The county treasurer shall, within twenty days after receiving the apportionment under section 79-1051, apportion the amount as follows: One-fifth of the whole amount to the public road fund of the county and the remaining four-fifths to the school districts in the county from which the rental was derived in proportion to the respective acreage of lands leased in each school district within the county by the United States Government which have been acquired for flood control purposes. The county treasurer shall determine the amount each district is to receive and make apportionment thereof.