When it rains, or snow melts or water flows into Portsmouth's stormwater system, it will ultimately make its way [or flow] and discharge into one of the following watersheds (arrows indicate direction of flow).
As storm water flows (or snow melts, etc.), it picks up debris, chemicals - such as fertilizers and pesticides - dirt, cigarette butts and other pollutants. Many times, rainfall events result in the closure of clam beds for 48 hours or more.
- Portsmouth Harbor Watershed
- Berry's Brook-Rye Harbor Watershed
- Winnicut River Watershed
- Great Bay Watershed