Inland Navigation Improvement and Waterway User Act

[AI summary unavailable — showing source text] Inland Navigation Improvement and Waterway User Act - Amends the Internal Revenue Code of 1954 to impose a tax on certain liquid fuels sold for use of vessels in commercial water transportation or used by such vessels without a previously taxed sale. Imposes forfeiture penalties for failure to pay such charges. Prohibits the violator from using any lock on inland waterways. Amends the Federal-Aid Highway Act of 1976 to direct the National Transportation Policy Study Commission to study the effects of user fees on different modes of domestic freight transportation. Authorizes the Secretary of the Army, acting through the Chief of Engineers, to replace locks and dam 26 on the Mississippi River, Alton, Illinois and Missouri, and to construct a new dam two miles downstream from dam 26. Authorizes the Secretary to undertake steps to provide for wildlife protection and recreational activities in conjunction with such project. Withdraws all authority for the Secretary of the Army to construct or study the feasibility of construction or modification of channels in the Mississippi River north of its juncture with the Illinois River. Directs the Upper Mississippi River Basin Commission to pr…