The U.S. Army Corps of Engineers (USACE) is working to maintain or restore at least half of the authorized channel width or the central 250 feet of the channel on the Crossings. The dustpan dredges are currently working to restore or maintain federally authorized channel dimensions on the Crossings, which remain 45 feet deep by 500 feet wide, for now.
All dredges working on the MRSC sought safe harbor prior to the arrival of Hurricane Ida and several are reported back on assignment while others are preparing to return to work and offering help with coordinated hydrographic survey assets and on scene conditions reporting.
DUSTPAN DREDGES WORKING ON THE CROSSINGS ABOVE NEW ORLEANS:
WALLACE McGEORGE: The industry dustpan dredge WALLACE McGEORGE resumed dredging full channel dimensions (500) feet at Red Eye Crossing (Mile 224 AHP) at 1200 hours yesterday (September 2, 2021). The dustpan began dredging on the Crossings on May 20, 2021 and ceased dredging operations in response to Hurricane Ida on August 28 before returning to work at Red Eye Crossing (yesterday).
JADWIN: The government dustpan dredge JADWIN is expected to commence dredging full channel dimensions (500 feet) at Medora Crossing (Mile 212 AHP) by tomorrow morning. The JADWIN began dredging on the Crossings on June 24 and ceased operations prior to Hurricane Ida on August 28, 2021.
CUTTERHEAD DREDGE(S) IN THE HOPPER DREDGE DISPOSAL AREA (HDDA):
ILLINOIS: The cutterhead dredge ILLINOIS (Great Lakes Dredge and Dock) sought safe harbor from the approach of Hurricane Ida and operations are underway to resume dredging in the HDDA over the next few days. The cutterhead had about four days of work left in the HDDA, unless additional material is added to their present contract. The ILLINOIS removed and beneficially utilized approximately 11.0 million cubic yards (mcy) of material from the HDDA under Hopper Dredge Disposal Area Cutterhead Rental Contract #1-2019 before the shutdown. The cutterhead dredge, equipment and survey crews are moving back into the area, it is too early to tell when the previously advertised full channel closures will be conducted at this point. Two full channel closures should be expected in the next week or so barring change.
The submerged dredge pipeline removal will require two 12-hours full channel closures from Mile 2 Above Head of Passes to Mile 0 (Head of Passes) no tentative dates have been proposed.
The HDDA contract detailed the removal of 10 mcy in the base and the USACE recently awarded an option to add an additional 2 mcy to this assignment. The material is beneficially being used in the West Bay Receiving Area through the submerged dredge pipeline that will be removed upon completion of the project as detailed above.
MISSISSIPPI RIVER SHIP CHANNEL CONDIITONS:
The Safety Zone around the downed powerlines crossing the MRSC at approximately Mile 107 AHP remains in effect as river operations, vessel transits and survey assets continue to move without entering this Temporary Safety Zone. The Ship Channel has been reopened with daylight only restrictions for ship traffic and vessels unable to transit through the area above the Huey P. Long Bridge – see following details.
The downed powerlines at Mile 107 Above Head of Passes, that cross the Ship Channel have effectively split the Ship Channel into two halves. Vessels cannot transit through the area until the powerlines are removed. A Marine Information Safety Bulletin (MSIB) issued by the U.S. Coast Guard (USCG) that established a Temporary Safety Zone through this reach of the Ship Channel is attached. The efforts to recover navigation are focused upon the removal of the powerlines, surveys of the channel and obstructions, and to restore shore or operational power to facilities and offices.
The USCG’s Marine Information Safety Bulletin (MSIB) providing details on this temporary Safety Zone is attached, efforts continue to clear this obstruction and resume maritime commerce. The following quote is reproduced is reproduced from the MSIB:
“This safety zone will be implemented on the Lower Mississippi River between Mile Marker (MM 105) and MM 108 AHP and is needed to protect persons and vessels from the safety hazards associated with the electrical transmission lines posing a threat of electrical transmission lines posing a threat of electrical shock present in the waterway.”
MISSISSIPPI RIVER STAGES DRIVEN BY HURRICANE IDA:
Saturday August 28, 2021 at 1400 hours the Carrollton Gauge (New Orleans) reading was 4.72 feet (pre-Hurricane Ida storm surge).
Sunday August 29, 2021 at 1400 hours the Carrollton Gauge crested at 11.36 feet, driven by precipitation and storm surge from Hurricane Ida.
Monday, August 30, 2021 at 1400 hours the Carrollton Gauge reading was 6.23 feet as the storm surge began to recede.
Tuesday, August 31, 2021 at 1400 hours the Carrollton Gauge reading was 4.93 feet as the storm surge and related precipitation receded and stages returned to pre-Ida levels.
MISSISSIPPI RIVER STAGE UPDATES:
The Carrollton Gauge (New Orleans) reading at 1200 hours today was 4.61 feet with a 24-hour change of – 0.06 feet. The National Oceanic and Atmospheric Administration’s (NOAA) National Weather Service Extended Streamflow Prediction (28-Day) for the Carrollton Gauge issued today forecasts stages will fluctuate between 3.3 feet and 4.5 feet over the next few weeks and then begin a slow fall to 2.5 feet on October 1 (2021). The highest crest recorded on the Carrollton Gauge in 2021 to date is 15.44 feet at 1700 hours on April 16, 2021.
The Carrollton Gauge crest attributed to the precipitation and storm surge from Hurricane Ida was recorded with a reading of 11.36 feet at 1400 hours on Sunday, August 29, 2021.
The Baton Rouge Gauge reading was offline but the crest recorded at Baton Rouge driven by Hurricane Ida was 17.35 feet at 0200 hours on August 30, 2021. The National Oceanic and Atmospheric Administration’s (NOAA) National Weather Service Extended Streamflow Prediction (28-Day) for the Baton Rouge Gauge issued today forecasts stages will fluctuate between 10.0 feet and 14.8 feet over the next few weeks and then begin a slow fall to 8.6 feet on October 1 (2021).