Date(s) 
1962- 
1966 
(cont. ) 
1986 
Table 3 (Concluded) 
Construction and Rehabilitation History 
(Figure 4). The outer 200 ft on each jetty was built as a head 
section with stone placed over the entire cross section. The design 
geometry was positioned 4 ft gulfward of the existing jetty center 
line with a top elevation of +5 ft mlt, a 3-stone-wide crown, and 
side slopes of 1V:2.25H and 1V:3H on trunk and head sections, 
respectively. The sections were built upon a 2- to 3-ft-thick 
blanket of 0.5-in. to 200-lb stone. The blanket extended beyond the 
cover layer toe distances of 10 and 50 ft for trunk and head 
sections, respectively. Core stone, typically 200 to 2,000 1b in 
size, then were placed providing the necessary side slope. One layer 
of cover stone was placed, except on the head sections, which used a 
double layer. Cover stone varied from a maximum of 16 to 18 tons at 
the heads to minimums of 2 and 6 tons at the north and south jetty 
landward ends, respectively. To decrease jetty permeability, 0.5- to 
H-in. filler stone was placed in the crown area beneath the cover 
layer. Prior to the repairs, the jetties were in a general state of 
deterioration with much of the south jetty and several spots of the 
north jetty at or below +3 ft mlt. In many cases core stone was 
exposed, or cover layer stone was not tightly interlocked. Due to 
these conditions and use of large core stone during original con- 
struction, the jetties were considered too pervious to wave, tide, 
and sediment motions. Scour on the channel side of the north jetty 
was evident from sta 50+00 to sta 190+00 where the authorized 30-ft- 
deep channel made its closest approach to either jetty. Along this 
section water depths were typically 40 ft or greater within 100 ft of 
the jetty center line, while on the gulf side the typical water depth 
was 10 ft. This was a major reason for repairing the gulf side of 
the north jetty, since the quantity of stone required would be much 
smaller. The total costs for rehabilitation of the north and south 
jetties were $3,440,000 and $2,564,500, respectively. Although data 
on complete stone quantities were not found, partial quantities and 
several similar construction or repair projects (with known stone 
quantities) built during this time frame yield an estimate of from 
600,000 to 1,200,000 tons of stone placed. 
The jetties have received no maintenance or repairs since rehabili- 
tation in the 1960's and are considered to be in good condition. The 
present channel is authorized at 40- and 42-ft depths between inner 
and outer jetty sections, respectively. 
21 
