Assessment of hydraulic jump dynamics on sediment deposition in river Orisa, Omu-Aran, Nigeria

Abstract

• Floods cause major global damage and affect the highest number of people. • Hydraulic jumps significantly influence sediment deposition in rivers. • River Orisa study shows a strong link between Froude ratio and deposition rate. • Higher Froude ratios increase energy loss and sediment settling rates. • 78–88% coarse sediments strongly affect deposition behavior in the river. Floods are among the most destructive natural disasters and are often intensified by hydraulic jumps that alter flow velocity, enhance sediment settling, or trigger resuspension, thus influencing riverbed morphology. This study quantitatively assesses the influence of hydraulic jump dynamics on sediment deposition in River Orisa, Omu-Aran, Nigeria. Forty-five sediment samples were collected from five locations—FRSC, BOVAS, Rore, Aran-Orin, and LMU. Flow parameters, including velocity, depth, and channel width, were measured in situ using an MGG/KL-DCB electromagnetic flow meter and measuring tape. Sediment particle size distribution was determined by sieve analysis. In a 5 m long, 300 mm wide laboratory flume equipped with different weirs, each sample was subjected to 60-minute flow runs to evaluate deposition rates based on the mass of settled sediments. Froude number ratios and energy dissipation were computed from the experimental data, with statistical analysis performed using descriptive statistics, ANOVA, and correlation. Results showed that 78.1–88.2% of the sediments were coarse fine aggregates. The Froude number ratio and deposition rates ranged between 0.019–0.013 and 108.94–45.47 g/s for BOVAS and Aran-Orin, respectively. Energy dissipation peaked at Rore (2.73 m) and was lowest at FRSC (2.025 m). A strong positive correlation (r = 0.977) existed between Froude number ratio and sediment deposition, while energy dissipation showed a weak negative correlation (r = –0.235). There is a strong relationship between the hydraulic jump and sediment deposition, hydraulic structures along River Orisa must be designed or modified to regulate localized hydraulic jumps.