Velocity profiles (A) at different longitudinal distances along the flume (taken at the flume's centreline) measured from the upstream flow straighter (X = 0 cm) and (B) representative of each designated zone in the flume. In both graphs; Y = vertical height within flume (with Y = 0 cm the flume bed), flow rate = 1.6 L/s, blue horizontal dotted line and triangle represent the water surface, dashed lines represent means and error bars are 95% confidence intervals.