Predicting the future is now possible, at least for some environmental engineers working with sedimentary discharge.
The University’s Department of Civil and Environmental Engineering and Louisiana’s Department of Natural Resources built a small-scale model of the Mississippi River Delta to assess the problem of decreasing marshland on the Gulf Coast.
“The model was built because marshland near the Gulf of Mexico is decreasing at one acre every 30 minutes,” said Shannon Dupont, project manager for the Louisiana Department of Natural Resources.
Clint Wilson, the project’s principal investigator and a civil and environmental engineering assistant professor, said this depletion is because newly constructed levees and dams are harming ship routes to the Port of New Orleans and hurting gas and oil imports from the Gulf.
“Results from this project should give us a clear indication regarding the relative feasibility and benefits of possible diversion arrangements that will eventually play an important role in restoring the vanishing Louisiana Coastal wetlands,” Wilson said.
According to the DCEE informational packet, the 675 sq. ft. model covers 76 miles of the Mississippi River south of New Orleans. It starts at Phoenix-Myrtle Grove to Head of Passes to the Southwest Pass in the Gulf which makes up 3,526 square miles.
The model cost the Department of Natural Resources $650,000.
Dean of the College of Engineering Pius Egbelu was able to fund the construction of the building that houses the model for $400,000 to $500,000, Willson said.
The DNR and DCEE have multiple diversion sites along the model river.
While the river is dry, they can form different shapes in the model to make the water flow in certain ways.
Then, the water is allowed to flow with the sediment to re-enact the actual river.
After the experiment has completed the allowed time to represent the number of years desired, aerial pictures are taken of the dyed sediment discharge to see where the flow resulted. Also, the sediment is collected and weighed to see how much would be diverted.
The amount of water and sediment in the model are controlled so they are proportional to actual Mississippi River data.
“It is capable of reproducing river flow from 400,000 to 1,250,000 cubic feet per second to account for the expected low and high flow from the change in seasons,” Willson said.
When all scenarios are tested, which Dupont expects to be around May, the DNR and DCEE will decide which scenario is most productive for water diversion and build an even larger model for further testing.
The end result will then be tested for other factors, such as ecological damage, which might result in the change of which diversion scenario will be selected for construction.
Traditionally, the Depart-ment of Natural Resources uses numerical models on a computer to eliminate human error. But through the use of an experienced model making company called Sogreah, located in France, the DNR and University engineers can physically view the results.
“No numerical models can show the results the physical model has,” Dupont said. “We can see a much larger scale with this model.”
Willson said local and University engineers have discussed the model for years, but planning did not begin until November 25, 2002 when DNR contracted the engineering firm of Brown, Cunningham and Cannuch, Inc.
Sogreah built the model in Grenoble, France between March and September 2003 using data collected by the U.S. Army Corp of Engineers and U.S. Geological Survey. When accuracy testing was completed, it was air-freighted to Baton Rouge on Sept. 26.
The building housing the model, located just off campus on River Road, has not yet been named, but Willson said a building dedication will take place sometime this spring.