Peeling back the Pavement - POLIS Water Sustainability Project

water supplies, and flooding all result in negative impacts on fish populations and
habitat. In this way, a distant land-use decision triggers a range of impacts on local
water resources and ecosystems.
Many studies and experts point to the need to plan human activities across entire
watersheds to fully assess land-use decisions for ecosystem impacts. 43 This rationale
is based on recognition of the water cycle as the pathway that integrates the
physical, chemical, and biological processes of the entire regional ecosystem. For
example, when an upstream city has a significant amount of impermeable surfaces,
a large quantity of polluted runoff is generated which directly affects downstream
communities and ecosystems. The Rainwater City recognizes the importance of
scale when considering the relationship between land use and ecosystem impacts.
As a result, a watershed governance approach is adopted to address the complex
and interdependent dynamics of water, land, and human and wildlife needs and
activities across a landscape.
An appropriate vehicle for integrating ecosystem-based land management into the
Rainwater City is an integrated water management plan that recognizes all water—
including rainwater—is connected. Such a plan uses the watershed as the primary
boundary for all land-use planning. It enables a bird’s-eye-view understanding of
ecosystem function and status within an entire drainage area and accounts for
ecological considerations that need to be integrated into land-use planning and
decision making. With an integrated water management plan, local governments
in a Rainwater City are enabled to develop and implement a rainwater plan for the
entire urban watershed or basin through changes to provincial or territorial legislation
via Local Government Acts and Municipal Acts. 44
Plans that focus on rainwater management across a region are rare in Canada.
However, there are exceptions. The City of Toronto’s Wet Weather Flow Management
Master Plan (approved in 2003) is a watershed-based stormwater plan that
treats the area’s natural landscape as a whole functioning system. The Toronto and
Region Conservation Authority (TRCA) is an important example of a watershed
governance body that is actively ensuring a “think like a watershed” approach in
the city. Working with the City, TRCA liaises with neighbouring municipalities to develop
consistent stormwater criteria for new development and protective measures
where development already exists. Metro Vancouver’s Integrated Liquid Waste
and Resource Management Plan is a leading document that uses an ecosystembased
approach to managing stormwater on a regional scale. Although its focus is
replacing the 50-year-old Lions Gate and Iona Island primary sewage plants with
advanced treatment facilities, the plan is also built around the goal of improving
the natural environment in the region. The plan ultimately integrates liquid and
solid waste recovery, rainwater management, and land-use planning for the entire
Greater Vancouver area.
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