Investigating the effect of buried walls through rockfill detention structures on the longitudinal water surface profile

Abstract

Rockfill structures in river training projects, such as detention dams, gabions, and levees, play a significant role in flood control. One of the common types of these structures is porous flood mitigation dams. This research investigated the surface flow profile by developing an analytical model based on specific energy relationships and Wilkins pore velocity and employing numerical methods based on estimation and correction methods. In order to examine the efficiency of the presented models, experiments were performed both with and without buried inside walls through rockfill media. The results show the accuracy and efficiency of analytical and numerical methods for calculating the water surface profile. In order to apply these methods in the experiments including buried curtain, the profile is divided into two parts, and the computations were done by considering two boundary conditions at the outlet and the buried wall position. Quantitatively, the root mean square error (RMSE) ranged from 3 to 5.5 mm, with a relative error between 3 and 9.3%. The relative error increased with higher core heights, particularly downstream of the core due to local flow acceleration and significant flow curvature. At a flow discharge of 0.19 l/s, the relative error was 3%, rising to 8% at higher flow rates. Therefore, the results indicate the appropriate correlation between the laboratory data and analytical and numerical solutions in the experiments, including wall. It was also observed that with the increase of the entrance discharge, the profile estimation accuracy decreased, and curvature in the surface profile was observed.

Keywords

• rockfill dam
• water surface profile
• analytical solution
• numerical estimation-correction method
• vertical and inclined curtains