Hydrological System of Pakistan and its effect on Environment

In Pakistan, changes in hydrological system have created problems as desertification, silting of dam reservoirs, water logging, and environmental pollution. A well established network of irrigation system which operated for a number of years is under threat because of such changes unless remedial measures are taken. Global warming has changed the Monsoon wind patterns and is affecting frozen water reserves threatening much needed supply of water to huge reservoirs in the coming years. Surface and groundwater are being contaminated due to pumping of industrial effluents in the main water courses. Sweet waters of aquifers are being polluted because of excessive discharge and consequent inevitable recharge. Chemical and biological contaminations are increasing in groundwater as a result of poor town planning, sewage, industrialization in urban areas, and excessive use of agricultural chemicals as pesticides and fertilizers. Toxic chemicals in groundwater are increasing in type localities as the Wah Cantt. area as compared to the recommended values of WHO. Similarly most of Sodium, Calcium, Magnesium ions concentrations has risen above the WHO standards due to concentration of industry in a small area.

Physical parameters as temperature, colour, odour, taste, turbidity, and electrical conductance of shallow aquifers have been found to vary depending upon the degree of contamination or recharge in small pockets. Vertical distribution of these parameters generally decreases with depth in the deeper layers of aquifers. Different areas can be successfully divided into various zones depending upon the Electrical Conductance which conforms with the degree of contamination.

author(s):
M. H. Malik
Institute of Geology
Punjab University, Lahore.