This bill amends the Internal Revenue Code to make certain amounts in the Harbor Maintenance Trust Fund available, without appropriation, for expenditures to pay:

• 100% of the eligible operations and maintenance costs of specified portions of the Saint Lawrence Seaway as well as those assigned to commercial navigation of all U.S. harbors and inland harbors;
• rebates of certain tolls or charges on the Seaway; and
• all expenses of administration relating to harbor maintenance tax incurred by the Department of the Treasury, the Army Corps of Engineers, and the Department of Commerce.

The Water Resources Reform and Development Act of 2014 is amended to:

• require allocation to certain donor ports and energy transfer ports of at least 20% of amounts made available each fiscal year from the Trust Fund, and
• authorize the Department of the Army to make the allocations equally between these kinds of ports.

A "donor port" is a port, subject to the harbor maintenance fee, located in a state in which more than 2 million cargo containers were unloaded from or loaded on to vessels in FY2012, whose total amount of collected harbor maintenance taxes comes to less than $15 million annually, and which received less than 25% of the total amount of harbor maintenance taxes collected at that port in the previous five fiscal years.

An "energy transfer port" is one, also subject to the harbor maintenance fee, through which more than 40 million tons of cargo were transported in FY2012, and at which energy commodities constituted more than 25% of all commercial activity by tonnage in that fiscal year.