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  • 28 Nov 2014

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Levee holds back flood of changes

Safety drives new look, as encroachments pile up on Marine Drive


by: TRIBUNE PHOTOS: CHRIS ONSTOTT - The U.S. Army Corps of Engineers says Marine Drive, the bike path, and thousands of trees, utility poles and even buildings erected on the Columbia River levee pose safety concerns and may need to be removed -- unless local officials and engineers can demonstrate they won't compromise levee safety.Motorists, bicyclists and joggers enjoying Columbia River views along Marine Drive may not realize it, but they’re traveling atop a mound of sand that’s the main bulwark against massive flooding of North and Northeast Portland.

The 18.5-mile Columbia River levee and related structures protect $20 billion worth of property, including Portland International Airport and the city’s backup water supply, from

deluge up to eight months a year.

Now, in response to levee failures in New Orleans during Hurricane Katrina, federal authorities say thousands of trees, buildings and other structures permitted in past decades atop the Columbia River levee pose safety concerns — and may need to be removed or altered.

The so-called levee encroachments include Marine Drive, hundreds of privately owned condos and other buildings, 4,000 trees, BPA transmission towers and miles of utility lines.

“Everything’s changed since Katrina,” says Dave Hendricks, director of special projects for Multnomah County Drainage District No. 1.

“All this stuff is no longer acceptable,” he says, unless engineers can demonstrate that it won’t compromise the levee system.

The U.S. Army Corps of Engineers, which helped build and expand the 31-mile levee system starting in 1939, wants all encroachments evaluated one by one before it certifies the system’s safety. Recertification is required every 10 years by the Federal Emergency Management Agency so property owners can qualify for flood insurance. It’s also required to retain Army Corps funding of levee repairs.

“Since Katrina, the Army Corps has rewritten the rules, or moved the goalpost,” says Tim Warren, a Clackamas developer and president of the Multnomah County Drainage District board of supervisors. “You go from being Grade A to non-compliance.”

A simple stop sign on Marine Drive, though permitted originally by the Army Corps, now is viewed as an encroachment that may allow water to penetrate the levee, he says.

Total cost of the levee certification process is unknown, but it figures to be in the tens of millions of dollars. Reed Wagner, executive director of the drainage district, says it could cost $2 million just to evaluate what needs to be done.

The 14-employee drainage district operates on behalf of three smaller neighboring drainage districts. They all date to World War I, when farmers banded together to share flood-control costs while converting the floodplain to agricultural fields.

The district oversees the levees, 11 pump stations and other flood-control work on behalf of 2,200 property owners south of the Columbia River, stretching from North Portland to Troutdale.

It’s unclear who’ll pay for all the projects required. “We don’t even have the $2 million,” Warren says.

The costs likely can’t be borne entirely by property owners, Wagner says, so the district may turn to local governments and taxpayers.

A flood of complications

Nobody disputes that the levee must be safe, and that regulators must adapt to changing scientific knowledge.

“If not for that levee, most of this area would be under water most of the year,” Wagner says. “We all reserve the right to get smarter.”

Portland oldtimers recall the devastating 1948 Vanport Flood that wiped out a city of 18,500 when the Columbia River broke through a railroad embankment doing double-duty as a levee.

“If it had been designed as a levee, it probably never would have been breached,” Hendricks says.

There also were two other “100-year floods” — bad enough they’re not expected more than once per century — in 1964 and 1996. In both cases, the Columbia River levee system held.

But the new Army Corps requirements could bring a flood of new problems, complications and controversies.

Authorities know that trees can harm the integrity of a levee, as water follows the roots to penetrate the structure. But removing a single tree means taking out its entire root system, and then patching up the levee.

“You’re talking somewhere between $5,000 and $30,000 a tree to remove them,” Hendricks says. “We live in a place where you don’t tear out trees.”

by: TRIBUNE PHOTOS: CHRIS ONSTOTT - The U.S. Army Corps of Engineers says the bike path and thousands of trees, utility poles and even buildings erected on the Columbia River levee pose safety concerns and may need to be removed.Most of the trees are close to the Columbia River or the Columbia River Slough, an environmentally sensitive wetland. While the Army Corps may deem some trees to be a threat to the levee, the National Marine Fisheries Service may prefer to keep riverfront trees to support endangered Columbia River salmon.

Just one property, Chinook Landing Marine Park, contains 400 trees that are encroachments, Hendricks says. The Metro-owned facility provides boat ramps and other amenities for 171,400 visitors a year.

Neither the Army Corps nor the drainage districts own the levy property outright. Rather, a patchwork of private and public owners own the land and provide easements. Their properties are the ones at risk.

There’s no inventory yet of riverfront condos, homes and commercial businesses that have foundations, fences or other structures on the levee embankment. A house perched off Marine Drive and Northeast 122nd Avenue is probably one of hundreds of affected structures now deemed to be encroachments, Hendricks says. There also are as many as 30 businesses deemed encroachments.

Property owners may have to undertake engineering studies to prove their structures aren’t a threat to the levee, or pay for new drainage systems.

“We would hope to find an engineering fix before we would have to remove a development,” Wagner says.

Much of Marine Drive is considered an encroachment. That might ultimately result in restricted access by semi trucks, Hendricks says. Parts of Sundial Road near the Troutdale Airport must be re-engineered.

