Notice to Navigators: Lower Mississippi River
Lower Mississippi River (LMR) Dredging Update 41521
The U.S. Army Corps of Engineers (USACE) continues working on the historic project to deepen the Mississippi River Ship Channel (MRSC) to 50 feet. The USACE has now completed approximately eighty percent (80 %) of Phase 1 of the deepening project. The Phase 1 section of the Ship Channel extends from Venice at Mile 13 Above Head of Passes (AHP) to Mile 22 Below Head of Passes (BHP). The completion of Phase 1 of the Ship Channel Deepening is expected to open up the first 150-175 miles of the Ship Channel to vessels with deeper drafts. The last status update including tables and a diagram of the Deepening Project issued by the USACE on March 19, 2021 is attached.
MISSISSIPPI RIVER SHIP CHANNEL DEEPENING PHASE 1:
The Phase 1 areas of the Ship Channel that could be deepened to 50 feet through the use of cutterhead dredges were completed. The remaining Phase 1 areas will all be deepened by the hopper dredge GLENN EDWARDS (Manson Construction). The USACE will deepen the Ship Channel from Venice to the Gulf of Mexico (Phase 1) with the three dredge contracts detailed below, specifically the two cutterhead dredge contracts and the one for the hopper dredge GLENN EDWARDS. The USACE expects to complete the deepening project in four progressive upriver phases to the upper end of the MRSC at Mile 233.8 AHP (Baton Rouge).
The details on the cutterhead dredge contracts worked under Phase 1 of the historic river deepening project are detailed below:
Southwest Pass Cutterhead Dredge Rental Contract #1-2020: was awarded to Weeks Marine on
August 20, 2020. The cutterhead dredge CAPTAIN FRANK dredged under this contract from
September 11, 2020 to March 3, 2021 and the E.W. ELLEFSEN dredged on this deepening contract from November 18, 2020 and completed the last assignment on March 19, 2021.
Southwest Pass Cutterhead Dredge Rental Contract #2-2020: was awarded to Manson Construction on August 27, 2020. The cutterhead dredge ROBERT M. WHITE worked on this contract from
October 23, 2020 until completion on March 18, 2021.
INDUSTRY HOPPER DREDGES WORKING ON DEEPENING IN SOUTHWEST PASS (SWP):
GLENN EDWARDS: The GLENN EDWARDS (Manson Construction) continues working on the Ship Channel deepening on assignment at the jetty end of SWP from Mile 18.0 BHP to Mile 20.0 BHP. The cutterhead dredge is working under Southwest Pass Hopper Dredge Rental Contract #9-2020 and will complete the final portions of the Ship Channel deepening project. The hopper dredge is also under contract for Fiscal Year 2021 channel maintenance and will be moved between the two contracts by the MVN dependent upon channel conditions. The GLENN EDWARDS has worked on the deepening project since January 14, 2021.
INDUSTRY HOPPER DREDGES WORKING IN THE AREA OF SOUTHWEST PASS (SWP):
STUYVEASNT: The industry hopper dredge STUYVESANT (Dutra Group) is working on assignment in SWP from Mile 10.5 BHP to Mile 11.8 BHP. The STUYVEASNT is working under Southwest Pass Hopper Dredge Rental Contract #6-2020 that was awarded to the Dutra Group in Fiscal Year 2020 to perform channel maintenance in Fiscal Year 2021. The STUYVESANT began work under this contract on March 24, 2021.
NEWPORT: The industry hopper dredge NEWPORT (Manson Construction) is now dredging on assignment near the Venice Jump from Mile 13 AHP to Mile 12 AHP. The NEWPORT is working under Southwest Pass Hopper Dredge Rental Contract #7-2020 that was awarded to the Manson Construction in Fiscal Year 2020 to perform channel maintenance in Fiscal Year 2021. The NEWPORT began work under this contract on April 3, 2021.
