Despite setback, Lake Delhi project on track

DELHI - Despite losing a month's prime construction time this summer, Lake Delhi officials still believe they can complete a new spillway, close the gates and start refilling the Maquoketa River impoundment yet this fall.

'Our expectation, weather permitting, is that the project will be completed in late fall and we can start refilling the lake,” said Steve Leonard, president of Lake Delhi's governing board.

The June 14 failure of a coffer dam - a steel wall designed to divert the river from the dike construction site - shut down the project until July 13 when the rain-swollen river receded enough to allow repair.

Since then, contractors have hauled in about 12,000 cubic yards of clay to build the base of the 235-foot-long earthen dam that impounds the river.

'We are now transitioning from clay work on the base to concrete work at the top of the spillway,” Leonard said.

Contractors found good clay deposits within a mile of the dam site, yielding short hauls that expedited the work, Leonard said.

'It's a far superior dike to the one that failed. The clay is almost impervious to water,” said Pat Colgan, a retired civil engineer and volunteer project coordinator.

The dam failed following heavy rains on July 24, 2010, sending the lake's contents flooding downstream. The lake community of more than 800 residents has since been without their lake.

Colgan said it takes time to shape and compact the clay and ensure that it won't leak or settle.

'Ten years from now no one will remember the month the dike was finished, but they would never forget a leaky dike,” he said.

Phase 1, repairs and upgrades to the concrete portion of the existing dam, has been completed at less than the budgeted cost, Colgan said.

The time required to refill the lake will depend on the flow of the river, he said.

'As a condition of the permit to rebuild the dam, we must maintain a minimum flow of 83 cubic feet per second. We expect enough excess flow in March and April to refill it,” he said.

Colgan and Leonard said more than 100 volunteers showed up on Aug. 1 to remove willows and other unwanted vegetation from the lake bed. A similar work day will be held in September, Leonard said,

About 450,000 bluegill fingerlings and 450 adult largemouth bass will be stocked in the refilled lake next April and May, said Department of Natural Resources fisheries biologist Dan Kirby. The adult bass will reproduce, and their progeny will eliminate the need for further bass stocking, he said.

River-dwelling game fish - walleye, catfish, northern pike and smallmouth bass - will recolonize the lake, he said.

Adult black crappies will be stocked in 2017 and adult white bass in 2018, Kirby said.

'I do think we will see a new lake effect with rapid growth of the stocked fish,” he said.