ABSTRACT
McGuinness (1969) describes the hydrogeologist’s work in the following way: What does the hydrogeologist see as the deficiencies in knowledge that is his responsibility to remedy? At one time he had a rather simple job. He mapped the geology of his area or refined mapping done earlier by others. He gathered as much information as he could on the depth and productivity of wells, the kinds of rocks they penetrated, and the kinds of water they yielded. He interpreted these data in terms of the subsurface stratigraphy and structure and of the water-bearing properties of the different geologic units. Ultimately, he prepared a report, maps, and charts showing where and at what depths water could be obtained, and in a general way, how much and of what quality. For rocks not penetrated by enough wells in his area to yield reliable information, he extrapolated information from other areas where similar rocks were better known, according to his experience and his familiarity with the literature. This procedure was fine for a start. As ground-water development progressed and demands became larger, he found it necessary to think in quantitative terms about the permeability and storage coefficients of the aquifers and the effects on ground-water levels of pumping increasing amounts of water from more closely spaced wells.
