to prevent non-point source pollution on land can apply equally to groundwater protection; practically any activity on the surface can have an effect on the quality of underground water. Being out of sight, it is not always apparent that damage has been, or is being, done to the groundwater resource and yet clean-up of groundwater pollution is expensive and may take hundreds of years.
The need to prevent groundwater pollution is therefore important because of the long term impact as well as the dependency on groundwater resources for many drinking water supplies.
The concept of groundwater pollution risk is based on the interaction between the potential pollution load and the vulnerability derived from the natural characteristics of the strata. Critical areas for groundwater pollution are determined by comparing the vulnerability map with a potential contaminant load map drawn up on the basis of records of industrial activity, urban development, mining activities, waste disposal sites, and agricultural field.
The framework for groundwater pollution control requires measures such as:
• Identification of threats to groundwater from point or diffuse sources, and by both conservative and degradable pollutants in the basin;
• Classification of groundwater in terms of vulnerability and definition of source protection zones; and
• Policies and strategies on how polluting activities may be controlled to reduce or to eliminate the risks.
3. Planning for Pollution Control
Pollution control planning comprises the following elements:
• Identification and initial analysis of water pollution problems and future predictions;
• Define management objectives and strategy;
• Derive management interventions, tools and instruments needed to fulfil the pollution management objectives; and
• Establish an action plan for implementation, monitoring and updating of the plan.
3.1 Problem identification and analysis
The first step is identification and assessment of existing and potential water quality problems. The objective of the assessment is not to solve the problems but to identify