The board of a district which has entered into an agreement pursuant to Section 52850, may, by resolution, direct that any money on deposit in the county treasury to the credit of any bond fund or bond reserve fund of the district, which was derived from an assessment against district lands securing said bonds and which is in excess of the amount required to pay principal and interest then due or to become due within six months thereafter upon bonds secured by the assessment, be applied to either or both of the following purposes:
(a)
The purchase of bonds secured by the assessment.
(b)
Deposit with the Federal Reserve Bank in San Francisco, California, subject to withdrawal therefrom only upon written orders of the district and the United States of America, or the department or agency thereof, including Reconstruction Finance Corporation, interested in the creation and maintenance of the fund, or by the district with the written consent of the United States of America, or the department or agency thereof, including Reconstruction Finance Corporation, interested in the creation and maintenance of the reserve fund.