60-4-109. Irrigable lands rendered unusable -- unpaid construction costs. (1) Whenever the department acquires irrigable land for highway purposes or so acquires land as to render other irrigable land unusable for irrigation, it shall pay to the owner of the irrigation or drainage project, in addition to other sums allowed by law, a proportionate share of the unpaid construction costs of the project or drainage district.

(2) The department shall also pay a lump-sum amount to the district sufficient to produce, on an amortized basis for a reasonable period not to exceed 90 years, a sum of money equal to the annual increase in operation and maintenance costs against the remaining lands under irrigation in the district resulting from the severance from the district of the lands acquired by the department and not overcome by bringing new or additional land under irrigation. For the purpose of determining the amount of the lump-sum payment, the annual operation and maintenance assessment of the district shall be considered to be the average for the 5 years, or so many years as the district has assessment experience if less than 5 years, preceding the date of acquisition.