OCR Text |
Show -2- represents interception, soil evaporation, and transpiration, plus such evaporation as may take place from water held on the ground at times of precipitation. For a small cropped area in an irrigated region, evapo-transpiration represents interception, soil evaporation, and transpiration by crop plants and accompanying weed growths, plus such evaporation as may take place from water surfaces during delivery of irrigation supplies. For a large area including different types of surfaces, evapo-transpiration represents interception, evaporation from soil and water surfaces, and transpiration by all kinds of plant growth. When evapo-transpiration is determined for the winter season or for annual periods in regions subject to snowfall, it includes evaporation from snow surfaces and intercepted snowfall. The term consumptive use is commonly used in considerations of irrigation hydrology in western United States. When determined for farm areas, it is designated farm consumptive use. When determined for relatively large areas, it is designated project consumptive use or valley consumptive use. The term is also used in discussing data obtained by tank, lysimeter, and plot measurements. However, it seems better to use evapo-transpiration for such data and to use consumptive use for the larger areas. When evapo-transpiration consumptions are determined for entire drainage basins, they usually are referred to as natural water losses, total evaporation, or simply evaporation. Water consumptions that are not utilized in crop production, such as interception, evaporation from water and bare land surfaces, and evapo-transpiration on areas of native vegetation, are sometimes referred to as nonbene-ficial consumptive uses. |
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. |