Final Report Former CFB Rockcliffe Redevelopment Stormwater Management Existing Conditions & LID Pilot Project Scoping Final Report August 2015 Prepared by: Mississauga – Guelph ‐ Kingston TABLE OF CONTENTS 3.6 Fluvial Geomorphology ............................................................... 71 1.0 INTRODUCTION ............................................................................ 1 3.7 Aquatic Ecology. .......................................................................... 73 2.0 REPORT PURPOSE ......................................................................... 2 3.8 Terrestrial Ecology ...................................................................... 80 2.1 Report Purpose ............................................................................. 2 3.9 Summary of Existing Conditions .................................................. 90 2.2 Policy Context ............................................................................... 7 4.0 MSS STORMWATER STRATEGY .................................................... 97 2.3 Overview of Existing Land Use ..................................................... 13 4.1 Introduction ................................................................................ 98 2.4 Overview of Proposed Land-Use .................................................. 15 4.2 Conventional SWM System Concept ......................................... 102 2.5 Geographical Context .................................................................. 17 4.3 Conventional SWM System Phasing .......................................... 114 2.6 Subwatershed Context ................................................................ 17 5.0 LID DEMONSTRATION PROJECT ................................................. 115 2.7 Local Climate ............................................................................... 17 5.1 Introduction .............................................................................. 115 3.0 CHARACTERISATION OF EXISTONG CONDITIONS ......................... 19 5.2 LID Demonstration Project Purpose .......................................... 116 3.1 Geology ....................................................................................... 19 5.3 Process ...................................................................................... 116 3.2 Hydrogeology .............................................................................. 33 5.4 Chapter Purpose ....................................................................... 116 3.3 Surface Water Features ............................................................... 48 5.5 Introduction to LID .................................................................... 117 3.4 Existing Drainage ......................................................................... 52 5.6 Summary of LID Lot-Level Controls............................................ 119 3.5 Hydraulics .................................................................................... 58 5.7 Summary of LID Conveyance Controls ....................................... 123 3.5 Hydrology .................................................................................... 60 Aquafor Beech Ltd. August 2015 – Final Report i 5.8 Phasing & Timing ....................................................................... 125 5.9 LID Pilot/ Demonstration Project Scope ..................................... 126 5.10 Suitability of LID Controls by Land-Use ...................................... 126 5.11 Overview of Proposed LIDs for Implementation ........................ 130 5.12 LID Pilot/ Demonstration Project – Phase 1A ............................. 146 5.13 Specific Projects ......................................................................... 158 5.14 LID Simulations (post Development) .......................................... 165 5.15 Scaled Conventional SWM Infrastructure Construction ............. 179 5.16 LID Design Guideance ................................................................ 182 5.17 Approvals .................................................................................. 185 5.18 Assumption Protocols & Monitoring .......................................... 187 5.19 Operation & Maintenance ......................................................... 204 5.20 Construction Sequencing ........................................................... 212 5.21 Erosion and Sediment Control (ESC)........................................... 214 5.22 Policy Considerations ................................................................. 218 5.23 SWM Working Group Summary ................................................. 221 5.24 Recommendation Summary ...................................................... 