Evaluating the impact of porcupine systems in the flow field of the river: a hydrodynamic model study

Abstract

ABSTRACT Riverbank and in-stream protection are crucial in numerous river stretches, where erosion of banks and bed material instigates river course alterations, consequently leading to land and property damage. In large Indian braided rivers like Brahmaputra, implementing tetrahedron frames commonly referred to as ‘porcupines’ has emerged as a cost-effective strategy for river training, yielding commendable outcomes in near bank sedimentation. Using flexible river training structures, such as porcupine, presents an appealing option for managing braided river channel networks in areas where permanent control structures like groynes or dams prove excessively costly or potentially ineffective, particularly in systems exhibiting highly dynamic flow regimes and morphology. This work aims to develop a hydrodynamic model that integrates the porcupine systems within its framework. The model’s effectiveness was assessed through a field test near Nematighat, Brahmaputra River, in collaboration with Assam’s Water Resources Department. The mathematical modelling provided some valuable insights regarding the flow characteristics surrounding the porcupine structure, shedding light on its hydrodynamic behaviour.