Lake Accotink Dam Repair
October - December 2012

The repair this time was to the shaft of the control gate, which was bent. It was bent because the crank which turns it from the top generates so much torque that if the gate encounters an obstruction and cannot turn, the crank will twist the shaft. The operator cannot see what is happening below.

The draining of the lake was only necessary because the “stop log” devices used to exclude water from the gate area for maintenance are inoperable. The contractor was unable to repair them.

The repairs this time were on a smaller scale than in 2009 - 2010, so the period the lake was dry was a matter of weeks, rather than a full year. The sediment released was presumably less this time, although we have no way of measuring other than judging by sight the downstream deposits in the creek. Unlike last time, no fish kills were evident. Draining in fall, however, did expose to view the lake's annual colonies of weird but fascinating bryozoans, Pectinatella magnifica.

Still more sediment-caused and sediment-causing issues are in Lake Accotink's near future. When the last dredging of the lake was completed in 2008, only the upstream side of the lake was fully dredged. Sediment accumulation is such that it may be expected to reach the level of the gate intake in another year or two, requiring another dredging project, again at a cost of many millions to taxpayers, and again causing sediment to be released downstream.

More Photos

Contact Friends of Accotink Creek.