Opening of the floodgates at the Ameren Missouri Bagnell Dam plant is one of those double-edged-sword scenarios.
The reason behind the need to open the gates is to manage the lake level after major rainfall in the Osage River basin and to prevent upstream flooding, dock damage and shoreline damage. Flooding downstream is always a concern as well, and Wednesday morning's toad strangler of a rain forced the evacuation of Camp Bagnell and the Riverview RV Park, which abut the river.
And, of course, there is damage to farmland below the dam, and the potential loss of livestock.
An upside to opening the floodgates is the spectacle of watching tens of thousands of gallons of lake water rush down the spillways into the Osage River.
Hundreds of people waited patiently Wednesday morning for the warning sirens to signal the opening of the gates. One woman said she and her husband had been there since 8 a.m. The first gate opened about 11 a.m. after emergency management officials were certain areas below the dam had been evacuated.
Cars and onlookers jammed both ends of the dam; spectators were lined up along the sidewalk on the dam and watched from the Ameren Missouri roadway above the river.
"I've seen it several times, and it's still an awesome sight," Bagnell Dam plant engineer Alan Sullivan said Wednesday morning.
The last time the floodgates were opened was May 20, 2011. While many area residents suffered damage to their homes, vehicles and personal belongings because of the flash flooding in low-lying areas earlier this week, Sullivan said the event isn't a major flood in terms of either lake levels or total outflow through the dam.
"The biggest issue was flash flooding when seven inches of rain fell between 2 and 6 a.m.," he explained. "The Osage River at the dam rose by six feet in three hours between 4 and 7 a.m."
And that was before the floodgates opened, which was expected to raise the river at least four more feet.
"We can handle flows as they are now with no major problem," Sullivan said. "However, we certainly recognize the serious flooding downstream resulting from the heavy rain on the river and outflow from the lake."
But the potential for more rain the remainder of the week has Ameren officials concerned.
"Wet grounds and heavy rain will result in more high flows into the lake and downstream," he said.
Bagnell Plant officials opened 11 of 12 floodgates between 11 and 11:30 a.m. Wedesday at only 10 percent capacity for a total increase in inflow into the river from 37,000 cfs (cubic feet per second) to 47,144 cfs as of mid-afternoon Wednesday.
Page 2 of 2 - That put plant officials in a holding pattern until they re-evaluated the situation later in the afternoon.
According to Ameren's website, the lake level was still peaking at 3 p.m. Wednesday at 660.74. Full pool is 660 feet above sea level.
What's the highest the lake has ever been?
Sullivan said records indicate the lake reached 665.45 in 1943, and 664.3 in 1986 which was after Truman Dam was built to help manage inflow.