OCR Text |
Show were suspected at all. However, the gradual rise of water tables, with resulting enlargement of natural springs and the development of new springs and the seepage return to flood-water channels, to small creeks, and, finally, to rivers, gave increasing evidence concerning the magnitude of losses of water through deep percolation. Moreover, it was found through experience that much less water need be applied to the farms to produce profitable crops than was formerly believed necessary, and the areas of land successfully irrigated by the water from a given stream were greatly increased without any apparent increase in the water supply. Obviously, such increase in area of irrigated land could not continue without limit, some water being actually consumed by the growing crops. 197. Definitions and Analysis.-Gross duty of water, headgate diversions, and net duty are familiar terms concerning water uses, but "consumptive use" is a term of recent origin, and should not be confused with the net duty on land and other terms used in discussions of duty of water. Some engineers have restricted the term consumptive use to "valley consumption," or net depletion of river flow, whereas others have used it to include water from all sources, or total water consumption, irrespective of whether it is from river water, rainfall, carry-over soil moisture, or absorption from ground water. It is believed that the use of the definitions given in this chapter will avoid confusion in the study of consumptive use of water in irrigation. |
Source |
Original book: [State of Arizona, complainant v. State of California, Palo Verde Irrigation District, Coachella Valley County Water District, Metropolitan Water District of Southern California, City of Los Angeles, California, City of San Diego, California, and County of San Diego, California, defendants, United States of America, State of Nevada, State of New Mexico, State of Utah, interveners] : California exhibits. |