ERDC/CHL CHETN-II-47
March 2004
Identification of and Remedial
Approaches to Hot Spots
by Donald K. Stauble and Mark B. Gravens
mation about the suspected causes and remedial approaches that have been applied to erosion hot
spots on several recent beach nourishment projects. These diverse examples form the basis for
general identification and steps that can be taken to mitigate for and anticipate the development of
hot spots on beach nourishment shore protection and environmental restoration projects.
BACKGROUND: Beach nourishment is an important component in urban flood and storm damage
reduction. Impact of coastal storms and nonuniform performance of beach fill-projects can result in
expenditure of considerable operations and maintenance and emergency operations resources to
restore these projects to their design level in the interval between planned renourishments.
Engineering guidance and analysis procedures are needed to anticipate the development of hot spots
in the project design phase, identify hot spots after project construction and provide techniques to
mitigate for the increased vulnerability to storm erosion and damages that may occur at these hot
spot areas, particularly in urban coastal settings with a dense infrastructure of upland development.
DEFINITION OF HOT SPOTS: Hot spots have previously been defined as follows:
a. An area that erodes more rapidly than anticipated during design or more rapidly than
adjacent portions of beach (Dean et al. 1999).
b. Regions of higher erosion relative to rest of project and/or regions where design expectations
were not met (Bodge et al. 1999).
c. Areas having a high erosion rate as compared to the adjacent beach (Kraus and Galgano
2001).
For this Technical Note a "hot spot" is defined as an area of beach experiencing higher erosion than
adjacent beaches. Hot spots are found along beach nourishment projects as well as coasts not altered
by engineering activities. In general, hot spots can be identified by shoreline position change (shore-
line is displaced landward in hot spot), sediment volume change (loss of sediment volume in hot spot
area profile), and/or percent of fill remaining after some time interval post-placement (less fill
remaining on active profile in the hot spot area). Hot spots may or may not be recognized on a non-
nourished eroding beach, due to the lack of significant dry beach widths. When a sufficient quantity
of beach nourishment sand is placed on a beach, the hot spot becomes apparent as the beach
readjusts toward the equilibrium profile. The shoreline in the area of the hot spot will usually be
further landward than the adjacent shoreline and the volume of sand remaining within the profile will
be less than adjacent areas. Information typically available to the coastal engineer to identify and
document hot spots include aerial photography, shoreline rate of change data, beach profiles from
which beach volume change can be computed, and anecdotal information.
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