Como Creek Final Report Feb 2002

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See what the City of Coquitlam has in store for existing urban watersheds.

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  • D - 95

    City of Coquitlam

    Como Creek Integrated Stormwater Management Plan: Flood Risk Management and Watershed Restoration ":

    February 2002

    WO22002002VBC '

  • CITY OF COQUITLAM

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    II A B

    COMO CREEK INTEGRATED STORMWATER MANAGEMENT PLAN: FLOOD RISK MANAGEMENT AND WATERSHED RESTORATION

    PREPARED BY:

    CH2MHILL 920 - 475 West Georgia Street

    Vancouver, BC V6B 4M9 Te1.604 684-3282 I Fax. 604 684-3292

    February 2002

  • COMO CREEK INTEGRATED STORMWATER MANAGEMENT PLAN FINAL REPORT TABLE OF CONTENTS FEBRUARY 2002

    TABLE OF CONTENTS

    PAGE

    EXECUTIVE SUMMARY

    PART A . STRATEGY FOR FLOOD RELIEF AND HABITAT RESTORATION IN THE FRASER MILLS LOWLAND

    CHAPTER I

    CHAPTER 2

    CHAPTER 3

    CHAPTER 4

    CHAPTER 5

    INTRODUCTION 1.1 Background .................................................................................................. 1-1 1.2 Approach ............................. : ........................................................................ 1-1 1.4 Study Area .................................................................................................... 1-2 1.5 Project Issues ............................................................................................... 1-2 1.3 Deliverables .................................................................................................. 1-1

    PROBLEM IDENTIFICATION 2.1 Introduction ................................................................................................... 2-1 2.2 Overview of Previous Reports ...................................................................... 2-1 2.3 Nature of the Problem .................................................................................. 2-2 2.4 Recent Storm Events ................................................................................... 2-4 2.5 Summary of Findings ................................................................................... 2-4

    WATERSHED MODELLING

    3.2 Rainfall and Streamflow Data ....................................................................... 3-1 3.3 Modelling Approach ...................................................................................... 3-1

    3.1 Background .................................................................................................. 3-1

    3.4 Selection of Storm Events ............................................................................ 3-2 3.5 Results for December 1999 Storm ............................................................... 3-2 3.6 Results for January 1968 Storm ...................... : ............................................ 3-3 3.8 Future Modelling Applications ...................................................................... 3-3 3.9 Summary of Findings ................................................................................... 3-4

    4.1 Watershed Vision ......................................................................................... 4-1

    4.3 Hydraulic Control Elevations ........................................................................ 4-2 4.5 Integration with Uplands Strategy ................................................................ 4-3 4.6 Popeye Creek Stream Corridor Restoration ................................................ 4-3

    4.8 2001 Action Plan .......................................................................................... 4-4

    3.7 Lowering the GVRD Sewer .......................................................................... 3-3

    ELEMENTS OF AN INTEGRATED LOWLANDS PLAN

    4.2 Plan Elements for Flood Relief and Habitat Restoration .............................. 4-1 4.4 Flow Control at Trans-Canada Highway ...................................................... 4-3

    4.7 Capital Cost Estimates .................................................................................. 4-4

    INTEGRATION OF LOWLANDS AND UPLANDS STRATEGIES 5.1 Summary of Flood Mitigation for the Lowlands ............................................ 5-1 5.2 Land Use and Aquatic System Overview ..................................................... 5-1

    i CH2M HILL

  • COMO CREEK INTEGRATED STORMWAT~R MANAGEMENT PIAN FINAL REPORT TABLE OF CONTENTS FEBRUARY 2002

    PART B . STRATEGY FOR FLOOD RISK MANAGEMENT AND WATERSHED RESTORATION IN THE COMO UPLANDS

    CHAPTER 6

    CHAPTER 7

    CHAPTER 8

    CHAPTER 9

    CHAPTER 10

    MANAGEMENT'STRATEGY FOR THE COMO UPLANDS 6.1 Problem Statement ..................................................................................... 6-1 6.2 Identifying Solutions to the Erosion Problem .............................................. 6-3 6.3 Identifying Solutions to the Flooding Problem ............................................ 6-5 6.4 Summary of Findings .................................................................................. 6-6 LONG-TERM WATERSHED RESTORATION 7.1 The Water Balance Approach ...................................................................... 7-1 7.2 7.3

    Adaptive Approach to Watershed Retrofit ................................................. 7-2 Step 1 - Preliminary Targets for Rainfall Capture and Runoff Control ....... 7-3

    7.4. Step 2 -Validation of Preliminary Rainfall Capture and ............................ 7-8

    7.5 Steps 3 and 4 - Facilitating the Process of Change ..... ............................. 7-10 7.6 Steps 5 and 6 - Ongoing Assessment of the Watershed ........................... 7-11 7.7 Watercourse Restoration ............................................................................ 7-12

