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Tennessean in-depth report: Army Corps of Engineers struggled with dams, forecasts

11:13 AM, May 9, 2010   |    comments
May flooding in downtown Nashville included the Titan's LP Field. Courtesy: Tennessean
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Written by Brad Schrade and Anne Paine, The Tennessean

When Mike Ezell left his overnight shift commanding the Old Hickory Dam on the morning of Saturday, May 1, he had no reason to think the next two days would be the most difficult of his 35-year career.

The lake was resting normally, at 444 feet above sea level, just as it had been when he started his shift 12 hours before.

But as he slept throughout the day, awaiting his next shift that evening, the weather changed dramatically. Rains that had swept in from the west intensified, and by the afternoon, creeks and tributaries throughout Middle Tennessee were spilling over their banks. TV was looping footage of a building floating down Interstate 24.

As Ezell drove back to work that evening, he saw an unfolding chaos, checking the usual markers along the way--storm drains, creeks and tributaries--all of them swollen with water.

"I knew it was going to be bad, but I didn't have any idea how," said Ezell, a powerhouse shift manager with the U.S Army Corps of Engineers.

By Sunday night, water was ripping through the heart of Nashville. The Gaylord Opryland Resort & Convention Center had evacuated 1,500 guests. Water was quickly rising into downtown streets. And residents in Bellevue, Antioch and other areas had been scrambling throughout the day to save any possessions they could--or simply survive the flash floods.

The epic rainfall, along with calculations and decisions made by a series of agencies and also inside Mike Ezell's control room during last weekend's historic floods, plays a central role in understanding how this disaster was able to wreak so much havoc in Nashville and across the region.

U.S. Sen. Lamar Alexander has promised a Senate committee hearing to understand what happened. Gaylord Entertainment Chairman and CEO Colin Reed continues to agonize over why emergency personnel had told him the Cumberland would stay below protective levees around the hotel, while his own security staff witnesses a more urgent situation.

For their part, Army Corps of Engineers officials say they see nothing they would have done differently--in fact, they say their actions prevented even further damage to downtown and a washout of the MetroCenter business district.

The Tennessean examined Corps maps, flood models, dam release data and lake level reports as well as conducted interviews with key Corps officials to piece together the events that saw Middle Tennessee's greatest flood on record since a series of dams were built in the 1950s, '60s, and '70s along the 687-mile Cumberland River.

No disaster expected

Two to 4 inches of rain was forecast for the Nashville area Saturday and Sunday--not the more than 17 inches that fell in some areas--as Bob Sneed and his wife set out from their Springfield home on April 30 for their weekend retreat near Lake Barkley.

Sneed, who for almost six years has served as the Army Corps' chief water manager overseeing the Cumberland, grew up in Goodlettsville and is a Vanderbilt engineering graduate. He has been with the Corps for three decades.

By Friday afternoon, the weekend rain forecast had grown increasingly wet, with some flash flooding expected.

Back in Nashville, Carol LeStourgeon, one of Sneed's most experienced assistants, was scheduled to run the water management office that Saturday. The office is the nerve center where decisions are made on how much water to release and keep in each of the Cumberland's 10 dams.

The aging federal dams--some in the midst of critical repair work--are relied upon to balance a variety of competing interests, including barge traffic, drinking water systems, aquatic life, lakefront homes, fishing, power plants and boat docks, among others. The Corps is charged with the high-wire balancing act of managing these needs while protecting the public through a system designed to control floods.

While the weekend's rain forecast meant small tributaries and creeks could fill up, the Cumberland was expected to handle the additional water without major flooding.

But by Saturday morning things began to change. Sneed started receiving phone calls from LeStourgeon that morning, each one warning of worsening conditions. The forecast put out for Sunday had grown worse as well, and Nashville and the Cumberland watershed could be in the bull's-eye of the storm. By noon, Sneed decided to come back.

"The river was getting juiced--primed," Sneed said. "There was a lot of water coming through the system."

That afternoon, as he drove through the storm, the National Weather Service issued flood warnings for Middle Tennessee. Up to 10 inches had already fallen in some areas. Mill Creek, which feeds into the Cumberland River across from Shelby Bottoms, had become so flooded that its waters engulfed I-24. pushing cars and even buildings along the interstate.

Even with the heavy rains, much of Middle Tennessee continued to conduct its business Saturday afternoon.

But at Old Hickory Lake, water began rising quickly. Water was already moving through the dam as usual to generate electricity, but authorities decided to open the spill gates to relieve the growing lake levels at 1 p.m. Saturday, according to Corps records.

Some question why they didn't release more water earlier in preparation for the heavy rains.

"At that time on Saturday morning we still didn't have a forecast that looked like anything that followed up," Sneed said.

The standard protocol is not to release water until a pool fills. Releasing a little extra water can simply put more flooding on those farther downstream, he said.

Downstream, flooding was already under way as Mill Creek, the Harpeth River, the Red River and other streams grew with the rainwater that would be dumped into the Cumberland.

