Corps evaluates Evansville levee system

Published Oct. 6, 2009

During five days in September, the U.S. Army Corps of Engineers Louisville District’s levee safety team crawled like ants all over 18.25 miles of levee and floodwall in Evansville, Ind., as part of this city’s ongoing levee evaluation for the Federal Emergency Management Agency (FEMA) flood insurance program.

The Corps assembled engineering teams in disciplines of geotechnical; structural; mechanical; electrical; and hydrology and hydraulics. Teams included 27 individuals to inspect both rural and inner city segments of the flood protection project, including 100 gates and 20 pumping stations. The Geographic Information Systems (GIS) component of the inspection was also performed where inspectors walk along the levee annotating and identifying conditions of the components of the project in an electronic GIS "notebook."

GIS specialist Paul Deatrick, geologist Jacob Nienaber and levee inspector Chris Alvey performed the GIS inspections.

At the Evansville First Avenue Pumping Station, large submersible pumps were inspected by mechanical engineers Mark Robertson, Brian Smith, Vu Nguyen, and electrical engineers John Dobson and Jeff Timbas. Mike Herke of the Evansville Levee Authority provided assistance lowering Corps inspectors into the sump area where the pumps are located. Robertson has gained notoriety of sorts earning the title, "pump expert" by his comrades, not only because he helps other districts build pumping stations, but his car license plate bears the same title.

The Louisville District can perform evaluations as part of the certification process if the local sponsor – in this case the Evansville Levee Authority – makes the request and obtains more than 10 percent or more of the total funds required from another federal agency. The local sponsor must pay for the remaining portion – 90 percent or less – for the inspection. The 10 percent of federal funding came from Housing and Urban Development (HUD) for Evansville. It cost $408,000 to complete the certification evaluation for this project.

Often times levee sponsors have a difficult time locating an architectural engineering firm who will perform levee evaluations for certifications, according to Dan Frank, Louisville District levee safety program manager. "They don’t want the responsibility or liability of signing on the dotted line," he said. "We find this happens quite a bit, especially in the aftermath of Hurricane Katrina."

The Louisville District has already performed several levee inspections as part of the certification process on other projects and has at least two more to accomplish. "It takes a lot of the district’s resources and people to perform the certification evaluations; however, our people gain firsthand knowledge of our levee projects and the requirements necessary for certification for accreditation," Frank said. "They see the whole picture."

Barry Schueler, civil works project manager, said it makes sense for the Corps to perform this levee inspection. "The Corps has the institutional knowledge, and I think it’s great the Corps is doing it," he said.

Levees across America need certification for FEMA to accredit them on new digital flood insurance rate maps as providing protection. This ultimately may impact citizens being required to purchase flood insurance.

Depending on the inspection findings, the Evansville levee certification evaluation could potentially allow the local sponsor to meet the requirements necessary for accreditation. By FEMA regulations, levee systems should provide protection from an annual one percent flood chance, referred to as the 100-year level. A 100-year water level is a statistical event that has a one percent chance of occurring each year at a given location. The Evansville levee, as well as most projects in the district, received a minimally acceptable rating in the 2009 inspection.

The Corps of Engineers built the original levee system after the Flood Control Act of 1937, and pumping stations were added beginning in 1964 and continuing through 1994.