Drought, Low Water Continue For Much Of Western Rivers
The extreme drought impacting the Mississippi, Ohio and Tennessee river valleys continues to translate into troublesome low water conditions—and in some places record lows—on the Western Rivers, with draft restrictions slowing the movement of barges on many waterways.
The Lower Mississippi River at Memphis, Tenn., hit a record low October 17, when the gage on the east bank near Mile 735 registered -10.79 feet. The previous record low was -10.7, set on July 10, 1988. Similarly, the Ohio River gage in Cairo, Ill., has also hit a record low of late.
“The river levels from Cairo, Ill., to Memphis, Tenn., are representative of 1988 levels, while locations downstream are closer to 2012 levels,” Jeff Graschel with the Lower Mississippi River Forecast Center said in an October 20 low-water update.
Rain is in the forecast for portions of Oklahoma and Arkansas for the week ahead, but with soil conditions so dry throughout the region, runoff projections are minimal.
“The problem is, we’re so dry that I would expect little if any runoff to develop,” Craig S. Ross, hydrologist at the National Weather Service’s Shreveport, La., forecast office, said during a navigation conference call for the Red River. “Only a moistening of the soils to ready for the next system, which wouldn’t arrive until sometime after Halloween, during the first few days of November at best.”
Ross said he doesn’t expect weather conditions to translate into river rises in his area of concern until next month.
Low water, shoaling and channel constrictions on the Ohio and Mississippi rivers have led to frequent groundings and, in response, loading draft restrictions. Towing companies have, in some locations, restricted barge drafts, both northbound and southbound, to 9 feet of draft on the Mississippi River, with liquid barge draft restrictions a touch lower than that. Likewise, channel restrictions have led southbound tows, in some cases, to be limited to a maximum of 25 barges.
Emergency dredging has been underway at various points in the system for weeks, in addition to normal low-water-season dredging at the crossings on the Lower Mississippi below Baton Rouge, La. Dredges at work on the Ohio and Mississippi rivers include the Hurley, Jadwin, Potter and Goetz. Points of concern on the Lower Mississippi range from Tunica Bluff at the southern end to Sycamore Chute in the north. As of October 20, the Hurley was dredging at Redman Bar near mile marker 740 on the Lower Mississippi. The Jadwin was about 60 miles downriver from the Hurley at Battle Axe. River closures due to groundings were reported at mile markers 921 and 631-632 on the Lower Mississippi River.
To augment dredging efforts and provide a bump on the lower Ohio and Mississippi rivers, the Tennessee Valley Authority has announced plans to release water from Kentucky Dam on the Tennessee River and Barkley Dam on the Cumberland River. Additionally, the Coast Guard reports it has 3,200 buoys on hand and another 4,000 on order for safely marking channel boundaries.
In the New Orleans area, low water levels have led to the closure of Harvey Lock due to reverse head conditions. The lock reopened briefly October 19, thanks to winds from the north pushing water levels down on the canal side of the lock. That opening, though, was short-lived, and by the next day the lock had closed again. At press time, the Harvey is the only lock to close due to low water in the New Orleans District.
“So far, there are no issues at any of the locks we have other than at Harvey,” New Orleans District Public Affairs Chief Ricky Boyett said.
Salt Water Sill
With the river languishing at just above 2 feet at the Carrollton Gage and with salt water creeping up from the Gulf of Mexico, the New Orleans Engineer District has begun construction of an underwater sill of river sand across the ship channel.
Salt water is always in the river near its mouth, moving upriver in the shape of a wedge. But with the river’s extreme low stage and slow flow rate—the Mississippi River at Belle Chasse has been dipping well below 100,000 cubic feet per second (cfs.) of late—the wedge is traveling alarmingly far upriver, threatening the freshwater supply of Plaquemines Parish, in particular.
