Water Balance Model for Canada

An Integrated Outreach & Continuing Education Program  

The Water Sustainability Action Plan for British Columbia is the partnership umbrella for an Outreach and Continuing Education Program (OCEP) that promotes a 'water-centric' approach to community planning and development. 

OCEP comprises inter-connected elements that give local governments and practitioners the tools and experience to better manage land and water resources. Two tools in the toolbox are the Water Balance Model and the Water Bucket Website. They are the twin engines driving OCEP. Water Bucket is used to tell the story of the Water Balance Model. To learn more about that aspect, click on Rainwater Management Community-of-Interest.

The Water Balance Model is web-based and was launched in September 2003 as an extension of Stormwater Planning: A Guidebook for British Columbia, released in June 2002. The Guidebook advanced this provocative premise: land development and watershed protection can be compatible. This radical shift in practitioner thinking resulted from recognition of HOW a science-based understanding could bridge the gap between high-level policy objectives.

A Scenario Comparison Tool:

"The Guidebook developed the water balance methodology to establish performance targets for rainfall capture; and the Water Balance Model evaluates the effectiveness of site designs that incorporate rainfall capture features such as rain gardens and absorbent soil. It does a continuous simulation over the period of record to test facility performance under different combinations of land use, soil and rainfall,” states Ted van der Gulik, Chair of the Water Balance Model Partnership.

A key message is that it is a ‘scenario comparison tool’. Because the Water Balance Model demonstrates how to achieve a light ‘hydrologic footprint’, it helps planners and designers wrap their minds around how to implement ‘green solutions’ on-the-ground. From a watershed planning perspective, the Water Balance Model can create an understanding of the past and compare it to many possible futures. There is no restriction on the scenarios that a user may choose to compare."

“The power of the Water Balance Model process lies in the conversations that result from users generating a single number – the percentage of rainfall that becomes runoff. Comparison of scenarios creates understanding, especially when the focus is on the hydrologic implications of the assumptions that underpin those percentages," concludes Ted van der Gulik.