District of North Vancouver's Bold Vision: Restore the Rainfall Capture Capacity of the Urban Landscape, One Property at a Time
In January 2010, the British Columbia Water & Waste Association (BCWWA) hosted a continuing education workshop to advance Living Water Smart, BC's Water Plan. The program included a presentation by Richard Boase of the District of North Vancouver. To learn more, click on Water Conservation: Demand Management Planning and Implementation in British Columbia.
His presentation was built around application of the Water Balance Model to achieve water conservation and rainwater management desired outcomes. The common link is soil depth because this factor is a key to rainfall capture capacity.
To download a copy of the presentation by Richard Boase, click on Impacts of Single Family Lot Redevelopment on Rainwater Management: Case Studies in the District of North Vancouver.
Restoring the Urban Landscape
The District of North Vancouver has a bold vision to systematically retrofit individual properties as they come up for redevelopment. The catalyst for pending action is the current incremental impact of property redevelopment on stream health.
“Our case study analysis clearly shows that our watersheds have been experiencing death by a thousand cuts as the house footprint has grown larger and larger over the decades,” states Richard Boase, Environmental Protection Officer (and Co-Chair of the Inter-Governmental Partnership that developed the Water Balance Model).
“The message for local governments is clear: single family properties hold the key to watershed health; we have to do a better job of educating residents about the link between their back yards and stream health; and we need to work directly with homeowners if we are to restore the rainfall capture capacity of the urban landscape.”
“North Van District is developing a landscape restoration strategy that we hope will be integrated into our Official Community Plan Update.”
MacKay Creek Watershed Case Study
“To demonstrate the need for action on residential properties, we analyzed redevelopment trends in MacKay Creek. Within 20 years, 10 percent of the existing lots could be redeveloped, with a consequent 25% increase in impervious area and 10% increase in annual runoff volume.”
“By improving soil depth to 400mm and collecting roof runoff in a simple rain garden at the time of redevelopment, the effective impervious area per lot would be 10% less than existing, and the runoff per lot would be 5% less than existing. This is why the Topsoil Law and Policy and Technical Primer Set is a potentially powerful tool to achieve a watershed restoration vision.”
About the Topsoil Primer Set
An absorbent topsoil layer has emerged as a fundamental building block for achieving water sustainability outcomes through green infrastructure. Targeted water sustainability outcomes are: less irrigation water use; and reduced rainwater runoff.
The Green Infrastructure Partnership has developed primers to provide municipal staff and designers with a starting point for law, policy and technical decisions. The Topsoil Primer set reflects and incorporates the experience and lessons learned by the City of Surrey, the City of Courtenay and the District of North Vancouver in pioneering implementation of absorbent landscape policies and requirements.
Posted February 2010