223 ATTACHMENT A – Scope of Work ATTACHMENT B – Hydrologic Model (Existing conditions) ATTACHMENT C – Hydrologic Model (Post Development No Control) ATTACHMENT D – Hydrologic Model (Post Development LID Control) ATTACHMENT E – SWM Working Group Presentations ii Aquafor Beech Ltd. August 2015 – Final Report LIST OF FIGURES Figure 16: The EPA SWMM Model Schematic and Subcatchment Delineation Figure 1: Project Area Delimitation Figure 17: Water Budget Analysis Results for the months of 2013. Figure 2: Land Uses/ Preferred Development Plan Figure 18: Surface Runoff Generated from Western Creek Figure 3: Catchment Delimitations Subwatershed (m3/s) (1996-2013) Figure 4: Rockcliffe Surficial Geology Figure 19: Surface Runoff Generated from Eastern Creek Subwatershed (m3/s) (1996-2013) Figure 4A: Overburden Materials. Figure 20: Aquatic Habitat Assessment: Western and Eastern Creeks Figure 5: Bedrock Geology Figure 21: Inventory of Existing Trees and Tree Groupings in the Figure 6: Bedrock Depth Contours Study Area Figure 7: Setback Distances Figure 22: Urban Natural Areas Figure 8: Maximum Grade Raise Figure 23: Preliminary Terrestrial Habitat Assessment – Study Area Figure 9: Overburden Potentiometric Contours (DST, 2013) Figure 10: Shallow Bedrock Potentiometric Contours Figure 24: Butternut Location Plan (Source: DST, 2014) Figure 10A: In-situ Infiltration Testing Conducted by Aquafor Beech Figure 25: Post Development Conditions Drainage Area Plan – (September 2014) Minor System Connectivity Figure 11: Surface Water Flow Measurement Locations Figure 26: Post Development Conditions Drainage Area Plan – Major System Connectivity Figure 12: Existing Drainage Conditions Figure 27: Eastern SWM Facility – Layout, Grading and Facility Figure 13: Existing Conditions Drainage Area Plan Attributes Figure 14: Precipitation Record (mm/hr) from 1996 to 2013 Figure 28: Western SWM Facility – Layout, Grading and Facility Attributes Figure 15: Average Potential Evapotranspiration Values between 1996 and 2013 Figure 29: Park Dry Pond - Plan View and Cross Section A-A Figure 30: Eastern Dry Pond - Plan View and Cross Section A-A Figure 31: Central Dry Pond - Plan View and Cross Section A-A Aquafor Beech Ltd. August 2015 – Final Report iii Figure 32: Southwest Channel – Typical Channel Section Figure 47: Soil Amendment- Typical Detail Default Ratio 3:1 Figure 33: Development Phasing Plan Figure 48: Soil Amendments – Typical Detail Import and Replace Figure 34: Development Phasing Plan & LID Pilot/ Demonstration Figure 49: Typical Enhanced Swale Detail Area (Phase 1A) Figure 50: Typical Bioswale Detail Figure 34-A: Overall SWM Locations including Recommended LID Lot-level and LID Conveyance Controls Figure 51: Example Permeable Interlocking Concrete Pavement Detail (Reference Only) 34-AFigure 35: Section 1A, Major Collector (26 m) Figure 52: Post-Development Land Use within the Delineated Figure 36: Section 1B, Collector (26 m) Subcatchments Figure 37: Section 2, Hemlock Core Street (24 m) Figure 53: Water Budget Volumes within the Proposed Development under Different Scenarios Figure 38: Section 3A, Local Road (20 m) Figure 54: Water Budget Volumes within the LID Pilot Area (Phase Figure 39: Section 3B, Local Road (20 m) 1A) under Different Scenarios Figure 41: Potential LIDs: Collector Road Cross Section 1B (26m Figure 55: Construction Sequencing for Residential Soakaways ROW) Figure 40: Potential LIDs: Major Collector Road Cross Section 1A (26m ROW) Figure 42: Potential LIDs: Core Street Road Cross Section 2 (24m ROW) Figure 43: Potential LIDs: Local Road Cross Section 3A (20m Local ROW) Figure 44: Potential LIDs: Local Road Cross Section 3B (20m Local ROW) Figure 45: LID Pilot Project #1- Phase 1A Candidate Development Blocks for LID Figure 46: Typical Soakaway Detail iv Aquafor Beech Ltd. August 2015 – Final Report LIST OF TABLES Table 17: Surface Runoff Volumes and Rates at the Outfalls of Western and Eastern Creeks Table 1: Relevant SWM Criteria Table 18: Findings of the Fluvial Geomorphology Assessment (DST, Table 2: Proposed Land Uses September 2013) Table 3: Groundwater Elevation Measurements, 2006 and 2013 Table 19: Aquatic Habitat Assessment Findings- Channel (NAD 83, Zone 18) Characteristics Table 4: Ranges of Water Levels Measured by DST in 2014 for Table 20: Total Bank Undercuts various Monitor Wells (NAD 83, Zone 18) – (Adapted from DST BH, Table 21: Water Temperature 2014) Table 22: Possible SAR Based on Presence of Potentially Suitable Table 5: Rockcliffe Hydraulic Conductivity Measurements (DST Slug Habitat (Source: DST, 2013) Tests Only) Table 23: Low Impact Development (LID) Suitability Matrix by Land- Table 6: Descriptions and Variability Regarding Infiltration Tests Use Table 7: In-situ Infiltration Testing Results (Aquafor Beech, Table 24: Screening