A crack in the Wanapum Dam on the Columbia River and the ensuing reduction of water levels have prompted crews to spend $7 million on fish ladders for chinook salmon.

The Wenatchee World reports that existing fish ladders at the Rock Island and Wanapum dams are being extended to allow the chinook to reach their spawning grounds.

Divers discovered a 65-foot crack across part of Wanapum Dam's concrete spillway in February, and workers have lowered the water level 26 feet to reduce pressure on the dam. That left the fish ladders there unusable.

At the Rock Island dam upriver, the ladders are usable for now, but crews are worried they won't be as levels drop further this summer.

About 1,200 to 1,500 spring chinook will soon be passing the Wanapum dam per day.