27 
water at high levels for irrigating purposes will render many 
other plants both possible and expedient. A close approximation 
of the ultimate developments can only be made when records of 
the rainfall, cost and economic values of the developments and 
complete surveys of the watersheds are obtainable. 
A rough approximation would indicate that there is still 
available : 
On the Island of Kauai. 
Oahu . 
JNIaui . 
Hawaii 
12,000 H. P. 
2,500 " 
4,000 " 
8,000 " 
26,500 " 
It is essential for power purposes that the permanency of the 
supply be assured. In the majority of cases in the Islands the 
storage of water is very expensive and difficult, but it should be 
borne in mind that the development of storage capacity increases 
the value of the water supply for irrigation purposes and inci- 
dentally renders security as a power source. The building 
of high level reservoirs would no doubt increase the estimate of 
the amount of available power. 
It is not always expedient, however, to develop available power, 
for the broken character of the country and limited amount of 
arable land at proper elevation makes the economic value of 
powers questionable. It is extremely important, however, that 
any owner of a source of power, or any individual or corporate 
interest, or the Territory, should be sure, when developing water 
for irrigating or other purposes, that all the power possibilities 
be fully investigated, and that the water be developed in such a 
way as to utilize it with the greatest possible economy. 
Many new developments will arise in years to come to require 
the use of electric power in our mills, in the development of new^ 
industries, the installation of labor-saving devices of all kinds, 
and possibly the manufacture of fertilizers for use in the field. 
These are details, but the main, underlying principle should be 
kept in view, namely, that the greatest amount of power can be 
developed with the greatest amount of water at the greatest head, 
and as all water power will prove of great economic value to the 
Territory, it should be conserved. 
THE GEOLOGY OF OAHU IN ITS RELATION TO THE 
ARTESIAN SUPPLY. 
Address of Professor C. H. Hitchcock. 
When it was first suggested that artesian flows might be made 
available in Oahu, some called attention to the fact that our 
rocks were volcanic, of a kind that had not been found productive 
