Objectives, Indicators and Targets...... 3-2 3.2 Objectives of Technical Update ...... 3-2 3.3 Data Sources and Methods...... 3-3 3.3.1 Data Sources ...... 3-3 3.3.2 Methods ...... 3-4 3.4 Existing Conditions and Interpretation...... 3-5 3.4.1 Hydrogeologic Units...... 3-5 3.4.2 Groundwater Recharge ...... 3-11 3.4.3 Groundwater Levels...... 3-11 3.4.4 Groundwater Modelling...... 3-23 3.4.5 Water Budget ...... 3-23 3.4.6 Groundwater Quality...... 3-34 3.5 Management Recommendations ...... 3-35 3.5.1 Development within former Brampton Esker Aggregate Pits...... 3-35 3.5.2 Groundwater Recharge ...... 3-37 3.5.3 Groundwater Levels...... 3-38 3.5.4 Groundwater Quality...... 3-39 3.6 References ...... 3-40 3.7 Appendix 3-A: Aerial photographs of Esker Lake North taken between 1999 and 2007…………...... 3-42

Toronto Region Conservation, 2010 i 4.0 BASEFLOW AND WATER USE...... 4-1 4.1 Watershed Objectives, Indicators and Targets...... 4-2 4.2 Objectives of Technical Update ...... 4-2 4.3 Data Sources and Methods...... 4-2 4.3.1 Baseflow Data ...... 4-2 4.3.2 Groundwater Data ...... 4-3 4.3.3 Surface Water Use Data ...... 4-3 4.3.4 Streamflow and Climate Data...... 4-3 4.4 Existing Conditions and Interpretation...... 4-4 4.4.1 Baseflow Trends ...... 4-4 4.4.2 Measured Baseflow Findings ...... 4-9 4.4.3 Etobicoke and Mimico Creek Water Use ...... 4-17 4.4.4 Summary of Findings ...... 4-23 4.5 Management Recommendations ...... 4-25 4.6 References…...... 4-27

5.0 STORMWATER MANAGEMENT AND STREAMFLOW ...... 5-1 5.1 Watershed Objectives, Indicators and Targets...... 5-3 5.2 Objectives of Technical Update ...... 5-4 5.3 Data Sources and Methods...... 5-4 5.3.1 Data Sources ...... 5-4 5.3.2 Method ...... 5-5 5.4 Existing Conditions and Interpretation...... 5-6 5.4.1 Existing Land Use...... 5-6 5.4.2 Areas Covered by Comprehensive Stormwater Management (SWM)Plans.... 5-10 5.4.3 Existing SWM Controls ...... 5-15 5.4.4 Stormwater Management Quality Treatment ...... 5-20 5.4.5 Stormwater Management Erosion Control...... 5-24 5.4.6 Stormwater Management Quantity Control ...... 5-27 5.4.7 Stormwater Management Retrofit Plans/ Strategies...... 5-30 5.4.8 Streamflow ...... 5-33 5.4.9 Summary of Recent Studies Relating to Stormwater Management...... 5-47 5.4.10 Summary of Findings ...... 5-49 5.5 Management Recommendations ...... 5-51 5.6 References ...... 5-53 5.7 Appendix 5-A: Detailed Land Use Breakdown...... 5-55

6.0 SURFACE WATER QUALITY...... 6-1 6.1 Watershed Objectives, Indicators and Targets...... 6-1 6.2 Objectives of Technical Update ...... 6-3 6.3 Data Sources, Monitoring Programs and Analysis...... 6-3 6.3.1 Data Sources ...... 6-3 6.3.2 Monitoring Programs...... 6-3 6.3.3 Analysis...... 6-6 6.4 Existing Conditions and Interpretation...... 6-6 6.4.1 Conventional Pollutants...... 6-6 6.4.2 Metals...... 6-17 6.4.3 Bacteria ...... 6-23 6.4.4 Summary of Findings ...... 6-25

Toronto Region Conservation, 2010 ii 6.5 Management Recommendations ...... 6-27 6.6 References ...... 6-28 6.7 Appendix 6-A: Other Water Quality Monitoring Programs...... 6-30

