FIG. 1.

Flow fields over the streambed in the control flume and the bedforms, successively increasing in height; these bedforms were used to generate landscapes of increasing flow heterogeneity in the flumes. (a) Bedform (side view); arrows indicate the position of the sampled microhabitat along a bedform. (b) Maps (bird's-eye view) of turbulent kinetic energy (joules) and flow velocity and direction (red arrows) in the control flume (no bedforms) and along the individual bedforms (2, 4, 6, 8, and 10 cm high) as derived from ADV measurements (5 mm above the sediment). The x axis refers to the position along an individual bedform, and the y axis refers to the flume width.