[StBernard] East bank levee authority remains concerned about safety of Lake Borgne floodwall

[Westley Annis]

East bank levee authority remains concerned about safety of Lake Borgne
floodwall

Print Mark Schleifstein, NOLA.com | The Times-Picayune By Mark Schleifstein,
NOLA.com | The Times-Picayune 
Email the author | Follow on Twitter 
on August 21, 2014 at 5:30 PM

East bank levee authority officials remain concerned about the long-term
safety of the newly-completed 26-mile floodwall stretching from the Lake
Borgne hurricane surge barrier along the eastern edge of St. Bernard parish
to the town of Braithwaite in Plaquemines Parish, the authority's president
said Thursday (Aug. 21).

Stephen Estopinal, president of the Southeast Louisiana Flood Protection
Authority-East, told authority members that he had been briefed earlier in
the week by Army Corps of Engineers officials on their plans to review
concerns raised by the authority about the 32-foot-high floodwall
"pertaining to what we think are design deficiencies."

The authority objected to the corps decision to build the wall atop sheet
pilings and batter pilings that were not coated with a rust-inhibiting
material. If the pilings rust more than anticipated by corps engineering
estimates, they might have to be replaced before the end of the walls'
50-year lifetime, which could require rebuilding wall segments at a cost of
millions of dollars.

Estopinal said the Coastal Protection and Restoration Authority also is
considering the authority's concerns.

Like all segments of the post-Katrina levee improvements in the New Orleans
area, the CPRA acted as the "local sponsor" for the corps-designed and built
projects. However, with construction of the projects essentially complete,
it is the authority's responsibility to operate and maintain the floodwalls
and other portions of the levee system.

Estopinal said the authority also continues to question the storm surge
modeling results on which the heights of levees and walls were based.

Last year, Baton Rouge-based engineer Bob Jacobsen completed a report for
the authority that concluded the corps' complex risk studies developed in
the aftermath of Hurricane Katrina were already outdated. The report
concluded that while heights and the resiliency of levee segments are
adequate to meet present National Flood Insurance Program and corps
requirements, some East Bank earthen levee locations could be overtopped by
waves accompanying storm surges created by hurricanes with a 1 percent
chance of occurring in any year, the so-called 100-year storm.

At the end of the levees' 50-year design life -- 2057 -- more levee segments
are likely to be overtopped, the study concluded.

"We are still not satisfied that the storm surge modeling reflects
accurately the hazard, and we still think there are areas in the system
which need to be addressed and approved," Estopinal said.

Estopinal said the authority also is still awaiting an independent peer
review of the entire levee system, which was required by Congress.

The CPRA already has published its own limited review of some of the design
concepts used by the corps, which also raised questions about overtopping
and the use of some construction materials, like the uncoated sheet piling.

The authority also heard from executive director Bob Turner that his staff
already is holding meetings in preparation of a potential closing of
floodgates and other structures if a low pressure system now in the Leeward
Islands becomes a tropical storm or hurricane and enters the Gulf.

Turner said his staff is prepared to begin closing the gates late this
weekend or early next week, if necessary, though on Thursday, most long-term
computer models indicated that if a storm formed, it would move up the East
Coast.

Authority officials are especially concerned about a swinging barge gate
that's part of the Lake Borgne surge barrier, one of two gates that block
water from the lake from entering the Gulf Intracoastal Waterway and the
Industrial Canal. Water levels in Lake Pontchartrain are unusually low this
year, Turner said, which has resulted in water levels in the GIWW being low.

The concrete barge must be carefully swung over and dropped onto pins
sticking up from a concrete sill, and the low water levels could make that
difficult, he said.

This is the first year that the authority is in charge of closing the gate.
The corps had that responsibility until construction of the barrier
structure was completed earlier this year.

Congress authorized the corps to continue to operate the barrier, including
the gates, in legislation signed into law earlier this year. But Congress
has not yet appropriated money to pay the corps' expenses. When that
happens, the authority must still pay 35 percent of the operation and
maintenance costs, Turner said, and is considering the option of continuing
to perform the operational requirements, in hopes those expenditures could
be used to offset the 35 percent cost of future upgrades and repairs.

The authority also voted unanimously to ask the state Interim Emergency
Board to give it $4 million needed to build a floodwall around two factories
on the northeast side of the Violet Canal. The walls of the factories had
been considered part of the 40 Arpent Canal levee but do not meet federal
standards necessary for the corps to certify the levee.

Without the certification, Estopinal said, there's a chance that the
National Flood Insurance Program would no longer consider the area affected
by that levee as being protected from a 1 percent flood, the so-called
100-year flood. That would mean major increases in flood insurance premiums
for as many as 40,000 residents of St. Bearnard Parish and the Lower 9th
Ward in New Orleans, he said.

Also affected would be two oil refineries and the Domino Sugar refinery in
that area, he said.

The authority also voted to enter into an agreement with the city of Kenner
to allow the Kenner Food Bank to continue using its present building for
food storage for nine months. The building is part of property purchased
from Kenner by the authority for the site of a new East Jefferson Levee
District headquarters building.