2024 Volume 12 Issue 2 Article ID: 23-16021
Groynes installation is a popular measure to prevent riverbank erosion in braided rivers. In this study, evaluation of groynes installation has been done at a vulnerable reach of the Jamuna River in Bangladesh. Four groynes (officially termed as cross-bars) have been installed at the erosion prone (right) bank of the river adjacent to Sirajganj town. Due to the unpredictable behavior of the braided river and critical climatic conditions, stability assessment of the groynes is crucial, as well as their impact on surrounding area. To perform the evaluation, 50 km reach of the Jamuna River has been analyzed by numerical model using iRIC Nays2DH software. After successful calibration and verification of the model, the simulations have been done using peak discharges for six different cases. Analysis of the model output reveals that cross-bar 3 is in vulnerable condition among the four based on scouring at the toe of the groyne. Additionally, the impact includes formation of a weak zone at 4.0 km upstream of the cross-bar 1. More than 2.0 km of riverbank becomes susceptible to erosion due to the attack of the stream flow, which shows the impact of the constructed cross-bars in the surrounding area. This study provides insights into the stability assessment of groynes and their impact in braided rivers.
