MUSKOGEE, Okla. — Representatives of an organization made up of Arkansas and Oklahoma port operators traveled to the nation's capital to plead their case for funding needed to maintain the navigational integrity of Marine Highway 40.

The McClellan-Kerr Arkansas River Navigation System stretches from Catoosa, Okla., to the Mississippi River and carries about 11.5 million tons of cargo annually worth an estimated $4.3 billion. The inland waterway also provides benefits that include hydroelectric power generation, flood control and recreational opportunities.

Port operators and those who rely on the inland waterway have expressed concerns about the backlog of critical maintenance needs that continues to grow due to a lack of congressional appropriations. Arkansas-Oklahoma Port Operators Association members say additional funding is needed to increase the channel's depth and permanently fix a structure near the confluence of the White, Arkansas and Mississippi rivers that keeps the system operational.

Port of Muskogee Director Scott Robinson said he and other AOPOA representatives spent most of a recent week in Washington briefing congressional staffers about the waterway's needs. They also met with a White House official to discuss projects that might be included in a potential infrastructure plan.

"I don't think any of the members in Congress could tell you what that infrastructure plan is going to look like," Robinson said. "This infrastructure plan would be a federal investment ... different than what we've seen before and require cost-share partners."

Robinson said AOPOA members have identified three key projects in addition to the critical maintenance backlog for which congressional appropriations will be needed. In addition to the Melinda Structure — a concrete levee that prevents the White River from flowing in the the Arkansas River upstream from its present confluence — and deepening the channel from nine to 12 feet, the organization would like to see funding made available for modern tow-hauling equipment at all locks along the MKARNS.

The cost of addressing the backlog of critical maintenance projects along the navigation system reportedly has increased 43 percent during the past two years — from about $100 million in 2015 to about $143 million. A critical maintenance project is defined as one for which the chance of failure during the next five years is 50 percent or greater.

A task force assembled by Gov. Mary Fallin in 2013 determined the temporary closure of the navigation channel due to a malfunction or system failure would have an economic impact of $2.9 million a day. Regional job losses due to the closure of the navigation channel, according to the task force's 2015 report, would total 11,836 with 8,743 of those occurring in Oklahoma.

Robinson said the group's efforts produced some results, with congressional representatives from three states signing on to the AOPOA's position paper. The document identifies the four primary needs that would increase reliability of the system and shipping efficiencies.