(a) The Commissioner of Indian Affairs (herein termed “Commissioner”) will engage in consultations with various tribes and other water users on the Indian Reservations listed in Article II (D) of said Supreme Court Decree, similar to those engaged in by the Regional Director with regard to Contractors as provided in §417.2 of this part. After consideration of all comments and suggestions advanced by said tribes and other water users on said Indian Reservations concerning water conservation measures and operating practices in the diversion, delivery, distribution and use of Colorado River water, the Commissioner shall, within the limits prescribed in said decree, make a determination as to the estimated amount of water to be diverted for use on each Indian Reservation covered by the above decree. Said determination shall be made prior to the beginning of each calendar year. That determination shall be based upon, but not necessarily limited to, such factors as: The area to be irrigated, climatic conditions, location, land classifications, the kinds of crops raised, cropping practices, the type of irrigation system in use, the condition of water carriage and distribution facilities, record of water orders, and rejections of ordered water, general operating practices, the operating efficiencies and methods of irrigation of the tribes and water users on each reservation, the amount and rate of return flows to the river, municipal water requirements, and other uses on the reservation. The Commissioner of Indian Affairs shall deliver to the Regional Director written notice of the amount of water to be diverted for use upon each Indian Reservation for each year 60 days prior to the beginning of each calendar year and the basis for said determination. The determination of the Commissioner shall be final and conclusive unless within 30 days of the date of receipt of such notice the Regional Director submits his written comments and objections to the Commissioner of Indian Affairs and requests further consultation. If after such further consultation, timely taken, the Commissioner does not modify his determination and so advises the Regional Director in writing or if modifications are made by the Commissioner but the Regional Director still does not agree therewith, the Regional Director may, within 30 days after receipt of the Commissioner's response, appeal to the Secretary of the Interior for a decision on the matter. During the pendency of such appeal and until disposition thereof by the Secretary, water deliveries will be made to the extent legally and physically available according to the Commissioner's determination or according to the Commissioner's determination for the preceding calendar year, whichever is less.

(b) Modifications of said determinations due to changed conditions, emergency or hardship may be made by the Commissioner, subject, however, to the right of the Regional Director to appeal to the Secretary, as provided in the case of an initial determination by the Commissioner. During the pendency of such an appeal, water deliveries will be made on the basis of the initial determination.