REPORT OF INVESTIGATioNs No. 41


tamned from well data, should be determined before the first well field is developed. A thorough knowledge of the hydraulics of an aquifer will enable the planners to predict how much water the aquifer will supply. In the design of a well field the planner should know how much water he can expect to pump from each well without overdrawing the aquifer; what the optimum spacing of wells should be to keep pumping interference between wells to a minimum; what the design of each well should be as to the diameter, depth of casing, length and setting for screens or depths of open hole in a consolidated rock aquifer; and the required pump specifications.
    The water in an artesian aquifer is under pressure much the same as water in a pipe leading from an elevated water tank, as shown in figure 12. The piezometric (pressure) surface in an artesian aquifer


Co
   200
LU
  S150

  00
-j
wi


Figure '12. Sketch showing similarity of an artesian pressure system and water
                pressure developed by an elevated tank.