96. JOHNSON, J.W., "Lessons in Coastal Engineering Gained from Califor- 

 nia Projects," Symposium on Coastal Engineering 3 Stellenbosch, South 

 Africa, June 1969. 



Keywords: Accretion, California (Channel Islands and Santa Monica), 



Detached breakwater, Downdrift beaches. Littoral transport. 

 Structural dimensions 



Experience gained at coastal engineering projects on the California 

 coast has led to a better understanding of littoral processes. Detached 

 breakwaters, constructed earlier at Santa Barbara and Santa Monica, have 

 had disastrous effects on the downdrift beaches. Lessons learned from 

 these projects have been applied to the Channel Islands-Port Hueneme area 

 where a detached breakwater serves as a sand trap. Material dredged from 

 this trap is bypassed to beaches downdrift of Port Hueneme. 



97. JOHNSON, J.W., FUCHS, R.A., and MORISON, J.R., "The Damping Action 

 of Submerged Breakwaters," Transactions of the American Geophysical 

 Union, Vol. 32, 1951, pp. 704-718. 



Keywords: Hydraulic model (two-dimensional). Submerged breakwater. 

 Wave attenuation. Wave reflection. Wave transmission 



The results of an experimental investigation on the damping action 

 of submerged rectangular breakwaters are presented. The experimental 

 data are compared with published theories. A new theory is presented 

 which compares more favorably with the experiments than the previous 

 theories. Also given is a summary of the published theoretical and 

 experimental information on the damping action of trapezoidal and tri- 

 angular breakwaters, reefs of various configurations, and plane barriers 

 of various orientations. 



98. JORDAAN, J.M., Jr., "Study of Durban Harbor Silting and Beach Ero- 

 sion," Proceedings of the 12th Conference on Coastal Engineering, 

 American Society of Civil Engineers, Vol. 2, 1970, pp. 1097-1116. 



Keywords: Accretion, Hydraulic model (three-dimensional). Littoral 



transport. Movable bed. Segmented breakwater, South Africa 

 (Durban) , Structural dimensions 



A 1:300 vertical, 1:100 horizontal scale model of 7 miles of coast- 

 line, including the major area of the port limits and the inner harbor, 

 was constructed to study combined wave, tide, and wind action on transport 

 of sand along the coast. The model study attributed the cause of beach 

 erosion to the existence of an offshore shoal produced by the localized 

 dumping of sand dredged from the harbor approaches. This shoal caused 

 selective wave action along the coastline, which was reproduced to scale 

 in the model. Wind and tidal action had a major effect on the redistribu- 

 tion of sand on the beaches as modeled but a minor effect on the perma- 

 nence of the harbor entrance channel . The model study was conducted by 

 the South African Council for Scientific and Industrial Research for the 

 South African Railways and the City Council of Durban. 



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