A bill to amend the Act entitled "An Act to authorize the Secretary of the Interior to construct, operate, and maintain the Auburn-Folsom South unit, American River division, Central Valley project, California, under Federal reclamation laws", enacted September 2, 1965.

Amends Federal law to authorize certain principal works for the Auburn-Folsom South unit of the American River Division, Central Valley irrigation project, California. Directs that certain expenditures, as determined by the Secretary of the Army, shall be nonreimbursable.

Authorizes the Secretary to: (1) maintain minimum water flows in the American River (down stream from Nimbus Dam) for fish, recreation and National Wild and Scenic River System purposes; and (2) release water from the Nimbus Dam necessary for the operation of the expanded Nimbus fish hatchery. Requires that the cost of water to be nonreimbursable, provided that the costs of construction, operation, and maintenance of such hatchery are borne by the State of California.

Requires that the costs for maintaining minimum flows in the American River shall be nonreimbursable, provided that the costs of constructing and operating the Hood-Clay Pump Connection and Clay Station Reservoir shall be reimbursable and repaid in accord with this Act.

Declares that certain water users shall have no obligation to reimburse the United States for any impact such use may have on the Central Valley project.

Authorizes the Secretary to enter into cost-sharing agreements with non-Federal entities to provide financing for the construction, operation, and maintenance of the Auburn-Folsom south unit.