When the dam jams

Jan. 26--Two Januarys ago, a Leaburg Dam motor failed catastrophically, creating a costly and troubling problem that the dam's owner, the Eugene Water & Electric Board, expects to take much of the rest of this year to fix.

On Jan. 19, 2012, the McKenzie River was running high, so the sound of the dam parts breaking -- a 3,000-pound iron rotor shattering and a 90-ton metal dam gate dropping 9 feet into the river -- apparently were drowned out.

Dam operators that day were trying to deal with a pile of debris that had pressed against the dam's No. 2 roll gate.

In especially heavy rains, branches, leaves, roots and sometimes even whole trees are washed into the McKenzie from the Leaburg Dam's 1,081-square-mile drainage area.

The rains were heavy that day. The Leaburg rain gauge measured more than an inch before the day was over. The previous day had been even wetter.

Dam operators were well aware of the problems that huge masses of tree debris could cause at the dam.

On the very same day the previous year -- Jan. 19, 2011 -- they were trying to clear storm debris that had stuck underneath the No. 1 dam gate, causing EWEB concern that the gate couldn't be shut and therefore would allow Leaburg Reservoir to drain completely when the rains stopped.

When debris gathers against a Leaburg Dam roller gate, EWEB crews try to "flush" it under the gates by lifting the gates high.

The Leaburg Dam has an unusual design that was favored in the United States in the late 1920s and early '30s. Not long after, it became obsolete.

Three rolling-pin shaped "rollers" with concrete piers in between them are strung across the river, holding back Leaburg Reservoir. The dam spills water by raising the rollers on tracks recessed in the dam piers.

The system's design flaw, the U.S. Army Corps of Engineers determined decades ago, is that the debris piles up and the dam operator has to raise and lower the gate to try to flush it out. The corps would later try submersible roller gates that instead can be lowered beneath the water surface to let accumulated junk flow over the them.

Leaburg Dam operators are experts at coaxing the junk underneath the rollers, said Terry Liittschwager, a retired commercial pilot who for half a century has owned a house near the dam and watched its operation.

"You'd have to jockey (the gates)," he said. "Some people got really good at jockeying them."

In the January 2012 incident, the No. 2 roller gate, in the center of the dam, stuck shut rather than remaining open.

Crews had raised the gate up to 9 feet in the debris-flushing maneuver, but then something inexplicable happened.

Suddenly, the 90-ton gate was in free fall, and the water gushing under the dam was stopped.

The dam operator had to quickly raise gates No. 1 or No. 3, or both, to keep water moving through. It would have taken about two minutes to re-establish the flow, said Roger Kline, EWEB's generation manager.

"You would have seen the water change its location (to the No. 1 and No. 3 spillways)," he said.

EWEB staff say the gate's collapse in and of itself wasn't a major calamity. But it remains stuck shut 24 months later, so the dam's ability to handle floodwater is diminished.

And the utility will need to spend about $1 million to fix it.

"It just wasn't that big of a deal," EWEB spokesman Joe Harwood said.

A second opinion

The Federal Energy Regulatory Commission's dam safety program, however, isn't so dismissive of the situation.

With roller gate No. 2 jammed, the dam's capacity to let water through is reduced by one-third, down to 66,000 cubic feet per second from 99,000 cubic feet per second.

Another storm, and another slug of branches and roots pressed against the other dam gates, could lead to a bigger problem, according to regulators.

"The hoisting mechanisms for the other two gates are the same type as the system that failed on gate No. 2 and therefore could potentially contain the same defects that resulted in that gate's failure," the regulator wrote to EWEB.

"A similar failure at either of the remaining gates could create a situation where the dam could no longer safely pass flood flows, and as shown by the failure of gate No. 2, the time required to return the gate operation could be significant."

EWEB Commissioner John Brown also is anxious about the facility.

"What would happen if another one of these (dam gates) fail next week? Then what would happen?" Brown said. "If roll gate No. 1 slams down and breaks, then we've got problems. ...

"If we all of a sudden dam that up, how quickly is it going to flood out all those houses -- and septic tanks (around the lake)?

"It would be a mess."

The two years since the hoist on gate No. 2 broke is demonstrating just how long it takes to get such a gate fixed, Brown added.

Latest and greatest

The Leaburg Dam problem highlights just how tricky and expensive it is to operate an 85-year-old dam on a high-flow river that routinely is awash is piles of balky floating debris. Even expensive upgrades to the gate mechanisms have provided no solution.

Roller dams, notwithstanding their debris problem, once were a pretty reliable way to hold back river water. They're powered by electric motors, which turn a sprocket and chain. One end of each roller has teeth that fit in the chain.

The rollers pivot as the chain draws them up through the wide grooves in the concrete piers. The three little houses on top of the piers shelter the engines and gearworks.

