Surface and Below Surface Waterfalls
June 27, 2014
Photographer: Hans Juergen Heyen
Summary Author: Hans Juergen Heyen
Shown above are photos of a small waterfall on the Erft River near Grevenbroich-Kapellen, Germany. Note the subsurface or underwater waterfall, which looks light green in contrast to the brighter, whiter, water at the surface. Water on the surface of the river can freely flow over the weir -- an example primarily of laminar flow. But, water deeper than about 16-20 in (40-50 cm) has to overcome the greater resistance of turbulent flow, as can be seen by the agitated white water. The smaller close-up photos show, at left turbulent flow and at right, laminar flow. Photo taken in May 2014.