CHAPTER ONE
INTRODUCTION
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:
1. Input,
2. Data management (data storage and retrieval),
3. Manipulation and analysis, and
4. Output.
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).