Laying drain pipe may be relatively simple, but the long distance, large volumes and elevation changes demanded some complex engineering. To accommodate a large flow of water over such a long distance, the Corps called for 84-in.-dia pipes. The piping is being fabricated off site and transported to the jobsite in 20-ft to 50-ft segments, Calico says.

While most of the piping is laid through prescribed rights-of-way, there are some areas where work is affecting private property and causing long-term road closures. In other areas, heavy construction with pile drivers and excavators is happening near businesses and homes.

"We're having to deal with some property owners, but we've done a good job of publicizing the work," Alikhani says. "You're going to have some inconvenience with a project like this, but [homeowners and businesses] in the area understand it's important."

Calico says there has also been some surprises on the project. One was the discovery of a 190-ft-long sunken barge along the banks of the Mississippi near the discharge basin. B&K employed a specialized dive and recovery team to remove it from the site. That delayed the schedule by a month, but the contractor has since made up the time by laying pipe in the ground faster than anticipated.

"It was a nerve-wracking process," Calico says. "A diver had to cut [the old barge] with a torch, and they removed it piece by piece. It could have been a much bigger problem, but we've got good contractors who know how to get these things done."

Calico says they also encountered some difficulty when driving the 500 60-ft piles for the pumping station. A tough layer of debris and sand was causing some of the wooden piles to split. MR Pittman Group and the Corps devised a method of pre-drilling the holes, filling them with water and installing steel cone points at the base of the piles.

"It initially gave us some grief and there was a learning curve, but once we came up with the right method, it was smooth sailing from there," Calico says.

Engineering a Pump System

One particular challenge of the project design was moving water over such a great distance and then lifting it over the 26-ft-tall Mississippi River levee.

Stefan Miller, a mechanical engineer with the USACE, helped design the siphoning system. Where a typical pump station may have a 100-ft discharge tube, the long span to the river required special planning and hydraulic engineering. The system requires water to be pushed upward, from a low point of 15 ft below sea level, to 17 ft above sea level at the top of the levee.