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

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More specifically, during the past year the Inflow-Outflow studies have been devoted to the derivation of equations from which can be estimated the virgin flow of the Green River in Wyoming, the Colorado River in Colorado, and a start has been made on studies of sub-basins of the Colorado River System in Utah. It was realized early in the investigations of the applicability of the Inflow-Outflow method of measuring stream depletions, and subsequent studies have confirmed the belief, that there are factors other than flows at inflow-index stations which, as independent variables, affect the relationship between inflow-index stations and outflow stations at State lines. For this reason, in the derivation of hundreds of possible equations, it has been necessary to try as independent variables such factors as those pertaining to base stream flows, precipitation, temperature, winter flows, summer flows, summer precipitation on the valley floor, summer precipitation on the watershed, summer temperatures at valley stations, summer temperatures at watershed stations, factors which might be indicative of ground-water conditions, "soil priming" in autumn months, etc. in multiple correlations and in many different combinations with the flows at inflow-index and outflow stations. As can be readily ascertained from the innumerable possibilities of combinations of factors affecting stream flows as independent variables in multiple correlation equations, the work on the Inflow-Outflow Method has been tedious and confining; and, although at this time, no claim can be made that this problem for any given sub-basin is solved, it is felt that the studies have been enlightening and that they must be continued in the future. For economy in both time and expense plans are now being made to have much of the detailed computation done on modern automatic computing equipment.