The purpose of this report is to present the facts regarding the available water supply of the Green River Basin and other data that will be helpful in planning to put this water to beneficial use. For some parts of the basin a mass of information is available; for other parts the data are less complete. An attempt is made in this report to present an analysis of all this information, supplemented by personal field studies, in such a way as to indicate the economic factors involved in utilizing the waters of the basin, and also to give facts from which the relative value of the irrigation and power projects may be readily deduced.