Leaburg Dam was powered that way for 75 years. In 2001, an engineering research firm figured the dam's original system was fine, as long as EWEB did nothing to increase the load. But, over the years, EWEB has tried to squeeze even more hydropower out of the Leaburg system.

In the 1950s, EWEB installed stand-up wooden "flashboards" on top of each of the dam's three roller gates, which allowed the dam to hold back more water and raise the level of the lake by 21 inches.

Raising the lake means EWEB can divert more water into a power canal and through its turbines, so it could produce more electricity.

EWEB eventually learned that the 1950s lake level put too much stress on the roller gates. They were "significantly overstressed" and needed reinforcement, according to an engineering report.

In the early 2000s, EWEB again wanted to raise the lake, this time by 18 inches.

EWEB wanted to retain more water because regulators had required EWEB to put a fish screen in its power canal to keep salmon out of the turbines. The screen restricted the flow and reduced the velocity of water -- and creation of electricity -- by about 14 percent, EWEB told the Federal Energy Regulatory Commission.

If EWEB raised the lake, it figured it could regain the lost velocity and power. The utility hired engineering firm Montgomery Watson Harza, later MWH, for advice.

MWH winnowed alternatives down to two:

Replace the three old electric motors and gears with a high-end hydraulic gate hoist system that could take the added pressure of a 1 { -foot lake rise.

Don't raise the lake level. Instead, replace the three aging electric motors and replace any gears that are worn out. Without the added pressure of a higher lake, the feeling was the system could continue on pretty much as it was.

In any case, the utility had to add $3 million worth of stiffeners -- long metal strips attached to the outside of the rollers and bracing inside the rollers to make up for the stress added in the 1950s.

EWEB made its choice: It would raise the lake. It bought three hydraulic systems manufactured by a Swedish firm from a Scottish marine engineering company.

A hydraulic motor, MWH's report said, virtually would be maintenance free.

"Engineering said: 'Hey if you put this in, you won't have to interface with it as much,'" Kline said. "It's kind of the latest and greatest."

Yet, apparently, nobody had tried operating a roller gate dam with a hydraulic motor. It was a novel application that the salesman touted in a Hydraulics & Pneumatics magazine article titled "A Big Hydraulic Motor Does a Dam Good Job."

EWEB installed the hydraulic motors in 2004 and raised the lake in 2005, but only by 6 inches. The utility decided against raising the lake the additional foot, in part because the plan had raised the ire of one or two dozen owners of expensive lakefront property.

In the end, the pressure on the dam was less than the engineers had prepared for. Leaburg Dam seemed set for the ages.

Then came that stormy day in 2012. When the operator had the gate fully raised -- at 9 feet up -- he suddenly realized the hydraulic pressure indicator was at zero, according to EWEB documents.

Something had gone drastically wrong in the No. 2 pier house, inside the motor casing where the massive raising-and-lowering rotor normally spun.

The roughly 6-inch-thick iron wheel broke into more than 20 pieces.

EWEB still doesn't know why it broke, but it hired a new engineering consultant to find a fix. U.S.-based Mead & Hunt produced an engineering report in June 2013.

The engineers found no other roller gate dam in the country had a hydraulic motor. The consensus at EWEB was that a new electric motor was the way to go.

The U.S. Army Corps of Engineers was adamantly in favor of the electric motor.

"This style of system requires little maintenance, and most have been in operation for 50 to 75 years with little or no problems."

So, this summer, EWEB plans to go back to the future and install a new electric motor and gears for roller gate No. 2.

"We believe the chain and hoist mechanism is still the right way to accomplish this task," Kline said, "so that's what we're doing."

In hindsight, would it have been better if EWEB had stuck with the electric drive instead of choosing the so-called "latest and greatest" technology?

Kline's not saying: "I'm not going to negatively comment about those who went before me," he said.

No recovery expected

When a consumer buys a product and it fails before its expected lifespan, the buyer generally asks for a refund or a replacement.

That apparently seemed logical to elected EWEB Commissioners Steve Mital and Dick Helgeson, who at a November 2013 board meeting asked the utility staff about recourse with the manufacturer or about insurance that would cover failure of the gate No. 2 mechanism.

"I hope we'd look to the manufacturer for some kind of compensation" Commissioner Brown said in an interview, "because if you have a 50-year life expectation and it lasts for seven, I'm sure we have some kind of recourse on them."

Kline confirmed that the motor didn't last as long as it was designed to.

"The standard (rule of thumb) is 20 years for any sort of rotating equipment or machinery. You would expect at least a 20-year life cycle out of it."

In 2012, EWEB hired a metallurgist to investigate what caused the rotor to shatter. But the metallurgist couldn't say definitively whether it was caused by the operation or by improper foundry practices when the rotor was cast.

"The most probable cause of this hydraulic motor failure is the defective rotor casting," he wrote in his report.

But EWEB has decided not to pursue a warranty claim, Kline said. The only warranty was a yearlong construction warranty, he said, long since expired.

