Bringing in the tides. From closing down to opening up delta polders via Tidal River Management in the southwest delta of Bangladesh

The southwest coastal delta of Bangladesh is not only geographically home to a dynamic interplay between land and water, and between fresh surface water and saline tides, but also to contentious debates on flood management policy and hydraulic engineering works. It has been argued that dealing with delta floods in this region boils down to adopting either open or closed approaches. This paper longitudinally structures the open-or-closed debate based on a number of emblematic water management projects in the region. Departing from a typical open wetland history, river and polder embankments increasingly started to constrain flood dynamics. Upheaval among rural populations in response to the negative impacts of hydraulic engineering plans and works coalesced in efforts to restore open approaches, synthesized in the Tidal River Management concept. Its resemblance to historic overflow irrigation is often used politically as a yardstick to challenge the dominant hydraulic engineering paradigm. This paper argues that dealing with floods in Bangladesh requires plans, policies and projects formulated against the historic background of complex interactions among social processes, environmental dynamics and technological interventions: a lesson to be incorporated in on-going policy-making processes and long-term delta management plans.