Stormwater (rain and snow) collected through stormwater sewers is directed back into natural watercourses. Management of stormwater is facilitated by the City’s Environmental Services team.

Catch Basins

The purpose of a catch basin (which is commonly located on the roadway), is to collect rainwater from properties and streets, and transport it to local waterways through stormwater sewers. Three lift stations help transport stormwater in the community.

Combined Sewers

In some older areas of the City both the stormwater sewer and sanitary sewer is combined into a single pipe, commonly called a combined sewer. This means that stormwater entering combined sewers must be treated. Additionally, it means that extreme rainfalls can overburden the sewage system. The City is currently in the process of separating combined sewers as part of annual budget allocations, limiting the risk of backups and releases into the environment.

Stormwater Management Ponds

Stormwater Management Ponds (SMPs) are engineered basins designed to collect and manage urban stormwater runoff. They temporarily store water during rainfall events and release it at a controlled rate, helping to prevent downstream flooding and erosion. Additionally, these ponds improve water quality by allowing sediments and contaminants to settle before the water is discharged into natural watercourses.

In Sarnia, notable SWMPs are located in the Heritage Park subdivision, Twin Lakes, Blackwell Glen, and near the Suncor Nature Trail. A total of eight such Stormwater Management Facilities are located in the community.

Stormwater Management Pond Safety

All recreational activities, including skating and swimming, are strictly prohibited on stormwater management ponds due to inherent dangers. Always practice caution around SMPs.

Certain characteristics of SMPs make them more dangerous than natural waterbodies:

  • Submerged inlet and outlet pipes maintain continuous water flow beneath the surface, regardless of ice formation
  • Water levels and ice thickness can change rapidly, making conditions unpredictable
  • Ice thickness varies, appearing stable in some areas while being thin or nonexistent in others
  • Pollutants like road salt can degrade ice quality, further increasing risk

Help protect the environment

You can help protect the environment by taking simple steps in and around catch basins and SMPs:

  • Don’t put anything down catch basins — stormwater collected in catch basins is not treated, it is directed back into local waterways. Anything you put in a catch basin such as oil, garbage, and hazardous materials ends up in the environment.
  • Preserve Natural Buffers — Allow native plants and grasses to grow around pond perimeters. These buffers should remain undisturbed; avoid mowing or altering them.
  • Limit Chemical Use — Reduce or eliminate pesticides and fertilizers on lawns near ponds. These substances can runoff into the water, causing algae blooms and harming downstream ecosystems.
  • Choose Native Plants — Planting native trees, shrubs, and flowers reduces the need for irrigation and chemical treatments. The St. Clair Conservation Authority can provide guidance on suitable species.
  • Manage Yard Waste Responsibly — Do not dump yard waste in or around ponds, as it can smother vegetation and introduce harmful chemicals. Compost organic materials on your property or utilize the City’s yard waste collection services.

Reports

The City is required to annually report on its stormwater management system: