137. O'ROURKE, J.J., "Discussion on Beach Erosion Studies," Transactions 

 of the American Society of Civil Engineers, Vol. 105, 1940, pp. 895- 

 898. 



Keywords: Beach fill. Compartment ed breakwater, Illinois (Lincoln Park- 

 Chicago), Structural dimensions. Wave attenuation 



Unusually high Lake Michigan levels in 1929 caused erosion and 

 destruction of parts of Outer Drive in Chicago as it passed through 

 Lincoln Park. In 1930, a series of groins were constructed to protect 

 this section of beach. They were ineffective because of a lack of lit- 

 toral transport in this area. Submerged bulkheads were constructed in 

 1939 to retain a bathing beach fill. Their effectiveness is assessed. 



138. OSADA, T., "Variation of Shorelines in the Vicinity of Harbors in 

 Niigata Prefecture," Proceedings of the Fifth Conference on Coastal 

 Engineering in Japan, Japan Society of Civil Engineers, 1958, pp. 

 123-136 (in Japanese) . 



Keywords: Detached breakwater. Segmented breakwater 



139. OZAKI, A., "On the Effect of an Offshore Breakwater on the Mainte- 

 nance of a Harbor Constructed on a Sandy Beach," Proceedings of 

 the Ninth Conference on Coastal Engineering, American Society of 

 Civil Engineers, 1964, pp. 323-345. 



Keywords: Accretion, Currents, Detached breakwater. Hydraulic model 

 (three-dimensional), Japan (Seppu) , Littoral transport. 

 Movable bed. Sand trap 



This paper describes an experimental attempt to prevent the rapid 

 blocking of a harbor entrance caused by littoral transport in the summer 

 period. This work was conducted at Seppu, a fishing harbor constructed 

 on a sandy beach in Hokkaido, Japan. This investigation was originally 

 sponsored by the Harbor Section of the Hokkaido Prefectural Office. One 

 of the top priority objectives, at that time, was to determine the effi- 

 ciency of two jetties constructed on the updrift side to counter the 

 littoral transport. Detailed observations, including preliminary model 

 experiments, were made from 1961 to 1963 on the general aspects (i.e., 

 condition and phenomena) of the coast. Meterological data were also 

 compiled. 



Based on the above, this paper suggests the utilization of natural 

 forces, i.e., waves, offshore currents, etc., by constructing an offshore 

 breakwater to curb the blockage of the harbor mouth. 



140. PALA, F. and D'ARRIGO, A., Untitled report to SII-Q2 (Protection of 

 Coasts Against the Sea, With or Without Preponderating Coastal Drift 

 of Materials), XVth International Navigation Congress, Venice, 1931. 



Keywords: Accretion, Detached breakwater, Italy (Posillipe and Salerno), 

 Segmented breakwater 



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