25-ton unreinforced tetrapods were stockpiled on the sea-side slope of the 

 first 200 ft of the dogleg adjacent to the main stem (sta 37+00 to 39+00) . 

 Repair with dissimiliar armor first occurred in 1974 when 246 40-ton unrein- 

 forced dolosse were placed on the sea-side slope of the last 230 ft of the 

 breakwater's main stem (sta 34+70 to 37+00). Various portions of the break- 

 water were repaired with armor stone in 1979. As of 1985, plans are being 

 formulated for additional rehabilitation of the main stem of the breakwater 

 (sta 34+70 to 37+00) with two layers of 42-ton fiber-reinforced concrete 

 dolosse (Plate 7) . This proposed work, together with the prior construction 

 history, is summarized in Table 3. 

 Hilo Harbor 



7. Hilo Harbor, Hawaii, the second largest harbor in the State of 

 Hawaii, is located on the northeast coast of the Island of Hawaii (Plate 8). 

 Construction of the 10,070-ft rubble-mound breakwater was completed in 1930. 

 The tsunami of April 1946 produced a 1 , 100-f t long breach in the structure and 

 severely damaged an additional 4,900-ft length with the average crown eleva- 

 tion being reduced to -3.0 ft mllw. Repair of damage caused by the 1946 

 tsunami was completed in 1948. Storms in 1951 and 1954 produced localized 

 damage which was repaired in subsequent years. In 1960, another tsunami pro- 

 duced significant damage; however, no repair work was done until 1968 due to 

 the possibility of totally rebuilding the breakwater as one leg of a proposed 

 tsunami barrier for Hilo Harbor. Localized damage to various areas along the 

 breakwater was repaired in 1973 and 1975. Dissimilar armor was first used in 

 1981. The sea side of the breakwater was repaired between sta 11+00 and 20+00 

 with one layer of uniformly-placed, 7.5-ton tribars. The construction and 

 rehabilitation history of the breakwater is summarized in Table 4. 



Humboldt Bay 



8. Humboldt Bay, California, is located on the Pacific coast of north- 

 ern California. The city of Eureka, about 280 miles north of San Francisco 

 and about 80 miles south of Crescent City, California, is located on the 

 northwest shore of Humboldt Bay (Plate 9) . The Humboldt Bay entrance channel 

 is protected by two rubble-mound jetties. Construction of the parallel north 

 and south jetties, 4,500 and 5,100 ft long, respectively, was initiated in 

 1889 and completed in 1899. The original jetty construction was rubble-mound 

 armor stone. Severe damage to the heads and portions of the trunks has re- 

 quired numerous rehabilitations and reconstructions of both jetties. Between 



