| OCR Text |
Show below the water table under at least two- thirds of the valley. The average specific yield of the aquifer material to a depth of 100 feet is estimated as 12 percent. Using these figures, the volume of water theoretically recoverable from dewatering 100 feet of the unconsolidated deposits in Heber Valley is calculated thus: 28,000 acres x 50 feet x 12 percent = 170,000 acre- feet ( approximately) for the upper 50 feet and; 28,000 acres x 50 feet x 0.66 x 12 percent = 110,000 acre- feet ( approximately) for the next 50 feet; total 170,000 + 110,000 = 280,000 acre- feet. The statement that 280,000 acre- feet of water is theoretically recoverable from the upper 100 feet of valley fill in Heber Valley should not be construed to mean that it is practicable, under present conditions, to recover all, or any substantial part, of that amount. The calculated 280,000 acre- feet of water could be removed only by dewatering the upper 100 feet of the aquifer. However, the ground water in the valley fill and the surface water in the Provo River and its tributaries are two parts of a system that is presently in dynamic equilibrium. Efforts to dewater any part of the aquifer would, of course, upset that equilibrium, and would have far- reaching effects on the system. This point is discussed in greater detail on pages 46- 47. Jan. Feb. Mar. Apr. May June July 968 Figure 13.- Water levels in well ( D- 4- 4) 23bcc- 1, near the south end of Heber Valley, and water stage in Deer Creek Reservoir. 33 |
