Environmental management of waterlogging problem in south-west coastal region of Bangladesh

Abstract

ABSTRACT

The south-west coastal region of Bangladesh has been very fertile and rich in biodiversity, and people had their own indigenous sediment management system. However, construction of polders, which started in early 60’s, led to the present waterlogging crisis. The compartmentalized polder system delinked flood plains from rivers. Sedimentation took place only in river channel, raising river beds; water remains trapped in beels, turning these into water logged area. Waterlogging hazard is a burning issue for Jessore, Khulna and Satkhira, the three coastal districts of the southwest region of Bangladesh. This study presents an assessment of the waterlogging problem and its impact on the coastal region, with a particular focus on Tala Upazila, Satkhira District. In this Upazila, there was no significant waterlogging in the past, as evident from satellite images of 1989. The fertile land started going under water gradually and after the massive rainfall of 2011 as much as 34 % agricultural land of the study area disappeared under waterlogging. There was a reasonable fresh water flow in Kabodak River in the past, as evident from the satellite images of 1999 and 2000. However, due to huge sediment deposition, Kabodak has lost its water carrying capacity. It has significantly affected local biodiversity in the area. Most of the farmers have turned into fisherman. Salinity of both groundwater and surface water in the study area is increasing with time. Many tube wells have become unusable due to high salinity. Local people are fighting the situation through innovative adaptation, particularly in the area of agriculture (e.g., floating agriculture). This problem might be mitigated through implementation of Tidal River Management (TRM), utilizing local knowledge and their involvement. TRM operation should be continuous and a list of successive tidal basins were proposed for future implementation. Excavation of the dead rivers as well as loop cut will drain out logged water to the downstream during rainy season and renew its normal tidal nature.