7.0 FLUVIAL GEOMORPHOLOGY ...... 7-1 7.1 Watershed Objectives Indicators and Targets...... 7-1 7.2 Objectives of Technical Update ...... 7-2 7.3 Data Sources and Monitoring...... 7-3 7.3.1 Data Sources ...... 7-3 7.4 Measuring Fluvial Geomorphology...... 7-9 7.4.1 Channel Morphology ...... 7-9 7.4.2 Flow Regime and Erosion Potential ...... 7-10 7.4.3 Stream Corridor Integrity and Continuity ...... 7-11 7.4.4 Spatial Analysis and Regional Curves...... 7-12 7.5 Existing Conditions and Interpretation...... 7-12 7.5.1 Channel Morphology ...... 7-12 7.5.2 Flow Regime and Erosion Potential ...... 7-20 7.5.3 Stream Corridor Integrity and Continuity ...... 7-23 7.5.4 Risk to Public and Private Property from Channel Evolution and Change ...... 7-23 7.5.5 Spatial Analysis and Regional Curves...... 7-27 7.6 Summary of Findings ...... 7-29 7.7 Management Recommendations ...... 7-32 7.8 References ...... 7-34 7.9 Appendix 7- A:Overview of Factors Influencing Fluvial Geomorphic Processes...... 7-35 7.10 Appendix 7- B:Migration Rate Assessment...... 7-39 7.11 Appendix 7- C:Cross-Sectional Assessment Results ...... 7-42 7.12 Appendix 7- D:Regional Curve Results...... 7-50

8.0 TERRESTRIAL NATURAL HERITAGE SYSTEM ...... 8-1 8.1 Watershed Objectives, Indicators and Targets...... 8-2 8.2 Objectives of Technical Update ...... 8-2 8.3 Data Sources and Methods...... 8-4 8.3.1 Data Sources ...... 8-4 8.3.2 Methods ...... 8-5 8.4 Existing Conditions and Interpretation...... 8-5 8.4.1 Quantity of Natural Cover ...... 8-5 8.4.2 Connectivity ...... 8-8 8.4.3 Quality and Distribution of Natural Cover...... 8-8 8.4.4 Summary of Existing Conditions ...... 8-14 8.5 Target Terrestrial Natural Heritage System...... 8-15 8.5.1 Quantity of Natural Cover ...... 8-17 8.5.2 Quality of habitat...... 8-18 8.5.3 Priority Management Areas ...... 8-20 8.6 References ...... 8-23 8.7 Appendix 8-A: Etobicoke and Mimico Creeks Watersheds – Terrestrial Natural Heritage System Refinement...... 8-24 8.8 Appendix 8-B: Etobicoke and Mimico Creeks Watersheds Terrestrial Priority Management Areas ...... 8-26

Toronto Region Conservation, 2010 iii 9.0 AQUATIC SYSTEM - INSTREAM BARRIERS TO FISH PASSAGE ...... 9-1 9.1 Watershed Objectives, Indicators and Targets...... 9-1 9.2 Objectives of Technical Update ...... 9-2 9.3 Data Sources, Field Surveys and Methods...... 9-3 9.3.1 Desktop Assessment...... 9-3 9.3.2 Field Surveys ...... 9-5 9.3.3 Data Synthesis and Analyses...... 9-6 9.4 Existing Conditions and Interpretation...... 9-7 9.4.1 Fish Species in Etobicoke and Mimico Creeks ...... 9-8 9.4.2 On-Line Stormwater Management Ponds in the Etobicoke and Mimico Creeks Watersheds ...... 9-9 9.4.3 Channelization of Etobicoke and Mimico Creeks...... 9-10 9.4.4 Impervious Cover in Etobicoke and Mimico Creeks Watersheds ...... 9-13 9.4.5 Overview of Barriers within Etobicoke Creek Watershed ...... 9-16 9.4.6 Overview of Barriers within Mimico Creek Watershed...... 9-30 9.4.7 Overall Summary of Existing Conditions...... 9-38 9.5 Decision Criteria for Selecting Prioritiy Barriers For Management ...... 9-38 9.5.1 Fish IBI Scores and Natural Stream Habitat Areas...... 9-39 9.5.2 Rehabilitation Projects...... 9-41 9.5.3 Riparian Vegetation Cover...... 9-43 9.5.4 Small Scale Barriers...... 9-43 9.6 Management Recommendations –Etobicoke Creek Priority Barriers...... 9-45 9.6.1 Category A - Lake to Headwaters ...... 9-45 9.6.2 Category B – Extending Existing Natural Habitat ...... 9-49 9.6.3 Category C – Stewardship...... 9-51 9.7 Management Recommendations - Mimico Creek Priority Barriers ...... 9-54 9.7.1 Category A – Lake to Headwaters...... 9-54 9.7.2 Category B – Extending Existing Natural Habitat ...... 9-58 9.7.3 Category C – Stewardship...... 9-61 9.8 Overall Summary of Management Considerations for Etobicoke and Mimico Creeks Watersheds ...... 9-63 9.9 References ...... 9-64 9.10 Appendix 9-A – Assessment Form for Barrier Survey...... 9-66

