The Water Balance Model for Canada:

Transcription

1 Watershed & Stormwater Management Webconference The Water Balance Model for Canada: Improving the Urban Landscape through Inter-Provincial Partnerships Kim Stephens, PEng,, Project Coordinator, Inter-Governmental Partnership & Bert van Duin, PEng,, Steering Committee Alberta Low Impact Development Partnership Do you know where you really are in the shifting paradigms of stormwater management? 1. Run it in Ditches 2. Run it in Pipes 3. Run it in Stormwater Pipes 4. Keep it from Stormwater Pipes 5. Well, Just Don t Cause Flooding 6. Oh, and Don t Pollute Either 7. It s the Ecology, Stupid 8. Water is Water is Watershed 9. Green and Bear It 10. Build the Vision, Create the Legacy 1

2 Universal Issues Population Surge Landscape Transformed Natural Hydrology Altered Creeks & Lowlands Impacted The Watershed Picture: Without Rainfall Capture Annual Rainfall as Runoff (%) 80% 70% 60% 50% 40% 30% 20% 10% Year Target Condition + Climate Change Impacts from Growth 2

3 Mind Map The Science British Columbia Alberta Drainage Planning in British Columbia Has Been Evolving Over the Decades 1960s: Pipe and Remove 1970s: Detain Peak Flows 1980s: Reactive Mitigation 1990s: Stream Stewardship (Proactive Management) 2000s: Rainwater Management (Sharing a Vision) 3

4 The Trickle-Down Evolution of Watershed Management in BC (How the Past is Influencing the Present) 1970s - society s reaction to the dam builders 2000s - society s reaction to the pipe sizers Land Use Change and Aquatic Impacts By 30% may be unable to sustain self-supporting supporting cold-water fish Initial Impact At About 10% 4

5 Why Manage Volume Erosion Sedimentation The Mean Annual Flood (MAF) is the channel-forming event Volume Increasing When the MAF increases, the channel erodes to convey the additional volume A consequence of channel instability is habitat degradation 5

6 Mind Map The Science British Columbia Alberta 6

7 Water Sustainability Action Plan for British Columbia WaterBucket Website Partnership Water $ave Tool Kit for BC Convening for Action: Roundtable on Water Sustainability Watershed/ Landscape-based Approach to Community Planning Water Balance Model for BC Green Infrastructure Partnership waterbucket.ca is the communication vehicle for the Action Plan 7

8 Communities-of of-interest Inter-Governmental Partnership: Vision To promote changes in land development practices so that: The built environment will preserve and/or restore the natural water balance over time Performance targets will be achieved for rainwater runoff volume and flow rate reduction at the source, where rain falls 8

9 The Water Balance Model is A tool that quantifies the benefits in terms of reducing rainwater runoff volume - of installing source controls under different land use, soil and climate conditions The Water Balance Model is the result of a Building Block Process: GVRD Report on Stormwater Source Control Evaluation Chilliwack Policy & Design Manual for Surface Water Management Stormwater Planning: A Guidebook for British Columbia UniverCity: The Sustainable Community at the Top of Burnaby Mountain 9

10 UniverCity on Burnaby Mountain was the trigger for the Water Balance Methodology Key Message: Anybody with a computer and internet connection can access the model 10

11 Where the Water Balance Model fits on the Modeling Hierarchy Strategic Functional Planning Policy Evaluation Decision Support Scenario Modeling Master Planning Pre-Design Detailed Design Operations How Water Moves Through Soil 11

12 Simplifying the Technical Language in British Columbia! Basic Source Control Types in GVRD Guidelines: Absorbent Landscape Rain Gardens Infiltration Swales Pervious Paving Green Roof Water Balance Model promotes Integration of Perspectives Planners: Tool for Better Use of Space Engineers: Tool for Pre-Design Landscape Architects: Tool for Green Solutions Ecologists: Tool for Watershed Function Educators: Tool for Social Marketing 12

13 Integration of Perspectives Right-handed planner Left-handed engineer Key Message: Integrate Actions at Three Scales: Improve Site Practices to Enhance Community Livability Site Neighbourhood: Watershed: Building size Hard surface Landscaping Lot size Road Design Green space Landscaping Zoning Road Design Green space Landscaping BMPs 13

14 How the Water Balance Model is being used to make better decisions: Local Governments - when communicating with the public Planners and Engineers when setting performance targets Developers and their Consultants - when testing scenarios Environmental Agencies - when monitoring watershed health Practical Site Level Solutions are Typically Landscape-based 14

15 Key Messages Break the connection Encourage rain gardens Break the Connection with a Rain Garden Simple Infiltration + Reservoir + Overflow 15

16 The first Engineered Rain Garden in British Columbia has been constructed by Westbild as a Demonstration Project on the Westwood Plateau in Coquitlam High Level Overflow Roof Drainage Discharges Into Rain Garden 16

17 Performance Monitoring Results During November 2004 Wet Weather Period Total Rainfall for 2-day period = 80mm Total Rainfall Volume = ~11.3m 3 Total Outflow Volume = ~8.2m 3 (i.e. 73%) Total Volume Absorbed = ~ 3.1m 3 (i.e. 27%) (This is equivalent to the first ~22mm rainfall) Rainfall Volume vs Discharge 18 cubic metres of rain flow meter installed % rain volume absorbed (22 mm) 40% rain volume absorbed (41 mm) 39% rain volume absorbed (37 mm) 42% rain volume absorbed (48 mm) Rainfall Runoff (m3) Overflow Discharge 93% rain volume absorbed (23.4 mm) 0 11/23/ /30/ /7/ /14/ /21/ /28/2004 1/4/2005 1/11/2005 1/18/2005 1/25/2005 2/1/2005 2/8/2005 2/15/2005 2/22/2005 3/1/2005 3/8/2005 3/15/2005 Date 44.5% overall Performance Monitoring Results During the period Nov/04 Mar/05 17

