HARRISBURG, S.D. (KELO) — The spillway replacement project at the Lake Alvin Recreation Area south of Sioux Falls is nearing its completion.

It’s a case of out with the old, in with the new at Lake Alvin, as crews are preparing to pour more cement at the spillway.

Penn State volleyball set for Pentagon Aug. 25

“This is a complete spillway replacement project,” South Dakota Game, Fish, & Parks Regional Supervisor Kip Rounds said.

The project was deemed necessary after flooding damaged the structure in 2019. After lowering the water level last July, the old spillway was removed and is being replaced by a 70′ wide stepped chute spillway.

“The previous spillway had a straight, smooth chute, spillway chute where the water flowed down, this new spillway has a stepped design, and you’ll notice looking at that, the purpose of that is to help reduce the water energy as it goes over the spillway and into the stilling basin to help further reduce erosion,” Rounds said.

Kip Rounds is a Game, Fish, & Parks regional supervisor and says with the water level down, there were also upgrades made to the beach area.

“We added some fish habitat structures to the lake basin. They’re exposed right now but once the water level is back to normal they’ll be underwater,” Rounds said. “We’ve also got some improvements in the park, so we added two new picnic shelters in the park near the beach area, as well as a new vault toilet at the beach area,” Rounds added.

The final step is to bring water levels in the 105-acre lake, which are down more than ten feet, back to spillway elevations.

“We anticipate with normal spring precipitation and the size of the watershed, we expect Lake Alvin to be filled up certainly this year, and likely this spring,” Rounds said.

With the beach area and boat ramps re-opening to the public in May.

Crews hope to have the last of the cement stairs poured by the end of this week, or early next week. Rounds says substantial completion of the project is scheduled for March, and final completion in May.