As no comprehensive and financial planning was foreseen for such a small additional action, the GTZ expert Schr ter was requested to establish all-season potable water wells in some villages as soon as possible and at a most economical level feasible only by means of the effective dowsing method. Verde Island extends over some 17 sq km and, because of its volcanic origin, is only inhabited by about 8000 persons who live in the flat coastal zone. During that critical season, drinking water had often to be brought by ship to the island. Surface water like perennial rivers or lakes is not present throughout the year. The underground is considered as being relatively impermeable with respect to the infiltration of water.
Ground water occurs especially in permeable fractures and weathered zones.
Thus, one can find most different conditions in close proximity on this island. In summary, peculiar problems arise for water prospecting because of the limited water storage capacity of the underground, the poor permeability, the lack of extended aquifers and the intrusion of salt water from the sea. For the areas lying next to the shore line, the same observations are valid as have been amply described in the Sri Lanka project. The totally different yields and qualities of wells existing on Verde island support these conjectures. Of the six communities on Verde Island, only San Andres had no water shortage all round the year due to several productive dug wells.