Introduction

Windward O`ahu, facing into the trades, is known as the wetter side of the island. Annual rainfall throughout the region ranges from 30 inches per year along the coastal areas of Waimanalo to 300 inches per year along the crest of the Ko`olau in the uppermost reaches of Kahana Valley. The average annual rainfall for the entire area is approximately 100 inches per year. This compares to an average annual rainfall of 24 inches for the Honolulu area.

The high rainfall has made the streams of Windward O`ahu a major element in the overall landscape. Moreover, the social and environmental values of stream systems in Windward O`ahu are well-recognized by the public.¹

The following listing derives from several sources and attempts to follow the Hawaii Stream Assessment. However, there are errors and inconsistencies in that document. Somewhat better is the apparently original source document for the Stream Assessment titled Stream Names used in USGS Maps of 1983 (anon.). Deviations from both documents in this listing reflect a better understanding of local waters from field observations and an attempt to avoid the concept that if a stream name is not printed on a USGS map it is "unknown."

¹modified from Wilson Okamoto & Associates, Inc. 1983. Instream Use Study, Windward Oahu. Dept. Land & Natural Resources, State of Hawaii. p. 3