Sediment management using bandal-like structures as nature-based solution

Abstract

To materialize the inherent opportunities of incoming sediment load, various interventions are being practiced for sediment management in rivers and delta systems. Broadly, the practiced methods can be divided into two categories: (i) management for accelerating siltation to enhance land reclamation and counterbalancing bank erosion (ii) management for de-siltation in the channels to maintain required navigational flow depth. The pre-requisites to achieve the above targets, simultaneously, are quite contradictory as land reclamation need more sediment, while less sediment load is necessary for the maintaining the navigational depth. To overcome the above constraints, Bandal-like Structures (BLS), the indigenous nature-based solution, has conceptualized to utilize through redistributing the local flowsediment regime to create a sediment deficit zone within the river side and a sediment surplus zone along the bankside that can eventually, be useful for the maintenance of navigational channels and bank stabilization, simultaneously.In this article, the experiences of BLS, to achieve both functions simultaneously are discussed based on the research experiences for last 20 years. Out of many implemented BLS at different scales in the Ganges-Jamuna-Brahmaputra (GBM) system, a well-documented case study of its application is showcased along a reach of the braided Jamuna River. Based on the evaluation of the performance of the implemented case study coupled with the existing indigenous knowledge, a hybrid approach integrating the conventional and community sciences, is proposed as a nature-based solution for sustainable sediment management in the river systems of Bangladesh.