Corps: Wappapello spillway sound despite overflow

WAPPAPELLO LAKE, Mo. -- The Wappapello Lake spillway is structurally sound, even with an overflow at times as high as 228,000 gallons of water per second.

This was the information provided Tuesday afternoon to Maj. Gen. Michael Walsh, president of the Mississippi River Commission, as he viewed the fast flowing water and damaged Route T from a hill near the Bill Emerson Memorial Visitor's Center.

Wappapello Lake crested at 400.03 feet Tuesday morning. It had risen an additional 2.8 feet since first overtopping the spillway at 2 a.m. Monday.

The lake was at 399.58 feet as of 9 a.m. Wednesday, still nearly five feet above the overflow spillway. The U.S. Army Corps of Engineers predicts lake levels will not drop below the spillway until next Wednesday, if no further rain falls.

"There has been no movement whatsoever (in the spillway wall)," Col. Thomas O'Hara, in charge of the U.S. Army Corps of Engineers St. Louis District, reported to Walsh.

Visitors only see a small section of the 740 foot long concrete structure that makes up the spillway, according to engineers. It extends down about 30 feet, including at least 10 feet into the bedrock. The top is 8 feet wide and slopes down to a concrete shelf 60 feet wide.

The high velocity water will not damage the spillway, but has sliced away sections of ground in a similar pattern to the 1945 overflow, according to O'Hara. The 2011 flooding also swept away a 400 foot section of Route T, a main road between the city of Wappapello and U.S. 60.

"We're going to be running water across here, if we don't get anymore rain, for nine days," O'Hara said. "At that point, we have to look at how to put this back together."

Walsh acknowledged it would take a long time to repair the damaged area.

Wappapello Lake Operations Manager Cindy Jackson said the Corps of Engineers will work with the Missouri Department of Transportation to develop ideas for how the area will be restored. MoDOT estimates the road contained $18 million in infrastructure, including water, phone, electricity and sewer lines.

"It probably will not go back in the same location," she said of the road, adding the goal will be to prevent this from happening again.

Plans are to make improvements to the area known as Iron Bridge Road while the main route is impassable, Jackson said, including adding gravel.

Walsh inspected flood impact maps of the area below Wappapello Lake before viewing the damage by the spillway. He questioned how communities downstream would be impacted by the volume of water topping the spillway.

"This is record level flows for them," O'Hara said. "Fisk is the first community impacted and they are ready."

The Corps has worked since heavy rainfall moved into the area more than a week ago to notify the public of the fast rising lake levels.

The St. Francis River at Fisk crested at 27.1 feet at 2 a.m. Wednesday. There has not been any flooding in Fisk, where previous high river levels barely topped 23 feet.

The dam is operating as it should, Walsh confirmed. The gate house is closed at this time because of the amount of water topping the spillway. It will remain closed until that amount falls.

How to repair the area damaged outside of the spillway and plans to open the visitor's center to the public are topics the corps is considering carefully, according to officials.

"We're just beginning to establish a process in terms of what it will take to bring this system back online and being able to maintain normal operations," O'Hara said. "We want to get back to a fully functioning site as soon as we can."

Wappapello Lake workers are divided between two operation points at this time, one at Redman Creek Picnic Shelter 1 and one at the visitor's center. They are traveling between the two locations by boat. Electricity, sewer and phone systems are limited at the temporary operation points. The main project office is intact, but does not have phone or sewer at this time.

Walsh and O'Hara praised the Wappapello Lake staff for what they have done during this emergency.

"The staff is doing amazing work," O'Hara said. "They are part of this community and they feel the pain high water is having on this community. We've had to force some of them to go home because they felt so committed."

Pertinent address:

Wappapello Lake, MO

Fisk, MO