Climate change is one of the challenges facing mankind today. Several definitions of climate change have been put forward by a number of scientific bodies. One such definition by the United Nations Framework Convention on Climate Change (UNFCCC, 1992) refers to climate change as, ‘a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods’.
There is growing evidence that global climate is changing. According to International Panel on Climate Change (IPCC,2001a), global mean temperatures have risen 0.3-0.6oc since the late 19th century and global sea levels have risen between 10 and 25cm (McCarthy et al.,2001) noted that global temperatures will continue to rise by between 1.4 and 5.8oc by 2100 relative to 1990 due to the emissions of greenhouse gases. As the warming process continues, it will bring about numerous environmental problems, among which the most severe will relate to water resources (Loaiciga et al., 1996; Milly et al.,2005; Holman,2006; IPCC,2007).
Temperature increase also affect the hydrological cycle by directly increasing evaporation of available surface water and vegetation transpiration. Consequently these changes can influence precipitation amount, timing and intensity rates and indirectly impact the flux and storage of water in surface and subsurface reservoirs (i.e. lakes, soil moisture, groundwater)(Toews,2003).
Water is one of earth’s most precious resources that is indispensably and intricately connected to life. Good drinking water is not a luxury; it is one of the most essential amenities of life. Safe drinking water is a priority for all.
This is the reason for which water must be given the necessary attention at all times. Although water is essential for human survival, many do not have sufficient potable drinking water supply and sufficient water to maintain basic hygiene. Globally, 748 million people lack access to improved drinking water and it is estimated that 1.8 billion people use a source of drinking water that is feacally contaminated (WHO/UNICEF, 2004).
Groundwater is the main source of water for drinking and irrigation in low rainfall arid and semi arid areas where are no significant surface waters sources. This is because groundwater is slow to respond to changes in precipitation regime and thus acts as more resilient buffer during dry spells. In fact worldwide, more than 2million people depend on groundwater for their daily support (Kemper, 2004). Furthermore groundwater forms the largest proportion (? 97%) of the world’s freshwater supply. By maintaining surface water systems through flows into lakes and base flows to rivers, groundwater performs the crucial role of maintaining the biodiversity and habitats of sensitive ecosystems (Tharme, 2003). The role of groundwater is becoming even more prominent as the more accessible surface water resources become less reliable and increasingly exploited to support increasing population and development (Bovolo et al., 2009).
The effects of global warming on water resources, especially on groundwater, will depend on the groundwater system, its geographical location, and changes in hydrological variables (Alley, 2001; Huntington, 2006; Sophocleous, 2004).
Knowing how climate change will affect groundwater resources is thus important as it will allow water resources managers to make more rational decisions on water allocation and management (Sullivan,2001) and enable the formulation of mitigation and adaptation measures.
Groundwater forms a major source of drinking water. The modern civilization, industrialization,
urbanization and increase in population have lead to fast degradation of our ground water quality.
The occurrence of groundwater depends primarily on geology, geomorphology and rainfall – both current and historic. The inter-relationships between these factors create complex patterns of water availability, quality, reliability, ease of access and sustainability. Climate change will superimpose itself by modifying rainfall and evaporation patterns, raising questions about how such changes may affect groundwater availability and, ultimately, rural water supplies.The quality of water from dug wells is largelydependent on the concentration of biological, chemical land physical contaminants (Musa et al., 1999).
The main drinking water sources, most especially in African countries are from boreholes, pipe borne, deep and shallow wells, dug outs, streams and rivers which are mostly of poor quality. Water quality is a growing concern throughout the developing world (UNICEF, 2013) and sources of drinking water are constantly under threat from contamination. In Ghana, 62 to 67% of the people depend on groundwater (GEMS/Water Project, 1997) and many cities and towns have problems with the quality of waterused in homes and work places (Nkansah et al., 2010; Obiri-Danso et al., 2009).