10.0 SUMMARY AND STRATEGIC MANAGEMENT DIRECTIONS ...... 10-2 10.1 The Natural Watersheds ...... 10-2 10.2 Human Influences...... 10-3 10.3 Future Challenges and Opportunities ...... 10-6 10.4 Strategic Management Directions...... 10-6

11.0 IMPLEMENTATION PRIORITIES ...... 11-2 11.1 New Policy Directions...... 11-2 11.2 Monitoring and Adaptive Management...... 11-7 11.3 Further Investigation ...... 11-8 11.4 Regeneration...... 11-9 11.4.1 Subwatershed Regeneration Plans...... 11-9 11.4.2 Priority Areas for Integrated Regeneration Projects...... 11-21 11.5 Summary of Implementation Priorities by Watershed Partner ...... 11-39

Toronto Region Conservation, 2010 iv LIST OF FIGURES

Figure 2 1: Etobicoke and Mimico Creeks Watersheds and Subwatersheds Boundaries...... 2-2 Figure 2 2: Land Use...... 2-5 Figure 2 3: Major Development and Redevelopment Plans ...... 2-7 Figure 2 4: Climate Normals - Temperature ...... 2-8 Figure 2 5: Climate Normals - Precipitation...... 2-8 Figure 2 6: Physiographic Regions...... 2-12 Figure 2 7: Surficial Geology...... 2-13 Figure 2 8: Stratigraphic Schematic ...... 2-14 Figure 2 9: Extent of Brampton Esker...... 2-15 Figure 2 10: Extent of Scarborough Formation...... 2-16 Figure 2 11: Extent of Thorncliffe Formation ...... 2-19 Figure 2 12: Extent of Oak Ridges Moraine Sediments (or Equivalent) ...... 2-20

Figure 3 1: Hydrostratigraphic Layers ...... 3-6 Figure 3 2: Etobicoke and Mimico Creeks Watersheds Cross-Section Locations...... 3-7 Figure 3 3: Cross-Section along Mimico Creek...... 3-8 Figure 3 4: Cross-Section along Etobicoke Creek...... 3-9 Figure 3 5: Cross-Section within Heart Lake Wetland Complex ...... 3-10 Figure 3 6: Oak Ridges Aquifer (or equivalent) Thickness (m)...... 3-12 Figure 3 7: Thorncliffe Aquifer Thickness (m)...... 3-13 Figure 3 8: Scarborough Aquifer Thickness (m) ...... 3-14 Figure 3 9: Groundwater Levels – Oak Ridges Aquifer (or equivalent) ...... 3-15 Figure 3 10: Groundwater Levels – Thorncliffe Aquifer Complex ...... 3-16 Figure 3 11: Groundwater Levels – Scarborough Aquifer Complex ...... 3-17 Figure 3 12: Groundwater hydrographs for Well W-366 ...... 3-19 Figure 3 13: Groundwater hydrographs for Well W-021 ...... 3-20 Figure 3 14: Geologic Cross-Sections from the Morrison Report (North, West-East)...... 3-21 Figure 3 15: Geologic Cross-Sections from the Morrison Report (South, West-East) ...... 3-22 Figure 3 16: Hydrologic Cycle ...... 3-24 Figure 3 17: Etobicoke Creek Water Balance...... 3-25 Figure 3 18: Mimico Creek Water Balance ...... 3-25 Figure 3 19: Groundwater Recharge ...... 3-28 Figure 3 20: Groundwater Discharge ...... 3-30 Figure 3 21: Extent of Brampton Esker...... 3-32 Figure 3 22: Heart Lake Wetland Complex...... 3-33 Figure 3 23: Esker Drainage Network...... 3-36

Figure 4 1: Mean Summer Baseflow - Etobicoke Creek @ QEW ...... 4-5 Figure 4 2: Mean Summer Baseflow - Mimico Creek @ Islington ...... 4-5 Figure 4 3: Percent change per year in mean summer baseflow between 1997 to 2006 for Etobicoke Creek (at QEW), Mimico Creek (Islington & Bloor), Main Humber River (at Weston Road), Don River (at Todmorden), Rouge River (near Markham) and Duffins Creek (above Pickering)...... 4-6 Figure 4 4: Average Annual Flows in cubic meters per year and Baseflow Index (BFI) Percentages in Etobicoke and Mimico Creeks (1966-2006) ...... 4-8 Figure 4 5: Etobicoke and Mimico Creeks - 2007 Baseflow Monitoring Sites...... 4-11

