ERDC/CHL CHETN-IV-61
December 2003
Figure 13. Detailed velocity fields upcoast of dual jetties for 11-sec, 3-m waves with maximum flood
current in channel. Dark color contours are slower currents
LITTORAL DRIFT DIRECTION CONCERNS: The use of spurs would probably be consid-
ered optimal for a region of coast that has a balanced littoral drift environment. There would be
little need to bypass sediment to an eroding downcoast region. The spur concept is to main-
tain/keep sediment on one side of a jetty, reducing its likelihood to shoal an inlet navigation
channel. If bypassing were desired, the spur would not necessarily direct sediment to an easily
accessible and protected location for dredging. However, spurs would probably aid in directing
sediment to a location that would move back to the beach during a wave reversal. Rather than
being impounded in the shadow of the jetty, the sediment would be more accessible to wave
action. If there is a large net movement of longshore sediment though, spurs on each jetty might
be beneficial in first, on the upcoast jetty, limiting sediment movement into the channel and
second, a spur on the downcoast jetty might reduce sediment entering the channel from that side
during wave direction reversals and reduce the eddy-type circulation patterns that move sediment
towards the channel when waves are from the upcoast direction.
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