In its defense, the manufacturer might point to other factors, including engineering reports in 2001 and 2013 that cast doubt on EWEB's maintenance practices.

In 2001, before the hydraulic motor was installed, the MWR report found that staff didn't keep maintenance records, lubrication was done regularly but not on a predetermined schedule, and the hoist chains hadn't been lubricated in several years.

The 2013 engineering report by Mead & Hunt found only one maintenance problem: "a regular chain lubrication regimen has not been carried out during the lifespan of the Gate 2 hoist system due to access constraints." But the consultant said the chain did not appear to be degraded.

"I would liken it more to maintenance records versus maintenance," Kline said.

"I'm confident that there was maintenance done to all the infrastructure that's in our care."

Operators since have upped their maintenance record keeping drastically, he added.

In any case, Kline said that EWEB had "no recourse" to collect from the Scottish hydraulic motor sales company or the Swedish manufacturer.

"(It's an) international manufacturer; it's been installed for north of eight years, and the cost of fighting would not equal the benefit of recovery," Kline said. "We had no indication, whichever way we looked at it, that there would be a path to recovering this investment."

Woulda, shoulda, coulda

Ironically, even as EWEB faces the $1 million cost of replacing the roller gate No. 2 hoist system, and eventually the other two, the utility doesn't need the energy the dam produces.

Today, the Leaburg Dam supplies just 2.6 percent of EWEB's power. But when EWEB decided in the early 2000s to raise the lake and get more power from the Leaburg Dam -- and spend a lot of money on hydraulic motors -- the times were different.

Lane County's economic boom was sending many new customers, including the Hynix computer chip factory, EWEB's way. And fracking technologies had yet to drive down the price of natural gas, a competing energy source.

If it were deciding today, EWEB might have left the lake level alone and maintained the electric gate hoist system.

"Right now," Kline said, "The future look of power is not the same as it was then. We would seek other alternatives most likely."

EWEB took out $42 million in 30-year bonds for studies and upgrades to get the Leaburg project relicensed with federal regulators for 40 years.

In years since, the utility has earmarked roughly $1 million or more a year for capital work at Leaburg Dam.

Simultaneously, EWEB is struggling with relicensing the Carmen-Smith Hydroelectric Project, another of its McKenzie dams. That could cost three times more than the relicensing of Leaburg Dam and its associated Walterville power project, EWEB Public Affairs Manager Lance Robertson said.

Is it worth it?

"That's a big question," EWEB Commissioner Brown said. "We have to make a $150 million decision on Carmen."

Relicensing would require a $40 million fish screen and a $22 million ladder, he noted. "It may not make economic sense given the long range outlook for power.

"We own the dam and we either relicense it or we decommission it. Right now were in limbo," Brown said. "I wouldn't be surprised if we didn't start talking about (decommissioning) -- I mean, $150 million to relicense a dam?"

Harwood, however, said it's impossible to know what the future holds.

"If you look out 20 or 30 years, you see this glut of natural gas and that's what's depressed the wholesale market (for electricity).

"What happens in five or six years, again this is pure speculation, when the environmental regulators catch up with the people who are fracking?

"Now, all of a sudden, environmental regulation adds a whole layer of cost.

"All of a sudden, hydro and wind and other things are not only profitable again, but they're cheaper."

In 2001, EWEB couldn't have predicted what came down the pike.

Moving forward

EWEB had to fix the Leaburg Dam fish ladder in spring 2013, ahead of fixing roller gate No. 2, because the fish ladder could have tipped over into the water, according to EWEB.

Currents had scoured away the riverbed underneath the ladder, leaving it hanging unsupported. Crews placed giant bags under the ladder and pumped them full of about 60 cubic yards of concrete to restore the ladder's foundation.

"That was a much higher risk" than the roll gate, Kline said. "It had a much larger and more likely liability for failure."

Kline emphasized that Leaburg Dam, even with roll gate No. 2 offline, could open wide with its other two gates and spill enough water to safely accommodate a 100-year flood.

With one gate closed, the dam's capacity for draining a swollen Leaburg Reservoir would be 66,000 cubic feet per second. On average, the dam spills only 3,000 cubic feet per second.

In the big flood of February 1996, the water was coming out of Leaburg Dam at 56,100 cubic feet per second. At times, the lake was rising so fast the water poured over the top of the roller gates, then-EWEB electric division Director Jim Wiley told commissioners in a December 2007 meeting.

Leaburg Dam couldn't control the level of the river, then-EWEB engineer Marc Anderson said at the same meeting.

"There was no dam, it was all McKenzie River," he said. At the time, the dam was fully functioning.

EWEB has been methodical and deliberate in figuring out how to restore roll gate No. 2, Kline said.

"Our focus is to try to do the right thing with the public's money, and if that means taking two years to replace the (hoist) by putting back the right (motor system) for the Leaburg Dam, that's what we're trying to do."

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