Impacts of Polluted Stormwater Runoff Polluted stormwater runoff is a leading cause of impairment of the nearly 40% of surveyed U.S. water bodies. Stormwater pollution causes flooding and the degradation of habitat for aquatic life. In the Chesapeake Bay watershed, storm water runoff is responsible for impairments in over 1,570 river miles and 44 square miles of estuarine waters. Over 10,000 stream miles have been degraded by past development, with major impacts to aquatic life in watersheds with as little as 10% land development. X Drinking Water X Recreation X Wildlife Habitat X Fishing
Construction Sites Produce A High Volume of Sediment Rate of erosion is greater per acre on urban construction projects
Inadequate Staffing Maryland regulations require that each active site be inspected for compliance “on the average of once every two weeks.” MDE is only able to visit 18% of the construction sites in areas under their jurisdiction due to inadequate staffing. (MDE 2007 Annual Inspection Compliance Report)
Sedimentation – the process by which the eroded particles are transported and deposited Erosion - the process by which land surface is worn away as sediment is detached by the action of wind, water, ice, or gravity
Types of Erosion on Construction Sites (1) Raindrop Erosion Breaks down soil structure Breaks down soil structure Sheet Erosion Shallow flow of water as it runs over the land Shallow flow of water as it runs over the land Rill Erosion Velocity and turbidity increase Velocity and turbidity increase Gully Erosion Rills come together in larger channels Rills come together in larger channels
Types of Erosion on Construction Sites - Illustrated
Splash Erosion The Process by which sediment particles are detached from the surface by the impact of individual raindrops.
Sheet Erosion The removal of surface sediments by water moving across as sheet flow.
Rill Erosion A concentration of sheet flow which cuts out small rill channels
Gully Erosion An extension of rill erosion into larger and more established gully channels
Monitor Construction Activities In Your Watershed What to watch for: Zoning notices and hearings Site clearing activities Other activities suggesting large development Muddy water flowing down streets
Maryland Law Environment Article Title 4, Water Management, §4-413 It is unlawful to add, introduce, leak, spill, or otherwise emit soil or sediment into waters of the State or to place soil or sediment in a position or location likely to be washed into waters of the State
Making It Happen IDENTIFY REPORT EVALUATE FOLLOW UP PICTURES