ERDC/CHL CHETN-IV-61
December 2003
Table 1 summarizes the characteristics of these spurs with regard to length, angle with the jetty,
and location along the length of the jetty. Typically spurs are located about 75 percent of the jetty
length from the local shoreline. The Bakers Haulover jetty spur is at the end of the jetty.
Table 1
Existing Spur Jetty Installations in United States
1) Spur
Distance from
Local Average
Ratio of Spur
Shoreline, m
Ratio of Spur
Angle (deg) of
Distance from
2) Length from
Average Shoreline
Length to Spur
Spur Relative
Jetty Tip to
to Length from Jetty
Distance to
to Jetty
Average
(opening
Spur Length,
Local Average
Tip to Average
Location
Shoreline, m
Shoreline
Shoreline
seaward)
m
Siuslaw
North jetty spur -
1) 480
0.74
0.18
45
River, OR
122 or 86 m
2) 650
perpendicular to
jetty
South jetty spur -
1) 640
0.80
0.13
45
122 or 86 m
2) 800
perpendicular to
jetty
Shark River,
North jetty spur -
1) 120
0.75
0.42
90
NJ
50
2) 160
Ft. Pierce
South jetty spur -
1) 220
0.63
0.27
90
Inlet, FL
60
2) 350
Bakers
North jetty spur -
1) 60
1.00
0.58
90
Haulover
35
2) 60
Inlet, FL
CHARACTERIZATION OF REGION ADJACENT TO JETTY: The sea side of a jetty is
usually shallower than the adjacent natural beach due to accumulation of sand along the struc-
ture. This shallow fillet region provides a platform for sediment movement toward the jetty tip.
Figure 6 shows a sampling of slopes adjacent to the jetty and at a 45-deg angle away from the
structure. Slopes are typically in the range of 0.1 to 1.0 percent on the East and Gulf coasts and a
slightly greater range band of 0.3 to 2.0 percent slope on the West and Great Lakes coasts, for
this limited sample. Typical natural beach slopes are in the range of 2.5 to 10 percent slopes. The
slopes at an angle that bisects the shoreline and the structure are similar, for the most part, to the
slopes along the structure, indicating a degree of spatial extent of this fillet form. The shallower
water depths will place breaker lines farther seaward along the jetty, so these smaller depths
require spurs to be farther seaward, and, as shown in Table 1, spurs have typically been located
seaward at least 75 percent of the jetty length.
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