A New Direction to Manage Stormwater
The idea of RainScaping is to reduce the amount of rainwater entering our storm sewers by increasing the amount that infiltrates into the ground.
RainScaping is changing the way water is managed in urban areas for a greater environmental benefit. The program has two distinct focuses that take a similar path to seek a common objective – to better manage urban stormwater using sustainable Low Impact Development (LID) practices. RainScaping can be applied to new undeveloped lands as part of the plan of subdivision process and to existing developed lands through retrofitting.
RainScaping offers numerous benefits:
- Improved water quality by reducing the amount of runoff entering our waterways
- Improved water quantity control, reducing flood risks
- Decreased costs compared to traditional stormwater management
- Increased resilience to climate change by improving groundwater recharge conditions
- Improved water-use conservation measures; and
- Reduced impact to drinking water.
Common Low Impact Development Practices
The strength of Low Impact Development is that it mimics the natural hydrologic cycle, moving water into the ground much in the same way it did before houses or parking lots were built there. The key function that development interferes with is the ability of stormwater to soak into the ground. "Greener" construction practices involve techniques and specifications that differ from those of traditional stormwater management. Low Impact Development is rapidly becoming the new norm in Ontario.
Many of the benefits of green roofs are achieved by the natural capacity of vegetated systems to regulate climate and promote efficient cycling of water and chemicals. Replacing vegetation and trees with dark, heat absorbing building and construction materials in urban areas results in more hot smoggy days and greater energy demand. By putting the vegetation back into the urban environment, green roofs help the natural regulatory functions of the environment to start working again.
Building parking lots, driveways and roads using permeable pavement helps to restore natural infiltration functions to the landscape and reduce impacts to watercourses by allowing rainwater to slowly infiltrate into the ground. Some contaminants are removed from the stormwater as it infiltrates slowly through the gravel sub-base and into the native soil.
Perforated pipe systems
Perforated pipe systems are usually combined with other pre-treatment best management practices such as vegetated swales or sediment traps to avoid clogging with sediment or hydrocarbons. Pollutants are filtered out of the stormwater as it infiltrates into the surrounding soils and the infiltrated runoff helps to sustain groundwater recharge and maintain baseflows in nearby streams.
Bioretention and Rain Gardens
Bioretention is a stormwater infiltration practice that treats runoff from paved areas by using the natural properties of soil and vegetation to remove contaminants. Other names commonly used for these types of practices includes rain gardens, bioswales, dry swales, stormwater planters and biofilters. The practice has the potential to provide a significant improvement in contaminant removal over other stormwater infiltration practices due to the added treatment benefits of microbial activity and plant uptake. By increasing infiltration and evapotranspiration, bioretention systems also help to reduce pollutant loads to watercourses and recharge groundwater.
Green landscaping within impervious surfaces, such as parking lots, can help reduce runoff.
For more information contact:
Lake Simcoe Region Conservation Authority