Ecosystem Restoration as Infrastructure–MRGO, Part 3

 

 

Katrina Memorial at Intersection of MRGO and Bayou la Loutre

It was somehow appropriate that the residents of St. Bernard Parish should put their memorial to those who died during Katrina at the intersection of Bayou la Loutre and MRGO. It was the cut through the Bayou la Loutre ridge that changed everything in the Pontchartrain basin.

By 2000 Louisianans had developed a consensus that MRGO should be closed. In 2004 the State representatives and senators for St. Bernard Parish sponsored a resolution in the Louisiana State Legislature to close MRGO permanently. It passed. On September 13, 2005 the same group of legislators pleaded with Congress: MRGO must be closed. But, how?

Congress directed the Corps to make plans for closure in Public Law 109-234, the Emergency Supplemental Appropriations Act for Defense, the Global War on Terror, and Hurricane Recovery, 2006, which appropriated $3.3 million to the Corps of Engineers to develop a comprehensive plan to de-authorize deep-draft navigation on MRGO and ordered the Corps to come up with its plan by December 2007.

In December 2006 the Corps of Engineers sent an interim report to Congress with no final recommendation, but the report did discuss alternatives. Option one: Maintain a shallow-draft MRGO navigation channel twelve feet deep and 125 feet wide. Option two: Close MRGO to both deep-draft and shallow-draft vessels. Option three: Stop maintaining MRGO–no more dredging, no more jetty repairs, no more buoys, no more lights or other navigation aids.

What to do at its intersection with Bayou la Loutre was the key to the first two options: a shallow-draft channel or complete closure. The Corps listed four variations under option one, the shallow-draft channel: construct a salinity control weir at Bayou la Loutre; or a salinity control gate; or a storm protection gate; or no structure at all. To close MRGO the Corps listed three variations: construct an armored earthen dam across MRGO at Bayou la Loutre; restore both banks of the bayou across MRGO; fill in MRGO from the Intracoastal Waterway to the Gulf of Mexico. Basically, the Corps had been pursuing the third option, cease all maintenance, since Katrina struck in August 2005. In the Executive Summary of the Interim Report, the Corps listed the armored earthen dam across MRGO as the best option for dealing with the hated channel and would fit best with the Corps’ Louisiana Coastal Protection and Restoration Technical Report, also do out in December 2007, the draft of which came out in July 2006.

 

MRGO Spoil Bank, armoured with concrete mats to halt erosion, at Intersection of Bayou Yscloskey

Also in December 2006 a group of scientists from Louisiana State University, the Coalition to Restore Coastal Louisiana, and the Lake Pontchartrain Basin Foundation detailed the how in Mister Go Must Go: A Guide for the Army Corps’ Congressionally-Directed Closure of the Mississippi River Gulf Outlet: Deauthorize MRGO; stop dredging it; restore the Bayou la Loutre Ridge and anchor it with native vegetation; break the channel into a series of lakes with lateral fills in four or more places and anchor them with native vegetation; restore the narrow landbridge between MRGO and Lake Borgne and anchor it with native vegetation; restore the original bank lines, particularly the west bank to protect the levees, with dredge and anchor them with native vegetation to reduce storm surges; allow natural infill to occur in the farthest reach of the channel where it crosses Breton Sound; reintroduce freshwater from the Mississippi at Violet at the rate of 7,500 cubic feet per second to reestablish historic salinity levels in Lake Borgne. In short, do the restoration work, divert fresh water, and plant lots and lots of trees. Those levees protected by wetlands or cypress forests did not fail when buffered by Katrina’s wind and waves. Scientists studying Asian tsumanis found that dense vegetation a hundred yards deep could reduce wave energy by up to ninety-five percent.

There was more: Fix and raise the MRGO levees to withstand a storm surge for a 500-year flood; restore habitats devastated by the channel; use effluent from wastewater plants to restore the cypress forest to the wetlands east of the Mississippi in New Orleans East and the Lower Ninth Ward; restore the landbridges in the Biloxi Marsh; restore the barrier islands.

Closing it to big container ships would require finding an alternate shortcut to the Port of New Orleans: Cut through the eastern ridge of the Mississippi and dredge a connecting channel between Breton Sound and the river, echoing an 1832 proposal by the Chief of Engineers of the State of Louisiana to bypass the sand-clogged passes in the bird-foot delta. Build the Millennium Port to accept containers somewhere along the river south of New Orleans. It would also entail enlarging the lock on the Inner Harbor Navigation Canal between Lake Pontchartrain and the Mississippi, a project that had been disputed by environmentalists for years, because it allowed saltwater into Lake Pontchartrain.

All of these proposals depended on the New Orleans District’s MRGO Reevaluation Study underway in 2007, and whether the navigation industry signed on to such a proposal and was guaranteed the construction of the Millennium Port and the enlargement of the Inner Harbor Navigation Lock. Whatever happened, it was not going to happen for another ten years. Meanwhile, habitat destruction would continue, and MRGO would remain a feature in the landscape.

---

            U.S. Army Corps of Engineers, Galveston District, “Closing the Mississippi River Gulf Outlet: Environmental and Economic Considerations,”

http://www.swg.usace.army.mil/mrgo/Documents/Publications/Closing%20the%20MRGO%20environmental%20and%20economic%20considerations.pdf; Day, John, Mark Ford, Paul Kemp, and John Lopez, “Mister Go Must Go: A Guide for the Army Corps’ Congressionally-Directed Closure of the Mississippi River Gulf Outlet,” Environmental Defense Fund et al., December 4, 2006, http://www.environmentaldefense.org/documents/5665_Report%20-%20Mister%20Go%20Must%20Go.pdf;  “Case Study: Mississippi River-Gulf Outlet (MRGO)(USA)” PIANC, http://www.pianc-aipcn.org/envicom7/13%20-%20mississippi.pdf#search=%22MRGO%20%22;  Drawing Louisiana’s New Map, 7, 47, 138, 141-142.