GEOPHYSICS IN TOWN-PLANNING - A CASE-STUDY

Geophysical surveys as aid to urban evaluation in the Vidyadhar Nagar area adjacent to Jaipur city, Rajasthan, have been conducted. DC resis tivity surveys over area covered by sand and dunes indicated the prese nce of a moderately thick surface layer underlain by a potable aquifer zone of substantial thickness over quartzite bedrock of even topograp hy deepening towards southwest. The results of the magnetic survey sho w, in general, normal structural behaviour barring a high in the south west part of the area. The high is explained as due to an intrusive fe ature at a considerable depth, hence inconsequential for town planning . Subsequently, Jaipur Development Authority has undertaken construct ion of urban complex with a high rise structure in the area. The paper presents the geophysical results along with chemical analysis of grou nd water and computer studies. The soundings reveal the suitability of the area for urbanisation, considering the presence of moderately thi ck surface horizon underlain by a promising aquifer formed over the qu artzite bedrock of even topography and disposition. The order of the r esistivity obtained and the chemical composition of ground water show the ground water to be of good quality for drinking purpose.