The financial tentacles from levee recertification will be extensive. One small example: The Port of Portland owns six inactive pipes extending through the levy, once used to haul sand to build up the airport property. Those must be removed or filled, and the levee restored, at an estimated cost of $200,000, says Phil Ralston, general manager for port environmental operations. The port likely would pass on the costs to the airlines, he says.

Airlines, in turn, might pass on costs to their passengers.

Drainage district leaders say they have a good working relationship with the Army Corps, which also does safety inspections of the local system. But federal requirements for levee recertification have been “a little fuzzy,” Ralston says.

Three Army Corps staff from the Portland district office, interviewed via a conference call, had trouble clearly articulating the agency’s rules and procedures and how they’ve changed in recent years.

Nevertheless, the process is starting to get clearer. In mid-January, the Army Corps notified two of the four local drainage districts that their shares of the levee system must be re-certified by 2014, though a time extension may be sought. The other two districts come up for recertification in 2017.

“The certification has to happen in the next two to four years, depending on the area,” Wagner says.

Tighter standards

Prompted by levee failures during Hurricane Katrina in 2005, the Army Corps has scrapped its use of levy safety standards spelled out in the Code of Federal Regulations, says Jeremy Britton, chief of the agency’s geotechnical design section at its Portland district office.

In 2007, the Army Corps started using a more rigorous checklist during levee safety inspections around the country.

Then the agency released its levy safety guidelines, in a 2010 engineering circular, that are “a lot more robust” than the Katrina-era federal code, Britton says.

In recent years, levies were usually built high enough and strong enough to withstand 100-year floods, though that term has fallen into disfavor. Now they’re called 1 percent floods, based on the assumption there’s a 1 percent chance one will occur in any given year.

Portland’s silty sand levees are designed at an even higher level — enough to hold back flood waters as high as the 1894 flood, the highest in recorded history — for 90 days. For added protection, typically there is at least three feet of fill atop that, which the Army Corps called “freeboard,” says Guy Fielding, levee safety program manager at the Portland district.

“Some types of encroachments that were permitted within that three feet, we’re not permitting any more,” Fielding says.

In addition, there are newer limits on encroachments above the freeboard level, though they are less strict, he says.

Marine Drive and most of the other encroachments of concern were built in that freeboard zone.

Now the Army Corps is more intensely analyzing encroachments, using teams of hydraulic, geotechnical, structural, mechanical and electrical engineers, says Portland district public affairs specialist Amy Echols.

Encroachments also are viewed in a different lens during the Army Corps’ annual levee safety inspections.

“The encroachments need to be handled regardless of the levy certifications,” Britton says. “They’re an issue just for levy safety, period.”


‘Sophisticated’ levee system a plus for Portland properties

The Columbia River levee protected Portland from flooding during the punishing storms of 1964 and 1996, and officials are confident the city remains well-protected.

“The levee is in the best shape it’s ever been in,” says Tim Warren, board chairman of the Multnomah County Drainage District No. 1.

But only 121 out of 1,451 U.S. flood-control systems have earned “acceptable” ratings so far in the first national inventory — ordered after Hurricane Katrina — and the Columbia River levee isn’t among them.

The U.S. Army Corps of Engineers gave the local levee system a “minimally acceptable” rating during its most recent inspection report in 2011, says Guy Fielding, levee safety program manager at the agency’s Portland district office. That’s the same rating as in previous inspections dating to 2007, he says.

Army Corps officials note that “minimally acceptable” ratings aren’t uncommon. Of the 1,451 flood-control systems inventoried so far, 1,004 scored “minimally acceptable” ratings and 326 were deemed “unacceptable.”

It appears the local drainage district, like its peers nationally, is being downgraded due to stiffer Army Corps standards since Hurricane Katrina.

The Portland drainage district is actually “very sophisticated,” says Jeremy Britton, chief of the geotechnical design section at the Army Corps’ Portland district. “They’re very good at what they do.”

Portland’s levees enjoy firmer ground, literally, than those in New Orleans.

“We have a nice solid base below ours, not like Louisiana — they’re on marshland,” says Dave Hendricks, director of special projects for the local drainage district.

Owners of the most high-profile property protected by the Columbia River levee system — Portland International Airport — also aren’t worried.

“We’re confident that the levee system that protects the airport now is in good shape,” says Phil Ralston, the Port of Portland’s general manager for environmental operations.

Still, the 2011 levee inspection and the looming levee recertification process are unearthing troubling concerns that must be addressed by the drainage district, in ways they never had to before.


Corps’ report finds trouble spots

The U.S. Army Corps of Engineers identified several problems with the Columbia River levee system in 2011 inspection reports, as detailed in executive summaries:

• “Unacceptable” encroachments not permitted on the levee, including at least 75 access roads, buildings, abandoned dredge pipes and utilities.

• Numerous “unacceptable” trees and other vegetation on the main levee, which “can compromise the integrity of the levee and prohibit flood fighting and inspection activities.”

• “Unacceptable” depressions and rutting in the main levee caused by vehicle traffic.

• “Unacceptable” slope stability in one stretch of the main levee.

• Levee heights were lowered too much where Marine Drive and Airport Way cross over north-south levees.

• The levee is too low where it accommodates an Interstate 84 off-ramp near the Sandy River.

• A soggy area in one of the north-south levees, despite dry weather conditions.

• “Unacceptable” animal burrows observed on the main levee embankment.

• A dangerous drop in height of the 142nd Avenue levee where Airport Way crosses that levee.

• Unwise reliance on sand bags should that area flood, as there are no sand bags nearby and those are “slow to deploy.”