Lake Charles Dredger Wins Contract

The New Orleans District, USACE, awarded a $1.43 million contract to Mike Hooks Inc., of Lake Charles, La., to build an underwater sill in the Mississippi River to check saltwater intrusion. Mike Hooks Inc., the low bidder, will use cutterhead Dredge 32 to build the sill from river-bottom sediment to protect fresh water for New Orleans. The same company and same dredge complete the job successfully in 1988. The 20-ft. high sill will be constructed at mile 63.7 above Head of Passes, where the river is 80 ft. deep. Location is at the upstream end of the BP Amoco oil refinery, where the 1988 sill was built, 12 miles downstream from the Belle Chasse water intake. Salt enters the river annually during this low-water season since the bottom is deeper than the Gulf of Mexico water surface up to about 15 miles south of Natchez, Miss. This year, below-average flows have caused the salt-water wedge to threaten fresh water supplies. Flow, the key influence on salt intrusion, was 165,000 ft. per second. The sill will be about 1,200 ft. long, lying crosswise in the river. Thickness at the base will range from 500 to 900 ft., depending on how well the dredged sand stacks up in the river bottom.