Dam failure could spell the end of Iowa's Lake Delhi

Delhi, Iowa — Lake Delhi, which has provided a summer retreat for generations of northeast Iowans, could be history.

The lake was created in the 1920s, when a hydroelectric dam was built on the Maquoketa River. The dam was breached Saturday after extraordinary rains pushed the lake level to unprecedented heights. Most of the lake water is now headed downstream.

About 900 cottages and homes line the lake, and owners fear their property values will drain away. "We just don't know," said Maggie Burger, a cabin owner and executive director of the Lake Delhi Recreation Association, which owns the dam. "We're kind of in a place today where we're not going to have lake water for a while because there's nothing to hold back the water."

The home values range from about $50,000 to $500,000. The properties are now sitting dry docked.

A state expert said the dam had a typical design, and although it was 88 years old, it was well maintained and operated.

"There was just more water than it was designed for," said Jon Garton, a dam safety engineer for the Department of Natural Resources.

If it is rebuilt, the dam would have to meet modern design requirements, Garton said. That could prove costly. "We would hold them to a higher standard so this couldn't happen again," he said of the failure. The decision on whether to rebuild would be up to the homeowners association.

The dam was built in 1922, and it originally had turbines to generate electricity, Garton said. The turbines were removed around the 1960s, he said. Ever since then, the dam served solely as a way to maintain Lake Delhi for recreational purposes, he said. It was not meant to serve any flood-control function, as some Iowa reservoirs are.

The dam's center is made of concrete, and it appeared to hold up, Garton said. The sides are earthen, and the south side failed after water poured over it.

Garton said Iowa has dozens of similar "low-head" dams, though most are smaller than the one at Lake Delhi. He said most are about 10 feet tall. The one at Lake Delhi was about 50 feet tall.

The natural resources department inspects dams every five years. The Lake Delhi dam was last checked in 2009. The inspector found minor damage left over from 2008 floodwaters, but nothing that could have led to the dam's failure, he said.