harbor-side slope. Observations during this inspection revealed that the separated 

 capstones identified in 1993 (sta 14+30) were in about the same position. 



During the broken/cracked armor unit survey of June 1995, a total of 191 broken 

 or cracked armor stones were identified. Of the 19 1 stones, 35 broken/cracked 

 armor units were located on the crest, 93 on the seaward slope, and 63 on the 

 harbor-side slope. Several broken stones documented during previous surveys could 

 not be found, indicating they had been moved away by wave and/or ice action. 

 Also, it was observed that stones were missing along the water's edge on the sea- 

 ward face of the structure at approximately stas 8+85 and 9+50. The 1994-95 

 winter was relatively severe with the presence of much floating ice. The voids at the 

 waterline on the main breakwater were subsequently repaired by CENPA during the 

 summer of 1995 using selected stones from the St. Paul Island quarry. 



During the 1995 survey, a detailed geologic inspection of the breakwater was 

 conducted by representatives of the Buffalo District. These personnel had experi- 

 ence in armor-stone quality and durability for coastal projects. Based on their 

 analyses, 22 percent of the above-water stones are experiencing advanced degrada- 

 tion. This degradation is attributed to two factors. First, the project contains about 

 25 percent geologically unacceptable stone. The unacceptable stone is a light gray, 

 vesicular banded basalt that has a marked platy structure. This stone likely came 

 from the Smithrock Quarry in Camas, WA. About one half of this stone contains 

 one or more significant cracks. These cracked stones exhibit common freeze-type 

 and/or blasting crack characteristics. The delamination process is being enhanced at 

 the St. Paul location because of the number of cycles of freeze-thaw and wet-dry 

 conditions as well as large waves and sea ice action. Secondly, a significant amount 

 of the stone on the structure is blast damaged. Fracture patterns and shape charac- 

 teristics observed on much of the stone are common in overshot rock. As observed 

 commonly in other breakwaters, this structure is predicted to continue to deteriorate, 

 and the degradation rate is likely to increase as time progresses at this environmen- 

 tally harsh location. It was also predicted that future project performance would be 

 significantly impacted in the next 3 to 7 years and repairs should be expected. 



During the breakwater survey of June 1996, a total of 230 broken/cracked armor 

 stones were identified on the main breakwater. Of the 230 stones, 54 were located 

 on the crest, 105 on the seaward slope, and 7 1 on the harbor-side slope. The rate of 

 breakage was slightly less for this survey than for previous years; however, the 

 harbor master indicated that the 1995-96 winter was milder than normal. As of the 

 June 1996 survey, the approximate locations of broken/cracked armor stones along 

 the outer portion of the breakwater are shown in Figure 39, and detailed data 

 obtained during the survey are presented in Table 5. Armor stone numbers identi- 

 fied in Figure 39 correspond to those listed in Table 5. As shown, only two broken 

 armor units are located around the head of the structure. Armor stone for the break- 

 water head consisted of soimd and durable granite from a quarry in Nome, AK 

 Shoreward of the breakwater head, broken stones were, generally, evenly distributed 

 along the length of the structure. The survey showed that 49 percent of the broken 

 stones were located on the shoreward half of the breakwater extension, and 

 5 1 percent on the outer half. About 23 percent of the observed broken stones were 

 along the crest, 46 percent on the seaward slope, and 3 1 percent on the harbor-side 



Chapter 2 Monitoring Program 47 



