Two-thirds of India is underlain by consolidated rocks and approximately one-half of this hard rock area is composed of Precambrian crystalline rocks. Many rural areas in India are dependent on ground water for drinking and irrigation water supply. Population growth and increasing demands for food and water have resulted in increased withdrawals of ground water in some areas and a decline in water levels. In contrast, the lack of technical expertise and seed money has inhibited the development of ground-water resources in other areas.
In this paper, the ground-water resources of two crystalline rock areas are described. The recent drilling of over 600 wells in these areas by the Evangelical Lutheran Church (E.L.C.) Water Development Project provided the data base. The geology, occurrence of ground water, and types of ground-water flow systems in these areas are discussed.
Well data such as yield, depth and thickness of overburden, aquifer depth, and well depth were analyzed statistically for both areas. The results helped to quantify the occurrence of ground water with depth and the distribution of well yields and expected well yields in different rock types and topographic settings.
Both step-drawdown and constant-rate pumping tests were conducted on 150 production wells. Aquifer transmissivity ranges from approximately 1 to 400 m2/day (meters squared per day) in both areas. Specific capacity results are also presented.
Ground-water levels in lower Paleozoic and Precambrian crystalline rocks of East Bradford and West Bradford Townships, Chester County, Pennsylvania, July and August 1987