Natural Flow. The Tribe has a quantified water right to the Natural Flow of the Bighorn River for current uses developed as of the date this Compact has been ratified by the Montana legislature and new development within the Reservation of 500,000 AFY. The use of this right is subject to Sections A.6. and A.8.a., of Article III, and the terms and conditions of the streamflow and lake level management plan agreed to in accordance with Section A.7., of Article III.
(1). The Tribe has a right to divert or use or to authorize the diversion or use of water from the Natural Flow of the Bighorn River within the Reservation, subject to the terms and conditions in Section C., of Article IV.
(2). The Tribe may change the source of water from the Natural Flow of the Bighorn River to surface flow or storage of any tributary within the Bighorn River Basin within the Reservation or to Groundwater within the Bighorn River Basin within the Reservation, subject to the terms and conditions in Section C.2.a., of Article IV.
(3). The use of the Tribal Water Right on units of the Crow Irrigation Project that divert water from the Bighorn River as part of that project is a use of the Natural Flow Tribal Water Right set forth in Section A.1.a., of Article III, in the Bighorn River Basin, and the use of this water shall be subject to federal law.
Natural Flow. The river water has been developed continuously since the olden days to meet the increasing water requirement of the river basin. Hence, the river flow regime has historically changed according to the water use development. Even in the past, new water uses (including storage/release of dam and abstraction from river) were planned based on the actual flow regime at that time. The proposed new water uses were implemented by coordinating them with the water uses that had already existed. At present, the existing water uses are managed based on the current flow regime. New water uses are planned and implemented not to infringe upon the existing water uses. Hence, it is considered impractical or unnecessary to reproduce the imaginary natural flow regime in the past days by removing the existing water uses when a new water use plan is prepared. From the above considerations, the river flow under the existing water use conditions (including water abstraction and water storage/release of dam) should be defined as natural flow when a new water development is discussed unless the existing water uses are revised. Usually, the flow records during a certain period in the past are necessary for planning a new water use. However, they are employed for the analysis of flow characteristics, assessment of hydrological probability and preparation of the operation rule of the new water use. Accordingly, the imaginary natural flow needs to be reproduced only when the flow regime has been largely disturbed by the water use development in the past. If the disturbance is not significant, the flow records in the past can be used as the natural flow under the existing water use conditions. In most of the rivers in Japan, the natural flow has been almost all abstracted at drought time since the olden days. However, the regulation of river flow by large storage dams was never made before World War II (1945). The large-scale water resources development of major river basins (including large-scale storage dam and water diversion) started only around 1955-1960. The water resources development plans before 1955-1960 were prepared based on the observed flow regime during a certain period because the flow records were scarcely disturbed during the above period.
Natural Flow. The United States has a water right to the natural flow in all the tributaries entering the Refuge above the most downstream point on the Refuge at the point the tributary enters the Refuge in the amount of the natural flow remaining after satisfaction of the following water rights:
a. all rights recognized under state law upstream from the Refuge with a priority date prior to the effective date of this Compact; and
b. any rights exempt from the basin closure set forth in Article III.A. of this Compact.
Natural Flow. The United States' water rights for natural flow apply to the portion of the streams specified in this Compact that flow over or form the boundary of land administered by the Fish and Wildlife Service.
