Within the Lower Little Horn and Lodge Grass Irrigation District there are 3,196.8 acres for which the District is obligated by contract to pay its proper share of the total construction costs. Within the Upper Little Horn Irrigation District there are 1,554.7 acres for which the District is obligated by contract to pay its proper share of the total construction costs. There are 3,237.6 acres, more or less, covered by contracts with private landowners, obligating such owners to pay their proper share of such construction costs. The total per acre charge against all such lands is $26.38. This amounts to an annual per acre rate of $0.6595. For the purpose of this notice the annual per acre rate is hereby fixed at $0.66. This annual per acre rate of assessment will continue for a 40-year period within which the total amount of construction costs of $210,726 is to be repaid without interest. The amount of each annual installment chargeable against each of the Districts for the acreage covered by their respective contracts shall be determined by multiplying the total acreage, under each contract entitled to Willow Creek storage rights, either directly or by subsituation, by the per acre annual rate.