The Army Corps of Engineers (www.usace.army.mil) said its unwatering mission in New Orleans has reached the halfway point, with inundation cut from 80 percent to 40 percent in the city and its surrounding parishes. Still, the corps warned that flooded areas may not be habitable for “a long while.”

According to the corps, the Federal Emergency Management Agency (FEMA, www.fema.gov) is working with local, state, and other federal agencies to develop plans that balance residents’ desire to get back into their homes with health and safety concerns. Meanwhile, the corps’ primary focus remains on unwatering the metro area.

The mission of unwatering New Orleans and the surrounding affected parishes is moving smoothly, said Maj. George Stejic, deputy of Task Force Unwatering, Corps of Engineers, in a prepared statement. Stejic estimated less than 40 percent of water remains in the metro area.

“In Orleans Parish, floodwater levels have fallen precipitously with most of the Ninth Ward and the southern part of Orleans Parish are dry enough for normal recovery operations to begin,” he said.

Water remains in the northern part of the parish and is going to be pumped out using Pump Stations 12 and 4, reinforced with about a dozen temporary pumps, he said. As floodwaters recede, some ponds will remain and will be drained using portable pumps.

Stuart Waits, project team leader for the New Orleans District, estimated that pumping efforts in the lower Ninth Ward were removing 12 million gallons of water a day. Corps personnel from the New Orleans, Little Rock, and Tulsa districts, contracted pump, drainage and electrical experts, and German and Dutch pump teams continue working with local water and sewage board officials.

Some construction work continues on the 17th Street and London Avenue canal breaches where helicopters are precision-placing 7,000-pound sandbags to reinforce existing repairs and crews are armoring sandbag closures with rock. The corps is monitoring the floodwalls around the clock and conducting hydro and over-bank surveying. Contractors are also maintaining cranes at the sites to regulate flow levels by adjusting sheet pile walls at the mouths of the canals into Lake Pontchartrain. Construction of the access road to the second London Canal breach north of Mirabeau bridge was completed on Sept. 14.

St. Bernard’s Parish is almost completely dry, Stejic said, with the only significant water remaining in the Chalmette extension. However, recovery in St. Bernard’s Parish is limited by the spill of petroleum products from local oil facilities.

In Plaquemines Parish, repairs to the levee breaches continue and the conditions for full scale pumping of the affected areas will soon be set. Most of the fixed pumping stations in Plaquemines Parish have survived the storm and will be available to unwater the parish.

A team of five Dutch experts from the Directorate General for Public Works and Water Management (Rijkswaterstaat, www.rijkswaterstaat.nl), equipped with three mobile water pumps, have been in Plaquimines Parish, establishing mobile pump stations there. The Directorate General for Public Works and Water Management is responsible for managing the water table in the Netherlands. The Dutch team has also offered assistance in fixing damaged pumps. The team’s mobile pumps can expel 3,000 cubic meters of water an hour and each pump can run for 48 hours continuously on one tank of diesel fuel. Dutch water pumps have been used with great success in several countries including Suriname, Poland, and the Netherlands.

Task Force Unwatering shifted pump repair priorities from Pump Station 1, which is now operating, to Pump Station 4 in Orleans Parish. The number of pumps that are operational at any given time is continually changing. At the time of the corps latest report on the unwatering effort (Sept. 15), 7.5 billion gallons of water were pumped out of the city. That’s down from a previous estimate of 11.8 billion gallons because one of the main pumping stations is running out of water to pump and most pumps in St. Bernard’s Parish are off because the pumping mission in that area is complete. As of Sept. 15, Task Force Unwatering estimates the overall effort will be completed in early October.

From a ground survey conducted by task force project managers, the corps has identified nine breaches that must be repaired to provide a minimum level of protection to the affected parishes. Of these, seven have been repaired to date, one is being used to allow drainage to leave St. Bernard’s Parish, and one is being addressed in Plaquemines Parish. Additionally, levees were deliberately notched at two sites in St. Bernard”s Parish to facilitate the unwatering mission. Of these, one has been closed and one is still in use. The Corps is actively making emergency closures of all breaches in a prioritized manner to improve the current protection. Progress at this time stands as follows:
• Breach on 17th Street canal in Orleans Parish. repaired
• Northern breach on London canal in Orleans Parish. repaired
• Southern breach on London canal in Orleans Parish. repaired
• Northern breach on the IHNC in Orleans Parish. repaired
• Southern breach on the IHNC in Orleans Parish. repaired
• Breach in St Bernard”s Parish. not repaired (water is flowing out naturally)
• Three breaches in Plaquemines Parish, two repaired

On the Inner Harbor Navigation Canal, corps contractors used crane barges to remove two barges from atop the Florida Avenue Bridge, also commonly known as the L&N Bridge.

— Flow Control Staff