ERDC assists USACE with turbidity assessment at Bayou Rigaud

Scientists from the U.S. Army Engineer Research and Development Center Environmental Laboratory (ERDC-EL) recently assisted USACE New Orleans District in measuring the turbidity near a dredging operation in the Bayou Rigaud Federal Navigation Channel.

Photo courtesy of USACE

The Bayou Rigaud Federal Navigation Channel passes within approximately 500 feet of the Louisiana Sea Grant’s Oyster Research and Demonstration Farm (LSG) and the Louisiana Department of Wildlife and Fisheries Michael C. Voisin Oyster Hatchery (MCV).

A cutterhead dredge is currently performing maintenance dredging of the channel. The dredged sediment is transported by pipeline and placed for beneficial use on Fifi Island adjacent to the channel.

“There is concern that dredge induced turbidity plumes — measure of water clarity reported as nephelometric turbidity units, or NTU — and associated total suspended sediments — TSS in milligrams per liter — could reach oyster operations and thus require additional filtering capabilities to protect oyster production” Justin Wilkens, ERDC-EL research biologist said.

As concerns over the potential hazard to oyster production increased, the USACE New Orleans District submitted a Dredging Operations Technical Support (DOTS) Program request to measure the turbidity in the channel through a technical demonstration. The DOTS Program provides environmental and engineering technical support to the USACE Operations and Maintenance navigation and dredging missions.

Wilkens and Shea Hammond, another ERDC-EL research biologist, needed to learn more about the dredge plume prior to it reaching the LSG or MCV facilities. To accomplish this, Wilkens and Hammond deployed the i3XO EcoMapper, an autonomous underwater vehicle (AUV).

Read the whole story at U.S. Army Corps of Engineers Engineer Research and Development Center website.