MĀKUA AREA DESCRIPTION
The beaches at ÔŌhikilolo and
Mākua Valley (transects 52 - 122) are located on
the west shore of Oʻahu. The shoreline is
composed of carbonate sand and limestone and basalt rock. The area is exposed
to southerly swells in summer months, northerly swells
in winter months and southerly to westerly waves from Kona storms throughout
the year but most often in the winter. Large waves may break on or near the
shoreline causing temporary erosion as the deep nearshore reef provides little
protection in most areas.
ÔŌhikilolo Beach south (also
known as Barking Sands, transects 52 - 58) has eroded at -0.5 ft/yr since 1967 averaged along
the length of the beach. ÔŌhikilolo Beach north
(transects 59 - 66) has accreted at 0.5 ft/yr since 1967 averaged along its length. Shoreline data
prior to 1967 was omitted from rate calculations to remove the effects of sand
mining, which likely performed. The
1910 T-sheet indicates sand dunes as high as 60 ft at
ÔŌhikilolo. The modern dunes are much lower, suggesting a large quantity of sand was removed. An
aerial photograph from 1949 shows vegetation stripped from beach dunes, typical
evidence of sand mining operations. Sand mining during that era has been
documented at several nearby beaches. An exposed limestone shelf near the water
line may be protecting the remaining beaches at ÔŌhikilolo
from further erosion.
Mākua Beach
(transects 67 - 122) has eroded at -0.2 ft/yr since 1967, averaged along the length of the beach. A
1949 aerial photograph may show a sand mining operation at Makua
Beach. A previous study (Hwang, 1981) also notes evidence for sand mining a t Makua in a 1965 air photo. Erosion in the north half of Makua Beach appear to have slowed since the 1960's.
Hwang (1981) found little net change in the position of the
vegetation line at Makua Beach and no clear trend in
the position of the water line from 1949 to 1975.
For more information see: http://www.soest.hawaii.edu/asp/coasts/oahu/index.asp
1 Hwang, D. (1981) "Beach changes on Oʻahu
as revealed by aerial photographs", State of Hawaii, Department of
Planning and Economic Development.
2 Sea Engineering, Inc. (1988) ÒOʻahu
shoreline studyÓ, City and County of Honolulu, Department of Land Utilization.
Keywords:
Oʻahu; ÔŌhikilolo Beach; Barking Sands; Makua Beach