The Littoral Sand Budget, Hawaiian Islands 1 
Theodore Chamberlain 2 * * * 
ABSTRACT: Profile surveys were made across 80 selected Hawaiian beach and 
nearshore environments at quarterly intervals for one and one-half years during 
1962-63. Also 70 additional beaches were measured at less frequent intervals. 
Using these profiles, supplemented by water-jet borings and measurements from 
aerial photographs, the total sand volume of each of the major Hawaiian beach 
systems was computed. The seasonal fluctuations of these volumes were also com- 
puted and related to the wave and littoral current regimes. 
The volume of littoral sand was found to be considerably less than the volume 
for many sandy continental areas. About 4.0 X IT 7 cu yd of sand is held in 
beach reservoirs on the seven major islands of the Hawaiian group; most is con- 
centrated on Kauai (1.4 X IT 7 cu yd) and on Oahu (1.0 X 10 7 cu yd) - Individ- 
ual beaches containing more than 1 X 10 6 cu yd are Keawanui on Niihau; Hana- 
lei, Polihale-Barking Sands, and Kekaha-Nohili-Bonham on Kauai; Bellows- 
Waimanalo on Oahu; and Papohaku on Molokai. The beaches on the island of 
Hawaii hold the smallest volumes of sand. 
Seasonal rates of erosion and accretion of beach sand reservoirs were found to 
be generally on the order of a few tens of cubic yards of sand per linear yard of 
beach per month. The higher rates were on exposed north and west coasts, with a 
maximum rate of several hundred cubic yards of sand per linear yard of beach 
per month recorded for Lumahai Beach, Kauai during 1962-63. 
Beaches are not static but are continually 
changing their composition, structure, and 
volume — seasonally, yearly, or over longer 
periods of geologic time. Nor are these beach 
changes isolated phenomena. Rather, they are 
related, by a complex series of equilibria, with 
the rates of sand production, alongshore trans- 
port, and loss. Consequently, it is possible to 
consider a sand beach at any one moment in 
time to be a sand reservoir connected by certain 
exchanges of energy with its surrounding en- 
vironment. Certain of the energy relationships 
between the beach and its surroundings will 
bring about a net increase in the volume of the 
beach: beach accretion. Other relationships will 
result in a net loss of sand from the beach: 
beach erosion. 
In certain cases there may exist an equi- 
1 Hawaii Institute of Geophysics Contribution No. 
124. Manuscript received June 29, 1967. 
2 Hawaii Institute of Geophysics, University of 
Hawaii, Honolulu, Hawaii 96822. Presently Senior 
Oceanographer, Ocean Science and Engineering, Inc., 
Washington, D. C. 
librium between accretion and erosion so that 
a constant beach sand volume is maintained. 
However, with most beaches this equilibrium 
is continually shifting so that the beach is con- 
tinually in a state of flux, now accreting, now 
eroding. These fluctuations in the amount of 
sand held on the beach are most pronounced 
between seasons, reflecting the seasonal varia- 
tions in the amount and types of wave energy 
that reach the beaches. However, diurnal, 
semidiurnal, and fortnightly fluctuations in 
beach sand volumes related to the tides, yearly 
and multi-yearly fluctuations related to long- 
period meteorological conditions, and noncyclic 
fluctuations, such as are caused by tsunami, are 
also common. 
Along any stretch of coast the various factors 
affecting the amount of sand on the beach and 
in nearshore waters can be summarized, and, if 
the coast is in equilibrium (i.e., if a constant 
littoral sand volume is maintained), these fac- 
tors can be quantitatively balanced against each 
other. Coastal streams and rivers, coastal ero- 
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