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40"30" 20" 159o27' W10" 50" 159o26'30" W159o27'40" W
40"30" 20" 159o27' W10" 50" 159o26'30" W159o27'40" W
22o 5
2' N
10"
20"
30"
21o 5
2'40
" N
22o52' N
10"20"
30"21
o52'40" N
23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 4342 454400mE452200mE
23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 4342 454400mE452200mE
2418
000m
N81
8283
8485
8687
8889
9091
9293
9424
1950
0mN
2418000m
N81
8283
8485
8687
8889
9091
9293
9424195
00mN
HISTORICAL SHORELINES
JanNov
19281950
Mar 1972
1926 T-sheet
AprJul
Oct
SeptNov
19751987
2007
19921999
1988Mar
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 1960
Apr 1975
Poipu, Kauai, Hawaii
400 300200
1200 900600
100
3000
0100
300
Scale 1:3000Meters
Feet
Contract C25514 Contract 7249
Charles Fletcher, Matthew Barbee, Siang-Chyn Lim,Julia Ehses, Matt Dyer, and Ayesha Genz University 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
159o27'40" W2418000mN
0
0 10km
10mi
Kauai
Poipu
ava
N
105
65
70
75
80
90
95
100
110
115
120
123
-2
-1
0
1
-2
-1
0
1
85
Shoreline Change Rate (ft/yr)
97 98
118
119
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 Poipu study area (transects 0 - 21) is located on the south coast of Kauai. The area is bounded by Lae o Kamilo to the west and Makahuena Point to the east. The shoreline is characterized by small pocket beaches interspersed among basaltic headlands.
Overall, the area is undergoing erosion at an average rate of -0.7 ft/yr. The area lends itself to division into three portions. The western portion (transects 65 – 97) is located between Lae o Kamilo and Kiahuna. This section is experiencing erosion at an average rate of -0.7 ft/yr. Poipu Beach Park (transects 98 – 118) to the east of Kiahuna has experienced erosion at an average rate of -0.5 ft/yr. Brennecke Beach (transects 119 – 123) has experienced chronic erosion at an average rate of -0.9 ft/yr. Previous studies1 did not analyze the Poipu 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.
Poipu
65
70
75 80
85
90
95
100
105
107
108
110
115
120
123
117
9798
119
Poipu Road
Poipu Road
Nu KumoiPoint
PoipuBeach Park
BrenneckeBeach
Lae o Kamilo
Kiahuna
MakahuenaPoint