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Bradford West Gwillimbury

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What is stormwater?

Stormwater consists of rainwater, melting snow or ice and other natural precipitation. Stormwater runoff is a major contributor to erosion, flooding and pollution in urban areas, watercourses and lakes.

What is stormwater management?

The Town of BWG has stormwater management facilities (SWMF) in place to help protect human health, property and the environment.

​​SWMF are very important in order to decrease the phosphorus load in Lake Simcoe. Properly working SWMF filter stormwater, decreasing the environmental impacts of everyday activities such as:&​
  • lawn watering
  • car washing
  • water runoff
  • precipitation
  • improper disposal of household hazardous wastes
  • road salt application​

There are many types of SWMFs within the Town. Below is a short description of each of the SWMF common in the Town of BWG:

​​What is phosphorous and
why is too much a problem?
Phosphorous is a nutrient found in things like manure and fertilizer.
Too much phosphorous can lead to nuisance algae growth, which in turn leads t​​​o low levels of oxygen in the water, and that can be harmful to fish, their food supply and their habitats. It can also be harmful to drinking water sources.

​Wet pond/retention pond

Wet ponds can be classified as quality and/or quantity ponds.

Quantity wet ponds are used to hold stormwater to ensure the downstream receiving waters and neighbouring areas are not flooded or washed out by a rapid increase of water. The pond slowly releases water into the downstream receiving waterway ensuring the natural environment is not impacted by flow rates.

Quality wet ponds allow the stormwater to settle out suspended solids, inorganics and organic matter before entering the downstream waterway and natural environment. The treatment of the stormwater is very important to mitigating environmental impacts to natural habitats.

Dry pond/detention pond

A dry pond stays dry except during precipitation events, so most of the time it is a large, low, grassy area. This type of pond allows the water to be maintained within the araa, and slowly releases stormwater into the downstream waterway. The slow release of water ensures sediments and contaminates have settled out, releasing a higher quality of stormwater into the environment. This type of pond is beneficial in situations of high peak flows to reduce the risk of impacts to human health and the environment.


Wetlands are shallow and generally have a larger land surface than a dry or wet pond. This type of SWMF is best suited for pollution removal due to the enhanced biological uptake and filtration through the different vegetation. Although a wetland does not have the same storage capacity of a dry pond or wet pond, and does not protect the environment from flooding after large precipitation events, a wetland can be used as a supplement to quantity ponds, providing additional quality treatment.

How does stormwater travel to a SWMF?

Stormwater enters a SWMF by flowing through a stormwater sewer, catchbasin or directly into the SWMF. It is important that only stormwater enters any part of a SMWF. Click for a graphic representation of the stormwater system.

Yellow Fish Road

BWG has partnered with the Lake Simcoe Region Conservation Authority (LSRCA) to bring the Yellow Fish Road program to the Town. This program is conducted by LSRCA and provides information to the public regarding stormwater, mainly focused around school aged children. This program helps children identify what a stormwater catchbasin and manhole are and where stormwater travels from in their neighbourhood. The children paint yellow fish next to storm sewers in their neighbourhood to help raise awareness that stormwater flows directly into the environment, and that keeping other materials out of catchbasins helps protect the environment. 

How can you help protect the environment?

You can help prevent the amount of chemicals and debris that get into SWMF and stormwater catchbasins after rain or ice/snowmelt. Here are some things you can do:​

Careful use of chemicals​

Avoid the use of herbicides and pesticides near storm sewers and catchbasins, especially if precipitation is in the forecast.

Rain garden/stone garden

​​A rain or stone garden allows precipitation and runoff to soak into the ground. This reduces total runoff and decreases the potential for flooding and erosion. The LSRCA offers helpful in​formation on building a rain garden.​​​

Rain barrel

A rain barrel can be placed under the eavestrough or somewhere where precipitation will be caught in the barrel. The contents of rain barrels can then be used to water the lawn, gardens and cleaning. This decreases the amount spent on water and decreases the amount of treated drinking water used for outdoor activities.

Permeable driveway

A permeable driveway can be constructed of permeable pavement, stone or other materials which allow precipitation to infiltrate into the ground. The use of a permeable driveway reduces runoff to the natural environment and allows precipitation to slowly percolate into the ground.

Trash removal

To ensure SWMF are able to properly operate they must be free of trash. Garbage can harm the facility and impact the overall quality of the stormwater entering the environment. Remove trash, leaves and other material that may be blocking a catchbasin or storm sewers to allow stormwater to properly flow and decrease the chance of flooding.

Always pick up animal waste, as it is high in organic compounds that increase the amount of phosphorus within the SWMF.

Site alteration

To ensure proper flow of stormwater to avoid property, human health and environmental impacts, all swales and stormwater features built into a property design should remain untouched and free of obstacles. Consult The Town of BWG Development Division for site alterations before completing work to ensure stormwater management will not be affected.

To help keep pollution levels down in water ways it is important to decrease the amount of impervious areas, this will decrease runoff and allow stormwater to absorb into the ground easily.