GOVERNMENT HOPPER DREDGES WORKING IN SOUTHWEST PASS (SWP):
WHEELER: The USACE’s hopper dredge WHEELER remains delayed working to secure a dry dock contract to repair a damaged propeller. The WHEELER will perform Readiness Exercise #1-2021 in SWP after these repairs have been completed.
CUTTERHEAD DREDGE(S) IN THE HOPPER DREDGE DISPOSAL AREA (HDDA):
ILLINOIS: The cutterhead dredge ILLINOIS (Great Lakes Dredge and Dock) has removed and beneficially used approximately 3.6 million cubic yards (mcy) of material from the HDDA under Hopper Dredge Disposal Area Cutterhead Rental Contract #1-2019. The contract includes the removal of 10 mcy in the base with options to add an additional 4 mcy. The project is expected to be completed by early 2022. The material is beneficially being used in the West Bay Receiving Area through a submerged dredge pipeline that will have to be removed up completion of the project. The pipeline retrieval will require at least one complete closure on the Ship Channel in the immediate vicinity of the submerged pipeline (Mile 2.0 AHP to Mile 0 – the Head of Passes).
The Carrollton Gauge (New Orleans) reading at 1000 hours today was 15.00 feet with a 24-hour change of - 0.07 feet, the most recent crest of 15.14 feet was recorded at 0800 hours yesterday (April 14, 2021) . The National Oceanic and Atmospheric Administration’s (NOAA) National Weather Service Extended Streamflow Prediction (28-Day) for the Carrollton Gauge issued today indicate cresting stage levels near 15.0 feet over the next few days before beginning a slow fall to 7.6 feet on May 13 (2021).
The Baton Rouge Gauge reading at 1100 hours today was 38.83 feet with a 24-hour change of + 0.19 feet. The National Oceanic and Atmospheric Administration’s (NOAA) National Weather Service Extended Streamflow Prediction (28-Day) for the Baton Rouge Gauge issued today indicate stage levels over 38.0 feet over the next few days before beginning a slow fall to 17.1 feet on May 13 (2021).
The graph below is reproduced from NOAA’s National Weather Service website and represents an experimental product to account for the complexity of accurately predicting long-range precipitation. This forecast projects stage levels based on expected precipitation for 2 days (top) and 16 days (bottom) and was developed within the North American Ensemble Forecast System (NAEFS) computer model and highlights Quantitative Precipitation Forecasts (QPF). Along with the forecasts, a shaded area is also provided to indicate uncertainty for the forecast each day in the future. These plots are experimental and not an official forecast product.
The following explanation was recently offered by a member of the Lower Mississippi River Forecast Center to further explain the diagram above. The accuracy of the forecasts are built into the shaded areas in the graphic, the shading represents historical data and errors determined by previous stage forecasts. Two-thirds of the time the future stage will be within the shading area and one-third of the time it will be outside of the shaded area. (Similar to tracking hurricane landfall forecasts).
A good reminder is that the forecast for New Orleans (Carrollton Gauge) is more accurate than areas further upriver especially as far upriver as Cairo (Illinois).
“The accuracy of the forecast can also be seen in the upper/lower bounds of the shaded area. The difference in the upper/lower bound of the shading at Cairo is roughly 10 to 15 ft by day 28. For New Orleans, it is roughly 3 to 4 feet.
Bottom-line, the New Orleans forecast is pretty good 2 to 3 weeks out since rainfall doesn't influence the forecast for a couple of weeks but as you go further upstream, the rainfall will cause stages to react quicker so forecasts are generally good 1 to 2 weeks out by the time you get to Cairo. The 16 day forecast typically performs better than the 2 day forecast.
If the rain is already on the ground and no more rain is forecast for the next couple of weeks, you can add an additional 1 to 2 weeks on the statement above.”
Please utilize the attached reports for complete details on the Ship Channel Deepening and the attached plot of the Carrollton Gauge levels for 2021 to date.
Best Regards,
Sean M. Duffy, Sr.
Executive Director
Big River Coalition
http://bigrivercoalition.org
Phone (504) 833-4190 x 805
Cell (504) 338-3165
