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Water Balance Model powered by QUALHYMO: A Team Effort

Note to Reader:

Developed by an Inter-Governmental Partnership as an extension of Stormwater Planning: A Guidebook for British Columbia, the “Water Balance Model powered by QUALHYMO” is the shared legacy of a team of senior practitioners. The tool is the outcome of a building block process that has depended on the commitment of a number of organizations, and especially the efforts of the champions within those organizations, to produce a series of deliverables that successively advanced the practice of rainwater management within British Columbia.

The Team

Kim Stephens, Executive Director with the over-arching Partnership for Water Sustainability in British Columbia, developed the Water Balance Methodology in 2000 for establishing performance targets for rainwater runoff volume reduction, and created the vision for the Water Balance Model (WBM) as a scenario modelling tool to make better land use decisions. He was Project Manager and principal author of Stormwater Planning: A Guidebook for British Columbia, released by the Province in 2002.

Jim Dumont, Engineering Applications Authority, created the vision for adapting QUALHYMO and incorporating the Stream Health Methodology (which is a function of flow duration, and hence stream erosion) for integration of good land use planning with innovative engineering design. Jim Dumont contributed to the early phases of QUALHYMO development when Dr. Charles Rowney developed this continuous hydrologic simulation model for the Ontario Ministry of Environment in the early 1980s.

Charles Rowney, Scientific Authority and developer of the QUALHYMO hydrologic simulation tool, embraced the BC team”s vision for merging it with the WBM to create a pan-Canadian model. As the Scientific Authority, Charles Rowney has been vested with the authority to define, oversee and manage the technical competencies of the “WBM powered by QUALHYMO”. Technical competencies are defined as the computational and scientific/engineering functions that are made use of, or embodied by, the integrated tool – whether they be promulgated by website/s through direct download or by other means.

Ted van der Gulik (Province of British Columbia), Chair, and Laura MacLean (Environment Canada), Co-Chair, championed the WBM within government and provided the necessary leadership to take both the original model and the replacement Water Balance Model powered by QUALHYMO from vision to reality. In March 2009, Richard Boase (District of North Vancouver) succceeded Laura MacLean as Co-Chair.

A Building Block Process

The WBM is the outcome of a building block process that has depended on the commitment of a number of organizations, and especially the efforts of the champions within those organizations, to produce a series of deliverables that successively advanced the practice of rainwater management within British Columbia. The deliverables comprised:

  • Province of British Columbia: Stormwater Planning: A Guidebook for British Columbia, published in 2002 (Champion: Peter Law)
  • Metro Vancouver (formerly known as the Greater Vancouver Regional District:) Report on Stormwater Source Control Evaluation, completed in 2002, (Champion: Robert Hicks)
  • City of Chilliwack: Policy & Design Manual for Surface Water Management, adopted by Council in 2002, (Champion: Dipak Basu)
  • Simon Fraser University: UniverCity – The Sustainable Community atop Burnaby Mountain, commenced in 2000, (Champion: Eric Emery)

The City of Surrey”s Fergus Creek Watershed Plan was the pilot for development of the Stream Health Methodology that is at the heart of the Water Balance Model powered by QUALHYMO.

Evolution of the Water Balance Model

The genesis of the WBM”s development was UniverCity, the sustainable community being built adjacent to Simon Fraser University atop Burnaby Mountain. Translating high expectations for this “green” development into practical design guidelines meant revisiting accepted drainage engineering practice; this need for innovation eventually led to the WBM”s development.

In 2001 the Stormwater Interagency Liaison Group (SILG), a technical committee of the Greater Vancouver Regional District, recognized the value of the water balance approach and funded the development of a working model to assess the affordability and feasibility of site design solutions for achieving performance targets.

The results of this applied research were incorporated in Stormwater Planning: A Guidebook for British Columbia, funded in large part by Environment Canada and released by the Province of British Columbia in June 2002. This guidance document, founded on BC case study experience, formalized a science-based understanding to set performance targets for reducing rainwater runoff volumes.

The Chilliwack Manual was the feedback loop for vetting the Guidebook content and the water balance methodology; in turn, the feedback loop for the Chilliwack Manual was a set of guidelines that were tested through pilot applications on development projects. The approaches pioneered in Chilliwack were also incorporated in the Guidebook, as were Chilliwack”s Design Guidelines for Developers.

In July 2002 the Inter-Governmental Partnership was formed to develop the WBM as an extension of the Guidebook. It began as a subgroup of SILG and quickly expanded to become a provincial group with municipal representation from four regions: Greater Vancouver, the Fraser Valley, Vancouver Island and the Okanagan Valley.

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