Fig. 5

Velocity profile on a 1 cm×1 cm section of the fine-grained microrelief illustrated with colored passive tracer particles (left). The 0.3 mm average water film thickness leads to a flow rate of 7.27 L h ⁻¹. The flow direction is top to bottom. The flow pattern is stationary and forms streams of increased velocity around teardrop shaped regions of decreased velocity behind bumps in the microrelief. At the bottom left we show a side view of the microrelief and water layer above. At the right we show a heatmap of the microrelief elevation