566 
VAUGHAN MACCAUGHEY 
plied by the Hawaii Section, U. S. Weather Bureau, shows the rainfall 
in various parts of the valley, for 191 6. 
Translating these data into terms of ecologic zones, the approximate 
annual rainfall is as follows: 
Coastal plain, seaward of Manoa valley 41 inches 
Middle of valley 90 
Upper valley floor 176 " 
Lower forest zone 106 " 
Fig. 3. Map of the eastern end of Oahu showing the relation of Manoa valley to 
the adjacent land areas. 
In general the valley becomes progressively hygrophytic as one 
advances toward the head, and conversely, progressively xerophytic 
as one approaches the sea. 
In Luakaha, a region in upper Nuuanu Valley, and separated from 
Manoa by only a narrow ridge, the annual rainfall is about 200 inches 
(196.99). 
The U. S. Hygrographic Survey maintained a rain-gauge on the 
summit of Mt. Olympus (2,450 feet) for a period of 67 days, and 
