Covington Dealing with "Slow-Motion" Landslide
From the City of Covington:
Neither a camera lens nor an untrained eye captures the gravity of the problem with the floodwall on the east side of Glenway and Wallace avenues.
When hikers on the Licking River Greenway and Trail look uphill, they see what basically appears to be a meandering wall of partially exposed dirt jutting up about 4 feet high, sprouting clover and chicory.
Only the slope isn't rising. It's falling. Or more technically speaking, "sloughing."
"What you're looking at is basically a landslide in very slow motion," Covington Public Works Director Chris Warneford said. "The levee is very gradually sliding toward the river. This problem has to be taken care of, now, because it's only going to get worse."
Step one is to gather technical information.
So the Covington Board of Commissioners recently approved a contract for $30,850 to ECD Midwest, LLC to do a geotech survey of the site, which Warneford said would likely take a month to a month and a half.
The goal, Warneford says, is to determine the cause of the sloughing and how to fix it.
One option might be a technique he calls "soil spiking" or "soil nailing," which has been used on part of Kyles Lane.
In essence, metal tubes with holes around their bottoms are "shot" or "nailed" horizontally far into the slope, and concrete is injected via high pressure into the tubes and out the holes. The effect creates "anchors" for the beams and plates that will then hold back the earth.
The U.S. Army Corps of Engineers must sign off on any plan for the fix. Warneford said Covington has been working closely with the agency and will seek both approval of any proposed fix and help applying for federal grants to pay for construction, which he said could cost $1 million to $1.5 million. It could begin next fall.
The floodwall and levee system was completed in the mid-1950s after more than a decade of discussion, design, and planning. The need for flood protection was solidified by the Flood of 1937, when rising waters from the Ohio and Licking rivers forced some 20,000 people in Covington to evacuate their homes and covered about 40 percent of the then-land area of the city.
But with age has come deterioration of that system. And even though the federal government built the flood-control network, the City legally owns it and must maintain it under those decades-old agreements with federal agencies.
And that maintenance can be expensive.
In 2015-16, for example, fixing a failing section of the earthen levee just to the north at the end of 21st Street, where there is no concrete floodwall, cost nearly $2.4 million. That fix required a whole different technique.
"We're hoping that this problem and its fix doesn't rival the 21st Street slide, but we really won't know what we're dealing with until we get the results of the geotech survey," said Bill Matteoli, assistant project engineer in Covington's Public Works Department.
Both projects reinforce the critical nature and magnitude of one of the little-noticed responsibilities of the Department.
"The flood-control system protecting Covington is a lot more involved than just the gate at the foot of Madison Avenue everybody sees being quickly installed when the Ohio approaches flood stage," Matteoli said. "It's miles of grassy slopes and concrete walls, much of which sits far from the public's eye."