A bill to amend the Reclamation Safety of Dams Act of 1978 to authorize improvements for the security of dams and other facilities.

Amends the Reclamation Safety of Dams Act of 1978 to: (1) authorize the Secretary of the Interior to make modifications to preserve the site security of Bureau of Reclamation dams and related facilities; and (2) provide for the reimbursement of all costs incurred for post-September 11, 2001 building and site security activities.

Requires: (1) dam safety and site security costs allocated to irrigation, municipal, and industrial water service for the Central Valley Project, California, to be collected by the Secretary exclusively through inclusion of such costs in operation and maintenance rates, capital water rates, or both; and (2) reimbursable operation and maintenance costs to be repaid annually.

Authorizes the Secretary to develop policies and procedures to provide for agreements with project beneficiaries for the return of reimbursable costs of site security activities.

Authorizes appropriations for: (1) the modification of structures resulting from new hydrologic or seismic data or changes in the state-of-the-art criteria deemed necessary for safety purposes, with obligations exceeding a prescribed limit subject to a reporting requirement; and (2) post-September 11, 2001, building and site security activities.

Requires the Secretary to: (1) report annually to specified committees on building and site activities undertaken; and (2) include in required reports the Secretary's response when a modification is the result of new data or criteria changes deemed necessary for safety purposes.