Local government stormwater infrastructure
Stormwater consists of rainwater and water from other sources that runs off impervious surfaces such as pavement and rooftops. Stormwater has implications for urban and rural planning, as it cannot infiltrate the ground and is typically channeled into storm sewers and watercourses.
As stormwater runs off in developed areas, it can gather pollutants such as oil, pesticides and other contaminants that can have an adverse effect downstream. This "non-point source" pollution in stormwater is the most common cause of poor water quality in lakes and streams in developed areas.
Urbanization has changed the natural hydrology of watersheds and caused excessive erosion and habitat degradation in receiving streams. The science of stormwater management has evolved and broadened to address these environmental and hydrological concerns.
Integrated stormwater management
Integrated stormwater management planning is a comprehensive approach to rainwater management that plans for a range of rainfall events, not just large storm events. Some of the guiding principles of an integrated stormwater management strategy include:
- Rain from frequent small events should be allowed to infiltrate the ground
- Runoff from heavy events should be retained and slowly released
- Runoff from extreme storms should be managed to prevent flooding
Local governments can integrate stormwater management objectives into their land use planning and decision-making by incorporating these objectives into their official community plan. Integrated stormwater management plans can be used to meet the stormwater component of a liquid waste management plan.
Implementation of integrated stormwater management can be accelerated by applying the following practices, designs and strategies:
- Beyond the Guidebook: Context for Rainwater Management and Green Infrastructure in British Columbia
- Stormwater Planning: A Guidebook for British Columbia (PDF, 9.7MB)
- Tackling Non-Point Source Water Pollution in British Columbia: An Action Plan (PDF,128KB)
- Capital Regional District: Managing Stormwater
- Stormwater Best Management Practices Guide Vol. 1a (PDF 1.4MB)
- Stormwater Best Management Practices Guide Vol. 1b (PDF 2.7MB)
- U.S. Environmental Protection Agency: Reducing Stormwater Costs through Low Impact Development
Stormwater management facilities and infrastructure
A comprehensive watershed management plan should incorporate design-with-nature features and other elements that mimic or support natural processes and ecological assets. For example, instead of conveying flows directly to waterways, constructed wetlands and other beneficial features can be incorporated into developments so that more stormwater runoff can infiltrate soil and recharge groundwater aquifers.
Local governments can use design techniques that take advantage of ecological and hydrological processes that allow communities to meet flood prevention objectives and preserve or enhance the health of aquatic and riparian ecosystems. Some innovative design elements that can be incorporated into new or existing developments include:
- Absorbent landscapes
- Extensive green roofs
- Infiltration swales and trenches
- Pervious paving
- Rain gardens
Local governments have the authority to implement stormwater solutions such as:
- Bylaws that limit impervious surfaces and encourage infiltration
- Alternative low impact subdivision bylaw standards
- Bylaws that prevent the release of contaminants into storm drains
- Watercourse setback zoning bylaws
- Development permit areas that protect watercourses and floodplains
The Metro Vancouver Regional District has extensive documentation on their design approach to stormwater management and facilities:
Stormwater infrastructure grants
Infrastructure planning grants
Local governments undertaking integrated stormwater management plans or related feasibility studies are eligible to receive infrastructure planning grant funding:
Projects funded by infrastructure planning grants include:
- Water Balance: Partnership for Water Sustainability in British Columbia
- The Partnership for Water Sustainability in B.C.
- Millstream Watershed Management Plan (PDF 3.6MB)
Capital grants can assist communities in developing low-impact infrastructure: