The USACE also offered an update on emergency operations to control the loss of flow at Neptune Pass located at approximately Mile 24 Above Head of Passes on the left descending bank (eastern side). The attached notice details the USACE efforts to control the flow at Neptune Pass, ultimately the goal is to limit the flow to the conditions in 2019 prior to the rapid growth of Neptune Pass – approximately 6% of the total flow estimated to be in the 30,000 cubic feet per second range. The emergency rock work detailed in the attachment anticipates the rock barges will begin work on this second effort to place rocks along the bank line.
The USACE plans to construct a control structure (sill type structure) inside of the crevasse in an effort to further prevent the crevasse from capturing more of the flow from the main channel (thalweg). Last year for the first time ever the USACE had to respond to shoaling at Neptune Pass as pilots reported the flow was impacting or pulling vessels toward the eastern side. Neptune Pass is one of several crevasses of concern on the eastern side of the Mississippi River Ship Channel between Belle Chasse and the Head of Passes.
Please review the attachments for complete details.