SIOUX CITY — U.S. Sen. Tom Harkin, D-Iowa, told reporters Monday while overlooking the swollen Missouri River that some revisions need to be made to the Army Corps of Engineers’ master manual but that it’s “not fair” to criticize the corps.

“They just didn’t count on two or three huge rainfalls,” Harkin said while standing with city and county officials at Prospect Hill. “If we didn’t have those rainfalls, their master plan would’ve worked.”

Harkin took a look at flood preparations and met with local and federal officials in Sioux City, Council Bluffs and Hamburg, Iowa, Monday.

Rainfall and snowpack have increased the amount of water in the Missouri River over the past 10 years to levels that haven’t been seen in more than 100 years, which Harkin said is another indicator that climate change is occurring.

Grasslands, wetlands and forests are disappearing as land is cultivated for farming. The construction of more shopping centers and parking lots speeds up the flow of rain water as it hits the blacktop, according to Harkin.

“I think it’s indisputable that something is happening to our climate,” he said. “Perhaps the basis of that manual needs to be revised for climate change that’s happening and the amount of snowpack.”

Harkin said officials don’t know what will happen to the river’s substructure once it recedes and that FEMA may have to look at mitigation.

“A lot of this is just out of our hands,” he said.

In the meantime, Harkin assured business owners and homeowners whose property is taking in water that a presidential disaster declaration is expected to be issued in the next couple of days.