"We could have pulled half a foot out of Old Hickory, if you assured it wouldn't cause harm downstream. That's still very little storage and would be filled back up quickly. It wouldn't have changed the crest (on the Cumberland) at all on Monday evening."

At 5:30 p.m., the National Weather Service issued more flood warnings and the dangerous conditions had spread to counties to the east.

By 7 p.m., the Cumberland River in downtown Nashville had risen more than 10 feet that day. That was when Sneed arrived at the office.

"I started making calls and lining folks up."

About this same time, downriver to the west at the Corps' Cheatham Lock and Dam, the crew there faced a crisis. Rising waters were overtaking the entire facility, which is one of the smallest in the river. The crew shut the turbines off and started to evacuate.

They placed the mobile electronic equipment that operates the lock into trucks and left before the facility was submerged. Furniture and files in the office were destroyed. The floodwaters moved in so fast and spread so wide that the Corps even lost parked vehicles that couldn't be evacuated in time.

The dam that sits about 10 miles up river from Clarksville became a "bump in the river," Sneed said.

"It was designed to overtop like it did," he said, as he looked at a photograph of the flooded facility. "Obviously based on this we've got a lot of damage. But there wasn't a threat to losing the dam. If that happened at Old Hickory or Cordell Hull you've got a big problem."

But at this point, much of the Corps' focus was around Nashville, with rain continuing and the little fingerlets of streams that lace the area pouring into the already racing and spreading Mill, Richland, Whites, Browns and other creeks that feed into the Cumberland.

Lake overwhelmed

At Old Hickory, inside the control room, Ezell's adrenaline started to rush Saturday night. He had reported back to work at 6:30 p.m. for another 12-hour shift. As the evening wore on, the lake--just feet away--would continue to rise and more water had to be released through the gates toward Nashville.

From noon Saturday to 7 a.m. Sunday, the Corps made adjustments to the flood gates 10 times as they struggled to manage the massive amounts of water that were flowing from tributaries into the lake.

At Old Hickory, by the time Ezell left at 6:30 a.m. Sunday, the river in downtown Nashville had risen nearly 10 feet higher, and was just 3 feet below the 40-foot flood stage, according to Corps records, even though there had been nearly a seven-hour lull in the rain.

Ezell arrived home and was exhausted. He tried to relax by telling his wife about the shift before she went off to church then tried to fall asleep, though his mind was racing.

"This is the worst I've ever seen it in my career," Ezell said later. "This was the worst. The lake elevation went up faster than it ever has since I've been here."

Old Hickory Lake, while it looks large, is small when it comes to holding storm runoff. It sits in the flow of the Cumberland River, and was not designed as one of the four, deep flood control projects in the Cumberland system. The flood control projects are J. Percy Priest, Center Hill, Dale Hollow and Wolf Creek.

But Sneed was still hopeful Sunday morning that the raging stormwater pouring into the lake could be managed. When he left his home in Springfield Sunday morning, he knew it was going to be a difficult day.

He'd packed a change of clothing in the anticipation that he may get stuck in Nashville that night. The roads were treacherous.

The water at Old Hickory had gone up 2 feet from the night before to 447.88 feet above sea level, and it was getting closer to the critical 452-foot mark. At the 452 level, the Corps has few options. They either let the water flow over the dam, which undermines the dam, or raise the spill gates and create a controlled free-flow.

Either scenario leaves communities downstream vulnerable.

"We're trying to hold it," Sneed said. "We're still hopeful at this point on Sunday morning we're going to keep Nashville below flood stage. We're holding back."

Dam crew in a bind

Within hours, those hopes were shattered. The heavy rains that morning kept pouring water into the Cumberland basin. By 10 a.m. Sunday, downtown Nashville had reached flood stage of 40 feet. Water level at Old Hickory Lake, above the dam, had climbed almost two more feet to 449.40.

Ezell had been home only a few hours, when his phone rang. It was Chris Campbell, the powerhouse shift manager who'd relieved him earlier in the morning. He needed backup.

When Ezell arrived at 11 a.m., the water had risen again, and it would keep rising for the next three hours before leveling off at 451.45, just a half foot from the water spilling over the gates.

Ezell knew the situation was getting tense. The phone on the control panel was ringing off the hook. With rains pouring, two men were ordered to the top of the dam to handle the increased spill gate movements.

The dam crew, taking directions from Sneed's office, was trying to get control of the water pouring into the lake, while trying to minimize flooding downriver. Three or four hours after Ezell arrived, they called in more help. They were trying to shut down lights and electrical equipment in areas of the dam that were going to be underwater.

"It's real, real hectic," Ezell said. "You're monitoring your headwater elevations. You're in communications with the hydraulics department in Nashville. They are constantly calling to get information from us. We're making calculations. They're making calculations. We're giving the guys orders to go out with the gates. There's a lot of steps we have to take to secure the project as the water is going up. It gets real busy."

At one point, Campbell turned to Ezell. "He's looking at me asking me, have I ever been through anything like this. I'm saying no. I have more experience than he does and he was leaning more on me. And I was trying to calm him down. We just supported each other through this thing."

