Hydrogeological Studies of The Karak Village N.W.F.P

Abstract

Karak is a district of N. W. F. P province. It consists of an east-west elongated alluvial plain surrounded by mountains. To the n011h and east lies Kohat Salt Range (Samana Range), south by the Shingar mountains while towards west it is open. Width ranges from 2Km to SKm and length about 32Km. The valley is arid with temperate climate. There are no canals in the area that meet the irrigation requirements. There is no big river flowing through the area. Whole of the area depends upon rain or ground water for domestic uses or for irrigation to a very small extent. The alluvium is eroded from the sunounding mountains and deposited by the small streams flowing in the area. The alluviUl~ is not very much sorted and consists mainly of gravel loams and clays. The hydraulic conductivities obtained by pumping tests are very low. Which suggest that the extent of ground water is very limited. The maximum thickness of the water conductive strata is not more than SOm. There is a need of finding the hydraulic conductive zones. Drilling too much boreholes is very expensive, therefore there is a need of some other technique for the estimation of hydraulic conductivities. One technique is by using the formation factors obtained by Vertical Electrical Soundings (VES). But this method does not account for clay contents. The approach used here accounts for the conversion of resistivity curves into seismic slowness curves. Then to establish a relationship between seismic slowness and hydraulic conductivity, so that hydraulic conductivity should be mapped throughout the area, to locate places for high hydraulic conductivities. The hydraulic conductivities obtained by pumping test, from resistivity logs, from surface resistivity curves and from the seismic slowness relationship are in good match