Investigation of flow characteristics in open channel with leaky barriers

Abstract

• Backwater rise and flow characteristic of open channel with leaky barrier were experimentally investigated. • Theoretical equation of the water level upstream the leaky barrier was presented. • The equation was easy to use and agreed well with the experimental results. • Solid volume fraction of the leaky barrier was the primary factor affecting backwater rise. Traditional flood control projects, such as dams and gates, may disrupt river connectivity, resulting in the fragmentation of river habitats. Leaky barriers, as a new method of flood defense, are gradually used in flood management especially in small rivers due to functions of the engineering in ecological and connecting rivers and regulating floods. Understanding the hydraulic effects and especially the backwater rise caused by leaky barriers is necessary to assess its impact and optimize the design. This paper investigates the influence of the leaky barrier on hydrodynamics through a designed flume experiment. A formula that reveals the backwater effects of the barrier was obtained by solving the momentum and continuity equations. Comparing the predicted and measured values of upstream water depth, the difference was within a reasonable range. Based on the results, the factors affecting the backwater rise are the Froude number of the approaching flow, downstream water depth, and the longitudinal length, drag coefficient, the solid volume fraction of the leaky barriers. Among the characteristics of leaky barrier, the solid volume fraction is the main factor affecting the backwater effect. The findings are helpful to understand the hydraulic influence of leaky barriers and can provide references for practical project.