| OCR Text |
Show the upper limit is that level to which a basin can be filled with water before it rejects additional water. This limit can not be considered applicable to most of the basins of the Central Arizona area because the supply of water reaching them is insufficient to fill them to that level. 2. The lower limit. For the purposes of this report, a lower limit is arbitrarily set at 100 feet below the water table in 1950. 3. The average area of the reservoir. Specific yield is the ratio, expressed as percent, of the volume of water that can be drained by gravity to the total volume of water-bearing material from which it was drained. Data regarding specific yields are meager and determinations of yields on materials in other states are cited to show general accordance with yields obtained in Arizona. The following table summarizes data on determinations of specific yield. Area and Reference Type of material Specific yield (Percent) Eloy district, Arizona (Smith, 11)40) Florence-Casa Grande area, Arizona (White, 193.")) Bill Williams River, Arizona (Unpublished data, U. S. Geol. Survey, Ground Water Branch, Tucson, Arizona) Escalante Valley, Utah (White, 1032) Xo data 8.86 - 13.3G Sands and gravels 20 - 25 Sands and gravels 9.8 - 30.9 Clays, clay-loams, silts and fine grained sands 1.3 - ")."> |
