Citywide Integrated Stormwater Management Plan (ISMP) DRAFT ACTION PLAN REVIEW Public Consultation November 16 th, 2016

Transcription

1 Citywide Integrated Stormwater Management Plan (ISMP) DRAFT ACTION PLAN REVIEW Public Consultation November 16 th,

2 Agenda DRAFT ACTION PLAN REVIEW Public Consultation Time 6:00 6:05 6:05 6:20 6:20 7:00 7:00 7:45 7:45 7:50 7:50 8:00 Activity Welcome & Introduction ACTIVITY: Community Mapping PRESENTATION: Background & Draft Action Plan ACTIVITY: Small-Group Discussion on Draft Action Plan Next Steps: How your feedback will be used Questions? 2

3 Welcome! How can we improve the quality of stormwater to ensure that our watersheds are healthy? How can we manage the quantity of stormwater to minimize flooding, erosion, and sewer overflows? What are some potential tools to help us manage our stormwater? What are some potential programs and regulations to help manage stormwater? How do we implement a stormwater management program? How do we monitor and measure success? 3

4 ACTIVITY Use the map to note: A. Where you reside. B. Stormwater management issues you are aware of. 4

5 What is an ISMP? Integrated Stormwater Management Plan An ISMP is a plan to help manage the amount of rainfall (or stormwater) we receive while protecting both our natural environment and our built environment 5

6 Why is New Westminster developing a Citywide ISMP? We live in a rainy climate! Reduce water quantity (volume of water) in our sewers to reduce Combined Sewer Overflows (CSOs) and address flooding etc. Strive for high water quality in our receiving waters (protect our watersheds) As the City redevelops, return as much as possible of the rainwater into natural watershed pathways and bring rainwater flows back to the surface where feasible in rain gardens, wetlands, and streams. 6

7 Why Water Quality Parking area runoff includes hydrocarbons, heavy metals attached to sediments Runoff from manicured landscape areas included nutrients from overfertilization and pathogens from pet waste Receiving waters are at risk habitat like shorelines of Brunette & Fraser, and recreational use of City waterfront 7 7

8 Why Water Quantity? Reduce sewer overflows, manage drainage Reduce street and property flooding Reduce erosion Anticipate climate change impacts which can increase volume. 8 8

9 Other reasons why an ISMP is important Climate Change impacts more severe weather Our community is growing! Increasing impervious areas areas where water can t seep into the ground Costly infrastructure management and costs Sustainable planning and development 9

10 The Process so Far WE ARE HERE Phase 1 Phase 2 Phase 3 Phase 4 What do we want? What do we have? How do we get there? How do we stay on track? Final Report Workshop A: Vision, Principles, and Barriers June 29, 2016 Workshop B: Windows of Opportunity Mapping July 27, 2016 Workshop C: Draft Action Plan August 24, 2016 Group Workshops: Technical Advisory Group / Interested Stakeholders October 25, 2016 Public Open House November 16, 2016 Workshop D: Coordinated Comments Early December 10

11 Why We Are Asking for Feedback Introduce the project and anticipated schedule Bring together members of the public to learn about best management practices for managing stormwater Discuss experiences and information that may be relevant to New Westminster Encourage interactive dialogue to exchange information and refine the Draft Action Plan 11

12 Outline of the Draft Action Plan I. Vision, Principles, and Actions Why Stormwater management is required Introduction to targets and programs to address priorities II. Best Practice Toolkit Tools to address stormwater management highlighting strengths & challenges III. Technical Background Record of process including stakeholder input and alternatives considered Program details and action plan 12

13 WHAT ARE THE EXISTING CONDITIONS? 13

14 Existing Conditions in New Westminster Environmental Aerial Imagery Terrain and Average Annual Precipitation Geology and Soils Infiltration Potential Infrastructure Sewer Catchments Land Use / Regulatory Land Use and Zoning Maps Pervious and Impervious Areas 14

15 Overview

16 Terrain & Average Annual Precipitation

17 Watersheds & Receiving Waters DRAINS TO FRASER RIVER

18 Geology & Soils

19 Predominant Infiltration Potential

20 Sewer Catchment Areas

21 Land Use

22 Impervious Areas by Parcel 22

23 Areas of Pervious & Impervious 23

24 BEST MANAGEMENT PRACTICES FOR STORMWATER 24

25 Best Management Practice Toolkit Trees & Tree well structures Infiltration swales Absorbent landscape Raingardens/bulges Pervious paving Green roof Rainwater harvesting Infiltration trenches Water quality structure Detention tank Constructed streams/wetlands 25

26 Absorbent Landscape: the role of trees Urban trees, vegetation and soil play a major role in stormwater detention. 26

27 Absorbent Landscape: the role of Soils 1. Crown Interception 2. Throughfall and Stemflow 3. Evapotranspiration 4. Soil Water Storage 5. Soil Infiltration 6. Surface Vegetation 7. Organics and Compost 8. Soil Life 9. Interflow 10.Deep Groundwater 11.Water Quality Improvement 12.Impermeable Surfaces and Surface Runoff Stormwater Variables of Absorbent Landscapes A schematic representation of the 12 stormwater variables of absorbent landscape. Keeping these variables in balance is the key to successful stormwater source control using absorbent landscape. 27

