High Occupancy Toll (HOT) Lanes
I-495 Capital Beltway Expansion Project
Upstream from Lake Accotink
Documentation of Sediment Control Failures
September 27, 2009, Report

September 27, 2009

And it goes on and on. Here are pictures from September 27, 2009, showing HOT Lanes construction sediment control failures along Accotink Creek and its Coons Branch tributary: 092709 Photos - Sediment contol failures continue

Pictures from Sept 27, 2009. There was a significant rain event on the 26th, but I have no information as to whether this was a 1, 2, or 5 year storm. It rained briefly during the site visit, but not enough to trigger the sediment contamination documented: 092709 Photos - Accotink-Issues. The pictures can be compared with those from a previous visit, 10 days previous - 091709 Photos - Accotink-Issues

The key issues here are:
1-Failures observed where the Washington & Old Dominion Trail crosses 495: 092709 Photos - W&OD Trail at 495

2-Silt fence failures at tributaries draining into Accotink Creek west of 495. These have been consistent problem sites, which have been significantly improved, but continue to fail: 092709 Photos - Accotink Creek west of 495

3-Sediment contamination of Coons Branch from a channel that parallels northbound 495, above 236: 092709 Photos - Coons Branch . This appears due to several contributing factors:
->channel always has water in it, even during dry periods, suggesting that it is an active tributary, but is not being maintained as such.
->channel is made of dirt, with occasional small riprap barriers.
->monitoring from the highway side fails to detect erosion gullies in the banks of the channel
->Upstream slopes (adjacent to 495) were inadequately seeded/stabilised, and have formed erosion gullies 092709 Photos - Erosion gullies

4-Ongoing construction work in Coons Branch (immediately adjacent to northbound 495, in the 236 interchange) has exposed dirt slopes that are directly in contact with Coons Branch. A minimal riprap barrier is not adequate, and sediment-contaminated water is flowing directly into Accotink Creek: 092709 Photos - Contaminated water

Contact the investigator, Kris Unger E-mail.

Contact Friends of Accotink Creek, E-mail.

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