Diverting Mississippi River water into the Atchafalaya River and Atchafalaya Basin
Update and Ground Patrol for Louisiana Environmental Action Network and Lower Mississippi Riverkeeper
by Wilma Subra
May 20, 2011
Morganza Spillway Structure
The Morganza Spillway east of Melville, Louisiana, was opened on May 14, 2011, to divert Mississippi River water into the Atchafalaya Basin. The diversion of Mississippi River water was necessary to lower the Mississippi River flood stage and reduce pressure on the levee system along the lower portions of the river. The opening of the Morganza Spillway was initiated in order to protect Baton Rouge and New Orleans from being flooded by the over topping of their levees and reduce the possibility of levee failure.
On May 22, 2011, 17 of the 125 bays in the Morganza Spillway were open and allowing Mississippi River water to flow into the Atchafalaya Basin. As the Mississippi River water passed through the Spillway, the water was roaring, foaming, creating rapids and dispersing water into the air on the Atchafalaya Basin side of the spillway. A crane mounted on a barge was rapidly placing large sand bags along the Mississippi River side of the levee, adjacent to the Spillway structure, to stabilize and raise the elevation of the levee. The water on the MIssissippi River side of the Spillway structure was near the top of the levees on either side of the Spillway. Large sand bags had been placed on top of the levee system to raise the level of protection where the Mississippi River levee system joins the Morganza spillway levees.
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| Mississippi River water flowing through the Morganza Spillway. |
The Morganza Spillway down stream from the Morganza Spillway structure was flooded with diverted Mississippi River water and the water was moving down the spillway and flooding agricultural fields, homes and businesses. The harvesting of the wheat crop in the Morganza Spillway area was completed just prior to the opening the spillway. The corn, soybean, rice and sugarcane crops within the Morganza Spillway have been destroyed by the flood waters. Meanwhile, the crops outside of the Morganza Spillway are desperate for rain.
Security in the area of the Morganza Spillway was very tight and access was very limited as compared to two weeks earlier when access was unlimited. Sheriff deputies and National Guard troops guarded the spillway structure and blocked the access roads in the area. Traffic was not allowed to stop or park within five miles of the spillway structure.
Old River Control Complex
The Old River Control Complex, northeast of Simmesport, Louisiana, diverts 30% of the Mississippi River flow into the Atchafalaya River on an ongoing basis. The Old River Control Complex consist of four structures that divert Mississippi River water into the Atchafalaya River: Auxiliary Structure, Low Sill Structure, Over Bank Structure, and the Sidney A. Murray, Jr. Hydroelectric Station. The Auxiliary Structure had all six gates open and the Low Sill Structure had 15 bays opened on May 22, 2011. The two structures were responsible for the largest portion of flow of Mississippi River water into the Atchafalaya River. The Over Bank structure had a small rate of flow. The Hydroelectric Station was discharging water which had been directed through the plant to generate electricity.
The water roaring through the Auxiliary Structure and Low Sill Structure produced whirlpools, large waves, rapids, water dispersed into the air and very dangerous condition. Egrets, pelicans and blue herons feasted in the churning waters that exited all four structures. Fishermen in boats and along the banks were no longer present due to the dangerous situations associated with the fast moving and very large quantities of water moving through the control structures.
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| Mississippi River water flowing through the Low Sill Structure at the Old River Control Complex. The Auxiliary Structure is visible in the background. |
Just down river from the Old River Control Complex, the Old River Locks were closed to boat traffic due to the high water stage. Tug boats with barges loaded with boulders, rocks, and gravel were anchored in the locks staging area. They were on standby in cast of emergency situations and needs to stabilize the banks at the Old River Control Complex.
Just upriver from the Old River Control Complex, backwater flooding from the overflow channel and Atchafalaya River inundated an oil well production field. Pump jacks were submerged in flood waters throughout the field.
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| Oil well pump jacks submerged in water just upriver from the Old River Control Complex. |
Further upriver from the Old River Control Complex, hundreds of deer, displaced by the floodwaters, grazed in a partially submerged soybean field. A corn field adjacent to the soybean field offered no attract to the deer.
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| Deer grazing in partially submerged soy bean field upriver from the Old River Control Complex. |
Security in the area of the Old River Control Complex, as well as upstream and downstream along the Mississippi River was extremely tight. Two weeks ago one could park and walk on the structures as well as walk on the banks of the structures. Current access is limited to only driving through the area. No parking, no stopping and no foot access.
Atchafalaya Basin and Atchafalaya River
The Morganza Spillway directs Mississippi River water into the Atchafalaya Basin. The Old River Control Complex directs Mississippi River water into the Atchafalaya River. As a result of the Mississippi River water being directed into the Atchafalaya River and Basin, homes and roads in the communities of Simmesport and Melville are under water along the edge of the Atchafalaya River. Homes outside of the ring levees in each of the communities are also flooded. The basin is filling with water. The Atchafalaya River is fast moving with waves, eddies and rapids on the river.
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| Homes submerged in Atchafalaya River water in Simmesport. |
In the community of Krotz Springs on the Atchafalaya River and in the Atchafalaya Basin, flooding from the Morganza Spillway waters has inundated the basin on the eastern side of the Atchafalaya River. Along the Atchafalaya River, roads and buildings, not protected by levees, are under water. On the southern side of the town, HESCO Baskets and bags have been used to construct levees to protect homes in areas that lacked levees. HESCO Baskets have also been used to form a levee on the southern perimeter of the Krotz Springs Refinery. Pipe line stations in the Krotz Springs area are surrounded by sandbags and HESCO baskets.
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| Krotz Springs Refinery with HESCO Baskets forming a protective levee. |
North of Krotz Springs, on the western side of the Atchafalaya River, sand boil areas are present on the dry side of the levee system. The sand boil areas indicate seepage of water under the levee system. During the severe drought conditions currently present throughout central and southern Louisiana, the presence of the sand boils are very east to detect.
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| Sand boil north of Krotz Springs on the western side of the Atchafalaya River. |
Security and Monitoring
Security throughout the areas along the levee systems of the Mississippi and Atchafalaya rivers, spillways and control structures are very tight. All access roads to the levee systems are blocked and manned. Access to the Morganza Spillway and the Old River Control Complex Structures are restricted to auto access with no stopping, parking or foot access. Deputies Sheriff personnel and National Guard troops are very present in each and every community. One cannot move around the communities without being observed by the troops.
Inspectors are continuously monitoring the levee systems for leaks, sand boils and levee failures, while measuring the height of the water and the levees.
