Making the Connection Between Rainwater Management and Stream Health at the Annual BCWWA Conference
Inter-Governmental Partnership rolls out ‘Beyond the Guidebook’ as part of stormwater management session at Penticton Conference
When Stormwater Planning: A Guidebook for British Columbia was published in 2002, it established the framework for rainfall capture and a performance target way-of-thinking and designing. The concepts and methodologies in the Guidebook were intended to stimulate a change in the mindset of practitioners and others, rather than cast in stone a set of prescriptive rules.
“In 2002, the Guidebook premise that land development and watershed protection can be compatible was a pretty radical shift in thinking. Five years later, we are proceeding with the next bold leap forward”, stated Kim Stephens, Program Coordinator for the Water Sustainability Action Plan, in his opening comments to his audience at the recent Annual Conference of the BC Water & Waste Association (BCWWA).
At the BCWWA Conference in Penticton, Kim Stephens and Jim Dumont made the latest in an ongoing series of Beyond the Guidebook presentations. “Beyond the Guidebook will take the Guidebook innovation to the next level of evolution”, Stephens continued, “Now that practitioners are becoming comfortable with what ‘rainfall capture’ means in practice, local governments and the development community are in a position to turn their attention to what is an achievable outcome that makes sense and results in a net environmental benefit.”
“The pilot for Beyond the Guidebook is the Fergus Creek watershed plan that the City of Surrey has recently completed. The Fergus Creek plan demonstrates how to protect stream health in the urban environment”, observed Stephens.
According to Jim Dumont, the water resource specialist who is responsible for development of the stream health application that is at the heart of the Water Balance Model powered by QUALHYMO, “Beyond the Guidebook is a runoff-based approach to drainage modeling that connects the dots between source control evaluation and stream health assessment. The rainwater management issue in a nutshell is that people want to have their cake and eat it too…because they want development, yet they want to avoid the types of in-stream environmental impacts that have historically resulted from changing the surrounding landscape through urbanization.”
In providing the audience with modelling context, Dumont pointed out that “evaporation is critical and typically gets overlooked’ in conventional drainage modelling. In highlighting the inherent weaknesses in design storm approaches, he emphasized that drainage engineers need to turn their minds to rainwater runoff reduction. “Design storm tools are inadequate to deal with runoff volume, stream erosion and water quality”, stated Dumont emphatically.
He commented that the Fergus Creek experience is being ported into the Water Balance Model. “The Water Balance Model does surface conditions quite well. By integrating the Water Balance Model with QUALHYMO, we can model systems that have a live storage component, and we can correlate what we do at the site with what happens in the stream”, explained Jim Dumont, “The methodology selected for the Water Balance Model powered by QUALHYMO is based upon shear stress as applied to the stream banks over time. This is a measure of the energy available to cause erosion in a stream. Continuous simulation is the key to generating scenario comparisons.”
Jim Dumont presented unit costs from the Fergus Creek Plan to underscore that “Going Beyond the Guidebook means less cost, not more, for green solutions. The key is eliminating the need for expensive detention ponds.”
To Learn More:
To download the co-presentation by Kim Stephens and Jim Dumont, please click on this link to Beyond the Guidebook: Making the Connection Between Rainwater Management and Stream Health.