Stormwater Frequently Asked Questions:
Catch basins are the main access point for storm water to get into the underground pipe system. The metal grates that are visible at the edge of the road are only a part of the catch basin structure. Under the sidewalk there is a barrel that collects water as well. The barrel is attached to a pipe that water flows away in.
The Storm Drainage Bylaw C-1241 (9) requires downspouts to end at least two metres away from any city sidewalk, reserve, road, park, alley, lane or surface drainage facility. The two metre buffer zone permits some of the run-off to absorb into the ground rather than enter the storm system. This also helps avert icing on sidewalks and lanes in winter.
Downspouts should never be connected to the weeping tile of your house or building. This increases the risk of basement flooding.
Grande Prairie's underground storm-drainage pipes are designed to deal with low-intensity rainfalls, which are the majority of what we receive. The underground pipes meet the North American Standard of draining one-in-five-year storms. The Grande Prairie area gets about 20 millimetres of rainfall in one hour in a one-in-five year storm event.
For detailed information on Alberta's legislation and guidelines visit https://www.alberta.ca/environment-and-parks.aspx
Prohibited materials are any substance that may, directly or indirectly, obstruct the flow of water within the storm drainage system or that may have a negative impact on the receiving waters.
Prohibited materials include, but are not limited to:
- soil, sediment, waste or other solid material;
- fecal matter, animal waste, dead animals or animal parts;
- cooking oils and greases, soaps or detergents;
- gasoline, motor oil, transmission fluid, and antifreeze;
- solvents, paint;
- cement or concrete wastes;
- water from hot tubs;
- sawdust, wood, fibreboard or construction material;
- yard waste;
- pesticides, herbicides or fertilizers;
- hazardous, industrial, or biomedical waste
Components of the surface drainage system include paved walkways and grassed or concrete drainage courses (swales). Bylaw C-1241 (13) requires that the surface drainage be kept clear of debris and obstructions at all times. Retaining walls, terraces, gardens, or sheds cannot be constructed or placed in these areas. These systems are designed to carry rainwater and any obstructions could contribute to flooding during a heavy rainstorm. Concrete swales commonly run along the back or side of residential properties. If a fence is built over a concrete swale, there must be at least 0.15 meters (6 inches) of clearance between the bottom of the fence and the top of the swale.
Usually the water contains toxic disinfectants and chemicals that control algae. Even if water tests show that these chemicals are depleted, they remain in the water as a variety of toxic compounds. The City recommends that water from hot tubs and larger pools be drained or pumped to a household sink, toilet or floor drain connected to the sewer system.
The City recommends using a commercial car wash to clean your vehicle. Water from commercial car washes is discharged to the city's wastewater treatment facility where the wastewater is cleaned and treated before being returned to the river. If you choose to wash your vehicle in the driveway or street, do not use soap. Even biodegradable soaps will cause harm to living things in the river. Use only water and ensure that dirt or oil from your vehicle does not get washed down the storm drain.
Prior to an area being developed, rainwater easily soaks into soils, is absorbed by vegetation, and is evaporated into the air or travels over land to receiving wetlands, creeks and rivers. When an area is developed with buildings, driveways, roads and sidewalks, the rain cannot readily soak into the soil and journeys over and around these solid surfaces as runoff, reaching a waterway much faster. With no stormwater ponds, a large volume of water would enter a stream all at once, causing flooding and bank erosion. Runoff also collects assorted pollutants and debris as it flows over these surfaces, resulting in polluted water. Stormwater ponds are built to temporary hold this water then slowly release it back to the waterway, imitating the natural runoff rate and quality before development occurs. Wet ponds are critical in reducing the sediment that enters the river system, which can become a major threat to aquatic life.
The storm sewer system is a network of sewers, ponds, ditches and wetlands that transport storm water to the Bear Creek and eventually to the Wapiti River. Stormwater does not undergo the same treatment process as wastewater so it is important to prevent pollutants from entering the system and damaging the water ecosystem. The main purpose of the storm drainage system is to prevent flooding.
It is important that you report any/all spills or discharge of prohibited materials whether accidental or intentional.
If the release creates an immediate danger to public health and safety, call 9-1-1 for the fire department's Hazardous Materials Team to respond.
You should also report it to Alberta Environment's response line at 1-800-222-6514.
For other violations and incidents, please report them to the City of Grande Prairie's transportation maintenance department at 780-538-0354.
Prior to disposing of water in storm drains, residents are encouraged to stop and think about what chemicals and other materials are in the water that could harm the river environment.
Only clean water should be put into storm drains. If the disposal water contains other substances it should be put into the sewer system through household drains or allowed to run-off on the ground to prevent the water from entering a storm drain directly.
The storm-drainage system is supported by the mill rate (property taxes). Major improvement projects to the storm sewer systems are currently financed through the Alberta Municipal Infrastructure Grant. Funding in future budgets for major storm drainage projects have been assigned to the Municipal Sustainability Initiative Grant.