Beyond the Guidebook 2010 Advances Runoff-Based Approach to Setting Watershed Performance Targets
RAINwater Management is About Protecting Streams
In October 1997, a focus group workshop convened by the Union of British Columbia Municipalities set in motion a chain of actions that culminated in the Province producing Stormwater Planning: A Guidebook for British Columbia. Released in June 2002, the Guidebook quickly became a catalyst for action to implement a ‘design with nature’ approach to rainwater management and green infrastructure.
Water Balance Methodology
“The Guidebook applied a science-based understanding, developed the water balance methodology to establish performance targets for rainfall capture, and demonstrated that urban watershed restoration could be accomplished over a 50-year timeframe as and when communities redevelop,” reports Kim Stephens, Program Manager for development and delivery of the Water Sustainability Action Plan for BC. He was Project Manager and principal author of the Guidebook.
“By 2007, it was time to focus attention on how to truly protect and/or restore stream health in urban watersheds. Beyond the Guidebook 2007 initiated the paradigm-shift from the single-function view of traditional ‘stormwater management’ to the integrated and holistic perspective that is captured by the term ‘RAINwater Management’.”
“Beyond the Guidebook 2007 foreshadowed Living Water Smart, British Columbia’s Water Plan and the Green Communities Initiative, both of which were launched by the Province in 2008. These established an over-arching provincial ‘design with nature’ policy framework. There is now clear guidance for aligning local actions with provincial and regional goals.”
“Building on case study experience, Beyond the Guidebook 2010 provides local governments with ‘how to’ guidance for developing outcome-oriented urban watershed plans. The foundation for ‘RAINwater management’ is the ‘runoff-based’ approach’ to establishing targets for rainfall capture at a watershed scale,” continues Kim Stephens.
“Stream health protection is a driver for Beyond the Guidebook 2010. The runoff-based approach addresses the interaction of runoff with the physical aspects considered important to the aquatic environment. Keyed to the estimation of the amount of water in the stream over a long period of time, the ‘runoff-based’ approach connects these dots:
- impacts to a stream;
- the causes in the urban landscape; and
- the mitigation methods needed to restore the natural water balance in the stream.”
“RAINwater management is about protecting streams, not how much volume one can infiltrate on sites. Hence, the ‘runoff-based approach’ leads to setting achievable watershed targets for rainfall capture and flow mitigation that would accomplish the most benefit for the stream.”
Contrast with Rainfall-Based Approach: “The runoff-based approach is more scientifically defendable than the simplistic ‘rainfall-based approach’ of matching calculated peak discharge rates resulting from design storms. The simple sounding difference is very significant for understanding and mitigating the impacts to stream stability and stream health,” concludes Kim Stephens.
To Learn More:
Click on Application of the “DFO Urban Stormwater Guidelines” has evolved over the past decade to protect stream health — This story provides context for the 4-page ‘Urban Stormwater Guidelines and Best Management Practices for Protection of Fish and Fish Habitat’ – how they set a direction in 2001; how they have evolved into ‘Beyond the Guidebook’; and how the Water Balance Model is a tool to correlate runoff volume management with stream erosion and water quality outcomes.
Develop Outcome-Oriented Urban Watershed Plans
“People learn through stories. Beyond the Guidebook 2010 is the ‘telling of the stories’ of how change is being implemented on the ground in British Columbia. Case study experience presented in Beyond the Guidebook 2010 clearly shows that a new land ethic is taking root in British Columbia,” states Kim Stephens.
“Beyond the Guidebook 2010 is more than stories. Building on case study experience, it provides local governments with ‘how to’ guidance for developing outcome-oriented urban watershed plans. It describes web-based tools that the Province has developed to support new approaches to water management.”
To Learn More:
Click on A crucially important message in Beyond the Guidebook 2010: “We now have the tools and experience to design with nature” — “So many in local government are searching for the magical ‘silver bullet’ to resolve watershed issues and challenges. Yet soil, vegetation and trees can do more for our watersheds than decades of planning, consulting and complicated engineering design will ever achieve,” states Richard Boase,Co-Chair, Inter-Governmental Partnership.
Framework for Moving from Planning to Action
“A framework for developing integrated and holistic plans is consolidated in a single table (see below). Originally released in 2008, Table 2 was developed in conjunction with the consultation process for Metro Vancouver’s Integrated Liquid Waste & Resource Management Plan,” explains Kim Stephens.
“In effect, Table 2 is a ‘mind-map’. It lays out the cascading logic for establishing, evaluating and implementing watershed-specific runoff targets that will protect stream health.”
Setting Watershed-Specific Performance Targets
“The Stream Health Methodology embedded in the Water Balance Model powered by QUALHYMO enables a watershed runoff target to be established; it also enables the user to assess how to meet the watershed target at the site scale,” continues Richard Boase. “Three questions provide an evaluation framework for determining the acceptability of a watershed-specific runoff target:
- What target will achieve the watershed health objective?
- What needs to be done to make the target achievable?
- Do the solutions meet the test of affordability and multiple objectives?”
“There must be clear linkages between the targets and development approval processes. Financial and legal tools must also be in place to ensure implementation of outcome-oriented strategies,” concludes Richard Boase.
To Learn More:
To download a PDF copy of Table 2, click on Developing Outcome-Oriented Watershed Plans: Framework for Moving from Planning to Action.
To download the complete document, click on Beyond the Guidebook 2010: Implementing a New Culture for Urban Watershed Protection and Restoration in British Columbia.
Click on Beyond the Guidebook: Establish Watershed-Specific Runoff Capture Performance Targets, released in February 2008 at the Water Balance Model Partners Forum hosted by the District of North Vancouver.
And to learn from the experience of those who are pioneering outcome-oriented approaches:
Click on Bowker Creek Blueprint brings new meaning in British Columbia to the Ian McHarg vision for “designing with nature” — “The Blueprint is a 100-year action plan to make the watershed restoration vision real,” states Jody Watson, Chair, Bowker Creek Initiative.
Click on The District of North Vancouver’s Bold Vision for a Municipality-Wide Integrated Rainwater Management Plan — “Through the Official Community Plan Update, the District is advancing a vision for restoring the rainfall absorption capacity of our watersheds, one property at a time, over time,” states Richard Boase.
Click on click on City of Surrey – “From Pilot Projects to a Watershed Objectives Approach” — “Surrey has moved beyond pilot projects; we are moving to a broader watershed objectives approach to capturing where rain it falls, to better protect our streams,” states Rémi Dubé, Acting Development Services Manager.
Posted October 2010