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“A basic tenet of hydrology is that rainfall and runoff have different return periods. Yet drainage practitioners persist in applying a rainfall-based approach that assumes rainfall will always result in the same magnitude of runoff,” stated Jim Dumont. “We are at a crossroad in the path defining the methodologies and applications used in rainwater management. In a nutshell, Beyond the Guidebook enables us to make a clear distinction between a rainfall-based approach and a runoff-based approach. The runoff-based approach is best suited to the analysis needed to assess effectiveness of mitigation techniques.”

The first published article about the “Beyond the Guidebook Initiative” appeared in the Journal of the Association of Professional Engineers and Geoscientists of British Columbia (APEGBC). “The Stormwater Guidebook for British Columbia, published in 2002, offers direction and guidance on how to do stormwater management planning, design principles, and objectives,” wrote Jim Dumont. “We must be driven to investigate the problems and issues that stimulated preparation of the Guidebook. In doing so, we will be able to advance the science and engineering practice in a manner intended by the Guidebook.”

Rainwater management is a key component of protecting quality of life, property and ecosystems. In the Greater Vancouver Region, a series of building block initiatives have resulted in a change in thinking among drainage practitioners. This change has seen the single function view of 'stormwater management' give way to the integrated and comprehensive perspective that is captured by the term 'rainwater management'.

“There is a need for a new approach to hydrologic design. A key message is that a rainfall-based approach does not work effectively. This is why I advocate a runoff-based approach. Duration of discharge is important because it links directly to stream health”, stated Jim Dumont.

Organized by Cate Soroczan, the event was an information exchange amongst agencies from across the country. It was also precedent-setting in terms of laying the groundwork for future inter-provincial collaboration. Twenty-plus representatives from seven provinces participated, namely: British Columbia, Alberta, Saskatchewan, Manitoba, Ontario, Quebec and Nova Scotia.

“Founded on British Columbia case study experience, the Guidebook formalized a science-based understanding to set performance targets for reducing rainwater runoff volumes and rates,” reports Kim Stephens.

The “Celebrating Green Infrastructure Program” is an outcome of a Consultation Workshop that was organized by the Green Infrastructure Partnership in May 2005. The goal of the program is to build regional capacity through sharing of green infrastructure approaches, experiences and lessons learned as an outcome of ‘designing with nature'. The program was launched in May 2006 when the first event in the 'Showcasing Innovation Series'was hosted by the District of North Vancouver. The Greater Vancouver program is a provincial pilot. The intention is that local governments on Vancouver Island and in the Interior will undertake similar initiatives.

COI Table of Contents – updated December 2009
This Community-of-Interest is the web-delivery vehicle for informing practitioners about the latest advancements in the state-of-the-practice for rainwater management.

From a drainage planning perspective, “Sustainability” means Design with Nature to improve the Built Environment while at the same time protecting the Natural Environment. The desired outcome is to sustain community livability.

The Stormwater Interagency Liaison Group (SILG), a technical committee of the Greater Vancouver Regional District, has provided funding so the Water Sustainability Committee (WSC) of the British Columbia Water & Waste Association can implement the Rainwater Management Community-of-Interest (COI).