Runoff

Proper drainage for properties

There are many benefits to managing water runoff on your property:

  • reduced risk of property damage from sewer backup or flooding;
  • healthier lawns requiring less maintenance;
  • less erosion on the property; and
  • attractive rain gardens or green driveways.

In addition, heavy rainfall can result in runoff that saturates the sewer system, leading to:

  • additional costs for the wastewater treatment plant;
  • runoff overloading the sewer system, resulting in untreated water being discharged into the waterways. That untreated water contains numerous pollutants, such as fertilizer, oil, grease and pesticides.

How to limit runoff

Modify eavestroughs

Eavestroughs that are directly connected to the foundation drain or that direct rainwater to an impermeable surface increase the amount of runoff going into the sewer system, which can overload the system.

Properly modifying eavestroughs can help divert, on average, 100,000 litres of rainwater annually from the sewer system per home.

Examples of improper eavestroughs

Connected to the foundation drain: the building's eavestroughs are connected to an underground pipe that takes the water to the foundation drain, which leads to the sewer system.

Directly to the street: the building's eavestroughs are connected to an underground pipe that takes the water to the street, which leads to the sewer system.

Drainage onto an impermeable surface less than 1.5 m from the foundation: the building's eavestroughs take the rainwater to a paved surface, which leads to the sewer system.

Disconnecting downspouts

The first step is to disconnect any downspouts from the foundation drain:

  1. use a saw or shears to cut the downspout;
  2. remove the section of downspout touching the ground;
  3. plug the pipe with a fitted stopper;
  4. make one of the modifications suggested below.

Important

  • Make sure that the water is directed to a permeable surface at least 1.5 m from the building foundation so that it does not seep into the foundation drain.
  • Water from eavestroughs must at all times remain on the property, and must never be diverted to a neighbouring property.

There are several options!

Four examples of proper eavestroughs

Rain barrel: A standard 200-liter rain barrel can save close to 6000 litres of tap water annually. The water collected can be used to water gardens and flower beds, and in other ways. If you cannot divert the water from your eavestroughs to a permeable surface, this is a good option. Just cut the downspout and attach it to the rain barrel.

Rainwater diverter: A rainwater diverter connected to a downspout redirects the rainwater to a grassy area located at least 1.5 m from the building foundation.

Modifying a connection to the street: To modify a connection to the street, find the pipe directing the rainwater from the downspout to the street, cut it more than 1.5 m from the lot line, street and foundation, and build a percolation pit.

Less wasted tap water

Less watering

Did you know that when you waste less tap water, you reduce the amount of runoff and other water discharged into the sewer system? A watering hose discharges 1000 litres of water per hour, which is the equivalent of what a person drinks in three years! Washing your car with a hose uses close to 400 litres of tap water. That water has been treated at significant cost in the water treatment plant.

A few tips for saving water

  • In July, lawns are dormant and require much less water. Your lawn only needs to be watered once a week. To avoid evaporation and waste, water early in the morning. Check the Info-arrosage tool to find out when watering is permitted.
  • Keeping your grass 7 to 10 cm long helps retain water and keeps the ground humid, particularly during dry spells.
  • Practice grasscycling, which involves leaving the grass clippings on the lawn. This helps the lawn resist dryness and at the same time helps fertilize the soil.
  • Reducing the amount of water you consume can also save money.

Water, think about it!

Tap water is a resource that we deplete faster than we realize! From May 1 to September 30, the by-law on the use of drinking water is in force in Gatineau. Check the Info-arrosage online tool to find out when you can water your lawn, fill your pool or wash your car.

Practice bioretention

There are a number of landscaping arrangements that maximize the absorption of stormwater into the ground and their percolation to water tables. Esthetic and effective, the solutions presented here help reduce the amount of water running into the sewer system.

Vegetated ditches

Water flowing off impermeable surfaces runs into ditches. Vegetation in and along ditches helps:

  • filter any sediments, fertilizer, pesticides and other pollutants carried by the runoff;
  • slow down and absorb part of the runoff without obstructing the flow; and
  • control erosion by stabilizing the walls of the ditch.

Rain gardens

Rain gardens are landscaping arrangements that are designed to collect stormwater. They are located in depressions in the ground that stormwater tends to flow into and then sit. You can direct water from eavestrough downspouts to them!

Did you know that trees, shrubs and plants intercept and retain surface water better than a lawn. A single tree can intercept 6,600 litres of water annually.

Ecological lawns

An ecological lawn refers to the use of indigenous plants that are naturally adapted to local conditions. Those species are more resistant to bad weather, and therefore require less maintenance than a traditional lawn and less artificial watering. Thus, they help reduce the use of tap water and, possibly, runoff.

Green driveways

Paved driveways are impermeable surfaces that prevent the absorption of stormwater, which increases runoff. There are a number of innovative and esthetic solutions. In addition to minimizing runoff, they reduce heat islands.

Grassy strips

Grassy strips help minimize paved surfaces by including green surfaces, which help refill the water table and reduce runoff. This solution percolates 17 times more water into the ground than a paved driveway, and lasts longer.

Permeable asphalt

With a proper initial design and winter maintenance, permeable asphalt can sustain freeze-thaw cycles and help absorb runoff. According to the Cement Association of Canada, every square metre of permeable asphalt allows 200 litres of water to percolate into the ground per minute.

Alveolated pavement

A rigid alveolated membrane is spread and seeded with resistant cover greenery such as clover to create an alveolated driveway that withstands winter conditions and can last up to 20 years. Alveolated pavements allow stormwater to drain naturally and percolate into the ground.

Permeable pavement

Permeable pavements use blocks spaced out on a layer of stone. Similar to traditional prefabricated pavements, permeable pavements allow stormwater to drain and percolate into the ground.

Contact Gatineau's Division de l'urbanisme at the service centre in your sector for more information and to review the by-law.

The measures proposed on this page are general and do not apply to all properties. In special cases such as high clay content or steep slopes, property owners should seek the opinion of a qualified contractor before starting a project.

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