Whenever the department determines that it is necessary to carry out any of the objects and purposes of this part, it shall prepare preliminary cost estimates, an estimate of the amount required to be raised for those purposes by the issuance of bonds, and a statement of the probable amount of money, property, materials, or labor, if any, to be contributed from other sources in aid thereof, and shall adopt a resolution declaring that the public interest and necessity require the carrying out of those objects and purposes and authorizing the issuance of bonds for the purpose of obtaining funds in an amount not in excess of that estimated to be required for those purposes.