Harahan Mayor Vinnie Mosca blasted the U.S. Army Corps of Engineers on Tuesday for asking his city to shut down its sewer system for several hours next week to allow crews to reroute pipes that are blocking the path of a massive drainage project.

Mosca said the corps should have known about the sewer line before it began work on the “Pump to the River” project that runs through Harahan and should not have proposed a plan he said would inconvenience residents and could create future problems for the city’s sewer system.

“Had they done their work appropriately in the beginning, they would have seen this” pipe was in the way, Mosca said.

Crews came across the 8-inch sewer pipe as they were working on Hickory Street near the fire station. Mosca said the project manager, Fleming Construction, let him know about the issue Tuesday.

To fix the problem, officials recommended relocating the pipe, which would mean it would have to be shut down for at least five hours next week. With only one of the city’s sewer pumps currently in operation — the other broke and a replacement has not arrived — Mosca said that would essentially require about 4,000 people to find other facilities for most of a day.

That plan is on hold until after Mosca and corps officials meet Wednesday.

The sewer line, as well as a water line owned by Jefferson Parish that is also in the path of the project, were not in the original design plans for the project, corps spokesman Ricky Boyett said.

That likely indicates they were not included on maps the corps and its contractors were working from, he said.

Mosca said the city provided the corps with maps of its underground lines before the project started.

The corps is planning to run a camera through the pipe to see its exact path before any more work is done, Boyett said.

Moving the sewer line could be more than just a temporary inconvenience for Harahan residents, Mosca said. Should a solution involve redirecting what is now a straight sewer into one that bends around the corps’ work, it could create blockages, he said.

“If somebody puts a diaper in there, we’ve got a problem,” he said.

The Pump to the River project, expected to cost more than $100 million, involves pumping water from the Soniat Canal through a station near Mounes and Hickory streets and into the Mississippi River. At present, all of Jefferson Parish’s drainage goes into Lake Pontchartrain.

The pumping proposal is a key element of the overall Southeast Louisiana Urban Flood Damage Reduction Project, commonly known as SELA, a corps effort to improve drainage in the New Orleans area so that it can handle heavy rainfalls.

Work on the Pump to the River project is expected to continue until 2017. It won’t be clear how much of a delay the pipelines in Harahan will cause until a plan is developed to deal with the obstruction, Boyett said.

“Everybody’s saying ‘Pump to the River: We’ve got to get it done,’ ” Mosca said. “Sure we do, but we’ve got to weigh what this does to our community.”