Date of Award


Degree Type


Degree Name




First Advisor

Trenhaile, Alan S.,


Physical Geography.




Ephemeral, flow-parallel streaks of sorted sediment are common in the swash zones of many beaches, although they are largely undocumented in the literature. Streaks were studied under a variety of conditions on four beaches along the northern shore of Lake Erie. They were always visible on two beaches and never visible on the others. As similar wave conditions were observed on all beaches, this suggests that the occurence of visible streaks is governed by beach characteristics, particularly sedimentology, rather than wave parameters or swash velocity. Streaks were found to consist of sediment that was more coarse-grained and richer in dark minerals than sediment from the adjacent spaces. Mobile sediment in the swash zone had a similar mineralogical composition to streak sediment, but was not similar in shape, and was similar in size on only one beach. Streak width (generally 2 to 4 cm) and spacing (generally 1 to 2.5 cm) were largely unaffected by variations in wave conditions and swash velocity, but were significantly greater on fine/grained than coarse-grained beaches. Attempts to detect flow-parallel sedimentary variations in the swash zone when streaks were not visible were unsuccessful. Although the mechanism responsible for streak formation is unknown, it is likely related to one of three processes: turbulence bursting in the boundary layer; helicoidal flow in the nearshore zone; or laminar, oscillatory flow streaking.Dept. of Geography. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1995 .P46. Source: Masters Abstracts International, Volume: 34-06, page: 2330. Adviser: Alan S. Trenhaile. Thesis (M.A.)--University of Windsor (Canada), 1996.