Sustainability Index of Tidal River Management: A Framework for Measuring Water Sustainability in Coastal Areas

The Tidal River Management (TRM) approach plays a significant role in enhancing diversified services of the ecosystem in the ecosystem of rivers affected by tides and their floodplains and reducing coastal hazards in southwest Bangladesh. The main aim of this investigation was to complete the development of the Sustainability Index for Tidal River Management (SITRM) and to assess the sustainability of TRM in coastal regions. In the first stage, the key components along with indicators of the Sustainability Index of TRM were identified to address problems of the coast. In the second stage of this study, a five-point Likert scale was applied to gather responses from key informants. In addition, it includes direct field observations and consultation meetings to collect information concerning the SITRM indicators. The results showed that the framework of SITRM included several important indicators to solve coastal problems, including drainage congestion, waterlogging, rising sea levels, new land formation, compensation, alternative livelihoods, and terrestrial biodiversity as indicators. It also established standard tidal flow thresholds for the Hari–Teka River at 600 m3/s (maximum) and 250 m3/s (minimum) for high tide and 550 m3/s (maximum) and 200 m3/s (minimum) for low tide. Moreover, the results showed that the Canadian Water Sustainability Index (CWSI), West Java Water Sustainability Index (WJWSI), and Water Poverty Index (WPI) are suitable for overcoming coastal problems and climate change issues.