Stormwater Management Program

Stormwater is rain or snow melt that runs over impervious surfaces such as streets, parking lots, driveways, and roof tops. All properties with impervious surfaces generate stormwater runoff. In general, greater amounts of impervious surfaces result in greater volumes of stormwater and more potential pollutants.

In developed areas, stormwater must be managed because it picks up pollutants as it flows into local surface waters via storm drains or road-side ditches. These pollutants can include sediment, nutrients, toxics, bacteria and trash. Consequently, local surface waters in more developed areas often fail to meet state and federal water quality standards.

The Clean Water Act requires municipalities like South Portland, which are referred to as “municipal separate storm sewer systems” (or MS4s), to comply with permit regulations that were established to minimize the harmful effects of polluted stormwater runoff and improve local water quality. To help accomplish these overall goals, the City’s Stormwater Management Program Plan identifies specific minimum control measures that must implemented over ongoing 5 year permit periods. See this fact sheet for more information.

Parking lots don't allow stormwater to soak into the ground...
...and instead put it into pipes that discharge into local waters.  

Storm drain and outfall