. Shore processes and shoreline development . WAVE CURRENTS 97 to and near the shore, may combine with waves which breakdirectly on shore to give a very pronounced beach drifting in thedirection of the current. With a longshore current moving in adirection opposed to that of the oblique waves, sand may travel Fig. 15. — Parabolic paths followed by debris particles impelled by tliecombined action of onshore swells (broken lines) and obUque windwaves (solid lines). After Kriimmel. with the current and coarser material with the beach drift, as wasfully recognized by Owens and Case^^. The directio
. Shore processes and shoreline development . WAVE CURRENTS 97 to and near the shore, may combine with waves which breakdirectly on shore to give a very pronounced beach drifting in thedirection of the current. With a longshore current moving in adirection opposed to that of the oblique waves, sand may travel Fig. 15. — Parabolic paths followed by debris particles impelled by tliecombined action of onshore swells (broken lines) and obUque windwaves (solid lines). After Kriimmel. with the current and coarser material with the beach drift, as wasfully recognized by Owens and Case^^. The direction of beach drifting will depend upon many fac-tors. Among these may be noted the direction from which thegroundswells approach the shore, in those cases where they arenot sufficiently refracted to strike the beach at right angles, andin which wind waves are on the whole less powerful in determin- 98 CURRENT ACTION M. O WAVE CURRENTS 99 ing the movement of shore debris. Another important factor isthe direction of the prevaihng winds, or of the dominant stormwinds, in case these develop waves of considerable power, andthe groundswells are weak, or do not approach the shore direction of the greatest stretch of open water is likewiseimportant, since weak winds blowing over a long stretch ofwater may develop larger waves than strong winds which crossa limited water area. A good example of the effect of lengthof fetch is found in the beach drifting along the sandspitwhich encloses Toronto Harbor on Lake Ontario. Here themovement of the beach material is westward against the prevailingwesterly winds, because the greatest stretch of water over whichwesterly winds can blow is 40 miles, whereas easterly winds cross180 miles of the open lake surface^^. Failure to recognize theimportant relation of beach drifting to the direction of greatestexpanse of open water has led many authors to unsound c
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