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. . . ~ 20 percent of these requirements in each reac~ Exhibit 0-4 sets out the amount of groundwater contribution to the net irrigation requirements shown in Exhibit 0-3, by reach. Since these figures assume that Association members will supply 100 percent of the crop requirements for their total acreage from a combination of surface and groundwater facilities, while in practice they might not seek to irrigate their entire acreage (hay pasture being a good example), the figures may be high and may lead to an overstatement of the effect of well pumping upon the stream. 9. Based upon the foregoing information, upon group- ing Association member wells within each reach at a distance from the surface stream equal to the average of the actual dis- tances of the member wells within the reach, and upon aquifer characteristics obtained from Ground Water Circular 11 of the U. S. Geological Survey, Applicant calculated the river deple- tions caused by the pumping of the Association members' wells over a continuous lO-year period. Calculations were made according to the method presented in the article by R. E. Glover and G. G. Balmer entitled "River Depletion Resulting from Pump- ing a Well Near a River," published in Transamerican Geophysical Union, Vol. 35, No.3, June 1954. Exhibit 0-5 sets forth groundwater withdrawal and other data used for the depletion calculations. 10. Exhibit 0-6 sets forth the tenth-year depletion rate at which replacement water would be required in each reach, on a month-by-month basis, to compensate the surface stream fully for the effect of such pumping as so calculated. This represents the maximum rate at which the Applicant should be required to provide replacement water. 11. Replacement water would be provided only at such times as would be necessary to meet a valid senior call. How- ever, Applicant has estimated the amount of water which would be required for 1974 and which would be made available to the ~ \