Louisiana Coastal Area 6 Project Profile: Medium Diversion at White Ditch
By Angelina Freeman, Environmental Defense Fund
The Coalition to Restore Coastal Louisiana, Lake Pontchartrain Basin Foundation, Environmental Defense Fund and National Audubon Society reviewed and provided comments on the six near-term Louisiana Coastal Area (LCA 6) project reports and final environmental impact statements.
Among the LCA 6, perhaps the most ground-breaking is the tentatively selected plan that incorporates pulsing for the Medium Diversion at White Ditch. White Ditch would provide freshwater, nutrients and sediments to restore degraded habitat and sustain a larger coastal ecosystem east of the Mississippi to support and protect the environment, economy and culture of southern Louisiana.
“We support and commend the recommended plan incorporating pulsing at 35,000 cfs (cubic feet per second) at high river flows to maximize sediment capture in the planning and operation of the diversion,” stated the groups in their letter to the Corps. “We agree that the recommended plan meets the LCA program and project objectives and is within the scope of the WRDA [Water Resources Development Act] authorization, and therefore agree that Congress raise the total project cost for the Medium Diversion at White Ditch Project.”
The recommended plan requires congressional action. The groups pledge to work with the newly-elected Congress to secure legislation required to change the authorization and funding required to begin project construction.
The White Ditch project is entering the Planning, Engineering, and Design (PED) phase. Sediment concentrations in the Mississippi River can vary significantly according to location, and the groups recommend a thorough analysis of site specific data and modeling in PED to improve prediction of the sediment efficiency of the diversion relative to location. The groups also recommended reevaluating the conveyance channel and whether natural channel formation can be effectively utilized allowing the engineering to be scaled back (thereby reducing cost) to be investigated in PED.