Littoral Sand Budget, Hawaii — Chamberlain 
177 
TABLE 21 
Rates of Accretion and Erosion, Selected Beaches, Hawaii* 
BEACH 
LENGTH 
4/62-6/62 
6/62-9/62 
9/62-1/63 
1/63-4/63 
4/63-7/63 
BEACH 
(yards) 
(2 mos.) 
(3 mos.) 
(4 mos.) 
(3 mos.) 
( 3 mos.) 
Waipiof 
1320 
-66.0 
-19.7 
+9.2 
+ 18.7 
-43.3 
Hilo 
500 
+■ 
+ 
+0.3 
+0.5 
+ 0.7 
-0.7 
Kaimu 
333 
+■ 
+ 
+0.3 
— 3.5 
+9.7 
— 8.0 
Punaluu 
266 
+■ 
-0.3 
-0.5 
-0.3 
+ 1-7 
Hookena 
220 
+ 
+ 
-0.3 
— 2.5 
—0.7 
— 1.0 
Kealakekua 
175 
0 
—2.3 
— 1.2 
+0.3 
+0.7 
Disappearing 
Sands 
100 
+ 10.0 
-0.7 
—6.5 
-0.3 
+ 5.0 
Hapuna 
500 
—4.5 
-15.3 
—0.7 
-9.0 
+ 27.0 
Kawaihae 
90 
-2.5 
+ 1-3 
— 1.0 
0 
— 2.7 
* Rates of accretion ( + ) and erosion ( — ) in cubic yards of sand/yard of beach/month, 
f Rates of change are not representative for the entire beach. Applicable only to vicinity of range. 
$ No data. 
mencement of the northeast trades, began to 
erode. 
Littoral Transport 
The organic sand-size constituents of the 
Hawaiian littoral sands are produced across the 
entire width of the reef and are transported 
landward by series of tortuous channels across 
reef flats, and by depressions or pockets on the 
reefs themselves. On the beach and in near- 
shore waters they are mixed with inorganic 
terrigenous particles and moved along or on 
and off shore in response to waves and currents. 
The lateral or alongshore transport of sand 
is limited, and alongshore transport distances 
of less than a few miles are the rule except in 
a very few cases, such as along the Mana Coastal 
Plain of southern Kauai, parts of southwestern 
Oahu, and the western coast of Molokai. Here 
the total volume of sand moving past a single 
point on the beach is appreciable, and the 
volume has been estimated by the U. S. Army 
Corps of Engineers to be approximately 20,000 
cubic yards per year. But it is more likely that 
in most areas of the Hawaii coasts the along- 
shore transport is not even one-tenth this 
amount. Littoral cells generally are small and 
bounded by numerous rocky points and cliffs, 
and, as evidenced by the distribution of sand 
bodies within the cells and by underwater 
observations at the cell boundaries, very little 
I sand escapes around the headlands and promon- 
tories that bound the cells. 
Evidence indicates that within the littoral 
cells, however, there is an appreciable littoral 
transport of sand perpendicular to the coast. 
Our measurements show that several thousands 
to several tens of thousands of cubic yards of 
sand per mile of coastline are continually in 
motion, either moving on shore or off shore, as 
shown by rates of erosion and accretion, de- 
pending upon wave and current conditions. For 
example, during the Kona storms of the winter 
of 1962-63 nearly 2 million cubic yards of 
sand were eroded from the beaches between 
Pearl Harbor and Kaena Point, Oahu — an aver- 
age of 62,000 cubic yards put into motion per 
mile of coastline. During the following spring 
and summer, 1.8 million cubic yards of sand 
were transported back onto those same beaches, 
or an average of 55,000 cubic yards of sand 
per mile of coast. 
On the eastern coast of Oahu between Kahuku 
Point and Makapuu Head, more than 500,000 
cubic yards of sand were eroded from the 
beaches during March, April, and May 1963, 
or an average of 10,000 cubic yards transported 
per mile of coast. During the period just prior 
to this erosion (November 1962-March 1963) 
443,000 cubic yards were added to the same 
beaches, or more than 9,000 cubic yards trans- 
ported per mile of coast. Similar rates of littoral 
transport were measured for the northern Oahu 
beaches. 
For the transport of 50- or 60-thousand cubic 
yards of sand per mile of coast during a 2- or 