Toronto Region Conservation, 2010 v Figure 4 6: Etobicoke Creek - 2007 Percent Contributions to Baseflow by Subwatershed...... 4-12 Figure 4 7: Etobicoke and Mimico Creeks Watersheds - 2007 Baseflow Normalized to Stream Length ...... 4-13 Figure 4 8: Etobicoke and Mimico Creeks Watersheds - Known Water Users by Type and Source...... 4-18 Figure 4 9: Percent of all Surveyed Water Users Categorized by Subwatershed (MOE, 2002:TRCA, 2003) ...... 4-19 Figure 4 10: Total Annual Withdrawals for all Surveyed Water Users Categorized by Subwatershed (MOE, 2002:TRCA, 2003)...... 4-19 Figure 4 11: Percent of all Surveyed Water Users Categorized by Purpose (MOE,2002:TRCA, 2003) ...... 4-19 Figure 4 12: Total Annual Withdrawals for all Surveyed Water Users Categorized by Purpose (MOE, 2002: TRCA, 2003) ...... 4-19 Figure 4 13: Etobicoke and Mimico Creeks Areas of Potential Surface Water Vulnerability...... 4-24

Figure 5 1: Land Use (based on 2002 ortho aerial photography) ...... 5-8 Figure 5 2: Etobicoke and Mimico Creeks Watersheds - Comparison of Land Uses by Watershed ...... 5-9 Figure 5 3: Etobicoke Creek Watershed - Comparison of Land Uses by Subwatersheds ...... 5-9 Figure 5 4: Areas with Comprehensive Stormwater Management Plans ...... 5-13 Figure 5 5: Etobicoke and Mimico Creeks Watersheds - Proportion of Urban Area with Comprehensive SWM Plans ...... 5-14 Figure 5 6: Etobicoke Creek Subwatersheds - Proportion of Urban Area with Comprehensive SWM Plans...... 5-14 Figure 5 7: SWM Pond Location Plan...... 5-16 Figure 5 8: SWM Controls within Etobicoke and Mimico Creeks Watersheds...... 5-17 Figure 5 9: Etobicoke and Mimico Creeks Watersheds - Proportion of Urban Area having SWM Controls...... 5-18 Figure 5 10: Etobicoke Creek Subwatersheds – Proportion of Urban Area having SWM Controls...... 5-18 Figure 5 11: SWM Quality Controls within Etobicoke and Mimico Creeks Watersheds ...... 5-22 Figure 5 12: Etobicoke and Mimico Creeks Watersheds – Proportion of urban area having SWM Quality Control ...... 5-23 Figure 5 13: Etobicoke Creek Subwatersheds – Proportion of urban area having SWM Quality Control ...... 5-23 Figure 5 14: SWM Erosion Controls within Etobicoke and Mimico Creeks Watersheds ..... 5-25 Figure 5 15: Etobicoke and Mimico Creeks Watersheds – Proportion of urban area having SWM Erosion Control ...... 5-26 Figure 5 16: Etobicoke Creek Subwatersheds – Proportion of urban area having SWM Erosion Control...... 5-26 Figure 5 17: Existing SWM Quantity Controls within Etobicoke and Mimico Creeks Watersheds ...... 5-28 Figure 5 18: Etobicoke and Mimico Creeks Watersheds – Proportion of urban area having SWM Quantity Controls ...... 5-29 Figure 5 19: Etobicoke Creek Subwatersheds – Proportion of urban area having SWM Quantity Controls...... 5-29

Toronto Region Conservation, 2010 vi Figure 5 20: Stormwater Management Retrofit Plans/ Strategies in Peel Region ...... 5-31 Figure 5 21: Proposed End of Pipe Facilities within the City of Toronto ...... 5-32 Figure 5 22: Node Locations for Comparison of Peak Flow Changes (original vs. updated)...... 5-35 Figure 5 23: Comparison of Mimico Creek Peak Flows at Node 9 (Drainage of the upper 1/3 of the watershed to Derry Road) ...... 5-36 Figure 5 24: Comparison of Mimico Creek Peak Flows at Node 16 (Drainage of the upper 2/3 of the watershed to Highway 27)...... 5-36 Figure 5 25: Comparison of Mimico Creek Peak Flows at Node 22 (Drainage of total watershed to the mouth of Lake Ontario) ...... 5-36 Figure 5 26: Comparison of Etobicoke Creek Peak Flows at Node G (Drainage of the Headwater areas of Spring Creek to Bovaird Drive)...... 5-37 Figure 5 27: Comparison of Etobicoke Creek Peak Flows at Node P (Etobicoke Creek watershed – including Spring Creek and Main Creek - to Highway 401) ...... 5-37 Figure 5 28: Comparison of Etobicoke Creek Peak Flows at Node W (Drainage of Etobicoke Creek to Dundas Street)...... 5-37 Figure 5 29: Comparison of Etobicoke Creek Peak Flows at Node Y (Drainage of total Etobicoke Creek watershed to Lakeshore Avenue near the mouth of Lake Ontario) ...... 5-37 Figure 5 30: Mimico Creek at Islington Avenue – Streamflow for 40 year period ...... 5-40 Figure 5 31: Mimico Creek at Islington Avenue – Streamflow for 10 year period ...... 5-41 Figure 5 32: Etobicoke Creek at QEW – Streamflow for 40 year period...... 5-41 Figure 5 33: Etobicoke Creek at QEW – Streamflow for 10 Year period ...... 5-41 Figure 5 34: Flood Vulnerable Clusters ...... 5-44 Figure 5 35: Brampton Esker Systems...... 5-46

