Economic Considerations on Ground Water Exploration and Development in Igneous and Metamorphic Rocks - 1979

Hydrogeology, Geology, & Environmental Issues / Field Methods & Procedures

Campbell presented a series of lectures during the two-week interregional UNESCO seminar on groundwater in hard rocks held in Coimbatore, India in 1979. He reported that the increasing need for water in the world has generated a strong demand for ground water, especially in crystalline rock areas. Current master plans for rural water-supplies make provisions on the basis of a minimum of one well for 500 to 1000 inhabitants (United Nations 1973).

This is considered a critical minimum below which high rates of migration will be experienced, which further stresses new areas, etc. The water supply required under such critical condi­tions is approximately 10 liters per capita per day, supplied by wells; one or more wells would be required to produce 25 m³/day for a village of 1000 inhabi­tants only. Adding village requirements for 500 head of livestock, a ground water supply of 50 m³ /day becomes the critical minimum water supply for the village.

Of course, supply requirements would increase linearly with popula­tion increase. It was estimated that for the period 1973-1978, tropical Africa would require a minimum of 150,000 wells. During the same period, India required 200,000 wells (United Nations, 1973). In countries such as Ghana, the Sudan and the United Republic of Tanzania, the need was estimated as several thousand wells per year, but budgeting and technical limitations have allowed only a fraction of this number of wells to be constructed. This is a widespread problem of critical proportions in most crystalline rock areas (Dijon, 1971).

In such areas, drilled wells, although capital intensive compared to dug wells, serve two roles; the first role is to supply emergency requirements, since such wells can be drilled in a matter of a day or two - as opposed to a month or more to construct a 30 meter-deep dug well. The second role is to promote rapid development of an area to assist in producing cash crops and industrial products (mining and small industry}, which in turn increases the region's wealth.

When a region begins to generate cash income, labor intensive activities (i.e. dug wells) become less attractive and capital becomes more available for capital inten­sive activities (i.e. drilled wells, mining, etc.) which further enhance eco­nomies of scale and subsequently standards of living. It is apparent that
roles in crystalline potential (relative generally high).