To increase the authorization of appropriations for the Reclamation Safety of Dams Act of 1978, and for other purposes.

Amends the Reclamation Safety of Dams Act of 1978 to: (1) delete a provision which included modification costs resulting from the nonperformance of reasonable dam structure maintenance as project costs reimbursable to the operating entity; (2) make reimbursable with respect to additional funds authorized to be appropriated by amendments made to the Act in 2000 costs incurred in the modification of structures resulting from new hydrologic or seismic data or changes in dam safety criteria; (3) include as reimbursable those costs allocated to irrigation without regard to the water users' ability to pay; (4) authorize the Secretary of the Interior to pay reimbursable costs pursuant to a repayment contract at any time prior to completion of construction; (5) extend through FY 2000 the authorization of appropriations for the above costs; and (6) decrease from 60 to 30 days after the Secretary has submitted a report on an existing dam the required waiting period before funds can be obligated to carry out actual construction to modify such dam.

Requires the Secretary, before selecting a reclamation facility for modification, to notify project beneficiaries and solicit their participation in evaluating such modification. Authorizes the Secretary to negotiate agreements with such beneficiaries for the cooperative oversight of planning, design, cost containment, procurement, construction, and management of the modifications. Requires the Secretary to consider and, where appropriate, implement alternatives recommended by such beneficiaries (requiring the Secretary to respond to such recommendations within 30 days). Requires the Secretary to provide to requesting beneficiaries information concerning the status and costs of such modifications.