Refraction (of water waves)

(1) Process by which direction of a wave moving in shallow water at an angle to the contours is changed. Part of the wave advancing in shallower water moves more slowly than the part still advancing in deeper water, causing the wave crest to bend toward alignment with the underwater contours. (2) Bending of wave crests by currents. (US Army Corps of Engineers, Low Cost Shore Protection: A Property Owner's Guide, 2004)