Figure 6 1: Current PWQMN/RWMP Water Quality Monitoring Station Locations in Etobicoke and Mimico Creeks Watersheds...... 6-4 Figure 6 2: Median TSS Concentrations (mg/L) across the TRCA Jurisdiction for the Ice-Free Period (April-November), 2003-2007 ...... 6-8 Figure 6 3: Median Chloride Concentrations (mg/L) across the TRCA Jurisdiction for the Ice-Free Period (April-November), 2003-2007 ...... 6-10 Figure 6 4: 2003-2007 Monthly Median Chloride Concentrations (mg/L) for Two Stations in Etobicoke Creek and One Station in Mimico Creek in Comparison to 150 mg/L Water Quality Objective ...... 6-12 Figure 6 5: Median Phosphorus Concentrations (mg/L) across the TRCA Jurisdiction for the Ice-Free Period (April-November), 2003-2007...... 6-15 Figure 6 6: Median Nitrates Concentrations (mg/L) across the TRCA Jurisdiction for the Ice-Free Period (April-November), 2003-2007 ...... 6-16 Figure 6 7: Median Un-ionized Ammonia Concentrations (mg/L) across the TRCA Jurisdiction for the Ice-Free Period, 2003-2007 ...... 6-18 Figure 6 8: Median Copper Concentrations (µg/L) across the TRCA Jurisdiction for the Ice-Free Period, 2003-2007 ...... 6-19 Figure 6 9: Median Iron Concentrations (µg/L) across the TRCA Jurisdiction for the Ice-Free Period, 2003-2007 ...... 6-21 Figure 6 10: Median Zinc Concentrations (µg/L) across the TRCA Jurisdiction for the Ice-Free Period, 2003-2007 ...... 6-22

Figure 7 1: Fluvial Geomorphology Monitoring Sites...... 7-4

Toronto Region Conservation, 2010 vii Figure 7 2: Longitudinal Profile Comparison of Bankfull Gradient for Site GET-5, Spring Creek...... 7-15 Figure 7 3: Longitudinal Profile Comparison for Site GET-6, Etobicoke Creek West Branch...... 7-15 Figure 7 4: Longitudinal Profile Comparison for Site GET-10, Etobicoke Creek Headwaters...... 7-16 Figure 7 5: Reaches Rated for Erosion Sensitivity ...... 7-25 Figure 7 6: Mimico Creek Active Erosion Hazard Sites...... 7-26

Figure 8 1: Etobicoke and Mimico Creeks Watersheds Existing Natural Cover...... 8-7 Figure 8 2: Etobicoke and Mimico Creeks Watersheds Existing Conditions Landscape Analysis...... 8-11 Figure 8 3: Etobicoke and Mimico Creeks Watersheds - Fauna Species of Concern to TRCA...... 8-12 Figure 8 4: Etobicoke and Mimico Creeks Watersheds – Flora Species of Concern to TRCA ...... 8-13 Figure 8 5: Etobicoke and Mimico Creeks Watersheds – Target System ...... 8-16 Figure 8 6: Etobicoke and Mimico Creeks Watersheds Refined Target System Landscape Analysis...... 8-19 Figure 8 7: Etobicoke and Mimico Creeks Watersheds Terrestrial Priority Management Areas...... 8-22

