Land, Larry F., authorDuke, Harold R., advisorEvans, N. A., committee memberNobe, K. C., committee memberSchmehl, W. R., committee memberLongenbaugh, R. A., committee member2021-10-122021-10-121967-03https://hdl.handle.net/10217/233953Also has numbering: CER67-68LFL17.The major objective of this study was to illustrate a method for comparing allocation patterns on the basis of water-use efficiency and economic soundness. Two supporting objectives include presenting three methods for calculating return flow and a technique for evaluating an allocation pattern. To make the study on irrigation water supply management, a hypothetical basin was used. The basin consisted of several unit-areas which were arranged in the shape of the basin. For a reference level of water application, two irrigation patterns, one using only ground water and the other using only surface water, were assigned to a unit-area. Various levels of water application were obtained by adjusting the reference level with coefficients. A combination of ground water and surface water sources was obtained by combining ground water with surface water application. From these various levels of water application and the two methods of distributing the water, several allocation patterns were devised for the limited amount of irrigation water. Water-use efficiency and economic returns were used in comparing the allocation patterns. The efficiency was determined from the volume of water consumed by crops and the volume delivered for irrigation. For economic comparison, it was assumed that the water was applied at a depth of three feet for each year and yielded a constant return for each unit of water. The water cost was also assumed to be a constant cost. The other farm costs were assumed to be the same for each irrigated acre. With these values the net return and the benefit-cost ratio were calculated for each allocation pattern. The results indicated that considerable return flow was lost when only surface water was used in the lowest part of the reach. However, if only ground water was used the cost in obtaining the water was higher. The most reasonable allocation pattern seemed to be one that balanced, to some degree, ground water and surface water applications.masters thesesengCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.Irrigation waterText