In the 1990s, the pioneering work of Richard Horner and Chris May at the University of Washington correlated the cumulative impacts of ‘changes in hydrology’ on stream health. Their findings provided a springboard to reinvent urban hydrology in British Columbia. This reinvention resulted in the rainfall capture approach and water balance methodology for establishing performance targets. If rainfall is captured to reduce site discharge, how does the water then get to the stream and what are the processes and timelines?
“Rainwater management has developed far beyond the simplistic assumptions that created the detention ponds of the 1980s. It is now time to take another leap forward, albeit by moving sideways, and recognize near surface lateral water flow, otherwise known as interflow,” states Alan Jonsson, Habitat Engineer with Fisheries and Oceans Canada. “Interflow is often the dominant drainage path in glaciated landscapes of British Columbia. Even undeveloped sites that are founded on till and bedrock rarely show overland flow because of interflow pathways. The challenge for engineers is to determine the influence of interflow on a site and then design and implement techniques that replace or restore it.”
TO LEARN MORE: To read the complete story posted on Water Bucket, click on "Understand How Water Reaches the Stream and Design for Interflow", urges Department of Fisheries and Oceans
"The stream health findings by Horner and May gave us a springboard to reinvent urban hydrology. Released by the Province in June 2002, Stormwater Planning: A Guidebook for British Columbia quickly became a catalyst to implement a ‘design with nature’ approach to rainwater management and green infrastructure," states Peter Law. Formerly with the BC Ministry of Environment, he chaired the Guidebook Steering Committee.
News Release #2011-38
September 14, 2011