Rainwater Management

“Our Governors have supported development of the Water Balance Model because this on-the-ground tool fits with the Foundation’s mission to support sustainable real estate and land use practices for the benefit of British Columbians,” stated Tim Pringle. it was a grant from the Foundation in 2003 that made it possible to immediately make the Water Balance Model an Internet-accessible tool. This research will directly inform urban planning and will be used to populate the model with performance data for rainfall interception by the tree canopy in an urban forest..

Bert van Duin reported that a pre-conference workshop on the Water Balance Model attracted an audience of over 90 in Cochrane, Alberta. Municipal representatives from communities throughout Alberta attended. The workshop was held in conjunction with Innovations in Urban Development, a conference on Low Impact Development hosted by the Town of Cochrane.

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'.

A consortium of agencies in the Greater Vancouver Region have collaborated to adapt design standards from areas of Europe and North America with similar climatic and soil conditions. The project has reduced information barriers that stand in the way of effective implementation of rainwater source controls in the Georgia Basin region of British Columbia.Key features of the research information have been displayed in a set of poster presentations that can be downloaded.

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) has taken the first steps along a pathway that will materially expand the capabilities of the web-accessible Water Balance Model: This has involved an evaluation of how to most effectively enhance the hydrology engine; and has led to the decision to merge the Water Balance Model with QUALHYMO.

Integated rainwater management planning is an approach that recognizes the complex relationship between the built and natural environment. This new planning approach integrates rainwater management with engineering, planning and the environment to reflect the values of each watershed and community.

“There is a greater heterogeneity of tree species and spatial dimensions (height and structure) and trees are generally more isolated, with large distances between them. Hence, we can expect different interception processes, whereby evaporation changes, microclimate gradients change due to variations in leaf surfaces and stem surface areas, and wind associated rainfall can change the throughfall distribution and ratio between stemflow and interception,” stated Dr. Hans Schreier.

The Alberta Low Impact Development Partnership (ALIDP) continues to make progress in defining how the Province's Water for Life vision will be translated into actions on the ground. At its April 2006 stakeholder meeting, ALIDP continued its discussions with British Columbia regarding the elements of an inter-provincial partnership.

When the International Water Association held its 10th International Specialist Conference on Watershed and River Basin Management in Calgary, this created an opportunity for a public unveiling of an inter-provincial partnership between British Columbia and Alberta that is founded on the Water Balance Model.

“Use of the tool will help design professionals understand what ‘thinking outside the pipe’ and ‘designing with nature’ actually mean in the context of ‘green’ subdivisions that have been built in recent years in British Columbia,” stated Richard Boase. “The tool enables assessment of the effectiveness of site designs that incorporate rainwater source controls such as absorbent landscaping, rain gardens, infiltration facilities and green roofs. The Water Balance Model can be applied at three scales: site, subdivision and watershed.”