Stormwater FAQ

Q: What is stormwater?

Stormwater runoff is the water generated when rain, snow melt, and surface drainage flows over land or impervious surfaces and does not absorb into the ground. Impervious surfaces are defined as hard surfaces where water is unable to soak or infiltrate into the ground, such as streets, parking lots, sidewalks, and roof tops.

Q: Where does stormwater go?

As stormwater runoff flows over land and impervious surfaces, it picks up sediment, contaminants, litter, nutrients, and other pollutants which then discharge into the waterways, untreated. Unmanaged stormwater could adversely affect Merriam waterways by causing water pollution, stream bank erosion, and even flooding.

Q: What can I do to help reduce stormwater runoff?

By capturing rain water where it lands, and infiltrating or slowing down the stormwater through stormwater treatment facilities (STFs), the pollutants and sediment have a chance to settle out rather than create adverse effects in Merriam waterways. These facilities can help improve the quality of water that flows to creeks, streams, and ultimately into our rivers.