Crack Found in Washington State Dam

Reuters:

A 65-foot-long (20-meter-long) crack has appeared along the base of a dam in Washington state, posing no danger to the public but prompting utility managers to lower water levels to assess needed repairs, a utility spokesman said.
The 2-inch-wide (5-cm-wide) crack appeared in the spillway of the 8,320-feet-long (2535-meter-long) Wanapum Dam, a large hydroelectric power plant on the Columbia River that currently can generate more than 1,000 megawatts of power, the utility said late Friday.
The spillway is a channel that allows surplus water to escape and is used for the controlled release of flows from a dam.
"As a precautionary measure, the water above Wanapum Dam (forebay) is being drawn down to reduce the pressure on the spillway while inspectors investigate," Grant County Public Utility District spokesman Thomas Stredwick said.
The dam, about 18 miles upstream from Priest Rapids Dam in a rural part of central Washington, was still generating electricity, Stredwick said. But lower water flows during repairs could force the utility to buy power on the open market and affect the broader Columbia River hydroelectric system.

According to wikipedia, the dam is 185 feet tall.  Based on the picture, I figured the thing must be damn long if it was that high.  Total length: 8320 feet.  Almost 1.6 miles long.

Here's a map of the dams in the Pacific Northwest (click to enlarge):