28 Infiltration Swale for low infiltration rates 1. Weir Keyed into Swale Side Slope 2. Growing Medium (300mm Min.) 3. Sand 4. Existing Scarified Subsoil 5. Perforated Underdrain (150mm Dia. Min.) 6. Drain Rock Reservoir (300mm Min.) 7. Geotextile Along All Sides of Reservoir 8. Trench Dams at All Utility Crossing Partial infiltration swale with reservoir and subdrain 28

29 Infiltration Bulges 29

30 Pervious Paving Reid Residence Lantzville, BC Rainfall flows through small aggregate in the cracks into drain rock and infiltrates into underlying soils 30

31 Extensive Green Roof 1. Wall Cap Flashing, waterproof membrane extends to 100mm above finished grade 2. Drain Rock, Paving Slab, or Other Buffer Equivalent 3. Wood, Steel or Concrete Curb/Edging 4. Planting 5. Growing Medium 6. Filter Layer 7. Drainage Layer 8. Protection Layer and Root Barrier 9. Waterproof Membrane 10. Thermal Insulation 11. Vapour Barrier 12. Area Drain 13. Structural Slab 14. Building Interior 15. Wall Flashing, waterproof membrane extends to 150mm above finished grade 31

32 Roof Drain Disconnect to Surface Swale or Infiltration Trench Note: Controlled overflow drainage to street or lane is required! 32

33 One/Two Families Have a Role! 33

34 Rainwater Harvesting Possible at new homes on private land Rainwater Tank Capture System 34

35 Water Quality Structures Possible at new homes on private land Oil-Water Separator Installation 35

36 Constructed Wetlands UniverCity at SFU 36

37 Putting It All Together 37

38 Everyone Plays a Role Meeting goals to protect receiving waters requires cooperation from public and private land use types: Single-family housing Multi-family housing Commercial / Industrial / Institutional Various types of streets 38

39 New Westminster s DRAFT Citywide Integrated Stormwater Management Plan 39

40 Draft Vision Rainwater management contributes to renewal and resilience in New Westminster New Westminster will manage rainwater to renew river habitats, urban forests and ecosystems, and to support intelligent urban design in a resilient community. 40

41 How Much is Enough: Citywide Targets Water Quality Volume Reduction Collect and treat the first 28 mm in 24 hours (70% of average annual rainfall) Capture (infiltrate or reuse at source) the first 28 mm in 24 hours (70% of average annual rainfall), except at unstable soils or related setbacks. 41

42 Special Areas - Impervious Area 42

43 Special Area Objectives Special Area Brunette Glenbrook Uptown/Queens / CSO catchment Queensborough Special Program Objectives / Description Provide stream stewardship apply higher targets (capture/treat first 50 mm of rainfall in 24 hours equalling 90% of average annual rainfall) consistent with overall Brunette watershed partners. Refocus on riparian/instream. Supply extended stream base flow from Queens Park constructed wetlands, Canada Games water harvesting and adjacent land uses. As well as Citywide objectives, reduce peak flows to restricted pipe sizes - to reduce flooding risk. Minimize pumping volume/cost customize targets to be similar to Richmond, in recognition of high water table and difficult soils. 43

44 GLENBROOK RAVINE

45 WHAT ACTION PLAN WILL WE USE FOR STORMWATER MANAGEMENT? 45 45

46 Overview of Action Programs Everyone plays a role public and private to protect New Westminster receiving waters Ongoing Existing Actions New Short Term Actions New Sustained Actions New Longer Term Actions 46

47 Ongoing Existing Actions / Programs Street & Catch Basin Cleaning Sewer Separation Sewer Cross- Connection Elimination Rainwater Management for Major Developments New Short Term Actions/ Programs Actions Watershed Public Awareness Demonstration Projects Updated Regulations Technical Training Awards & incentives New Sustained Actions/ Programs Absorbent sites: trees, soils and pervious paving Surface parking water quality treatment - onstreet and offstreet Monitoring & Adaptive Management New Longer Term Actions/ Programs Absorbent Lanes Roof Rainwater Harvesting & Re- Use 47 47

48 Draft Action Plan Phase-In Year General Strategy Immediate and On-Going Actions Remove Barriers, Build Capacity Expand Green Infrastructure (GI) into NEW Non-SF Projects Expand GI into NEW One/Two Family / Lane Housing Expand GI into RETROFITS (fee-bate / incentive programs) Long-Term Aspirations (e.g. rainwater harvesting, absorbent lanes) 48

49 ACTIVITY Please discuss the Draft Action Plan in smallgroups at each table with the facilitator. A. Can you refine the approaches? B. Is there other information you want to share? 49

50 Thank You! 50