Sediment as a pollutant is harmful by itself and is even more so when combined with pesticides, fertilizers or animal waste. Sediment pollution can cause serious ecological and physical damage to streams, rivers, ponds, lakes, and estuaries, as well as cost us all through taxes and lost revenue.

Farms that are managed with sound conservation plans and construction sites that use Best Management Practices (BMPs) for erosion control have a greatly reduced potential for being sources of polluted runoff. On the other hand, a summer rainstorm can remove many tons of soil from a one acre cornfield or construction site that has inadequate erosion controls. The sediment from such sites washes into nearby streams, resulting in muddy, sediment-ladened waters. Sedimentation occurs when the sediment settles to the bottom of a stream or other body of water.

Sediment pollution is harmful

• Sediment deposited on a stream beds smothers the aquatic habitat which, according to Pennsylvania Fish and Boat Commission biologists, degrades water and habitat quality negatively impacting the entire food chain.

• Sediment pollution in lakes, reservoirs and bays can introduce excess nutrients resulting in algal blooms; block the amount of available sunlight for aquatic plants; reduce water depth resulting in warmer water temperatures; and speed up the water bodies natural aging process (eutrophication).

• Sedimentation can cause radical changes in the course of a stream which, by redirecting the flow, may lead to greater accelerated erosion and destruction of aquatic and riparian habitat.

• Sediment entering small streams in upland areas can be carried downstream into larger, navigable rivers and reservoirs necessitating costly dredging. Pennsylvania DEP estimates that for every dollar spent keeping soil stabilized, taxpayers save $50 to $500 in dredging costs.

• Sediment pollution can increase the cost of water filtration for public drinking water. According to Philadelphia Water Department, muddy waters cost rate payers for sediment filtration and removal and dredging near the water intakes.

• Sediment pollution, according to PA Fish and Boat Commission and Trout Unlimited, costs Commonwealth residents tens of million dollars each year in lost revenue (e.g. hotel rooms, restaurants, etc.) associated with recreational fishing because of degraded water quality and reduced fish habitat. Other forms of tourism that may suffer include hiking, swimming and sightseeing.
  
• Sediment deposition can contribute to accelerated streambank erosion which translates into property losses for public and private property owners.

During the Spring of 1996, volunteer streamwatchers from the Delaware Riverkeeper Network and the Perkiomen Valley Watershed Association investigated nonpoint source pollution in two major tributaries of the Perkiomen Creek -- the Skippack Creek and East Branch Perkiomen Creek. Located in southeastern Pennsylvania, the Perkiomen Creek is the largest tributary to the Schuylkill River. Both the Perkiomen and the Schuylkill are suspected to be major contributors of nonpoint pollution to the Delaware River Estuary.

Volunteers learned to use topographic maps to delineate the Perkiomen sub-watersheds and, with the guidance of conservation officials and Riverkeeper staff, were trained to observe construction sites and farm conservation practices, and how to look at the entire riparian corridor (streams, natural drainage ways, wetlands, springs, etc.) as one inter-connected area. Armed with cameras and data sheets, the volunteers visited streams throughout the two watersheds to look for sources of sediment pollution, streambank erosion, sediment deposits, and riparian corridor conditions.

What they found was disturbing: Poorly maintained construction sites, sediment choked streams, severely eroded streambanks, sediment smothered stream bottoms, and a loss of property as a result of stormwater runoff and erosion. Using information gathered by the streamwatchers, Riverkeeper staff wrote Muddy Waters: A Citizens Guide To Investigation and Reducing Sediment Pollution. The volunteer observations were distilled into a slide presentation for municipal officials and interested watershed residents. A Summary of Findings and Recommendations was prepared which included a variety of suggestions for municipalities, community groups, and riparian property owners to reduce sediment pollution and restore riparian corridors.

Summary of Findings

• Stream bottoms smothered by sediment and numerous sediment and gravel bars.

• Severe streambank erosion throughout both watersheds.

• Many stream corridors are maintained as lawn and other urban land cover (e.g. pavement, rooftops, compacted soil). Erosion is usually more sever in these areas.

• Some construction sites and practices were found wanting with regard to erosion and sediment controls and there is evidence of sediment pollution from these sites observed in nearby creeks.

• The number of active farms in the watersheds has decreased. While most remaining farmers have implemented conservation plans, sedimentation from past farming practices is still evident in the creeks.

• Stormwater runoff appears to be increasing with urbanization.

• Better stormwater management and planning on a watershed basis must begin now to avoid increased future flooding and erosion.

• Municipalities need to protect riparian corridors from inappropriate development practices by adoption and enforcement of strong erosion control laws (ordinances) at the local level.

• Long-range restoration and protection plans are needed for each watershed to effectively improve water quality, create healthy riparian habitats, increase recreational opportunities, and reduce flooding and loss of property. Such plans must identify and address the causes of stormwater, sedimentation and erosion problems before embarking on major restoration efforts.

• Municipalities, counties and residents need to organize on a watershed basis (across municipal boundaries) to initiate stormwater studies and develop watershed protection and restoration.