CHAPTER ONE
1.0 INTRODUCTION
In recent times, the GPR is fast becoming the preferred method in geophysical methods used in hydrological studies. It is an electromagnetic method that detects interfaces between subsurface materials with differences in dielectric constants. The GPR measures changes in the electromagnetic properties of sediments that cause reflection of electromagnetic energy.
The GPR provides an image of the subsurface at higher resolutions. It is a non-invasive, non-destructive technique which finds geological and non- geological applications (keary et al., 2002). The GPR is very important due to the fact that among geophysical methods, the Ground Penetrating Rader (GPR) bearing some limitations is most feasible techniques used for hydro-geological conditions related with mining activities for shallow workings Singh(2006). It was used in recent past to study densities and fractures of funnel rocks (Cook, 1975), Glacier (Harrison, 1970;Watts and England 1976) and Salt domes (Holser et al.,1972), and to locate buried pipe and cables (Annan et al., 1984). It was also used in engineering and geological data collection on land and on water by Ulriksen (1982) and Gorin and HAeric (1989). Pyke et al., (2008) reported that, in some geological conditions such as clean sand, gravel and limestone, strong GPR reflections are often recorded along the water table, and this really shows that the GPR technique is suitable for locating the water table and studying of the soil strata.
The water table is the below ground level that marks the transition between ground that is saturated with water and ground that is not saturated.
It is the surface where the water pressure head is equal to the atmospheric pressure (where gauge pressure = 0).
 The Ground penetrating radar (GPR) is a high-resolution technique for imaging shallow soil and ground structures using electromagnetic (EM) waves in the frequency band of 10-1000 MHz, this geophysical method has become increasingly applicable and popular among geoscientists over the last 20-30 years, its application has been carried out in a geophysical field work in the southeast outskirts of Enschede, The Netherlands. The area is a flat land covered by grass and sparse deciduous trees, used for mainly agricultural practices since the area is dominantly inhabited by farmers. The soil composition is mostly of clay and sand or a mixture of both, which initiates the aim of this preliminary fieldwork.
