Littoral Sedimentary Processes— Inman, Gayman and Cox 
109 
* SYMBOL a NUMBER INDICATE GAGING STATIONS 
SLANTED NUMBERS ARE VALUE OF ANNUAL 
RAINFALL IN INCHES 
LETTERS DESIGNATE DRAINAGE AREAS 
FIG. 3= Rainfall and drainage basins on Kauai. Dotted lines indicate outline of drainage areas. Numbers and 
letters, designating stream gaging stations and drainage areas, respectively, are referred to in Table 1. Note area 
of lowest rainfall along western coast. Isohytel lines from the Meteorology Department, Pineapple Research 
Institute, and the Experiment Station, Hawaiian Sugar Planters’ Association, 1948. 
There are at least five well-developed sea valleys 
which cut the shallower portions of the insular 
shelf. All of these, except the one off Hanalei 
Bay, appear to terminate above the 450-ft con- 
tour. 
CLIMATE 
The annual precipitation varies from an av- 
erage of about 50 inches, on the windward 
(northeastern) shore, to over 450 inches, at the 
summit of Mt. Waialeale, and decreases to less 
than 20 inches in the rain-shadow produced on 
the extreme lee side of the island. Vegetation 
varies from tropical rain forest on the windward 
side, to arid on the southwestern slopes. Figure 
3 shows the drainage pattern, the outlines of 
the major drainage basins, and the contour lines 
of mean annual rainfall, or isohyets, for the 
island, as well as the location of several stream- 
flow gaging stations. 
Langbein and Schumm (1958) have shown 
that the sediment yield from a drainage basin 
varies as a function of climate, and that the 
maximum yield occurs for an effective precipi- 
tation of about 12 inches. The effective precipi- 
tation 5 is obtained from the actual precipitation 
by correcting for evapotranspiration losses to a 
standard temperature of 50 F. Sediment yield is 
less for precipitation either greater or less than 
5 Langbein and Schumm (1958) define "effective 
precipitation” as the amount of precipitation that 
would be required at a mean temperature of 50 F to 
produce the actual annual runoff from the basin. 
