Drainage and your property

Proper drainage around your home will help reduce risk of basement flooding, reduce problems with your basement foundation (cracking, shifting), extend the life of your sump pump and reduce the volume of water that flows into the sewer system. The Canada Mortgage and Housing Corporation (CMHC) recommends 3 principles to improve water management on your property.


 1. Drain water away from your house and avoid causing drainage problems on neighbouring properties. 

• Build up the ground around your house so that water flows away from your basement walls. CMHC recommends at least a 5% slope away from your foundation walls and a 2% slope for impermeable surfaces next to your house (driveway/patio).

• Disconnect your downspouts if they are directly connected to your home's sewer system. Place an extension on your downspouts to direct roof runoff at least 4 m away from your house so that water doesn't pool next to your basement. The extension can direct water toward a rain garden or backyard where it can soak into the ground without causing problems. Use a splash pad, pebbles or crushed rock to absorb the impact of water and prevent soil erosion. 

• A French drain or bioswale can also be used to convey water away from your home. If you have a waterfront property and your runoff is being conveyed directly into a water body, try to add some curves or pooling areas to your conveyance system to slow down the water and allow sediment and other pollutants to settle out. 

Remember to disconnect your downspouts!

Extend your downspout so water drains away from  your house

Use a splash pad to prevent erosion

     2. Let runoff soak into the ground on your property
       

•      Limit the amount of paved or other hard surfaces. Use permeable pavers, paved driveway strips or gravel for increased driveway permeability.
•      Direct water toward a rain garden, which should be at least 4 m from your house. Rain gardens work great for everyday rain events, however it is important to consider designing an overflow system (swale or perforated pipe) to help convey excess water toward the street during a heavy rainfall event. 
•      Soil aeration can reduce compaction and allow better infiltration. Water pooling on your property for an extended period is a good indication that your soil may need aeration.

 

If possible, reduce large paved areas

Modular paving stones, or permeable pavers, allow water to infiltrate into the ground

    3. Capture and reuse water

•      Place a rain barrel under your disconnected downspouts to capture rooftop runoff. Elevate the barrel above ground level so that a tap or hose can be installed for easy water collection.

Raised rainbarrel system. Photo: The Transplanted Gardener

      Visit  the Canada Mortgage and Housing Corporation website for more practical information on how to improve drainage on your property to avoid basement flooding.

12,000 rain gardens

The Puget Sound region of Washington State is tackling water quality issues with a new campaign to install 12,000 rain gardens by 2016. Once completed, these rain gardens will soak up 160 million gallons of polluted stormwater runoff each year. This innovative campaign offers financial incentives and comprehensive educational materials to neighbourhoods as a way to encourage individuals to do their own part to reduce the amount of pollutants entering the environment while solving drainage problems around their own homes. By encouraging individuals to become neighbourhood champions and recruit others, entire neighbourhoods are coming together to learn about and install rain gardens.The campaign currently has 706 raingardens installed.

Check out the website to find some great resource materials and learn more about the program.

http://www.12000raingardens.org/index.phtml

Constructed wetlands

"S" shaped constructed wetland

At the headwaters of Frenchman's Creek in Dartmouth, a wetland was constructed to treat stormwater runoff from the adjacent sports fields and parking lot. The wetland has a serpentine shape and varying depths in order to maximize residence time of the runoff in the wetland. This allows for increased removal of nutrients and metals through plant uptake and adsorption. This stormwater treatment feature essentially acts as a kidney purifying the water. The runoff leaving this site now enters the natural environment at a much higher quality than it would if directly released without treatment. 

This wetland would require occasional maintenance to maximize function. Construction was done by Jeff Pinhey and Rob Leblanc in 2007. 

The marsh is predominantly vegetated with cattails