Fort Smith board hears solutions for flooding, levee certification

On a rainy Tuesday, the Fort Smith board of directors discussed multi-million dollar projects necessary in the near future to best usher water out of the city and to best protect the city from a 100-year flood.

Flooding in downtown Fort Smith and many parts of north Fort Smith has been a problem for decades. The Cambridge, Mass.-based engineering firm of Camp, Dresser and McKee presented Tuesday (Sept. 14) to the board a few possible reasons for the flooding and some potential — and potentially expensive — solutions.

First, much of the water and sewer pipes in the downtown area are old. Another problem is that sedimentation has built up in a main line carrying storm water out of the downtown area. Yet another problem is a sewer line placed inside portions of a large drainage pipe along Carnall Street that prevents maximum outflow of water to the Poteau River.

One of the solutions, an up to $138,000 removal of sediment, is underway. The city has bid the job and the work could begin this year.

The other solutions could take up to 5 years. Potentially more than $1.65 million to realign sewer lines along the Carnall drainage route would see design work in 2011 and construction no sooner than 2012. This work would include the re-routing of about 400 acres of watershed to an improved Carnall drainage network. Preliminary engineering works suggests the option would greatly improve the flooding situation in downtown Fort Smith.

However, more than $16 million needed to improve the May Branch and Town Branch could take 3 to 4 years. Of that, an estimated $10.4 million is for May Branch and is part of an overall $30 million-$32 million comprehensive plan to improve May Branch from the Arkansas River to Park Avenue, said City Engineer Stan Snodgrass. Snodgrass told board members they were working close with the U.S. Army Corps of Engineers to ensure that any work on May Branch does not negate a previous agreement in which the Corps would match up to 50% of the costs.

“And keep in mind that all of this (cost estimates and timelines) are very preliminary,” Snodgrass told the board.

During the study session, the board also heard a review of the ongoing levee certification process.

According to Snodgrass, the city has about 5 miles of levee along the Arkansas River. Roughly 1.8 miles is known as the Fort Smith Levee and Seawall, and was built in 1947 by the Corps of Engineers. The remaining portion is known as the Rice Carden Levee and was built by railroad company Kansas City Southern in 1965. About 800 linear feet of the Rice Carden washed out in 1990. In 1998, the city agreed to take ownership of the Rice Carden for the purpose of building a hiking trail and other features for an overall riverfront master plan.

The Fort Worth-based engineering firm of Freese and Nichols said certifying the levee requires meeting several criteria, to include a wall or levee 3 feet above the estimated 100-year flood level, ability to close roads that pass through a levee or wall, embankment stability and the evaluation of pump stations.

John Rutledge, with Freese and Nichols, said overall the levee and walls are in good shape, with adequate slope protection and embankment stability. However, there are a few problems. Deficiencies found in the 5 miles of walls and levees included the Rice Carden washout, inability to adequately close roads, trees growing on the levees and a missing section of the floodwall.

The estimated cost to address all the problems is around $2.76 million, with about $1.2 million of that to fix the Rice Carden washout, Rutledge said.

Specific proposals and options on the drainage issues and levee certification will be included in a 5-year street and drainage program scheduled to be presented to the board during its Sept. 28 study session.