Increased sea water intrusion in the vicinity of Tidal Link Drain at south Sindh (Pakistan)
The Tidal Link Drain is a man made drain which delivers the drainagewater across Pateji and Cholri Dhands into the Arabian Sea via Shah Samando creek. TheTidal Link is 41 Km long from its point of juncture with Kaddan Pateji Outfall Drain(KPOD) in the North-East up to Shah Samando Creek in the South-West. The verticaltidal range in the area is about 5 m. The tidal link was designed to carry about 3,118cusecs of drainage waters. After completion of Tidal Link Drain, sea water intrusion andhigh erosion/sedimentation have been noticed at the tidal link and adjacent area due tochanges in the hydraulic regime in the area. The devastation caused by tropical cyclone“2A” in May, 1999 in the Indus delta has also created some drastic morphologicalchanges in the area. This physical process creates breaches in the Tidal link drainbetween RD-30 and RD-125. These openings allow free exchange of water between thetidal link drain, Dhands and the Rann of Kutch.The analysis of tidal behavior, tidal current measurements and water samplescollected in the study area shows that a small tidal creek type system of drainagechannels has now been developed in Cholri Dhand and this system of channels is nowused to flush water during ebb tide from surrounding Dhands of LBOD through TidalLink Drain. It is observed that the LBOD can now be described as a “New River” that isforming an “Estuary”, which is an integral part of the creek system of the coastal area.The tidal link now acts as a tidal stream in which tidal fluctuations are very much visibleand the sea water is now approaching the land. The main problem concerning the LBODoutfall is the increased hydraulic gradient due to seawater intrusion. The LBOD runparallel to the Indus River and discharges the saline water at the same level (sea level) inan active creek area of the Shah Samando Creek. The same altered hydraulic gradientcreates very strong ebb currents in the region, which are responsible for making breachesin the tidal link drain and erosion and accretion in the Dhands.
| Main Authors: | , , |
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| Format: | article biblioteca |
| Language: | English |
| Published: |
2010
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| Subjects: | Oceanography, Tidal Link Drain, LBOD, Dhands (ponds), saltwater intrusion, Indus delta, hydraulic gradient, 1999 cyclone, sea level rise., |
| Online Access: | http://hdl.handle.net/1834/40754 |
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