Application of geophysical methods to the study of the productivity of water drillings in crystalline aquifers: case of the Toumodi region (Central Côte d'Ivoire)

In Ivory Coast, the phenomenon of decline of water drilling is found in rural and urban areas in the crystalline and crystallophyllian basement. The sub-prefecture of the department Angoda Toumodi does not rest (55%). Although several factors such as the condition of equipment, operating conditions, power conditions, the lithological conditions, problems of monitoring of hydraulic and quality parameters, etc., may partly explain this phenomenon, a fundamental question needs to be asked: drilling decline is it not related to a bad implementation of drilling? Thus, this study aims to analyze the productivity of water wells in operation, implemented by the method geomorphic from geophysical measurements. The study area is sub-prefecture of Angoda which lies between longitudes 5° 00' and 5° 10' West and latitude 6° 35' to 6° 45' North with an area of 660 Km2. It meets the plutonic, volcanic and schistose. The technique chosen is dragged geophysical electrical resistivity of the particular device gradient or rectangle measuring electrical resistivity. The results showed, firstly, poor implementation of some wells on fractures resulting in dieback, and secondly, the proper implementation of further drilling manifested by a specific constant flow. The results show that the method is suitable for the problem. Thus, to overcome the problems of wasting water wells, one must couple the geomorphological and geophysical methods.