construction similar to that in the original work, workmen made repairs on the 

 east breakwater in the years 1927, 1928, 1930, 1932 to 1940, and 1946 to 1978. 

 During 1980, the eastern 4,400 ft of the east breakwater was rehabilitated 

 (Plate 2) . Two layers of 2-ton unreinforced dolosse were placed on the 

 lakeside of the trunk and around the east head (Plates 3 and 4, respectively); 

 29,700 dolosse were placed with a concentration of 161 dolosse per 25 lin ft 

 of the breakwater. On 6 April 1982, a particularly severe storm (hindcast 

 waves of 12 ft in height) occurred simultaneously with the highest lake level 

 (+6.1 ft low water datum) ever recorded and caused damage to the rehabilitated 

 dolos section. Although there was some displacement of dolosse over the crest 

 of the trunk section, primary damage was localized on the tip of the head 

 section where a hole about 20 ft in diameter at the armor surface penetrated 

 to the original stone. The number of units broken due to displacement from 

 the damage hole is not known, but total breakage on the entire dolos section 

 after the April 1982 storm was reported as 487 or 1.6 percent of the units 

 placed. A diver's survey indicated that the broken dolosse are generally in a 

 zone 4 to 6 ft above and below the water level. The head section was repaired 

 in September 1982 by placing approximately 200 dolosse in the localized damage 

 area. Presently (1985), plans are being formulated for rehabilitation of an 

 additional 3,300 ft of the east breakwater trunk using two layers of 9- to 

 20-ton armor stone (Plate 5) . Table 2 summarizes the construction and rehabi- 

 litation history of the breakwater. 

 Crescent City Harbor 



6. Crescent City Harbor, California, is located on the Pacific coast 

 about 17 miles south of the Oregon-California border (Plate 6) . The existing 

 outer breakwater is 4,670 ft in length. The main stem and easterly extension 

 (dogleg) of the breakwater are approximately 3,670 and 1,000 ft in length, re- 

 spectively. The original project did not call for the dogleg but intended for 

 the main stem of the breakwater to extend out to Round Rock. The main stem of 

 the original breakwater, beyond sta 37+00, sustained severe damage and was re- 

 constructed on two occasions. Finally, this portion of the main stem was 

 abandoned, and the 1,000-ft dogleg referred to above was added. Two- 

 dimensional stability tests were conducted of the tetrapod breakwater designs 

 proposed for the trunk portion of the 1,000-ft dogleg (Hudson and Jackson 1955 

 and 1956). In 1957, 1,836 25-ton unreinforced tetrapods were placed on the 

 sea-side slope from sta 41+20 to the end of the dogleg (sta 46+70), and 140 



