Physico-Chemical Environment of Coastal Areas in the Vicinity of Lbod And Tidal Link Drain in Sindh, Pakistan after Cyclone 2a

Abstract

This paper presents the results of preliminary assessment of water quality along the coastal areas in the vicinity of Left Bank Outfall Drainage (LBOD) and Tidal Link Drain (TLD) in Sindh province after the cyclone 2A occurred in 1999. The water samples were collected from various RDs of Tidal Link Drain and lakes during September 2001 to April 2002 and were analysed for salinity, nitrite, phosphate, ammonia, silicate and suspended material in water. The results of the study showed considerable variations in water quality depending upon the location along the coast in the vicinity of LBOD and RDs. The salinity ranged between 4.39-65.25 ppt in Tidal Link Drain samples whereas 2.4-38.05 ppt in samples collected from lakes. The values of suspended material at various RDs of Tidal Link Drain ranged between 56.6-2134 ppm and at the lakes between 68-297 ppm. The data of continuous monitoring at RD-93 showed the range of PO4 (8.6-25.2 µg/l), SiO3 (554.96-1462 µg/l), NO2 (0.557.2-25.2 µg/l) and NH3 (9.38-23.62 µg/l). The concentration of nutrients in water samples collected from different RDs was found in the range of PO4 (10.85 to 11.47 µg/l), SiO3 (1624 to 2635.08 µg/l), NO2 (20.38 to 44.8 µg/l) and NH3 (24.08 to 26.6 µg/l). Sindh coastal areas which situated at the north-western boundary the Arabian Sea are highly vulnerable to flood damages due to flash floods during SW monsoon or impact of sea level rise and storm surges coupled with cyclones passing through Arabian Sea along Pakistan coast. It is hoped that the obtained data in this study would act as a database for future investigations and monitoring of LBOD and Tidal Link Drain coastal waters. Keywords—Tidal Link Drain, Salinity, Nutrients, Nitrite salts, Coastal areas.