FLASHBACK: City of Surrey Innovation Resulted in Evolution of Performance Target Approach to Rainfall Capture
Note to Reader:
In October 2010, the Okanagan Basin Water Board hosted the From Rain to Resource Workshop in Kelowna. A presentation on the East Clayton ‘green’ development in the City of Surrey provided the opportunity to showcase how a series of demonstration applications commissioned by the City enabled Jim Dumont to evolve science-based understanding and develop the “Stream Health Methodology”. This methodology is the foundation for a performance target approach to capturing rain where it falls and mimicking the natural Water Balance.
Genesis for Stream Health Methodology in Water Balance Model
Looking back, application of the water balance methodology to the East Clayton ‘green’ development can now be seen as the genesis for the Stream Health Methodology that is embedded in the Water Balance Model powered by QUALHYMO.
Application of Performance Targets
“With hindsight, the significance of East Clayton is two-fold. It was an early application of performance targets at a neighbourhood scale. Also, and most importantly the analysis combinedmass balance and flow duration 
totest the achievability of performance targets,” states Jim Dumont, Engineering Applications Authority for the Water Balance Model Partnership.
“But it was the South Newton case study where the methodology really came together in terms of how to integrate the mass balance and stream erosion analyses. Until then, they were separate analyses.”
“In South Newton, we were able to demonstrate that distributed rainwater infiltration systems could result in a multi-million dollar net reduction in the City’s 10-Year Capital Plan, while enabling development to proceed. The saving results from elimination of a number of detention ponds.”
“The experience gained in East Clayton and South Newton was then applied in Fergus Creek. The Beyond the Guidebook methodology was formalized as the Stream Health Methodology, and subsequently incorporated in the Water Balance Model when it was integrated with the QUALHYMO engine. The Stream Health Methodology is a function of flow duration, and hence stream erosion,” concludes Jim Dumont.
To Learn More:
To read the complete story posted elsewhere on the Rainwater Management community-of-interest, click on East Clayton ‘Green’ Development in Surrey established BC precedent for implementing performance target approach to rainfall capture.
