Small Community Infrastructure Sustainability - Drinking Water

Use of Water Balance Model encouraged for effective rainwater management

Three provincial Ministries and the federal Department of Fisheries and Oceans (DFO) have formed a Vancouver Island Coordinating Team to facilitate a consistent, science-based approach to rainwater management on Vancouver Island. Implementation is keyed to use of the Water Balance Model for British Columbia, a web-accessible decision support and scenario modeling tool that was developed in 2003 by an inter-governmental partnership. The mission of the partnership is to promote ‘sustainable drainage' practices province-wide.

WATER BALANCE MODEL TRAINING:

The Water Balance Model VI Coordinating Team - a regional sub-group of the inter-governmental partnership - recently met with the Cowichan Valley Regional District and its member municipalities (Duncan and North Cowichan) to initiate the pre-planning for a Water Balance Model Training Workshop that would be held in the Cowichan Valley in mid-2007.

The three Ministries on the Coordinating Team are Environment, Agriculture & Lands, and Community Services. "Our Ministries are aligning our efforts and collaborating with DFO because we believe this will enable us to be collectively more effective in achieving desirable rainwater management outcomes. We are providing local governments and the development community on Vancouver Island with the tools and experience that will help them design with nature", explains Jay Bradley (Ministry of Agricultural and Lands), team leader.

Developed as an extension of Stormwater Planning: A Guidebook for British Columbia, the Water Balance Model enables users to visualize how to implement rainwater runoff source control solutions. "Because people typically need numbers to understand what an infrastructure decision means on-the-ground, the tool helps users wrap their minds around the implications and achievability of performance targets for capturing rainwater where it falls", adds Peter Law (Ministry of Environment) who was Chair of the Guidebook Steering Committee.

Published in 2002, the Guidebook was the catalyst that has resulted in British Columbia being recognized internationally as a leader in implementing a natural systems approach to rainwater management. The Guidebook's premise that land development and watershed protection can be compatible represented a radical shift in thinking in 2002. The Guidebook recognized that water volume is something over which local government has control through its infrastructure policies, practices and standards.

BEYOND THE GUIDEBOOK:

At present, the main focus of the Water Balance Model is on the use of source controls for runoff volume reduction to protect property, habitat and water quality. "Less volume means less flooding of agricultural and/or suburban lowlands. This is one reason why the Water Balance Model has emerged as the rainwater management tool of choice in making sustainable land development decisions – it demonstrates how to achieve a light hydrologic footprint", observes Bradley.

"Provincial grant programs no longer support the traditional ‘pipes and pavement' approach to drainage planning. The Ministry of Community Services focus is on programs that reduce rainwater runoff volume at the site level, by capturing rain where it falls", reports Chris Jensen (Ministry of Community Services).

To advance the state-of-the-practice in rainwater management, the inter-governmental Water Balance Model Partnership has begun rolling out an initiative called "Beyond the Guidebook". According to Bradley: "This will take the Guidebook innovation to the next level of evolution. ‘Beyond the Guidebook' has two precedent-setting elements: correlating runoff volume and stream health; and quantifying the relationship between the urban forest canopy and the interception of rainfall volume. Stay tuned!"

To sustain the early success of the Water Balance Model, and in response to ‘needs and wants' identified through discussions with the Alberta Low Impact Development Partnership (ALIDP) and others, the British Columbia Inter-Governmental Partnership (IGP) is moving  along a pathway that will materially expand the capabilities of the web-accessible Water Balance Model: After evaluating  how to most effectively enhance the hydrology engine, the decision was made to merge the Water Balance Model with QUALHYMO. For more information, please click here.