Identifying dam-induced wetland changes using an inundation frequency approach: The case of the Atreyee River basin of Indo-Bangladesh

摘要

Identification and monitoring of hydro-ecologically complex, seasonal floodplain wetlands poses a great challenge, but is essential for sustainable management of wetland and wetland resources. The present paper concentrates on wetland delineation and monitoring in the Atreyee River floodplain with reference to the flow regulation imposed by a dam built in 2012. We applied a water presence frequency approach to wetland delineation, representing the continuum of wetland appearance based on a frequency gradient, and we found that the areal extents of low, moderate and high-frequency water presence wetland areas are approx. 607, 367 and 176 km(2), respectively. The construction of a dam on the Atreyee River has curtailed the average and maximum discharge by approx. 67% and 80% during monsoon time; this has had the impact of reducing the wetland area from approx. 1280 km(2) to 629 km(2) in the post monsoon season and shrinking the stable part of the wetland by 78% in the post-dam period. Isolation of the wetland from the river, agricultural extension, encroachment of built-up land, etc., are responsible for the growing fragmentation of the wetland, therefore bringing increased susceptibility to further wetland loss. Such a trend of precious wetland habitat loss threatens rare and endangered species as well as the lives and livelihoods of the dependent people. (C) 2017 European Regional Centre for Ecohydrology of the Polish Academy of Sciences. Published by Elsevier Sp. z o.o. All rights reserved.