18 The Watershed Picture: With Rainfall Capture 80% Annual Rainfall as Runoff (%) 70% 60% 50% 40% 30% 20% Target is Specific to each Watershed as determined in each Watershed Plan 10% Year Watershed Target (varies) Mind Map The Science British Columbia Alberta 18

19 Alberta Low Impact Development Partnership Planning Philosophy Promoting Sustainable Development Decision Support Tool Infrastructure Standards Alberta Challenges Population and urban growth are leading to deterioration of our environment For instance, Calgary has grown by over 25% in the last decade Differences in servicing strategies Edmonton has combined and separated drainage systems Other communities have fully separated drainage systems Urban development is altering the hydrological balance of our watersheds 19

20 Alberta challenges Little is known about the interaction between surface and sub-surface conditions Increased volumes of stormwater are changing stream morphology Example: West Nose Creek watershed in Calgary region The biggest impact is on smaller streams and urban wetlands Calgary has a very progressive Wetland Protection Policy Alberta Challenges Alberta Environment is encouraging sustainable infrastructure, resource conservation and pollution prevention Alberta Water for Life Strategy goals: Safe and secure drinking water supply Healthy aquatic systems Reliable water quality for a sustainable economy 20

21 Alberta Challenges Alberta is susceptible to drought conditions and future availability of water may be threatened Research by Prairie Adaptation Research Collaborative (PARC) cautions for reduced flows in late summer and greater variability Residential land development can generate 10 to 100 times more storm runoff when compared to predevelopment conditions Stormwater ponds attenuate peak flows, but they do not reduce the volume of runoff In addition, they may worsen thermal pollution and are questionable with respect to finer sediments, nutrients and operation during winter months Benefits of Low Impact Development Need for a complete, integrated approach to water management (water-centric or water-sensitive) Stormwater source controls and LID strategies reduce the runoff peak flows AND volumes Reducing the discharged volumes results in reduced pollutant loadings and improved hydrological balance in the watershed Through stormwater collection and reuse, the demand on potable water supplies is lessened 21

22 Alberta Low Impact Development Partnership The Alberta LID Partnership was formed in November 2004, after a LID workshop organized by the Alberta chapter of ALMS Initial reactions were mixed planners and architects are open minded (past experience with LEED) while engineers are cautious until they realize that they need each other to implement change The invitation by the BC IGP to participate in the evolution of the Water Balance Model brought people together who share a common vision By March 2005, The Terms of Reference for ALIDP were finalized, and a Steering Committee was elected. ALIDP Membership The membership is open to all Alberta municipalities, individuals s and organizations with interest in land development and environmental protection The City of Calgary The City of Edmonton The City of Red Deer The City of Lethbridge The City of Airdrie The Town of Cochrane The Town of Okotoks The Towns of Black Diamond and Turner Valley MD of Rocky View Alberta Environment Bow River Basin Council North Saskatchewan Watershed Alliance Elbow River Watershed Partnership University of Calgary UDI Alberta Alberta Real Estate Foundation Alberta Chapter of CMHC Alberta Lake Management Society 22

23 ALIDP Goals 1. Facilitate development of an Alberta LID strategy to promote changes in land development practices: Sites will be designed to mimic the natural hydrologic conditions to the extent possible Adequate stormwater source controls will be implemented where suitable Performance targets for stormwater runoff volume and rate reduction will be achieved ALIDP Goals 2. Coordinate the regulatory, technical and communication aspects of LID strategy 3. Develop an outreach and education program to enhance public understanding of LID 4. Anticipate future issues related to sustainable development, watershed protection, and climate change 23

24 Early Challenges and Discussions ALIDP and national initiatives allow for exchange of ideas and information Universality with local variations (e.g. cold climate) Do not get stuck on particular methods but look at the entire toolbox available, and allow it to evolve Need regulatory framework and clear information on why we would be interested in doing this Early Challenges and Discussions Need first of all public education and outreach Provides impetus for further research, pilot projects, etc. by pooling resources ALIDP is more than just a model Commitments to partnership, not to any tool. But need tools to demonstrate impacts and what practically could be done 24

25 ALIDP Action Plan Formalizing the ALIDP Map out the process what is needed to make LID a reality in Alberta Identify stakeholder needs Develop public education and outreach programs Promote further research through demonstration projects Examples of on-going and new LID initiatives Stormwater re-use for irrigation Full-scale test sites of green roof system, swale, bioretention area and permeable pavement Bioretention and permeable pavement at University of Calgary Experimental constructed wetland (69 th Street SW, Calgary) Land-use bylaw template Nose Creek Basin Instream Flow Needs Initiative Preparation of BMP Scoping Study (Calgary) Preparation of BMP and Source Control Manual (Calgary) Conceptual design of LID subdivisions minimizing impacts on streams and wetlands 25

26 Alberta British Columbia After ALIDP is formalized, the ALIDP is expected to enter into an inter-provincial partnership with the BC IGP Synergies between 1998 British Columbia Strategy & Alberta s Water for Life initiative BC IGP has already created Alberta page on national portal Joint presentations being done by BC IGP and ALIDP Feed-back from ALIDP led to evolution of QUALHYMO From BC to Alberta to Canada to??? The Mission is to Create a Legacy Influence choices by individuals and organizations Use the term sustainability as a lens for considering approaches that influence choices 26