Due to the size of our population, the City of Casa Grande is required to conform to permit requirements for small municipal separate storm sewer systems (MS4 permit.)
In accordance with the MS4 permit, we recently created and implemented an SWMP intended to eliminate discharges of pollutants which may be transported by stormwater runoff. This program will maintain and enforce Minimum Control Measures to ensure compliance with the permit. The City’s plan is available to download.
Our Stormwater Management Program (SWMP) is designed to prevent or reduce the pollutants in our stormwater runoff in order to protect the washes, streams, and retention basins.
Stormwater is considered any precipitation that falls from the sky – primarily in the form of rainfall in our desert climate.
When enough precipitation occurs, stormwater runoff can flow over the land, lawn, and impervious surfaces like roads and parking lots that do not allow the liquid to soak into the ground. As this runoff water travels, it picks up pollutants such as chemicals, oils, debris, as well as soil and sediment.
The contaminated stormwater then enters washes, streams, and retention basins, posing a threat to wildlife and ultimately penetrating into our groundwater supplies. Controlling contamination to runoff is essential to maintaining our vital resources.
The City will follow a procedure for new construction projects that limits the silt and sediment in the runoff from construction sites through contractor education, an active project inventory, and site inspection.