ABSTRACT
In many parts of semiarid areas, water pollution from agricultural sources is plagued with uncertainty of various proveniences. Groundwater quality issues in arid and semiarid lands are very complicated. Human activities result in the groundwater resources being polluted, aquifers being incorrectly exploited and utilized, and abstraction facilities being vandalized. Groundwater development has already reached a critical stage, resulting in acute scarcity of the resource. Overdevelopment of groundwater resources results in declining groundwater levels, shortage in water supply, intrusion of saline water in coastal areas, and increased pumping lifts necessitating deepening of groundwater abstraction structures. These have serious implications on the environment and socioeconomic conditions of the populace. The primary groundwater management issue in many semiarid countries today is pollution. This may derive from a point source, perhaps a leaking solvent store at a factory, or it may be diffuse, such as the threat posed by the use of agricultural fertilizers and pesticides. The key to understanding the transport of a pollutant from the ground surface or near surface into an aquifer is an understanding of recharge. Land zonation of different classes of aquifer vulnerability is a valuable tool for management and planning.
292This chapter describes the contamination of the groundwater under the main headings: (1) resource value versus access, (2) contamination source identification and prioritization, (3) vulnerability and protection, and (4) borehole performance and monitoring. In this chapter, recent developments within the interlinked areas of groundwater pollution, aquifer recharge, and vulnerability are highlighted. This chapter provides an up-to-date description of the relationship between pollution, recharge, and vulnerability set against the current groundwater protection policies of the arid and semiarid regions.
