Cost‐Effective Hybrid Groyne Series for Riverbank Erosion Prevention

Groynes are widely used river training structures and have proven effective in flow regulation and bank protection. Recently, hybrid groynes have gained popularity in the field of river training engineering. However, systematic approaches for their optimal design and placement remain limited. In the present work, a linked simulation–optimization model is proposed to determine cost‐effective hybrid groyne series. At the same time, it also ensures the riverbank stability. The flow simulation model solves the unsteady equations of open channel flow. The optimization model is formulated here in three different formulations to handle different real‐field issues. The first formulation is designed to provide complete flexibility in determining all the decision variables, that is, the groyne type, number, length, and position. The second formulation defines some fixed locations of the groynes on the vulnerable river reaches and the optimization model determines the best value of the rest decision variables. The third formulation, however, fixes the groyne types, lengths, and numbers, and the optimization model determines the optimal locations of the same. The proposed optimization models are solved here using the binary coded genetic algorithm (GA). The model is then applied for two hypothetical test cases and reliable results are derived. Out of the three formulations, the first formulation is found to behave more robustly because of no restrictions imposed. Compared to previous optimization studies which focused on individual, uniform, and straight groyne types, the present framework introduces a generalized tool for designing hybrid groyne series.