To combat the intrusion of salt water, the Corps and its dredging contractor, Weeks Marine, is constructing the sill at Mile 63.8 (above Head of Passes), just upriver from Myrtle Grove, La. During the construction process, carried out by Weeks Marine’s cutter suction dredge JS Chatry, the Corps will monitor salinity levels in the river to determine how high the sill will need to be built. Boyett said the sill should reach an elevation of -55 feet by October 21, after which time the Corps will monitor salinity levels and the shape of the salt water wedge over the course of several days.
“That will make a determination of whether we need to go above -55,” Boyett said.
The Corps will adjust the height of the sill up in 5-foot increments and will likely not need to go higher than negative 45 feet, which would reduce the available draft in the river by five feet.
“Draft restrictions may be issued as construction of the sill progresses,” the New Orleans District said in a press release announcing the start of construction.
Plaquemines Parish is employing a pair of reverse osmosis machines to supply freshwater to its east bank communities and to the Buras-Boothville-Venice area on the west bank. Currently, the parish pipes freshwater from Belle Chasse south to Port Sulphur.
Low water isn’t just a Mississippi River issue in Louisiana. To the west, the Red River is low, particularly below Lock & Dam 1 (Lindy C. Boggs Lock & Dam) in Marksville. Lock 1, along with Old River Lock on the Mississippi, is currently closed to navigation for dewatering and maintenance. On the Red, there’s a growing concern that, when Lock 1 reopens on November 12, the channel will be too shallow for navigation.
“Our main concern is for the CLECO power plant at Boyce, La.,” said Richard Brontoli, executive director of the Red River Valley Association, in a letter to the state’s congressional delegation. “Their fuel is delivered by barge and, after a two-month closure, they must replenish it for continued operation.”
Besides the power plant, Brontoli mentioned supplies bound for a fuel distribution terminal in Alexandria, La., and steel coils bound for the Shreveport-Bossier, La., region.
“If there is no navigation, CLECO will be in a serious situation and all industries will question the reliability of using navigation for transporting their products,” Brontoli said.
Brontoli is calling for the Vicksburg Engineer District to receive funding for emergency dredging by October 28 to allow time to execute a contract and dredge the channel below Lock 1. Below Lock 1, towing vessels can opt for either navigating down the Atchafalaya River or accessing the Mississippi River through Old River Lock.
The Red River Valley is in a drought, just like much of the United States, but the Mississippi River has a direct impact on water conditions below Lock 1 on the Red.
“The Mississippi River has the largest impact on the height of the Acme [gage on the Black River] and Lock 1 lower gage in low water periods,” Brontoli said.
The Vicksburg District is hoping to deploy the dredge Dubuque below Lock 1 to clear the channel in time for navigation to commence on the Red on November 12.
Tennessee-Tombigbee Waterway Holding Pool
And while drought conditions cover much of the South and Midwest, not all waterways are suffering due to lack of rain. East of the Mississippi River, the Tennessee-Tombigbee Waterway is holding pool, thanks to its locks and dams, from the Jamie L. Whitten Lock & Dam in the north to Howell Heflin Lock & Dam in the south.
“While most waterways are subject to drought, we are much less impacted than the Mississippi River,” said Justin Murphree, the Mobile Engineer District’s project manager for the Tennessee-Tombigbee Waterway.
The Tenn-Tom offers a 9-foot channel, maintained by its 10 locks and dams, that extends from the Tennessee River in the north to the Port of Mobile in the south.
“While most boats from the Mississippi River will consider the Tenn-Tom a restriction in itself, we can verify that we are a reliable system for anything that can fit in a 600-foot by 110-foot lock chamber,” Murphree said.
“It’s a slack water waterway,” said Mitch Mays, administrator of the Tennessee-Tombigbee Waterways Development Authority and president of the Tennessee-Tombigbee Waterway Development Council. “The water might get low, but the channel is still open.”
Mays said the ports and terminals along the waterway have the ability to move cargoes from truck to barge, and there’s ample room for vessels to come down from the Mississippi and Tennessee rivers.
“The bottom line is the Tenn-Tom has capacity,” he said. “All the locks operate 24/7, and the channel is open.”
Note: This article includes information that previously appeared on www.waterwaysjournal.net but not in the print version of The Waterways Journal.