    Runoff Control Targets

    Retrofit Strategy

    7.8 Summary of Findings .................................................................................. 7-12 SHORT-TERM FLOOD RISK MANAGEMENT 8.1 8.2' 8.3 Culvert Upgrading and Bedload Interception .............................................. 8-4

    8.5 Summary of Findings .................. ; ............................................................... 8-9 ELEMENTS OF AN INTEGRATED PLAN FOR THE COMO UPLANDS 9.1 Description of Uplands Plan Elements ....................................................... 9-1 9.2 Plan Elements for Long-Term Watershed Restoration ............................... 9-1 9.3 Plan Elements for Short-Term Flood Risk Management ............................ 9-1

    Options for Flood Risk Management .......................................................... 8-1 Community Storage for Runoff Control ...................................................... 8-1

    8.4 Inter-Watershed Connections ..................................................................... 8-8

    CONCEPTS FOR RAINFALL CAPTURE AT.SOURCE 10.1 Performance Targets for Rainfall Capture ............................................... 10-1 10.2 Land Use Redevelopment Scenarios ...................................................... 10-2 10.3 Examples of Rainfall Capture Techniques .............................................. 10-8

    PART C . IMPLEMENTATION OF THE COMO CREEK WATERSHED MANAGEMENT PLAN

    CHAPTER 11 IMPLEMENTATION ACTIONS FOR COMO WATERSHED 1 1.1 Introduction ............................................................................................. 11-1 11.2 Summary of the Como Watershed Plan ................................................ 11-1 11.3 Description of Watershed Actions .......................................................... 11-3 11.4 Overall Costs of the Watershed Actions ................................................ 11-3 11.5 Financing the Watershed Management Plan ............ ............................ 11-4 11.6 Measuring Success ................................................................................ 11-4

    CHAPTER 12 CONCLUSIONS AND RECOMMENDATIONS 12.1 Conclusions ............................................................................................ 12-1 12.2 Recommendations .................................................................................. 12-2

    ii CHPM HILL

  • a d 8 s:

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    COMO CREEK INTEGRATED STORMWATER MANAGEMENT PLAN FINAL REPORT TABLE OF CONTENTS FEBRUARY 2002

    LIST OF TABLES Follows Page

    Table A

    Table 4-1

    Table 4-2

    Table 7-1

    Table 9-1

    Table 1 1-1

    Figure A

    Figure 1-1

    Figure 2-1 Figure 2-2 Figure 213

    Figure 3-1 Figure 3-2

    Figure 4-1 Figure 4-2

    Figure 4-3 Figure 4-4

    Figure 5-1 Figure 5-2

    Figure 6-1

    Figure 7-1 Figure 7-2 Figure 7-3 Figure 7-4 Figure 7-5

    Figure 7-6

    Implementation Actions for the Como Creek Watershed Management Plan ........ ES-2 Elements of an Integrated Plan for Flood Relief and Habitat Restoration ............. 4-2 In the Fraser Mills Lowlands

    2001 Action Plan Projects for Flood Relief and Flow Control in ............................ 4-5 Fraser Mills Lowlands

    Components of an Integrated Strategy for Managing the Complete ..................... 7-3 Spectrum of Rainfall

    Elements of an Integrated Plan for Flood Risk Management and Watershed ....... 9-1 Restoration in the Como Uplands

    Implementation Actions for the Como Creek Watershed Management Plan ........ 11-3

    LIST OF FIGURES

    Shared 50-Year Vision for Watershed Restoration

    Existing Watershed

    Problem Identification Potential for Flood Inundation Existing Control Points

    Levels of Modelling Intensity Duration Frequency Plots for Storm Events

    Concept for Surface Water Management in Fraser Mills Lowlands Elements of an Integrated Plan for Flood Relief and Habitat Restoration In the Fraser Mills Lowlands Proposed Control Elevations Schematic of Plan Elements and Flow Paths at Como and Popeye Drainage Outlets

    Fish Habitat Values and Constraints Watershed Health Classification System

    Typical Stream Bank Erosion in the Como Creek Ravine

    Typical Distribution for Annual Rainfall Events Strategy for Managing the Complete Spectrum of Rainfall Events Typical Distribution of Small Storms and Average Rainfall Intensity Typical Volume Distribution of Annual Rainfall Estimated Annual Water Balance for the Como Watershed Under Natural Forested Conditions Creek Health (B-IBI) versus Watershed Impervious Land Cover

    iii CHZM HILL

  • ;p

    COMO CREEK ~NTEGRATED STORMWATER MANAGEMENT PIAN FINAL REPORT TABLE OF CONTENTS FEBRUARY 2002

    Figure 7-7 Figure 7-8 Figure 8-1 Figure 8-2 Figure 8-3 Figure 8-4 Figure 8-5

    . Figure 8-6 Figure 8-7 Figure 8-8 Figure 8-9 Figure 9-1

    Figure 10-1 Figure 10-2 Figure 10-3 Figure 10-4 Figure 10-5 Finure 10-6

    Effectiveness of Source'Storage and Community Storage in Reduction Erosion Options for Long-Term Watershed Restoration in the Como Uplands Options for Short-Term Flood Risk Management in the Como Uplands Identification and Assessment of Opportunities and Constraints For Community Storage Tier C Storage Volume Needed for the Como Watershed Como Creek Culvert at Rochester Avenue Booth Creek Culvert at Austin Avenue Como Creek Culvert at Austin Avenue Como Creek Culvert at Rochester Avenue (top view) Booth Creek Diversion Culvert Inlet at Sheridan Operation of Inter-Watershed Connections for Flood Control

