Ground water hydrology may be defined as the science of the occnrrence, distribution, and movement of water below the surface of the earth. Geohydrology has an identical connotation, and hydrogeology differs only by its greater emphasis on geology. Ground water referred to with out further specification is commonly understood to mean water occupying all the voids with in a geologic stratum. This saturated zone is tobe distinguished from an unsaturated, or aeration zone where voids are filled yith water and air. Water contained in saturate:! zones is important for engineering works, geologic studies, and water supply developements Conseqently, the occurrence of water in these zones will be emphasized here. Un-saturated zones are usualiy found above saturated zones and extending upward to the ground surface. Because this water includes soil moisture with in the root zone, it is a major concern of agricultlre, botmy and soil science. No rigid demarcation of waters, between the two zones is possible, for they possess an iriterdependent boundary and water can move from zone to zone in either science, including eology, hydrology, meteorology, and oceanography are concerned with earths water, but ground water hydrology may be regarded as a specialized science combining elements of geology, hydrology, and fluid mechanics. Geology governs the occurrence and distribution of ground water, hydrology determines the supply of water to the ground, and fluid mechanics explains its movement. To provide maximum development of grofnd water resources. for benefical use requires thinking in terms of an entire ground water basin. In order to inorease the natural supply of ground water, man has attempted to artifially recharge ground water basins. Coastal aquifers come in contact with the ocean at seawater of the coastline. Fresh ground water is discharged in to the ocean. the seaward flow of ground water has been decreased or even reversed, Sea water penettating in land in aquifer.