Living polders: dynamic polder management for sustainable livelihoods, applied to Bangladesh

This project aims to develop a decision support model for the management of ‘living polders’, in which controlled flooding and sedimentation (Tidal River Management, TRM) allow the land surface level to keep up with sea level rise. The research focusses on the Bangladesh delta, but also includes an evaluation of the ‘worldwide potential’ of the concept.

Project presentation UDW-II Kick-off meeting at 9 May 2016

Summary

Managed deltas are social-ecological systems that provide flood- and food security. However, land subsidence and sea level rise render deltas vulnerable to flooding, the impact of which is exacerbated by population growth and urbanization. These stresses affect institutional requirements for delta systems. Polders can mitigate these threats by offering flood protection and increased food production. In Bangladesh, polders increased yields, but at the delta level, they affected rivers' drainage capacity and siltation. At the polder level, they caused land subsidence, and waterlogging.

In response, in 1990, local people themselves breached dikes of the Dakatia beel polder, to re-allow tidal flows. This eroded silt from the tidal channels enabling drainage of waterlogged areas, and re-allowed sedimentation inside polders, raising soil surfaces and fertility. Ever since, Tidal River Management has been experimented with, however, its full potential has not yet been reached due to fundamental knowledge gaps regarding physical and institutional boundary conditions.

Rather than being an obstacle, sediments provide a high potential for a Building with Nature approach, which works with rather than against the forces of nature. This project builds on this notion and seeks to explore the potential of Living Polders that accrete along with rising water levels. The project offers comprehension of integrated, coevolving physical and institutional processes across delta- and polder scales. Subsequently, it provides pathways to optimization through a Decision Support System for dynamic polder management and associated business cases. Project outcomes are evaluated for application elsewhere, thus offering business opportunities for the Dutch water sector.

Details

Project number

W 07.69.201

Main applicant

Dr. F.S.J. van Laerhoven

Affiliated with

Universiteit Utrecht, Faculteit Geowetenschappen, Departement Innovatie-, Milieu en Energiewetenschappen

Team members

Prof. dr. J. Griffioen, N. Hafiz BSc, Z. Hossain, Dr. ir. A.. Islam, Dr. M.J. van der Meulen, N.U. Rahi, Prof. dr. M. Shah Alam, V. Upraity MA