Figure 9 1: Fish Sampling Locations in Etobicoke and Mimico Creeks Watersheds...... 9-4 Figure 9 2: Sheet Flow Conditions Preventing Fish Passage South-West of Clark Boulevard and West Drive...... 9-7 Figure 9 3: Graphic Depicting Fish Passage Calculation...... 9-7 Figure 9 4: Location of On-line Stormwater Management Ponds in Etobicoke and Mimico Creeks Watersheds...... 9-11 Figure 9 5: Channelized Streambed of Etobicoke and Mimico Creeks Watersheds ...... 9-12 Figure 9 6: Percent Impervious Cover in Etobicoke and Mimico Creeks Watersheds, 2008 ...... 9-14 Figure 9 7: Natural Flow in Etobicoke West Branch Subwatershed ...... 9-15 Figure 9 8: Impacted Flow in Lower Etobicoke Subwatershed ...... 9-15 Figure 9 9: Impacted Flow in Mimico Creek Watershed ...... 9-15 Figure 9 10: Existing Instream Structures - Etobicoke Creek Watershed...... 9-17 Figure 9 11: Lower Etobicoke Existing Instream Structures, including: Etobicoke Main Branch, Tributary 4, and Little Etobicoke...... 9-19 Figure 9 12: Weir at CN Railway Line ...... 9-21 Figure 9 13: Spring Creek Existing Instream Structures within Spring Creek Subwatershed...... 9-23 Figure 9 14: Erosion North-East of Drew Road and Bramalea Road...... 9-24 Figure 9 15: Chinguacousy Park Dam North-West of Queen Street and Central Park Road...... 9-24 Figure 9 16: Channel Erosion at Avondale Tributary at Dixie and Clarke...... 9-25 Figure 9 17: Upper Etobicoke Existing Instream Structures including: Tributary 3, Etobicoke West Branch and Etobicoke Headwaters Subwatersheds ...... 9-27 Figure 9 18: Flow Dissipating Weir in Tributary 3 South-West of Midway Boulevard and Dixie Road...... 9-28 Figure 9 19: Weir Structure in West Tributary located North-West of Courtney Park

Toronto Region Conservation, 2010 viii Drive and Tomken Road in 2006(a) low flow and 2008 (b) high flow...... 9-28 Figure 9 20: Step Weir at Drew Road East of Dixie Road...... 9-29 Figure 9 21: Perched Culvert North of 407 West of Dixie Road...... 9-29 Figure 9 22: Existing Instream Structures in Mimico Creek Watershed ...... 9-31 Figure 9 23: Existing Instream Structures in Mimico Creek Main Branch ...... 9-33 Figure 9 24: Existing Instream Structures in Mimico Creek East Branch ...... 9-35 Figure 9 25: Damaged Infrastructure south-west of Clark Blvd. and Walker Dr. (MCE 103) ...... 9-36 Figure 9 26: Existing Instream Structures in Mimico Creek West Branch ...... 9-37 Figure 9 27: Index of Biotic Integrity - Etobicoke and Mimico Creeks Watersheds ...... 9-40 Figure 9 28: Rehabilitation Projects – Etobicoke and Mimico Creeks Watersheds (2009) ...... 9-42 Figure 9 29: Riparian Cover for Etobicoke and Mimico Creeks Watersheds ...... 9-44 Figure 9 30: Priority Category A – Lake to Headwaters- Etobicoke Creek Watershed * ..... 9-46 Figure 9 31: Weir at Toronto Golf Club Bridge (ECLOW006) ...... 9-48 Figure 9 32: Weir 500m South of Q.E.W. (ECLOW011) ...... 9-48 Figure 9 33: Weir at Bloor Street West of Dixie Mill Road (ECLOW029)...... 9-48 Figure 9 34: Weir at Britannia Road and East Road (ECLOW039) ...... 9-48 Figure 9 35: Weir South of Queen Street West of Centre Street (MEE023)...... 9-49 Figure 9 36: Natural Barriers Weybridge Park (MEE033), Near Valleywood Development (MEE059), North of Mayfield between Hurontario and Kennedy (MEE060)...... 9-49 Figure 9 37: Priority Category B – Extending Existing Natural Habitat- Etobicoke Creek Watershed * ...... 9-50 Figure 9 38: Priority Category C – Stewardship Projects – Etobicoke Creek Watershed .... 9-52 Figure 9 39: Rock obstruction north-east of East Gate Parkway and Tomken Road (ECLE031)...... 9-53 Figure 9 40: Old sediment fence north-east of Bovaird Road and 410. (SPHL009)...... 9-53 Figure 9 41: Priority Category A – Lake to Headwaters – Mimico Creek Watershed ...... 9-55 Figure 9 42: Weir at Q.E.W. (MC005) ...... 9-56 Figure 9 43: Weir at Q.E.W. (MC007) ...... 9-56 Figure 9 44: Weir 500m south of Berry Road (MC011) ...... 9-57 Figure 9 45: Weir 100 m north of Berry Road (MC013)...... 9-57 Figure 9 46: Weir 10m south of Meadowcrest Road (MC016)...... 9-57 Figure 9 47: Weir 10m north of Meadowcrest Road (MC017) ...... 9-57 Figure 9 48: Weir 80m south of Meadowvale Drive(MC020)...... 9-57 Figure 9 49: Weir 90m south of Meadowvale Drive (MC021)...... 9-57 Figure 9 50: Weir 240m north of Meadowvale Drive (MC024) WSC...... 9-58 Figure 9 51: Weir 70m downstream of Dundas Street (MC029) ...... 9-58 Figure 9 52: Weir 260m north-west of Skyway Ave and Highway 27 (MC055) ...... 9-58 Figure 9 53: Ramp at upstream end of Zahavy Way Rd Crossing (MC083) ...... 9-58 Figure 9 54: Priority Category B – Extending Existing Natural Habitats – Mimico Creek Watershed...... 9-59 Figure 9 55: Railway Crossing 300m north-east of Goreway Drive and Brandon Gate Drive (MCE011)...... 9-60 Figure 9 56: Weir 100m south of Intermodal Drive (MCE050) ...... 9-60 Figure 9 57: Weir 250m north-west Highway 407 and Goreway Drive (MCE049)...... 9-60 Figure 9 58: Priority 1 Area (MCW042) ...... 9-61 Figure 9 59: Priority Category C – Stewardship Projects – Mimico Creek Watershed...... 9-62