Priest Lake fills up

By Sunday afternoon, the Cumberland river in downtown Nashville had reached 45.64 feet as Mayor Karl Dean, his police chief, fire chief and others stood in the lobby of the city's emergency management building atop a hill near Belmont University.

The rains were scheduled to pass that evening and predictions were the crest would come through downtown around 48 feet sometime Sunday night. At Old Hickory Lake, the discharges would reach more than 200,000 cubic feet per second by 6 p.m. that evening--three times the amount passing through the dam when the day started, according to Corps discharge data.

And there was another problem emerging. J. Percy Priest Lake, which dams up the Stones River, and flows into the Cumberland between Old Hickory Dam and downtown, was filling up fast. The Corps had hoped to hold back water from Percy Priest, to allow the waters from Old Hickory to pass through downtown, and shave some feet off the flood crest.

But the furious rains Sunday had disrupted that plan. Waters at Percy Priest had climbed four feet Sunday to reach 498 feet above sea level when the day closed--that's six feet below the top of the dam.

Opryland began evacuating Sunday evening and city officials started to raise concerns about a leaking levee in MetroCenter, causing an evacuation there. Sneed slept over in Nashville that night.

'It's real violent'

When Ezell reported back to work at Old Hickory at midnight Sunday, he heard the scream of the waters flowing through the spill gates. It sounded like a jet engine as the muddied waters filled with trees and debris slashed through the dam gates in a violent brown fury.

"My anxiety level went up again," he said. "When you pull in you see how much we were discharging. I knew it was higher than I'd seen in a long time. When the gates are open like we had them open right at the dam it's real violent."

Ezell was concerned about what was happening downstream and what damage the waters may cause, but he believed there was no other choice but to release water from Old Hickory or risk losing control.

"I guess most things that you think about that's weighing on you is 'Am I doing everything that I can? Am I doing everything correct because you know the gravity of what's going to happen if things go wrong.'"

By the time Ezell left at 6:30 that morning that waters on Old Hickory had dipped below 451 feet, and would drop below 450 by noon. Originally, the Cumberland had been expected to reach its highest point overnight, but it was still rising when Sneed arrived at the office Monday morning.

"It was very disappointing to see we had not crested, but also to get the new of (the Opryland) levee," he said. "It bothered me when it happened. I was in Nashville in 1975 (last time Opryland got flooded). I wasn't a Corps employee. I remember when that happened."

Dam releases necessary

As the floodwaters continued to pour over the banks of the Cumberland in downtown Nashville on Monday, the Corps' work was not done. The water kept rising at J. Percy Priest Dam, reaching 504.01 feet by 6 p.m. Monday as the water crested that same hour in Nashville at 51.86 feet.

City and state officials were anxious throughout Monday that Nashville's remaining water treatment plant off Omohundro Drive be spared. Sneed said that was on the Corps radar as they made decisions throughout the day, but didn't change their operations.

The Corps' leadership believe the actions of their team during the 48-hour storm that dumped a record 13 inches at the Nashville Airport, and more in some places, lessened the possible damage.

They held the Percy Priest Dam level above 444 feet, near the top of the dam, from late Monday until late Thursday, measuring releases to minimize problems downstream, they said.

"You're talking about controlled releases versus uncontrolled releases," said Lt. Col. Anthony P. Mitchell. "You run a serious threat to the population when you have uncontrolled releases. Uncontrolled releases could have resulted in about an additional four feet of water in Nashville."

Flooding takes top priority, and protection of the dams to prevent whole communities from being crushed by the walls of water behind them is part of that.

"I know that they have to release water when the dam overflows," Alexander said Friday, on his way to Clarksville to see the damage there.

"They have no choice. So I don't find fault with the operations. We can look into it."

But he said he would like to see better information available that's more accessible to a homeowner or businessperson worried about whether to move to high ground. Something more like the way tornadoes are tracked on television, radio and media websites.

The Corps isn't the one providing data for potential flooding. Those predictions, which changes as factors change, come from the River Forecast Center of the National Weather Service, using Corps water level information on the Cumberland, gauges and local reports on streams and creeks from trained volunteers and professionals. Rain forecasts are part of the modeling, too.

From there media and emergency management agencies take over, getting out the word.

"Looking back, it went pretty well," James LaRosa, a hydrologist with the weather service in Nashville said of the forecasts. "It's pretty good but like any science, there's certainly a little bit of uncertainty."

The Corps knows accusations and rumors are already afoot that it might have flooded people on purpose or failed in other ways that caused unnecessary damage downstream. In fact, the Corps is not sitting by idly while the talk festers. Their public affairs office is planning to include a link on its website for the public to ask about rumors or other questions they have about their actions during the flood.

"The amount of rain was far more than what was forecasted and it landed in areas that weren't really equipped to hold that," Mitchell said. "There were a number of lives saved and a considerable amount of damage that was minimized. Public safety is our number one concern when operating those dams."

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