The construction of the saltwater sill to the first targeted elevation of -55 feet was completed on September 26, 2024, at approximately Mile 63.7 Above Head of Passes (AHP). Weeks Marine relocated the buoys (locations noted below) marking the one-way channel for Contact Pilot coordinated transits. The cutterhead dredge J.S. CHATRY had been released to work in the New Orleans Harbor, the dredge has completed all assignments in the Harbor and is back on standby near the sill location.
The Marine Safety Information Bulletin (MSIB) from the U.S. Coast Guard (USCG) is attached, the USCG will use the daily U.S. Coast Guard, Captain of the Port New Orleans Navigation Outlook to update transit conditions.
The latest river stages are forecast to continue a slow fall back to extremely low river stages, with minimal precipitation forecast over the next week (or longer). The J.S. CHATRY will remain on standby as the USACE continues to monitor the location of the saltwater wedge, the USACE decision on augmenting the sill’s height from -55 feet to -30 feet with a 620-feet navigation will be determined over the next few weeks (estimated).
The USACE will continue to monitor the location of the saltwater wedge that was estimated to be at Mile 32.5 AHP yesterday (October 15, 2024). This indicates the higher river stages over the last few weeks have pushed the wedge downriver approximately 30 miles.
The following information is reproduced from the USCG Navigation Outlook issued yesterday (attached):
All vessels are limited to one way traffic from MM 63.5 to 65 AHP confined to a channel 500’ wide. The channel follows the Left Descending Bank (LDB) and is marked on its West side by four white buoys with fixed white all-around lights.
- All vessels transiting this zone shall check-in with and take direction from the Contact Pilot onboard the CANDICE 30 minutes priorto arrival on Channel 67.
- All vessels shalltransit at their slowest safe speed between MM 63.5 to 65 AHP.
- Alliance Anchorage area above MM 65.4 is OPEN.
Mariners be advised of new buoy locations:
- Buoy #1: 29 42 10.6563 N; 089 58 43.424 W
- Buoy #2: 29 42 8 N; 089 58 41.7536 W
- Buoy #3: 29 41 55.7722 N; 089 58 34.4502 W
- Buoy #4: 29 41 54.0127 N; 089 58 33.494 W
The Carrollton Gage (New Orleans) reading at 0900 hours today was 4.12 feet with a 24-hour change of + 0.99 feet. This reading is higher than expected and highlights one of the changes at the Carrollton Gage as there is little precipitation to account for this rise. During low river stages the Carrollton Gage exhibits swings of a foot or more for short periods, the best explanation is that as the saltwater wedge migrates upriver the Carrollton Gage is recorded changes related to tidal or wind impact. The stage tomorrow is forecast to be at 2.90 feet and highlights the variability of the critical Carrollton Gage at New Orleans, these rapid spikes do not occur during higher river stages.
The National Oceanic and Atmospheric Administration’s (NOAA) National Weather Service Extended Streamflow Prediction (28-Day) for the Carrollton Gage issued today forecasts that stages will rise to 4.4 feet tomorrow and will then resume a slow fall to 2.2 feet on November 13 (2024).
