A little over two months after a potential flooding crisis threatened Manhattan, Brian McNulty says the outlook on Tuttle Creek Lake depends on if you’re a lake-half-full or lake-half-empty kind of person.
McNulty, operations manager for the U.S. Corps of Engineers at the lake, said his team’s workload is smaller now than it was in late May, but the Corps is still keeping a close eye on the lake’s water level, which stood at 1,114.71 feet above sea level Friday morning.
Despite drastically increased outflows from the lake in June and July, the lake only recently fell below 50% of its flood control space, and a high Missouri River — where Tuttle Creek Lake’s water ends up — as well as seasonal outflow restrictions mean the lake will drain slowly. Rain from this past week has caused the lake to hover around 1,114 feet.
“We’re waiting for downstream conditions to drop so we can continue to make more releases,” McNulty said. “Tuttle Creek, Milford, Harlan County, Clinton and Perry lakes still have a good part of their flood pools filled right now, so there’s still quite a bit of water that has to be moved downstream. The Missouri River between Kansas City and St. Louis, Missouri, is still above flood stage, so that’s been limiting our outflows from the Kansas River.”
Still, it’s a far cry from May 31, when the lake peaked at 1,135.84 feet, just inches from the top of the dam’s emergency spillway gates. If the lake threatened to spill over the gates, dam officials would have considered opening the gates to preserve the dam’s structural integrity. The resulting water torrent would have likely caused significant flooding in neighborhoods just downstream the dam, like it did in 1993, the only time the Corps has ever opened the dam’s emergency spillway gates and the only time the lake level has ever been higher.
Back then, the situation seemed dire. Officials put out an evacuation advisory, which warned residents in affected neighborhoods that there was a substantial risk of flooding in the next 24 to 72 hours. Although that notice never escalated to an evacuation order, emergency personnel went door-to-door in those neighborhoods urging residents to make emergency plans and even consider voluntarily evacuating.
But the lake level subsided after careful calculations from the regional Corps office allowed local lake officials to increase Tuttle Creek Lake’s outflows to a record 30,000 cubic feet of water per second from its stilling basin. Those rushing flood waters did cause some flooding along the Big Blue and Kansas rivers downstream the lake, but the damage never crept to residential areas.
High outflows continued through June and July, and now with the lake level down, both the lake and its officials have a lot more breathing room.
“There’s minimal flood risk on the Blue River with the lake half empty,” McNulty said. “Even if we start to release more water from the lake, it should stay within the channel of the Big Blue.
“We’re not working nearly as much overtime now as we during the peak of the lake in late May and June,” McNulty continued. “The workload has dropped just because the lake is back down in the flood pool and we have some storage space available.”
With the lake level down, McNulty said the Corps has started to see some of the damage done by the surging flood waters. He said waves in the flooded campgrounds swept away a lot of top soil, and three buildings at one of the campgrounds were completely destroyed.
Although Tuttle Creek State Park, which is managed by the Kansas Department of Wildlife, Parks and Tourism, is open with minimal flood damage, all of the Corps’ campgrounds at Tuttle Creek Cove and Stockdale Park remain closed for the rest of the season, and McNulty said some might still not be open next year.
This summer also served as a reminder for property owners along the lake that the water level will occasionally creep onto their properties, McNulty said. Most of the Corps’ easements on those properties go up to 1,140 feet above sea level.
Although the Corps only manages operations at the dam, McNulty said coordination between his team and area emergency management officials went very well during the flood scare.
Vivienne Uccello, city public information officer, said the Manhattan Fire Department and Riley County Police Department incurred $25,000 in additional manpower and supply costs during the flood situation’s emergency response phase. However, the true cost of this summer’s flooding won’t be known for months, she said.
“There are still roads and bridges underwater in Riley County and Pottawatomie County, and the city is still responding to infrastructure damage caused by flooding,” Uccello said. “When thinking about the impact, it’s important to consider the opportunity costs, as well. County and city staff continue to be pulled away from their regular duties, meaning there are fewer resources available for other projects including road repairs.”
Like most of the Corps’ dams across the nation, Tuttle Creek Lake was built as a flood control tool, and McNulty said the lake “did the job it was meant to do.”
“The lakes are all managed in accordance with the water control manual, and the bigger the flood, the closer we follow that manual,” McNulty said. “The downstream conditions, when there’s space available — they dictate what the outflow is.
“I know there is some criticisms that we didn’t release water when the lake was coming up, but if you look downstream, the reason we didn’t release more is because there was so much flooding in addition to what we were storing upstream of the dam,” McNulty continued. “Everybody had their share of water this year in the whole basin. There were a lot of people who were flooded both above and below the lake, so the lake did what it was designed to do, and we operated it in accordance with the manuals.”