The Inland Waterway Revenue Act of 1978 (Public Law 95-502) established a barge-fuel tax of four cents per gallon that became effective in October of 1980. The tax rate will increase to ten cents per gallon by 1985. The tax revenue is used to recover part of the cost of governmental provision of a navigable river system;This study examines the effects of various taxing methods at rates that are estimated to recover all of the costs of providing an inland waterway system for commercial navigation. Impacts of the alternative waterway user fees on transport modal shares and revenues, relationships between origins and destinations, tax revenue generation, and transport costs of corn, wheat, and soybean haulage in 1985 are projected;A linear programming model that specifies alternative transport mode, crop, origin, destination, and time period combinations is developed. A model solution is that combination which minimizes the total annual cost of transporting and handling grain from U.S. grain-surplus regions to domestic and foreign grain-deficit regions. Six solutions are found under six different user fee scenarios. No user fees exist in one scenario. A fuel tax, ton-mile tax, and a combination of fuel and ton-mile tax are used as three alternative scenarios of user fee imposition. Rail rate increases, in response to a ton-mile tax, are incorporated in the last two scenarios;The solution results indicate that up to 255 million bushels of corn, wheat, and soybeans will be diverted from barge transport to rail and truck after user fees are imposed. Most of this diversion is Iowa- and Minnesota-produced grain. Each crop has around 15 percent of its respective barge traffic diverted when taxes are imposed. Total user fees collected on grain shipments range from 50 million to 61.2 million and, based on the grain that moves by barge after tax imposition, the tax revenues represent a per bushel average that ranges from 2.65 to 3.27 cents.