Seasonal Variations — TsEU 
281 
ary phase. These corrected values formed the 
basis of the depth contours of the maps (Figs. 
2 to 8). Contours were drawn not only from 
the location of the soundings but also from 
the known configuration of the ponds and 
channels. 
Areas of the different contours in the ponds 
were then obtained by means of a polar plani- 
meter (for description and use see Welch, 
1948: 79-82). Using these data, the volumes 
of the several ponds were then determined, 
using the method outlined by Welch (1948: 
95). The volumes of the several ponds are 
shown in Table 1. 
The volumes of average and maximum tidal 
exchange as well as the percentage exchanges 
in volume at mean and maximum tidal range 
were computed on the basis of these area and 
volume figures. The volumes of average tidal 
exchange are the product of the area at the 
zero tide line and the mean range of tide. 
The percentage exchanges in volume at mean 
tide range were obtained by dividing the vol- 
ume of average tidal exchange by the total 
pond volume at mean high water. The vol- 
umes of maximum tidal exchange are the sum 
of the maximum volume above and the mini- 
mum volume below the zero tide line; that 
is, the result of multiplying the pond area 
(at zero tide) by the difference in height be- 
tween the lowest and highest tide. The per- 
centage exchanges in volume at maximum 
tidal range were obtained by dividing the 
volume of maximum tidal exchange by the 
total pond volume at the maximum high wa- 
ter. The values for minimum and maximum 
height of tides and the mean range of tide 
were calculated from the 1949 Tide Tables 
for Waikane, Kaneohe. The value for mean 
low water was obtained from the United 
States Coast and Geodetic Survey. Inasmuch 
as the walls above the zero tide line are almost 
vertical, the volumes for the higher tides were 
based on the area at the zero tide line. The 
values for pond 11 were not computed be- 
cause the shoreward margin of the pond is 
gradually sloping and irregular. 
Fig. 4. Contour map of pond 1 showing depth in feet and location of station 4. 
