By Amy Wold, LWF Policy Director
A new proposal to control flow through Neptune Pass, an active crevasse on the Mississippi River east bank, would continue to allow land building while addressing navigation concerns along this vital transportation route.
Louisiana Wildlife Federation submitted comments to the U.S. Army Corps of Engineers (Corps) this week on Environmental Assessment (EA) #589 Finding of No Significant Impact that praised the Corps for their innovative solution that benefits multiple stakeholders.
The plan, as outlined in EA #589 Finding of No Significant Impact, includes the construction of a control structure that would allow 80,000 cfs through the structure during a Mississippi River flow of 1 million cfs. In addition, the plan places Sediment Retention Enhancement Devices (SREDs) at the outfall of the pass in Quarantine Bay to not only provide stability for the river-side structure, but also provide for more efficient capture of sediment.
SREDs are essentially speed bumps of various shapes made of dirt, rock, or other materials designed to slow down water flow, and as the name suggests, enhance the ability of an area to retain sediment. The idea here is that as the sediment builds up on the eastern side of the river, this new land will naturally slow down the crevasse flow over time for a more sustainable project long term.
This is a drastic improvement from the 2022 proposal which presented a full closure of the crevasse which later Corps modeling showed would fail as the river simply went around it during high water events. Reconnecting the Mississippi River with surrounding marsh is how south Louisiana was built and it has been a recommended part of coastal restoration and protection plans for decades.
This new proposal from the Corps incorporates constructed elements – the sill and SREDs – as well as incorporating nature-based solutions that rely on the river’s ability to deliver sediment and land building to Louisiana’s marshes.
Read LWF’s full comments HERE.
Read the USACE Press Release HERE.
