The Hawaii water resource region is one of 21 major geographic areas, or regions, in the first level of classification used by the United States Geological Survey to divide and sub-divide the United States into successively smaller hydrologic units. These geographic areas contain either the drainage area of a major river, or the combined drainage areas of a series of rivers.[1][2]
The Hawaii region, which is listed with a 2-digit hydrologic unit code (HUC) of 20, has an approximate size of 6,428 square miles (16,650 square kilometers), and consists of 9 subregions, which are listed with the 4-digit HUCs 2001 through 2009.[3]
This region includes the drainage within the state of Hawaii. Includes all of Hawaii.[3]