WASHINGTON — Legislative approval of a 9c-a-gallon increase in the user fee on barge diesel fuel to help finance  improvements of locks on the U.S. inland waterways system was commended by the National Grain and Feed Association (N.G.F.A.) as a means to make  much-needed infrastructure updates.

The higher user fee, starting April 1, 2015, was part of a tax-extender bill approved by Congress that President Barack Obama has indicated he will sign into law.

The barge diesel user fee assessed on barge and tow-boat operators will increase to 29c a gallon from the current 20c a gallon. Funds raised by the user fee will be matched dollar-for-dollar with tax revenues to finance waterway projects. The N.G.F.A. said money raised from the fee change was expected to generate about $40 million annually in additional revenues for the Inland Waterways Trust Fund.

“The increase is supported strongly by both barge carriers and their customers — including the agricultural shippers that consist of our members — to provide the financial wherewithal to make the necessary improvements to our nation’s waterways infrastructure,” said Randy Gordon, president of the N.G.F.A. “America’s inland waterways infrastructure is in desperate need of renovation and modernization, and this much-needed increase in the user fee is absolutely essential to the future global competitiveness and economic growth of U.S. agriculture and other industries and job creation they represent.”