Laboratory experiments on pressure distribution along sinuous riverbanks

The pressure gradient along riverbanks is one of the main driving forces for lateral hyporheic exchange, substance and energy transport in riparian zones. In order to reveal the discipline and main factors of disturbed pressure distribution along sinuous riverbanks, series of experiments are carried out in an adjustable slope test flume. Different geometries of sine-shaped channel models are built and put into the flume to form different boundaries of riverbanks. The pressure head data are measured in a wavelength range of riverbanks to study the characteristics of pressure distributions in different layers, different sinuosity of riverbanks and different hydraulic conditions. A sensitivity analysis of influence factors is also conducted. The experimental results show that the pressure distribution along the sinusoidal riverbank is a curved shape. The pressure distributions in different layers are almost the same. When the riverbank sinuosity is relative low, the pressure variation reaches the crest value and trough value respectively at the most concave and convex location of riverbanks. Under subcritical conditions, the disturbed pressure along the riverbank is mainly affected by the bank amplitude-to-wavelength ratio a/λ and Froude number Fr. The sensitivity analysis reveals that the influence of a/λ is relatively strong.