BASINS (NEVADA)

The U.S. Geological Survey (USGS) and the Nevada Division of Water Resources, Department of Conservation and Natural Resources, have divided the state into discrete hydrologic units for water planning and management purposes. These have been identified as 232 Hydrographic Areas (256 areas and sub-areas, combined) within 14 major Hydrographic Regions or Basins. These 14 Nevada Hydrographic Regions (Basins), along with the approximate surface areas, counties of coverage, and number of hydrographic areas and sub-areas are: (1) Northwest Region: Covers 3,052 square miles (1,953,280 acres) of northern Washoe and Humboldt counties and encompasses 16 hydrographic areas; (2) Black Rock Desert Region: Covers 8,632 square miles (5,524,480 acres) of parts of Washoe, Humboldt, and Pershing counties and includes 17 valleys (hydrographic areas), two of which are divided into two sub-areas each; (3) Snake River Basin: Covers 5,230 square miles (3,347,200 acres) in parts of Elko and Humboldt counties to include eight hydrographic areas; (4) Humboldt River Basin: Covers over 16,843 square miles (10,779,520 acres) in parts of eight counties: Elko, White Pine, Eureka, Humboldt, Lander, Nye, Pershing, and Churchill: and the largest stream (Humboldt River) wholly within Nevada. This basin contains 34 hydrographic areas and one sub-area; (5) West Central Region: Covers 1,656 square miles (1,059,840 acres) and includes parts of Pershing, Lyon, and Churchill counties and comprises five hydrographic areas; (6) Truckee River Basin: Encompasses 2,300 square miles (1,472,000 acres) containing parts of Washoe, Pershing, Douglas, Carson City, and Storey counties comprising 12 hydrographic areas; (7) Western Region: Covers 602 square miles (385,280 acres) and is wholly contained in Washoe County and contains nine valleys (hydrographic areas) one of which is divided into two sub-areas and another divided into one sub-area; (8) Carson River Basin: Covers 3,634 square miles (2,325,760 acres) and includes parts of six counties: Douglas, Carson City, Lyon, Storey, Churchill, and Pershing: containing five hydrographic areas and one sub-area along the Carson River and its tributaries; (9) Walker River Basin: Covers 2,931 square miles (1,875,840 acres) of Mineral, Lyon, and Douglas counties (and a very small portion of Churchill County) including five hydrographic areas, one of which has been divided into three sub-areas; (10) Central Region: By far the largest hydrographic region in Nevada covering 46,783 square miles (29,941,120 acres) in 13 counties: Nye, Elko, White Pine, Lincoln, Clark, Humboldt, Pershing, Churchill, Lander, Eureka, Lyon, Mineral, and Esmeralda. This region includes 78 valleys (hydrographic areas), 10 of which are divided into two sub-areas and one into three sub-areas; (11) Great Salt Lake Basin: Covers 3,807 square miles (2,436,480 acres) of the easternmost portions of Elko, White Pine, and Lincoln counties. It consists of eight hydrographic areas, one of which is divided into four sub-areas; (12) Escalante Desert Basin: This basin covers a large area in Utah but only a very small part of it is in Lincoln County: 106 square miles (67,480 acres): and is made up of only one hydrographic area; (13) Colorado River Basin: Covers 12,376 square miles (7,920,640 acres) including parts of Clark, Lincoln, Nye, and White Pine counties and is divided into 27 hydrographic areas; (14) Death Valley Basin: Covers 2,593 square miles (1,659,520 acres) of Nye and Esmeralda counties including eight hydrographic areas, one of which has been divided into two sub-areas. (A listing of Nevada's Hydrographic Areas and Sub-Areas is presented in Appendix A-1 (listed sequentially by Hydrographic Area number and Hydrographic Region/Basin), Appendix A-2 (listed alphabetically by Hydrographic Area and Sub-Area name), and Appendix A-3 (listed alphabetically by principal Nevada county(ies) in which located).)