stormwater

storm +‎ water

stormwater (countable and uncountable, plural stormwaters)

1. Water that is not absorbed into soil and rapidly flows downstream, increasing the level of waterways.
   • 2007 October 2, Anthony Depalma, “City Agrees to Help Regulate Delaware River by Releasing Water From Reservoirs”, in New York Times‎:

     Community groups have collected 12,000 signatures demanding that New York City permanently lower the levels of the Cannonsville, Pepacton and Neversink Reservoirs to 80 percent of capacity so that stormwater runoff can have a place to go rather than charging down the river in flash floods.

• masterwort