Editor's note: The first pulse, scheduled for June 25, has been canceled.
COVINGTON, Va. – The Norfolk District, U.S. Army Corps of Engineers will deviate from Gathright Dam’s existing water control plan in order to conduct six pulse releases from June through October 2013.
The pulses, conducted by the Norfolk District in cooperation with the Virginia Department of Environmental Quality and the Virginia Department of Game and Inland Fisheries, will begin at approximately 6 a.m. and end at 2 p.m. and will increase levels 3 to 4.5 feet in the Jackson River.
The agencies advise people who use the river to be aware of the river fluctuations caused by the pulses.
“The pulses will allow for a full season of monitoring data to be collected,” said Owen Reece, Norfolk District hydraulic engineer. “The data will help to document the water quality and environmental benefits of an alternative water control plan.”
The 2013 pulse dates are scheduled for the following Tuesdays:
The deviation from the water control plan will also slightly reduce river flow by 11 percent from the dam, resulting in a 1-inch drop in the Jackson River.
The releases will not have negative effects on the water levels at Lake Moomaw; levels are expected to remain slightly above where they would have been under the existing water control plan. The water reserved in the lake from the reduced flow will be used for the pulse releases.
The pulse releases will be similar to test pulse releases previously conducted in August 2010, September 2011 and October 2012. Those controlled releases, which were single events, tested whether the pulses effectively removed algae and improved water quality.
The 3,000 cubic-feet-per-second test pulse in August 2010 showed the pulse raised dissolved oxygen levels in the river, scoured excess oxygen-consuming algae and “slightly improved” aquatic habitat of the Jackson River downstream of Covington.
"We expect the proposed changes in flow, coupled with major pollutant reductions in the basin, to significantly improve water quality in the Jackson River," DEQ Director David K. Paylor said.
The temporary deviation is based on the preferred alternative in the Environmental Assessment and Finding of No Significant Impact documents, which were prepared to assess the potential impacts of the Gathright Dam Low Flow Augmentation Project on the Jackson River. The project and development of the preferred alternative were a cooperative effort between the Norfolk District and the Commonwealth of Virginia.
The EA and FONSI are available at http://www.nao.usace.army.mil/About/Projects/GathrightMoomaw.aspx.
Virginia Department of Environmental Quality
Norfolk District Public Affairs