The construction program has been completed on the Ahtanum Unit of the Wapato Indian Irrigation Project and the construction costs have been established as $79,833.64. The area benefited by this development has been established at 4,765.2 acres. Under the requirements of the acts of February 14, 1920 (41 Stat. 409) and March 7, 1928 (45 Stat. 210), these costs are to be repaid to the United States Treasury by the owners of the lands benefited.

The cost per acre under § 138.1 is, therefore, established at $16.7535. Under the provisions of the acts of February 14, 1920 (41 Stat. 409) and March 7, 1928 (45 Stat. 210) is based on forty equal annual payments, the annual per acre assessment is hereby fixed at $0.42 per acre for the year 1957 and each succeeding year until the entire cost for each tract shall have been repaid to the United States Treasury. On those tracts where payments have been made pursuant to part 134 of this chapter, annual assessments beginning with the year 1957 at the rate of $0.42 per acre will be made until the entire cost of $16.7535 per acre shall have been repaid to the United States Treasury. Landowners may pay at any time the total of the then remaining indebtedness. Under the act of March 10, 1928 (45 Stat. 210) the unpaid charges stand as a lien against the lands until paid.

Payments are due on December 31 of each year and shall be made to the official in charge of collections for the project.

In conformity with the act of July 1, 1932 (47 Stat. 564); 25 U.S.C. 386(a) no assessment shall be made on behalf of construction costs against Indian-owned land within the project until the Indian title thereto has been extinguished.

Indian-owned lands passing to non-Indian ownership shall be assessed for construction costs and the first assessment shall be due on December 31 of the year that Indian title is extinguished. Assessments against this land will be at the annual rate of $0.42 per acre and shall be due as provided in § 138.3, and payable promptly thereafter until the total construction cost of $16.7535 per acre chargeable against the land has been paid in full.