Manhattan Levee project costs exceed estimates by $21.4m

MANHATTAN (KSNT) - The project to protect the eastern side of Manhattan from severe flooding has almost doubled in price since 2016.

According to the U.S. Army Corps of Engineers (USACE), the levee project on the south and east sides of the city will reduce the chance of flooding by fourfold. Without the levee, flood depths could exceed 15 feet and pose a catastrophic threat to the Manhattan business district.

In 2022, the City of Manhattan and the U.S. Army Corps of Engineers (USACE) started work on the Manhattan Levee, a project that was estimated to cost $24.8 million back in 2016. Since then, the project cost has ballooned in cost to $46.2 million.

27 News looked into the reasons behind the cost increase.

Historical Significance

In the 1930s, the federal government proposed building infrastructure that would help control the possibility of flooding from major Kansas rivers. The proposal, under the New Deal program, would've seen the construction of a Tuttle Creek Reservoir. However, lack of funding during the Great Depression halted the proposal. The flood of 1951, a day some call 'Black Friday', changed that.

On Friday, July 13, 1951, flooding on the Big Blue River spilled into the Manhattan business district. The district was covered with eight feet of water, causing more than $20 million in damage, according to The Mercury. Two people died in the flood.

A levee was built in the 1960s following the big flood. The levee is credited with saving the city in 1993 after floodwaters came within three to four feet of spilling over. If not for the levee, the USACE said the floods could've caused $18.9 million in damage in 2014 dollars.

"It was used in 1993 and that is the flood of record since the levee had been built, and it was very critical protection for the city," Manhattan Stormwater Compliance Engineer Bill Heatherman said.

Project costs

27 News asked why the cost of the project has been steadily increasing. The USACE said inflation accounts for nearly half of the increase.

Last month, the City of Manhattan heard from a USACE spokesperson on the project. According to the presentation made to city officials, the newest cost figure for the project is $46,276,000, a $21,428,000 cost increase over eight years.

The entire project is cost-shared 65% federal and 35% by the city. Heatherman said the city's portion of the project is stormwater utility funded, with some other utility sources. 

"The additional costs forecast for the future would also be primarily stormwater utility fund, but with a financing plan that is still being developed," Heatherman said.

"Other factors driving the cost increases included an increased number of major utility lines to be relocated and construction of a new stoplog closure structure on the existing UPRR tracks that was not originally anticipated in the initial 2016 cost estimate," the USACE said in their response.

The USACE said other factors contributing to the heightened project cost include several major utility line relocations, engineering and design cost increases and a revised 15th/16th Street closure due to UPRR comments and added signals requirements.

Scope of work

Earlier this year, the City of Manhattan announced the first phase of the levee project was nearing completion. The levee will work in conjunction with the Tuttle Creek Dam to reduce flood risk for 10,000 citizens, 1,600 acres and more than $1 billion in private, commercial and government development.

“This project has raised the height of the levee, as well as replaced critical structures and equipment along the levee that were installed during the original construction project in the early 1960s," the City of Manhattan said a the press release.

The work being done to improve the levee network in Manhattan includes building an earthen structure to hold back floodwaters, construction of under-seepage berms and relief wells that are designed to reduce the pressure on the levee.

What is a stoplog? Vortex Hydra Dams describes stoplogs as elements used in flood gates to adjust the water level. The USACE said phase two of the project is the construction of a stoplog located on the United Pacific Rail Road (UPRR) tracks.

Because the tracks cross the levee and are unable to be relocated, the city is responsible for installing the closure that will act like a flood wall during flooding conditions. When conditions are clear, trains will be able to pass through as normal. When there are flooding conditions, train traffic will be stopped ahead.

"The levee protects from Big [Blue] River flooding which doesn't happen frequently but when it does it can be catastrophic if you don't have means to protect yourself," Heatherman said.

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