Increased flood protection for portions of the Manhattan area could be an expensive proposition.
That was the conclusion of a report heard Monday by Pottawatomie County commissioners concerning the idea of raising and possibly extending the levee that protects the city’s east side.
In a joint meeting last Thursday, Manhattan city commissioners and county commissioners from Pottawatomie and Riley Counties reviewed a Corps of Engineers study of the levee system around the east side of Manhattan.
Increasing flood protection for downtown Manhattan and the industrial park on the east side would require raising the levee by 1.5 feet and, perhaps, extending it past the Dix Addition. The cost could range anywhere from $18 million to $38 million, Pott County commissioners said Monday.
“They haven’t decided what our share of the cost would be,” said Commissioner Stan Hartwich, who attended the meeting along with Commissioner Gary Yenzer.
The commissioners noted that the study is a proposal only and not a federal mandate.
The levee was constructed in the 1940s and 1950s, the idea being to protect the downtown portion of the city against a 100-year flood. Since then, however, an additional six decades worth of flow and rainfall data has been accumulated, refining the definition of a 100-year flood that was used at the time the levee was built.
Following the 1993 flood, the Corps decided to study the levee system to determine whether additional protection was needed in the event of a 100 and 500-year flood.
The current five-mile levee along the Big Blue River protects about 1,600 acres and $1 billion in private and governmental investment. City engineer Rob Ott said the issue is risk management. “The question being asked by the Corps of Engineers in the study is how do we get back closer to the original authorization for the levee as designed in 1940’s, 1950’s to handle larger flows both on the Kansas and Big Blue,” he said. “And since there is such a large amount of property being protected by the levee do we want to provide greater level of protection….”
While raising the levee would provide added protection for the industrial park in Pott County, the downside, according to Yenzer, is it could divert more flood water to the east into residential and business districts along U.S. 24.
“The area where the sale barn is could be underwater,” Yenzer said.