282 
PACIFIC SCIENCE, Vol. VII, July, 1953 
TABLE 1 
Area, Volume, and Volume Exchange of the Ponds and Boat Channel 
POND 
AREA 
VOLUME AT 
ZERO TIDE 
VOLUME OF 
AVERAGE 
TIDAL 
EXCHANGE 
PERCENTAGE 
EXCHANGE IN 
VOLUME AT 
MEAN TIDAL 
RANGE 
VOLUME OF 
MAXIMUM 
TIDAL 
EXCHANGE 
PERCENTAGE 
EXCHANGE IN 
VOLUME AT 
MAXIMUM 
TIDAL RANGE 
1 
Square feet 
5,800 
Cubic feet 
21,000 
Cubic feet 
8,100 
26 
19,300 
51 
2 
5,400 
8,000 
7,500 
43 
18,100 
75 
3 
4,000 
5,100 
5,600 
46 
13,600 
80 
4 
1,700 
2,300 
2,400 
45 
5,680 
78 
5 
23,000 
97,000 
32,000 
23 
75,100 
46 
Channel 
33,000 
200,000 
47,000 
18 
110,000 
37 
CURRENTS AND TIDES 
Tidal current patterns were noted in ponds 
1 to 5 of the main pond systems. Observations 
were made on two flood and two ebb tides, 
with winds of force 3-4 coming from the 
north on the flood tides, and winds of force 
0-2 coming from the southwest and west on 
the ebb tides. To trace the water flow a sat- 
urated solution of fluorescein dye in sea water 
was poured into the water at various points. 
The movements of the fluorescein dye were 
noted at intervals, the total time of observa- 
tion for each pond depending on the speed 
of the dye movements. 
The currents on the flood tides reach the 
ponds by way of the channels north and west 
of the net house (Fig. 1, B), and on the ebb 
tides they leave the ponds by the same route; 
that is, currents enter and leave ponds 1 and 
5 from the adjacent channels, enter and leave 
pond 2 mostly through pond 1, and enter 
and leave the smaller ponds, 3 and 4, through 
pond 5, though some slight water exchange 
exists between ponds 2 and 3. On the flood 
tides no currents were observed entering pond 
5 by way of the tide flats (Fig. 1, 10). Instead, 
water coming in from the channels moved 
onto the flats. 
Short-period reversals of flow several min- 
utes in length were noted, especially on the 
flood tides and at some of the gates. It was 
not in the scope of this study to investigate 
the phenomenon, but it is suggested that per- 
haps these reversals may be either the result 
of long-period waves sweeping over the outer 
reef and reaching the island as imperceptible 
changes in water level or the cumulative re- 
sult of interference patterns of the smaller 
off-shore waves. 
As it was not possible to establish an auto- 
matic tide gauge on the island, approxima- 
tions of the tide were made using a tide staff. 
The height of the tides was recorded in inches 
above an arbitrary 2ero level by means of a 
tide staff nailed to the dock (Fig. 1, A). A 
series of comparisons, including those of the 
three diurnal cycles, was made between the 
observed Kaneohe tide and the theoretical 
Honolulu tide. The times of high and low 
water as well as the amplitude of the tidal 
curves were compared. 
The regularity of tidal movements is sub- 
ject to the influences of wind. For example, 
it is generally known that an onshore wind 
tends to raise the level and an offshore wind 
tends to lower the level of the sea along a 
coast. Steady winds did not affect the times 
of high and low water but merely their heights . 
Variable winds, on the other hand, not only 
affect the heights but also the times of high 
and low water. In an enclosed bay such as 
Kaneohe, with its wide shallow front as en- 
trance and two comparatively narrow chan" 
nels as exits, a period of high onshore winds 
can raise the sea level higher and maintain 
