NORTH WAIMĀNALO AREA DESCRIPTION
North Waimānalo (transects 0
- 217) is the northern half of a nearly continuous 4-mile-long beach extending
from Wailea Point through Bellows Air Force Station
and Waimānalo to Kaiona
Beach Park (see Waimānalo map for southern
half). The coast in this area is exposed to consistent easterly tradewind waves year-round and refracted northerly swell
during the winter months. The inner shelf and shoreline are protected from the
full energy of open ocean waves by a wide fringing reef platform.
Overall, North Waimānalo is
characterized by erosion in the north and accretion in the south. The far
northern portion of North Waimānalo (transects 1
- 34) was lost to erosion between 1988 and 1996. Waves break against a stone revetment
at high tide in this area. Rates are calculated for this section up to and
including the first historical shoreline with no beach and depict the speed at
which the beach disappeared (up to -1.5 ft/yr).
South of transect 34 North Waimānalo
is divided by jetties at Waimanalo Stream and the remains of a similar
structure at lnaole Stream. Transects 35 - 84 are
experiencing moderate erosion with the highest erosion rates at the northern
end (-1.1 ft/yr),
threatening further beach loss. Central and southern areas (transects 85 - 217)
is approximately stable to accreting with the greatest
accretion in the south (1.1 ft/yr).
Study results generally agree with those of previous studies
(Hwang, 1981; Sea Engineering, 1988), which found erosion at the far northern
portion of North Waimānalo and accretion on the
north side of the Waimānalo Stream jetties.
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; Bellows Beach; Wailea Point; Waimanalo; Kaiona Beach
Park; lnaole Stream