Temporal Dynamics of Vegetative Cover and Surface Water Bodies in the Indus Delta, Pakistan

Abstract

Under the current scenario of diminishing Indus River flows and changing the climate, the Indus Delta, the world’s 5th largest delta which has undergone rapid changes in water bodies and vegetative cover since last few decades, is under serious risk of losing its ecological functions. Assessing the temporal variation in vegetative cover and water bodies of the Indus Delta is essential for the future planning and ecosystem management in this region. The present study quantified the temporal patterns of the surface water bodies and vegetation cover, including crops, mangroves and other natural vegetation in the Indus Delta, by using field survey and remote sensing technique during the last 27 years. Results showed that the area covered by vegetation declined from 3002.35 km2 (22.98% of the entire delta) to 2817.03 km2 (21.56%) from 1990 to 2017, within which the area covered by mangrove forests declined from 1032.49 km2 (7.90%) to 812.55 km2 (6.22%). However, the area of water bodies increased from 1611.67 km2 (12.39%) to 3007.15 km2 (23.8%) in the same period. The reduction in freshwater flow to the delta, surface and subsurface seawater intrusion from the Arabian Sea and irrigation waters are the potential causes. The study would be helpful for policymakers to mitigate negative impacts and protect the ecosystem of the Indus Delta.

Assessment of water quality parameters due to longitudinal salinity inundation at Indus Delta: a case study of Kharo Chan, District Sujawal

“…This finding aligns with the observations made by Shahab et al [24], who reported that the highest TDS values in Pakistan are typically found in the lower part of Sindh, which corroborates the results of this study. Siyal [16] has also reported that 64% of water bodies of the Indus Delta do not satisfy WHO standards for drinking water in terms of TDS, which is in accordance with the results of this study. Data depicted that at about 57 km from the ocean, the river water maps with the limit of WHO in terms of TDS and EC.…”

“…78% of the natural surface water bodies have been reported to be saline in the delta which is because of the seawater inundation. Siyal [16] reports that 66% of the surface water samples from the delta do not meet the standards of drinking water. Figure 3.…”

“…The literature reveals that seawater intrusion into the Indus Delta Pakistan, is increasing at an alarming rate which severely affects the livelihood of the people and leads to environmental degradation [13]. Furthermore, various ill effects of seawater intrusion have also been pointed out such as the engulfing of fertile land [10], stunted growth of mangrove forests [14], loss of nutrients [15], and reduced flow of freshwater [16].…”

“…The surface water of many regions has also been studied for the same menace as the Yangtze River in China has been studied by He et al [18] and Hau River by Ni et al [19]. Physicochemical parameters for various lakes, ponds, streams, and natural depressions located in the Indus Delta have been studied by Siyal [16], who has quantified the area taken away by the sea. In the same way, Ahmed et al [20] have explored this spatiotemporal variation of various dissolved organic nutrients and chlorophyll-a across the various creeks of the Indus Delta including the Khobar Creek.…”