AZ vs. CA:12 California Exhibits, Vol. XII; Nos. 1350-1383; 1400-1446; 1501-1518; 1601-1603; 1701-1703

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-21- Extract From Upper Colorado River Commission, Fifth Annual Report (April 1, 1954) (pp. 8-9). During the past year considerable detailed technical work was done with respect to the Inflow-Outflow Method of measuring consumptive uses of water in the Upper Colorado River Basin and within the Upper Basin States in conformity with Article VI of the Upper Colorado River Basin Compact and as generally outlined in the Inflow-Outflow Manual of Appendix D, Vol. Ill of the Official Record of the Upper Colorado River Basin Compact Commission. The general objective of the Inflow-Outflow studies has, of course, been to find methods of measuring stream depletions within a river basin, sub-basin, or State by utilizing the changes in relationship between the sum of virgin flows of certain key tributaries near the rim of the stream basin and the outflow station of the basin, sub-basin, or at a State line. The so-called "rim stations" located high on the watershed, and preferably above points of man-made stream depletions, are called inflow-index stations, the flows at which are correlated with the observed flows at the outflow station in the derivation of equations from which future flows (after additional man-made depletions occur) can be estimated. The equations must be adjusted to portray virgin conditions of stream flow because Article VI of the Compact states, "The Commission shall determine the quantity of the consumptive use of water, which use is apportioned by Article III hereof, for the Upper Basin and for each State of the Upper Basin by the inflow-outflow method in terms of man-made depletions of the virgin flow at Lee Ferry,------------."