General principles of artificial ground-water recharge

The natural subterranean reservoirs formed by the porous and permeable rocks differ from surface reservoirs chiefly in that they have complex structure and great internal resistanc• to the How of water. Their full utilization requires systematic development based on the geology and hydrology of the aquifer and the principles of hydraulics distinctive of ground water. The methods of increasing recharge are of two kinds: (1) Indirect methods, in which increased recharge is accomplished by locating production wells as close as practicable to areas of rejected recharge or natural discharge, and (2) direct methods, in which water from surface sources is conveyed to points from which it percolates into a body of ground water. The direct methods can also be divided into two groups: (1) Recharge by surface application, and (2) recharge through wells. This paper discusses the different methods in relation to geologic structure and ground-water hydraulics and gives numerous examples.