anahola, kauai, hawaii · the anahola study area (transects 45 - 174) is located on the east coast...
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20"159o19' W 40"50" 30" 159o18' W10" 50"
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Anahola, Kauai, Hawaii
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Kauai
Anahola
ava
HISTORICAL SHORELINES
Erosion rate measurement locations(shore-normal transects)
Historical beach positions, color coded by year, are determined using orthorectified and georefer-enced aerial photographs and National Ocean Survey (NOS) topographic survey charts. The low water mark is used as the historical shore-line, or shoreline change reference feature (SCRF).
Movement of the SCRF along shore-normal transects (spaced every 66 ft) is used to calcu-late erosion rates.
Mar
Apr 10Apr 12
1988
19751975
Jul 1987
SepNov
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19921996
2007
1927 T-sheet
Sep 1999
Contract C25514 Contract 7249
Charles Fletcher, Matthew Barbee, Siang-Chyn Lim,Matt Dyer and Ayesha GenzUniversity of Hawaii Coastal Geology GroupSchool of Ocean and Earth Sciences and Technology1680 East West Road, Honolulu, HI 96822, U.S.A.
The preparation of this poster was financed in part by the Coastal Zone Management Act of 1972, as amended, administered by the Office of Ocean and Coastal Resource Man-agement, National Ocean Service, National Oceanic and Atmospheric Administration, United States Department of Commerce, through the Office of Planning, State of Hawaii.
Latitude/Longitude coordinatesUTM coordinates
22o09'50" W467400mE
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Scale 1:3000Meters
Feet
N Erosion RateAccretion Rate
SHORELINE CHANGE RATES
Historical shoreline positions are measured every 66 ft along the shoreline. These sites are denoted by yellow shore-perpendicular transects. Changes in the position of the shorelines through time are used to calculate shoreline change rates (ft/yr) at each transect location.
Annual shoreline change rates are shown on the shore-parallel graph. Red bars on the graph indicate a trend of beach erosion, while blue bars indicate a trend of accretion. Approximately every fifth transect and bar of the graph is numbered. Where necessary, transects have been purposely deleted to maintain consistent alongshore spacing. As a result transect numbering is not consecutive everywhere. The rates are smoothed alongshore using a 1-3-5-3-1 technique to normalize rate differences on adjacent transects.
AREA DESCRIPTIONThe Anahola study area (transects 45 - 174) is located on the east coast of Kauai. The area is bounded by Aliomanu Beach to the north and Kahala Point to the south. The shoreline is composed of calcareous sand beach interrupted by basalt headlands with a fringing reef offshore.
Overall, the area is eroding at an average rate of -0.4 ft/yr. The area lends itself to division into three portions. Aliomanu Beach (transects 45 – 88) is located to the north of Kuaehu Point. This section of the study area is experiencing erosion at an average rate of -1.1 ft/yr. Anahola Beach (transects 89 – 128) to the north of Anahola River has experienced erosion at an average rate of -0.6 ft/yr. Anahola Beach Park (transects 129 – 174) to the south of Anahola River has experienced accretion at an average rate of 0.3 ft/yr. Previous studies1 found similar trends in shoreline change for the Anahola study area shoreline.
1 Makai Ocean Engineering and Sea Engineering, 1991 Aerial Photograph Analysis of Coastal Erosion on the Islands of Kauai, Molokai, Lanai, Maui, and Hawaii. State of Hawaii Office of Coastal Zone Management Program.
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AnaholaBay
Anahola R
iver
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AnaholaBeach Park
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AliomanuBeach
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