Stormwater Management Program (SWMP)
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.
What is Stormwater?
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.
How We Keep Our Stormwater Clean
The City will implement an inclusive education and outreach program to reach a diverse population about how community members can take action to keep our water resources clean.
The City will ensure that the public participation program focuses on all community members. All stormwater meetings/events will be publicized and open to the public.
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.
The City will limit the number of pollutants in post-construction runoff through a stormwater control inventory, enforcement, site plan reviews, and maintenance of stormwater BMPs.
The focus of the IDDE program is to detect and eliminate illicit discharges into the MS4 through education and training, dry and wet weather monitoring and identifying unpermitted discharges.
The City will ensure that pollution from municipal sources is minimized and that City staff is properly trained in operating and maintaining the stormwater system.