The Pacific Northwest 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 Pacific Northwest region, which is listed with a 2-digit hydrologic unit code (HUC) of 17, has an approximate size of 302334sqmi, and consists of 12 subregions, which are listed with the 4-digit HUCs 1701 through 1706.[3]
This region includes the drainage within the United States that ultimately discharges into: (a) the Strait of Georgia and of Strait of Juan de Fuca, and (b) the Pacific Ocean within the states of Oregon and Washington; and that part of the Great Basin whose discharge is into the state of Oregon. Includes all of Washington and parts of California, Idaho, Montana, Nevada, Oregon, Utah, and Wyoming.[3]
| Subregion HUC[4] | Subregion Name | Subregion Description | Subregion Location | Subregion Size | Subregion Map | |
|---|---|---|---|---|---|---|
| 1701 | The Kootenai, Pend Oreille, and Spokane River Basins within the United States. | Idaho, Montana, and Washington. | 36600sqmi | |||
| 1702 | The Columbia River Basin within the United States above the confluence with the Snake River Basin, excluding the Yakima River Basin. | Washington | 22600sqmi | |||
| 1703 | The Yakima River Basin. | Washington | 6210sqmi | |||
| 1704 | The Snake River Basin to and including the Clover Creek Basin. | Idaho, Nevada, Utah, and Wyoming. | 35600sqmi | |||
| 1705 | The Snake River Basin below the Clover Creek Basin to Hells Canyon Dam. | Idaho, Nevada, and Oregon. | 36700sqmi | |||
| 1706 | The Snake River Basin below Hells Canyon Dam to its confluence with the Columbia River. | Idaho, Oregon, and Washington. | 35200sqmi | |||
| 1707 | The Columbia River Basin below the confluence with the Snake River Basin to Bonneville Dam. | Oregon and Washington. | 29800sqmi | |||
| 1708 | The Columbia River Basin below Bonneville Dam, excluding the Willamette River Basin. | Oregon and Washington. | 6250sqmi | |||
| 1709 | The Willamette River Basin. | Oregon | 11400sqmi | |||
| 1710 | The drainage into the drainage boundary to the Smith River Basin boundary, excluding the Columbia River Basin. | California, Oregon, and Washington. | 23200sqmi | |||
| 1711 | The drainage within the United States that discharges into: (a) Puget Sound and the Straits of Georgia and of Juan De Fuca; and (b) the Fraser River Basin. | Washington | 16800sqmi | |||
| 1712 | The drainage of the Great Basin that discharges into the state of Oregon. | California, Nevada, and Oregon. | 17300sqmi |