The Chesapeake Bay: Problems

---

Sediment???

• Sediment: Sediment is the floating particles of clay, sand, and dirt in a body of water that settle to the bottom. Although plants and animals require sediment to survive, too much can be deadly. After a rain storm all of the dirt on the ground is picked up and washed into the water stream. Soil erosion also contributes to sediment in the Bay along with wind, ice-floes and water currents. Sediment can smother bottom dwelling plants and animals, such as oysters and clams. When sediment is floating in water it can cloud the water, not allowing sunlight to reach leaves of SAV (Submerged Underwater Vegetation).

• The Downsides Of Sediment
  • Sediment carries excess nutrients, particularly phosphorus, into Bay waters, compromising water quality.
  • Accumulations of sediment can clog waterways and ports, making traffic difficult or hazardous, and requiring dredging.

• Our Plan To Reduce Sediment*: In the Chesapeake 2000 agreement, the Chesapeake Bay Program partners have committed to correcting sediment-related problems in the Bay and its tributaries, as part of the effort to remove the Bay from the list of impaired waters. Federal, state and local partners are developing management strategies to reduce sediment. The Bay Program is working to prevent the loss of the sediment ‘trapping’ capabilities of the lower Susquehanna River dams. Currently, these dams trap about 50 percent to 70 percent of the sediment that flows downriver and prevents it from entering the Bay. As early as 1991, the U.S. Geological Survey (USGS) estimated that the dams will reach their storage capacity by 2021, if new new management plans are not put in place.

• Reducing Sediment Levels**: Best management practices (BMPs) help reduce soil erosion and thus reduce sediment flowing into waterways. Farmers can help reduce sediment loads by using BMPs such as:
  • Implementing soil conservation plans for their farms, such as planting cover crops after harvesting and no-till farming;
  • Constructing stream bank fencing;
  • Planting vegetated buffers at the edge of crop fields; and
  • Strip cropping, which alternates different crops in rows throughout the same field.

  In urban areas, stormwater runoff adds to the sediment problem in waterways. Urban communities can control the amount of runoff they yield during storms, by:

  • Reducing impervious surfaces, such as roads and parking areas (impervious surfaces prevent rainfall from being absorbed into the soil and send it instead into waterways);
  • Creating rain gardens, which are designed to capture and filter runoff from impervious sites;
  • Planting streamside buffers, which allow plants to filter water and trap sediments;
  • Creating and implementing storm water management plans, which both protect natural areas that control runoff and identify areas that can be restored to further reduce runoff.