The Army Corp of engineers lowered the water level of the Mississippi River at St. Anthony Falls in Minneapolis for the first time in 20 years on Wednesday.

The engineers will inspect the sewer tunnels that can only be accessed after the river is lowered about 13 feet.

A park ranger from the National Park Service gave a tour of the site. He said in years before, they’ve found some interesting things in the water.

"I think we even found a car in there. The river has such force that a lot of floods will scour out small artifacts. So we're looking things over 400 pounds," said David Wiggings.

Before the lower dam was built in 1891, the river was kept at the shallow level. The Mississippi River will be back up to normal levels on Thursday evening.