Simple method for estimating well yield potential through geostatistical approach in fractured crystalline rock formations

Abstract

In inland Tanzania, because of the low annual rainfall and poor surface water runoff, increasing the supply of safe drinking water is a major issue. To solve the issue and to design for the drinking water supply at region of fractured zones in crystalline rocks, the simple method is applied to find the relationships between the pumping discharge of drilling wells and the field survey data in the Tabora Region, Tanzania. The field data used included results of electrical resistivity tomography (ERT) survey, electric resistivity borehole logging, the geological column (as geological information) and size of lineaments (as spatial information). A multiple correlation equation developed in this study demonstrates that the pumping discharge of a drilling well can be determined from two surface data sets: ERT survey results and lengths of topographic lineaments. This study also demonstrates that surface hydro-geophysical surveys are highly effective for exploration of groundwater resources in Tabora Region, and thus assist in locating potential drilling sites where water resources are scarce. Application of this equation enables prediction of the well yield potential in developing areas and is expected to increase the water supply in the Tabora Region, where water resource surveys are being conducted. Areas suitable for residential use, which are identified as regions on the application map where the well yield potential exceeds 5 m3hr-1, are found at the northern part of the Tabora Urban and Tabora Rural east and north from Tabora Urban. From the case study in the Tabora Region, this proposed simple method has possibilities to be able to apply for other regions in Tanzania and surrounding countries of Tanzania where are under similar conditions and environments to the Tabora Region.