In a paper titled “Streambank and floodplain geomorphic change and contribution to watershed material budgets,” published by the US Geological Survey in May 2022, Accotink Creek was one of sixty-eight stream systems studied across the Chesapeake and Delaware Bay drainage areas.The US Geological Survey confirmed this floodplain trapping efficiency as part of the Difficult Run study conducted in Fairfax County.The Chesapeake Bay Expert Panel states that about 82% of all sediment generated in Piedmont streams is captured by the floodplains in the stream system before it gets to the tidal river system and the Chesapeake Bay.The Chesapeake Bay Expert Panel, US Geological Survey and George Mason University have provided a tremendous amount of data that reveals what is likely to happen to the sediment before it gets to the Potomac River, and what is actually happening when Accotink Creek reaches tidewater: Restoration project above Lake Accotink will reduce the sediment load above the lake as required by the County’s Municipal Separate Storm Sewer System (MS4) Permit, address impacts related to excessive stormwater flows and improve habitat for stream organisms.No amount of dredging in Lake Accotink can reduce the load above the lake. Fairfax County must reduce sediment load and restore stream channels above Lake Accotink to meet our Accotink Creek TMDL requirements.
The sediment load reduction required above Lake Accotink has nothing to do with the lake, but is based on reducing sediment load to the streams and restoring conditions to support benthic macroinvertebrates.Degraded benthic macroinvertebrate (insects, worms, clams, crayfish, etc.) populations in the stream.The Accotink Creek Total Maximum Daily Load (TMDL) was assigned to Fairfax County based on: That sediment is harming water quality, but the primary impact is to the stream channels themselves and the aquatic animals that live in them and terrestrial animals that depend on them. Educational Resources for Teachers and StudentsĪccotink Creek does discharge a lot of sediment due to the excessive storm flows from its highly developed drainage area eroding stream banks.
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