Keywords: Wave attenuation, Wave refraction 



If a submerged dam or raised area on the seabed is built, shaped 

 in plan like a prism, a wave traveling across it will undergo two devia- 

 tions: one when entering the prism and one when leaving it, just as with 

 a light ray passing through a prism of glass, In a similar way submerged 

 dams could be built having a plan the shape of a lens, thereby affecting 

 the wave orthogonals as glass lenses affect light rays, 



202. VEDEL, P., "Island Harbors and the Accumulation of Material Caused 

 by Detached Works," Transaations of the American Soo-tety of Civil 

 Engineers^ 1905, pp. 139-158. Discussions by L.M. Haupt, pp. 351- 

 352; W.H. Hunter, pp. 354-355; A.E. Carey, pp. 380-381; Closure, 

 pp. 384-385. 



Keywords: Accretion, Denmark (Arnager, Hundested, and Snogebaek) , Design 

 guidelines, Littoral transport. Offshore island-. Sediment sizes 



An outline is given for a method of estimating (without a claim of 

 accuracy) approximate limits for accumulations which may form behind a 

 detached solid work, before a stable equilibrium is established, provided 

 the movement of material is due only to wave action. Such an estimate 

 will be necessary for forming an opinion of how far out from the shore a 

 given structure should be placed to ensure against its becoming land- 

 connected in time. 



203. VERA-CRUZ, D., "Ondas Na Rebentacao," Memoria No. 199, Laboratorio 

 Nacional de Engenharia Civil, Lisbon, 1962 (in Portuguese). 



Keywords: Submerged breakwater. Wave attenuation 



Laboratory tests for determining the height of reformed waves after 

 breaking on gentle slopes belonging to submerged obstacles are described. 

 The measured values of the ratio of the breaking depth to breaking wave 

 height are presented and compared with values already published. The 

 results tend to confirm the mathematical theories which consider solitary 

 waves to be the limiting case of an oscillatory wave. 



204. VERGARA, M.A., and CORNEJO, J., "Tombolo Formation Controlling 

 Littoral Drift," Coastal Sediments '77, Fourth Annual Symposium 

 of the Waterways , Port, Coastal and Ocean Division, American So- 

 ciety of Civil Engineers, Nov. 1977 (not published in proceedings). 



Keywords: Detached breakwater. Hydraulic model (three-dimensional). 



Littoral transport, Mexico (Salina Cruz), Movable bed. Ship 

 hulls, Tombolo 



For controlling littoral drift, the location of a structure near 

 the shore which causes tombolo formation, is more effective than other 

 systems more frequently used. An experimental study carried out in a 

 physical sedimentological model, using bakelite, was developed to find 



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