Money allocated to the department for flood control projects shall be reallocated to public agencies upon order of the department after application therefor has been made to it by such agencies showing the necessity, purpose and use to be made of the money or by the showing that such agencies have made necessary advances or incurred obligations for the purpose of expediting projects for which the allocation is made and giving such other information as the department may require. Expenditures of the reallocated sums shall be reported to the department as and when required by it. The reports shall give such information as it may require.