The use geographic information system for hydro-geological purposes has become widely acceptable in most of the developed countries. Although it is a recent technology or it is only appreciated recently, most of its foundation has been used for quite a long time. The age of computer and information technology has made acquisition of data through remote sensing, interpretation and display of the result (obtained) through GIS a very reliable, simple and standard source of important information. In some countries such as Canada and India, research centers have been established for the study and applications of GIS to various fields and the result been achieved so far has been commendable. Remote sensing provides a platform for much environmental data while GIS remain the most outstanding means of interpreting, manipulating and storage of this data. Ground water resources are dynamic in nature as they grow with the expansion of irrigation activities, industrialization, urbanization etc. (Das, 2008). Thus GIS with its advantages of spatial, spectral and temporal availability of data covering large and inaccessible areas within short time become a very handy tool in accessing, monitoring and conserving ground water resources.
Dangermond (2011) underscored the importance of GIS applications in our dynamic contemporary world characterized with rapid changes and facing many challenges and difficult problems such as climate change, urbanization, security, poverty and mineral explorations etc, which are affecting us as individual as well as impacting our organizations and governments.
DEFINITIONS FROM DIFFERENT STANDPOINT
Like the field of geography, the term Geographic Information System (GIS) is hard to define. It represents the integration of many subject areas. Accordingly there is no absolutely agreed upon definition of a GIS (deMers, 1997). A broadly accepted definition of GIS is the one provided by the National Centre of Geographic Information and Analysis; defines GIS as a system of hardware, software and procedures to facilitate the management, manipulation, analysis, modeling, representation and display of geo-referenced data to solve complex problems regarding planning and management of resources (NCGIA, 1990).
Rhind (1989) proposes that GIS is a computer system that can hold and use data describing places on the Earth’s surface. Fuller definitions give more idea of what GIS can do, as well as what they are. Burroughs (1986) defined GIS as ‘a set of tools for collecting, storing, retrieving at will, transforming, and displaying spatial data from the real world for a particular set of purposes.
ARONOFF (1989) defines GIS as a computer-based system that provides the following four sets of capabilities to handle geo-referenced data:
2. Data management (data storage and retrieval),
3. Manipulation and analysis, and
Geographic information systems have emerged in the last decade as an essential tool for urban and resource planning and management. Their capacity to store, retrieve, analyze, model and map large areas with huge volumes of spatial data has led to an extraordinary proliferation of applications. Geographic information systems are now used for land use planning, mineral exploration and exploitation, utilities management, ecosystems modeling, flood control, fire hazard control, hazardous materials, storm control, landscape assessment and planning, transportation and infrastructure planning, market analysis, visual impact analysis, facilities management, tax assessment, real estate analysis and many other applications, its relevance to our day to day life cannot be overemphasized.
The use of remote sensing and geographic information system for hydrogeological purposes has become widely acceptable in most of the developed countries (Longley et.al 2005; Asiyanbola 2017; Khodaei and Nassery 2011).
Groundwater is the water present beneath Earth’s surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock become completely saturated with water is called the water table. Groundwater is recharged from and eventually flows to the surface naturally; natural discharge often occurs at springs and seeps, and can form oases or wetlands. Groundwater is also often withdrawn for agricultural, municipal, and industrial use by constructing and operating extraction wells. Groundwater is widely distributed and is used for domestic, industrial and agricultural purposes throughout the world. Groundwater is a valuable natural resource that is essential for human health, socio-economic development and functioning of ecosystems. Groundwater is often cheaper, more convenient and less vulnerable to pollution than surface water. Therefore, it is commonly used for public water supplies. For example, groundwater provides the largest source of usable water storage in the United States (Abdulazeez, et. al 2016; Sander P., Chesley M. and T. Minor 1996; IAEA 1994).