Lake Delhi dam opens gates to avoid damage

DELHI - The unfinished Lake Delhi dam was forced into operation Monday when the rapidly rising Maquoketa River necessitated the opening of floodgates to prevent damage to an earthen dike still under construction.

After persistent and at times heavy rains over the weekend pushed the river toward flood stage, employees of General Constructors Inc. of the Quad Cities reinforced part of the dam with sandbags to ensure that floodwaters did not overtop a steel wall keeping water out of the construction area.

'It was a challenge managing the flow both upstream and downstream,” said Pat Colgan, a retired civil engineer and volunteer coordinator of the effort to rebuild the dam after it failed during a July 2010 flood.

Colgan said just one of the dam's three floodgates was initially opened but that all three were opened by 11 a.m. Monday.

'We wanted to lower the water above the dam to keep it from eroding the earthen dike, but we had to do it gradually to give workers enough time to move a crane and backhoe out of the way below the dam,” he said.

Colgan said the increased flow through the gates washed out an earthen cofferdam below the dam.

'We probably won't rebuild it since we were going to need it for only another week,” he said.

Steve Leonard, president of Lake Delhi's governing board, said the rain-swollen Maquoketa River 'provided a true test” of the rebuilt dam's new floodgates and the leadership team's ability to manage and operate the facility.

'Everything worked like it is supposed to,” he said.

Leonard said the extent of the damage won't be known until the floodwaters recede.

'We're hoping that there will be no significant damage and that we can just pump out the water, clean up the mess and get back to work,” he said.

Phase one of the project, repairs and upgrades to the flood-damaged concrete portion of the dam, went off almost without a hitch. But phase two, construction of an adjacent earthen dike and concrete spillway, has been plagued with weather-related delays.

The June 14 failure of a cofferdam shut down the project until July 13 when the rain-swollen river receded enough to allow repair, and muddy conditions in late October and November further delayed progress.

Delaware County Emergency Management Coordinator Mike Ryan said flood damage at the Lake Delhi dam was 'a concern” until all three gates were opened.

Ryan said the Maquoketa River - which was projected to crest Monday night at 13.7 feet, just below minor flood stage - presented no threat to people or to property other than at the Lake Delhi dam.

Colgan said weekend rainfall totaled 3 inches at his Lake Delhi residence.