Reconstruction of Lake Alvin spillway ready to begin

YANKTON, SD (KELO) — Major repairs are planned this summer at a spot popular with boaters and beachgoers just south of Sioux Falls.

Construction of a new concrete spillway at the Lake Alvin Recreation Area is expected to begin next month.

The South Dakota Game, Fish and Parks Commission received a briefing on the project Friday morning.

Lake Alvin is southeast of Sioux Falls and east of Harrisburg in northern Lincoln County. A dam on Nine Mile Creek created it. The recreation area receives approximately 120,000 visits per year.

Heavy rains in 2019 damaged the current spillway.

Adam Kulesa is the planning and development administrator for the state Division of Parks and Recreation which manages the area.

He told the commission that a contractor had recently been selected and construction equipment would begin arriving on site on July 8.

Stormwater from Sioux Falls, Tea, and Harrisburg flows into the watershed year-round. The same goes for runoff from agricultural fields in the region.

The construction plan for the new spillway provides for the lake’s water level to gradually drop, starting July 15, at a maximum rate of one foot per day. This will eventually cause the lake to drop 10 to 15 feet.

Kulesa said the drawdown would lead to the shallower western end of the lake being temporarily out of water. During the project, parts of the recreation area will be closed, like the boat ramp and beach, he said, but the hiking trail will remain open.

Fish in the lake will gradually congregate in deeper water on the east side due to the drawdown, according to Kulesa. Fish kills this winter will depend on the severity of weather conditions, he said.

Derek Dorr is the Southeast Regional Director for the Parks Division. He said the work will include repairing water pipes and concrete, installing a new fountain and replacing the current shelter with two new ones.

Kulesa said the contractor intends to complete concreting work on the new spillway this fall and prepare the site before the spring 2025 runoff begins. He said he is confident the lake will rise quickly to the level of the spillway in spring.

“This lake remains very consistent,” Kulesa said.

The swimming beach will reopen next spring. Water quality issues have forced the lake to be temporarily closed to swimming several times in recent decades. Kulesa said planned improvements won’t solve that problem.

The improvements also include a new low-water outfall that will aid fish management.

According to the GFP webpage for the recreation area, “it is named for Alvin Dempewolf, Harrisburg’s only World War soldier who died overseas.” Construction of the dam was completed in August 1954 and the lake completely filled in 1957. The dam’s concrete spillway was completely replaced in 1994.”

Kulesa said the current project would cost between $4.5 million and $5 million in total. He said the Lincoln County Commission will receive a briefing on June 25.

The Legislature allocated $6.5 million in 2022 for work at Lakes Alvin and Newell. This was not enough and the Legislature this year sent an additional $1,995,604 for the two projects. Funding from the Federal Emergency Management Agency will also help fund the Lake Alvin work, Kulesa said.

Commission Chair Stephanie Rissler of Vermillion asked about public information plans. Dorr said there will be advertising and signs on the radio.

“I’m trying to get the message out as best we can,” Dorr said. “Trying to mitigate it as best we can.”