    Elements of an Integrated Plan for Flood Risk Management and Watershed Restoration in the Como Uplands

    Typical Existing Residential Street Impermeable Surface Area of a Typical Older Home Impermeable Surface Area of a Newer Home Block With Several New Two-Family Dwellings 1mpermeable.Surface Area of a New Two-Family Home Installation of Rainfall Capture Techniaues

    Figure 10-7a Installation Detail of Infiltrator Chambers Figure 10-7b Installation Detail of Infiltrator Chambers Figure 10-8 Mixing of a Soil and Organic Matter to Create a Good Landscape Soil Figure 10-9 Permeable Pavers (Rima Pavers by Westcon) Figure 10-1 0 Spaced Wood Deck Figure 10-1 1 Skinny Buildings Figure 10-1 2 Multi-storey Building with Underground Parking Figure 10-1 3 Absorbent Soils and Flow Control Over Parking Garage Figure 10-1 4 Installation of Cisterns in Parking Garages or Landscape Areas Figure 10-1 5 Rainwater Reuse Figures 10-1 6a-b Rainfall Capture Techniques for Medium Density Multi-Familv and Commercial Figure 10-1 7 Figures1 0-1 8a-b Figure 10-1 9a Figure 1 OT1 9b Figure 10-1 9c Figure 10-20 Figure 10-21 Figure 10-22 Figure 10-23 Figure 10-24 Figure 10-25 Figure 10-26

    Green Roof on a Large Airport Building Bioswales and Rain Gardens for Parking Area Runoff Local Urban Roadside Drainage Local Urban Roadside Drainage Concept at Lawn Local Urban Roadside Drainage Concept at Tree Key Functions of Riparian Habitat Stream Restoration Characteristics Pool and Riffle Construction Macro Pool for Summer Rearing Habitat and Deep Water Refuge Placement of Large Organic Debris Boulder Clusters Placed in Stream Brush Layering for Erosion Control

    iv CHPM HILL

  • Executive Summary

    CHZM HILL

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    Restore natuxal. water balance through a Watershed Retrofit Strategy. ,I,\

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    \ a -I- - -I- lestore natural rainage pattern of IVO separate ubwatersheds. LEGEND 1 1 - 1 - 1 1 W a Q S h e d m ----

    w- ............... Endmed-

    tdluwalemxrsa

    timize Operation of L*lershedrnnedian eh#een~andpopeye

    Zestore Popeye :reek and riparian

    reeks.

    :reale new drainage oubl to erve Boovl /popeve tributary rea.

    COMO CREEK WATERSHED MAHIIGEMEH Puul /I

  • COMO CREEK WATERSHED MANAGEMENT Pwc FINAL REPORT E~ECUTNE SUMMARY FEBRUARY 2002

    Executive Summary

    1. Drivers for a Watershed Plan The pressing need for a Como Creek Watershed Management Plan is driven by the drainage problems in this watershed, particularly the chronic flooding in the Lowlands. The City of Coquitlam is impacted by the consequences, which include:

    periodic property damage and road closures caused by flooding. high-risk of flooding related failure, such as road washout. sigruficant staff time to deal with the ongoing drainage problems. rapid watercourse erosion and instability in the Como Creek Ravine.

    . . Watercourse erosion is a particularly sigruficant impact because it increases the risk of flooding and degrades aquatic habitat. There is a strong expectation for aquatic habitat restoration from Coquitlam residents and the environmental agencies, and profitable land use must also be allowed to continue. The Como Watershed Plan provides watershed management solutions that integrate engineering, planning and ecological perspectives.

    2. Integrated Solution for the Como Watershed Providing flood control and restoring aquatic habitat are complementary objectives because flooding and habitat degradation have the same root cuuse:

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    Increased Impervious Sugace due to development alters the natural water balance - The volume and rate of surface runoff from the Como Uplands is much greater as a result of urban development.

    ~~ - ~ ~

    The City of Coquitlam has recognized the need for an infegrufed so2ution that not only recognizes and supports land use change, but also eliminates the root cause of drainage- related problems. The Como Watershed Plan presents an integrated solution for the entire watershed to provide immediate flood relief, and eventually restore aquatic habitat. The Plan is organized into three parts:

    Part A develops specific solutions to provide immediate flood r...