Toronto Region Conservation, 2010 ix Figure 11 1: Subwatershed Regeneration Plans – Key Map...... 11-10 Figure 11 2: Etobicoke Creek Headwaters Subwatershed Regeneration Plan...... 11-11 Figure 11 3: Etobicoke Creek West Branch Subwatershed Regeneration Plan...... 11-12 Figure 11 4: Spring Creek Subwatershed Regeneration Plan ...... 11-13 Figure 11 5: Tributary 3 Subwatershed Regeneration Plan ...... 11-14 Figure 11 6: Etobicoke Creek Main Branch Subwatershed Regeneration Plan...... 11-15 Figure 11 7: Little Etobicoke Creek Subwatershed Regeneration Plan...... 11-16 Figure 11 8: Tributary 4 Subwatershed Regeneration Plan ...... 11-17 Figure 11 9: Lower Etobicoke Creek Subwatershed Regeneration Plan ...... 11-18 Figure 11 10 Lake Ontario Drainage Subwatershed Regeneration Plan...... 11-19 Figure 11 11: Mimico Creek Watershed Regeneration Plan...... 11-20 Figure 11 12: Screening Map #1 - Regeneration Areas/Actions Addressing Criteria of Urgency and Scale/Effectiveness...... 11-24 Figure 11 13: Screening Map #2A - Ongoing Regeneration Partnerships and Initiatives... 11-25 Figure 11 14: Screening Map #2B – Planned Municipal Capital Works ...... 11-26 Figure 11 15: Screening Map #2C - Major Development or Re-development Planning Areas ...... 11-27 Figure 11 16: Priority Areas for Integrated Regeneration Projects and Habitat Enhancement Projects ...... 11-31

Toronto Region Conservation, 2010 x LIST OF TABLES

Table 3 1: Watershed Objectives, Indicators and Targets...... 3-2 Table 3 2: Groundwater Quality Parameters...... 3-34

Table 4 1: Watershed Objectives, Indicators and Targets...... 4-2 Table 4 2: Streamflow Gauges - Etobicoke and Mimico Creeks...... 4-4 Table 4 3: Etobicoke and Mimico Creeks Average Annual Total Flow and Baseflow Percent Change per Year for Period of Record and 10-year Period (1997- 2006) ...... 4-9 Table 4 4: Water Use Summary by Subwatershed ...... 4-21 Table 4 5: Vulnerability Assessment Category Classification...... 4-22

Table 5 1: Watershed Objective, Indicators and Targets...... 5-3 Table 5 2: Land Use Categories ...... 5-7 Table 5 3: Summary of Stormwater Management Ponds by Type...... 5-15 Table 5 4: MOE Table 3.2 Water Quality Storage Requirements based on Receiving Waters 5-20 Table 5 5: Summary of SWM Retrofit Opportunities in Peel Region ...... 5-33 Table 5 6: Summary of Proposed End of Pipe Facilities within the City of Toronto (25 Year Strategy)...... 5-33

