(a) The cost apportionment principles of 33 U.S.C. 516 are applicable to the costs of bridge alterations recommended by reporting officers in the interest of navigation during preauthorization planning, including studies conducted under the Continuing Authorities Program.

(b) The bridge owner shall bear such part of the cost as is attributable to the direct and special benefits which will accrue to the bridge owner as a result of the alteration, including the expectable savings in repair or maintenance costs. That part of the cost attributable to the requirements of railroad or highway traffic shall also be borne by the bridge owner, to include any expenditure for increased carrying capacity of the bridge, and such proportion of the actual capital cost of the old bridge as the used service life bears to the total estimated service life.

(c) In general, the Federal government's participation in the cost of a bridge alteration shall be limited to providing a functional facility equal in every respect, as near as possible, to the existing facility, while also providing navigational clearances required to meet the anticipated and reasonable needs of navigation.

(d) If the bridge owner or other local interests desire improvements or modifications in the new bridge design for reasons other than that required by the navigation improvement project, the reporting officer may recommend such improvements if such local interests provide necessary assurances to pay the costs apportioned to them.

(e) In the case of small boat harbors and channels, the costs of bridge alterations, strictly for recreation navigation shall be apportioned in accordance with the procedures provided in this regulation. Bridge alteration costs associated with small boat harbors and channels and not apportioned to the bridge owner by the procedures in this regulation, shall be cost shared on the basis of 50 percent Federal and 50 percent non-Federal, the same as the costs of other general navigation facilities.

(f) Reporting officers shall obtain letters of intent from local interests for non-Federal costs apportioned under the provisions of this regulation, in accordance with established procedures for preauthorization feasibility studies. If such letters cannot be obtained from the bridge owner, the reporting officers shall then include in their report a statement that the cost of such alterations shall be borne by the bridge owner or, in the alternative, be apportioned between the bridge owner and the Government as provided under the principles of Section 6 of the Truman-Hobbs Act (33 USC 516).