A month has passed since the September flooding ravaged through South Dakota, but a couple rural lakes are still reeling from the disaster.
In the midst of the Sept. 11-12 rainstorm that brought 8 to 10 inches of rainfall to the Hanson County area, the auxiliary spillway responsible for maintaining the water levels of Lake Hanson collapsed, draining nearly the entire body of water. What used to be a 61 acre spring-fed lake is now a small stream.
“The lake filled at a rapid rate that night and into the morning hours, and it got to the point where that auxiliary spillway just couldn’t hold back the volume,” said Julie Brookbank, a member of the Lake Hanson Board of Directors. “Once that washed out, the lake basically drained out.”
Brookbank was one of several Alexandria locals with a lakefront property who witnessed a full body of water dissipate into a small creek in less than 24 hours.
The rural lake that sits roughly 15 miles east of Mitchell utilizes two spillways -- one on the north side and one on the south side -- of the lake, allowing water from Pierre Creek to flow in and out of the lake. On the south side of the lake sits the auxiliary spillway, which was put in place to allow runoff when the water levels of the lake significantly rise beyond the average height.
Brookbank said the auxiliary spillway gave out due to the increased volume of water spilling over into Pierre Creek during the torrential rainstorm.
Hanson wasn’t the only rural community that temporarily lost its local lake in the flooding. Roughly 70 miles southwest of Hanson County sits another empty lake on the edge of Platte, a direct result of the same Sept. 11-12 rainstorm.
In the 12 years Tom Steinhauser has resided in Platte, never has he experienced an extreme rain like the one last month.
“The guys I talked to who have lived here for many years have never seen something like this before. The water was so extreme that it took the road right out,” said Steinhauser, co-owner of the Platte Creek Lodge. “Hopefully we can get our lake back."
Unlike Lake Hanson’s spillway failure, the root cause of Lake Platte’s drainage and destruction was the Platte Lake Road washing out near the spillway on the south side of the lake. According to Steinhauser, the spillway that sits along the Platte Lake Road managed to stay intact throughout the severe flooding.
“I know the spillway was built around the 1930s and 1940s, and it’s lasted a long time. I haven’t heard of the road giving out like it did, and it just shows you how much water we got during the storm,” he said.
Retracing history of rural lakes
To Steinhauser’s recollection, the Platte Lake hasn’t ever experienced a natural disaster that’s drained the lake.
However, that’s not the case for Lake Hanson. In 2007, Brookbank said the same auxiliary spillway gave out in the middle of a severe rain event.
“After that breakage, the lake was essentially empty in the matter of a couple of hours,” she said of the 2007 spillway failure. “That was a horrific rain event as well, which happened in about a 24-hour period.”
Considering the 2007 spillway failure occurred in May, Brookbank said Mother Nature allowed the board of directors to vet for a solid replacement.
According to Brookbank, it took roughly 57 days for the spillway to be reconstructed. Once it was finished in June of 2007, the lake filled up to capacity in less than two weeks.
“We were able to have the new auxiliary spillway engineered and put in place by the end of June,” Brookbank said, noting the winter months looming add more pressure for the reconstruction of the same spillway. “The board is taking a look at what sources we can pursue to help fund the work and who can do the work, so all the same questions we had in the past aren’t unfamiliar to us.”
Regardless of how the funding and timeline will take shape over the next few months, potentially reaching into the spring of 2020, Brookbank said the Lake Hanson Board of Directors is focused on bringing a full body of water back to life as soon as possible.
While the future remains uncertain for both rural lakes, there’s a shared optimism between Platte and Hanson locals.
With the long history of cattle grazing along the lake, paired with agricultural runoff flowing into the body of water, Steinhauser said the Platte Lake isn’t known for great water quality.
“I think it could be a blessing in disguise, if we can get some of the sediment cleaned out before water flows back into the lake,” Steinhauser said. “With it being dammed back in the early 1930s, there is a lot of runoff that has been funneling into the lake, but farming practices are starting to change in a good way.”
Considering the local golf course sits along Lake Platte, Steinhauser said revamping the lake could be a huge asset for the community.
“It would be nice if it could turn into a fishing destination of some sort, because as of now it’s full of rough fish,” Steinhauser said, noting carp and bullheads are the primary fish inhabiting the Platte Lake.
Jeff Smith, Mitchell city councilman and Alexandria native, said there is an opportunity for Lake Hanson to implement a sturdier auxiliary spillway to withstand severe flooding events.
“It’s not a big lake, but it provides nearly the same amount of recreational activities as most lakes,” Smith said. “Beings this isn’t the first time the spillway has done this, it could potentially allow for a better spillway.”