Table 6 1: Watershed Objectives, Indicators and Targets...... 6-2 Table 6 2: Surface Water Quality Monitoring Station Details...... 6-5 Table 6 3: Standard Suite of Water Quality Parameters Analyzed for Stream Samples ...... 6-5 Table 6 4: Median Chloride Concentrations in Comparison to 150 mg/L and 250 mg/L Objectives...... 6-11 Table 6 5: Summary of Etobicoke and Mimico Creek Water Quality Targets...... 6-26

Table 7 1: Etobicoke and Mimico Creeks Watersheds, Objectives and Targets ...... 7-2 Table 7 2: Streamflow Gauge Etobicoke and Mimico Creeks Watersheds ...... 7-5 Table 7 3: Inventory of Fluvial Geomorphic Monitoring Sites and Data Usage Summary...... 7-6 Table 7 4: Migration Rate Assessment...... 7-13 Table 7 5: Bankfull Channel Gradient (BFG - %) ...... 7-14 Table 7 6: Cross-Sectional Area Analysis ...... 7-17 Table 7 7: Detailed Cross-Sectional Assessment for GET-5, GET-6 and GET-10 ...... 7-20 Table 7 8: Erosion Threshold Values Calculated from 2002 Data...... 7-22 Table 7 9: Erosion Exceedence Analysis ...... 7-23 Table 7 10: Erosion Sensitivity Ratings ...... 7-24

Table 8 1: Watershed Objectives, Indicators and Targets...... 8-2 Table 8 2: Total Natural Cover by Broad Habitat Type * ...... 8-5 Table 8 3: Total Existing Natural Cover by Subwatershed *...... 8-6 Table 8 4: Quantity of Natural Cover by Subwatershed: Watershed Refined Target Terrestrial Natural Heritage System compared with Total Existing Natural Cover by Subwatershed ...... 8-17 Table 8 5: Terrestrial Priority Management Areas in the Etobicoke and Mimico

Toronto Region Conservation, 2010 xi Creeks Watersheds ...... 8-21

Table 9 1: Watershed Objectives, Indicators and Targets...... 9-2 Table 9 2: Summary of Etobicoke Creek Instream Barrier Assessment (2005-2008)...... 9-16 Table 9 3: Lower Etobicoke and Etobicoke Main Branch Subwatersheds, Instream Barrier Assessment (2005) ...... 9-20 Table 9 4: Tributary 4 Subwatershed, Instream Barrier Assessment (2005)...... 9-20 Table 9 5: Little Etobicoke Subwatershed, Instream Barrier Assessment (2005) ...... 9-21 Table 9 6: Total Spring Creek Subwatershed, Instream Barrier Assessment (2008)...... 9-22 Table 9 7: Main Branch of Spring Creek Subwatershed, Instream Barrier Assessment (2008) ...... 9-24 Table 9 8: Bramalea Tributaries within Spring Creek Subwatershed, Instream Barrier Assessment (2008) ...... 9-25 Table 9 9: Tributary 3 Subwatershed, Instream Barrier Assessment (2008)...... 9-26 Table 9 10: Etobicoke West Branch, Instream Barrier Assessment (2008)...... 9-29 Table 9 11: Summary of Etobicoke Creek Headwaters Instream Barrier Assessment (2008) ...... 9-30 Table 9 12: Summary of Mimico Creek Instream Barrier Assessment (2009) ...... 9-30 Table 9 13: Mimico Creek Main Branch, Instream Barrier Assessment (2009)...... 9-32 Table 9 14: Mimico Creek East Branch, Instream Barrier Assessment (2009) ...... 9-34 Table 9 15: Mimico Creek West Branch, Instream Barrier Assessment (2009) ...... 9-36 Table 9 16: Decision Criteria for Selecting Priority Barriers for Management ...... 9-39 Table 9 17: Etobicoke Creek Priority Barriers for Management Category A...... 9-45 Table 9 18: Etobicoke Creek Priority Barriers for Management Category B...... 9-49 Table 9 19: Management Considerations for Priority Category C – Stewardship Opportunities ...... 9-51 Table 9 20: Mimico Creek Priority Barriers for Management Category A...... 9-54 Table 9 21: Mimico Creek Priority Barriers for Management Category B ...... 9-58 Table 9 22: Mimico Creek Priority Barriers for Management Category C ...... 9-61

Table 11 1: New Policy Recommendations for the Etobicoke and Mimico Creeks Watersheds ...... 11-3 Table 11 2: Priority Areas for Integrated Regeneration Projects...... 11-32 Table 11 3: Priority Areas for Habitat Regeneration Projects ...... 11-37

Toronto Region Conservation, 2010 xii