ASSESSMENT OF WATER QUALITY OF LBOD SYSTEM AND ENVIRONMENTAL CONCERNS

Abstract

The system of Left Bank Outfall Drain (LBOD) is one of the major drainage projects ever carried out in Pakistan and World. This system has developed a positive impact on the productivity over large areas of land within its catchment areas, twin problem of salinity and waterlogging in these areas have reduced considerably. However, much of the positive effects in the upper reaches of the drainage catchment have been set off by negative impacts in the tail reaches. Here wetland areas were salinised and a landscape of small lakes interconnected with densely grown wetland vegetation was changed to one large water body with saline and infertile fringes. Drainage System nowadays is facing serious problem of industrial, agricultural, pesticide and municipal effluents by disposal of different pollution sources. The TDS values of collected samples range from 1500 to 23000 mg/L. Similarly the results of other water quality parameters like; calcium, sodium, chloride and magnesium are also higher than the permissible national standards. These contaminants caused degradation of LBOD system and placed serious environmental and health threats. Apart from causing degradation of drainage water quality and the large water bodies’ also causing health threat to the local population through waterborne and vector diseases such as malaria have been on a steady rise. It is argued that much of these negative effects could have been avoided by just applying sound engineering principles. This paper presents adverse environmental impacts, such as pollution of the drainage waters, groundwater, and destruction of wetlands.