Date(s) 
1950- 
1951 
1954- 
1957 
1958- 
1959 
1961- 
1962 
Table 9 (Continued) 
Construction and Rehabilitation History 
Repairs were made at a total cost of $566,700 using 16,940 and 
13,570 tons of stone on the north and south jetties, respectively. 
The jetties were repaired, and three spurs were constructed on the 
channel side of the south jetty. The majority (80 percent) of the 
jetty repairs used 8- to 13-ton cover stone; the remainder was mostly 
25 to 2,000 1b, and the spurs were built using 25-1b to 10-ton 
(quarry-run) stone. The spurs were placed about 1,000 ft apart with 
the outermost approximately 2,400 ft from the jetty's seaward end. 
Each spur was about 200 ft long and extended seaward, offset from the 
jetty axis at a 30- or 60-deg angle. The spurs were needed to reduce 
scour and undermining of the jetty caused by tidal flows. Stone 
quantities were 19,300, 52,640, and 72,870 tons for the spurs, north 
and south jetties, respectively. The total repair and construction 
costs were $2,145,500. 
Sections of the north and south jetties (2,150 and 355 ft long, re- 
spectively) were capped with concrete. These sections extended sea- 
ward from the existing caps, and it appears they terminated at the 
jetties' existing seaward ends. The condition of the outer 640- and 
1,100-ft sections of the north and south jetties could not be de- 
termined from information at hand. The concrete was grouted through- 
out the cover stone void spaces lying between 0 and +6 ft mlt (the 
existing crest elevation). Prior to placing concrete, large voids 
were filled with 5- to 50-lb chinking stone. A total of 7,290 cu yd 
of concrete and 2,800 tons of stone was placed at a total cost of 
$387,600. 
The passage of Hurricane Carla in September 1961 caused significant 
damage to the seaward ends of the jetties. The outer 300 ft of the 
north jetty, including the outermost 250 ft of concrete cap, essen- 
tially was destroyed. In 1962 the jetties were surveyed and in- 
spected in preparation for planned rehabilitation. The concrete caps 
essentially were intact, although numerous cracks and sections of the 
caps had subsided. However, this was not a true indication of their 
general condition. There was significant subsidence of the side 
slope armor and underlayer core stone creating void spaces beneath 
the caps and exposing core stone on the steepened side slopes. The 
rehabilitation was recommended based on expected failure of several 
jetty sections, under storm conditions, leading to a loss of channel 
protection and increased shoaling. Scour and undermining were con- 
sidered major sources of jetty deterioration. Center-line elevations 
varied from -10 to -35 ft mlt and from -10 to -20 ft mlt on seaward 
800 and 1,000-ft sections of the north and south jetties, respec- 
tively. Scour holes were evident at their extreme seaward ends. 
(Continued ) 
40 
