At the northernmost tip of the Barataria-Terrebonne Estuary is the Morganza Spillway and, just to the north of the spillway, is the Old River Control Complex, built between 1957 and 1986. These two Mississippi River control structures impact the estuary by controlling the inflow of freshwater from the Mississippi River. The structures prevent the capture of the Mississippi River by the Atchafalaya River.
The Old River Control
Complex
A tour of the Old River Control Complex includes a complete overview of the building of the structure, the history of Old River, the historical flooding of the Mississippi River and the recent (in this century) attempts by the river to change direction and follow the course of the Atchafalaya River into the Gulf of Mexico.
The river has often changed course over time and this change to follow the Atchafalaya River channel would be a natural development, if it were allowed to happen. The Old River Control Complex, however, is in place to keep this change from happening. If the Mississippi were allowed to change course, it would turn the present river channel into a saltwater estuary and the effects on the effects on the economy and fabric of life in southern Louisiana would be catastrophic. Corporations have constructed billions of dollars worth of petrochemical plants, refineries, grain elevators, and fossil fuel and nuclear electrical generating plants, most of which depend upon fresh water for their manufacturing process, along both banks of the Mississippi River. Also, cities below Baton Rouge, including New Orleans, would be hard-pressed to find drinking water. The Atchafalaya Basin could not accept the Mississippi flow without massive flooding, extensive relocations of communities, businesses and industries, and the upheaval of the social and economic patterns of that area. All port activities along the Mississippi River as we know them today would be disrupted and probably closed.
All of this information and more is included in a very informative booklet available from the Army Corps of Engineers (see page 75 for contact). In addition to the Old River Control Complex, the nearby Sidney A. Murray Jr. Hydroelectric Station, Louisiana's first hydroelectric plant, is also open to tours. Call (504) 492-2153.
The Morganza Spillway
Just south of the Old River Control Complex is the Morganza Spillway. Groups travway. Groups traveling tto the Old River Control Complex via Hwy. 3131 will cross over the Morganza Spillway. The spillway was constructed in 1954 and has only been opened once, in 1973, and this was not due to flooding but to alieve water pressure at the Old River Control Complex. The purpose of the spillway is to control flooding on the Mississippi River by diverting water into the Morganza Floodway and the Atchafalaya Basin. Today most activity regarding both flood control and diversion of river water into the Basin and estuary areas takes place at the Old River Control Complex. There are no guides at the Morganza Spillway; however, it is interesting to see the structure up close. Also, as you approach the spillway from False River, crawfish ponds are visible in the floodway area, an example of how closely economic development is tied to hydrological modifications, like the spillway. The dead trees, visible on the right of Hwy. 3131 as you head north, are the result of trapped floodwaters that remained caught within two levee systems. The hardwood trees, not able to live in standing water, died due to lack of oxygen. This is an example of how difficult it is to maintain a balance in an area altered by dams and levees.
False River - New Roads
False River is really not a river at all, it is a 22-mile long oxbow lake. An oxbow e. An oxbow lake is formed when a river changes course, leaving a wide loop of channel cut off from the main flow. This is what happened between 1713 and 1722 when the Mississippi River changed its course. Located 30 miles from Baton Rouge on Hwy. 190 and Hwy. 1, False River provides an interesting stop enroute to Morganza Spillway and The Old River Control Structure. There are public boat launches, picnic tables and barbecue grills, a gazebo and a fishing pier located on False River near City Hall in New Roads (take Morrison Parkway). Also in the area is Alma Plantation Sugar Mill, which produces raw sugar and black strap molasses and has a country store; and Bergeron Brothers Pecan Shelling Plant, which offers tours between October and March.
For more information on this area contact the Chamber of Commerce at (504) 638-3500.
ACTIVITIES:
- Order the booklet describing the Old River Control Structure and use it in class to discuss the area before taking the trip. The booklet can be ordered by contacting the Army Corps of Engineers at (504) 492-2169.
- Using a Louisiana state map, identify the location of the control structure and discuss the importance of its proximity to the Atchafalaya Basin and thalaya Basin and the Barataria-Terrebonne Esstuary. Give concrete examples of how vital freshwater is to the basin and the estuary: for crawfishing in the basin, for example, and for replacing lost sediment in the estuary.
- Discuss the problem of saltwater advancing into the basin and the estuary and the role freshwater releases from the Mississippi River play in countering the advance of saltwater into these areas.
- Discuss what happens when saltwater enters a freshwater area.
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