WA TERSHED BA SINS OF UT A H R. Douglas Ramsey GREAT BASIN REGION Roger E. Banner ESCALANTE DESERT-SEVIER LAKE BASIN – The Ellie I. Leydsman McGinty Escalante Desert-Sevier Lake Basin is a large basin found within the Escalante Desert-Sevier Lake Sub-region. The The USDA Natural Resources Conservation Service basin is almost entirely located within the state boundar- (NRCS) and the United States Geological Survey (USGS), ies. The basin spans 10 counties, including: Beaver, Gar- as part of a national effort, have generated watershed, or field, Iron, Juab, Kane, Millard, Piute, Sanpete, Sevier, and hydrologic, boundaries for the United States. Hydrologic Tooele. The basin consists of nine sub-basins, including: boundaries define the aerial extent of surface water drain- the Beaver Bottoms-Upper Beaver, East Fork Sevier, Es- age to a point. Hydrologic units, through four levels, were calante Desert, Lower Beaver, Lower Sevier, Middle Sevi- created in the 1970s. Since the 1970s, the USGS devel- er, San Pitch, Sevier Lake, and Upper Sevier sub-basins. oped a hierarchical hydrologic unit code (HUC) for the The basin is bounded on the east by the Escalante Moun- United States. The hierarchical system divides the country tains, the Awapa Plateau, and the Wasatch Plateau, and it into 21 regions, 222 sub-regions, 352 basins, and 2,149 extends west to the House Range, Wah Wah Mountains, sub-basins. During the late 1970s, the NRCS initiated a Indian Peak Range, and Needle Range. It is bounded on national program to divide the sub-basins into watersheds the north by the Tintic Mountains and Mount Nebo, and and sub-watersheds (NRCS, 2009a). Consequently, re- it extends south to the Paunsaugunt and Markagunt pla- gions are the largest level, and within regions, there are teaus and the Pine Valley Mountains. The basin encom- sub-regions, basins, sub-basins, watersheds, and sub-wa- passes 10,463,981 acres, with 10,392,078 acres in Utah. tersheds. Annual precipitation averages 15 inches. Annual reference The state of Utah falls within four specific regions, includ- evapotranspiration is approximately 13 inches, yielding ing: the Great Basin Region, the Upper Colorado Region, a net surplus in water, largely due to the portion of the the Lower Colorado Region, and the Pacific Northwest Rocky Mountains that occupies the eastern portion of the Region (Figure 4.1). Within the Great Basin Region in basin. The dominant vegetation types are pinyon-juniper Utah, there are three sub-regions, including: the Escalante and big sagebrush. Salt desert shrub types are also preva- Desert-Sevier Lake, the Great Salt Lake, and the Bear Riv- lent. The topographic diversity and elevational range of er. Within the Upper Colorado Region in Utah, there are this basin (4,400 feet to over 12,000 feet above sea level) seven sub-regions, including: the Colorado Headwaters, also supports a wide array of environments that stretch to Upper Colorado-Dolores, Upper Colorado-Dirty Devil, subalpine zones. Aspen and spruce-fir communities sepa- Great Divide-Upper Green, Lower Green, and White- rated by dry and wet meadows characterize vegetation in Yampa. Within the Lower Colorado Region in Utah, the upper elevations. there is one sub-region, the Lower Colorado-Lake Mead. Within the Pacific Northwest Region in Utah, there is one A key management concern at lower elevations is the sub-region, the Upper Snake. spread of cheatgrass that predominantly invades semides- ert shrub communities. This is also a significant issue in Within the state of Utah, there are 15 basins nested within other basins that span western Utah. Cheatgrass has been the regions and sub-regions. The majority of the basins ex- blamed for much of the reduction of fire return intervals tend into Utah from other states. These 15 basins contain and the occurrence of larger fires. The Milford Flats fire in 68 smaller sub-basins (Figure 4.2; Tables 4.1 and 4.2). The July of 2007 burned more than 363,000 acres of land and sub-basins are often named for the primary surface waters is considered the largest fire in recorded history of Utah. that are found within that specific sub-basin (Figure 4.1). Each of the 15 basins will be described in terms of physi- GREAT SALT LAKE BASIN – The Great Salt Lake Ba- cal features, land cover, and general climate. Land cover sin is located in Utah, Nevada, and Idaho and is found data were extracted from the generalized SWReGAP data within the Great Salt Lake Sub-region. It is the largest ba- layer (reference section on Vegetation of Utah). Elevation sin in the state, spanning nine counties, including: Beaver, data were extracted from high-resolution digital elevation Box Elder, Davis, Iron, Juab, Millard, Salt Lake, Tooele, models, and climate data were extracted from Daymet cli- and Weber. The basin contains 10 sub-basins, including: mate models (Thornton et al., 1997). the Curlew Valley, Great Salt Lake, Hamlin-Snake Valleys, 29 Figure 4.1. Major hydrologic regions and surface water features in Utah. 30 Figure 4.2. Watershed basins and sub-basins in Utah. 31 Table 4.1. Hydrologic sub-regions, basins, and sub-basins within the Great Basin Region and Pacific Northwest Region. REGION SUB-REGION BASIN SUB-BASIN Beaver Bottoms-Upper Beaver East Fork Sevier Escalante Desert Lower Beaver ESCALANTE DESERT - ESCALANTE DESERT - Lower Sevier SEVIER LAKE SEVIER LAKE Middle Sevier San Pitch Sevier Lake Upper Sevier Curlew Valley Great Salt Lake Hamlin-Snake Valleys Northern Great Salt Lake Desert Pilot-Thousand Springs GREAT SALT LAKE Pine Valley GREAT BASIN Rush-Tooele Valleys REGION Skull Valley GREAT SALT LAKE Southern Great Salt Lake Desert Tule Valley Jordan Provo JORDAN Spanish Fork Utah Lake Lower Weber WEBER Upper Weber Bear Lake Little Bear-Logan LOWER BEAR Lower Bear-Malad BEAR RIVER Middle Bear Central Bear UPPER BEAR Upper Bear PACIFIC NORTHWEST Goose UPPER SNAKE UPPER SNAKE REGION Raft 32 Table 4.2. Hydrologic sub-regions, basins, and sub-basins within the Lower Colorado Region and Upper Colorado Region. REGION SUB-REGION BASIN SUB-BASIN Fort Pierce Wash Kanab LOWER COLORADO LOWER COLORADO - LOWER COLORADO - Lower Virgin REGION LAKE MEAD LAKE MEAD Meadow Valley Wash Upper Virgin COLORADO COLORADO Colorado Headwaters-Plateau HEADWATERS HEADWATERS Ashley-Brush Duchesne Lower Green Lower Green-Desolation Canyon LOWER GREEN LOWER GREEN Lower Green-Diamond Price San Rafael Strawberry Willow Chinle Lower San Juan SAN JUAN LOWER SAN JUAN Lower San Juan-Four Corners McElmo UPPER COLORADO Montezuma REGION Dirty Devil Escalante Fremont UPPER COLORADO - UPPER COLORADO - Lower Lake Powell DIRTY DEVIL DIRTY DEVIL Muddy Paria Upper Lake Powell Lower Dolores UPPER COLORADO - UPPER COLORADO - Upper Colorado-Kane Springs DOLORES DOLORES Upper Dolores Westwater Canyon Blacks Fork GREAT DIVIDE - UPPER GREEN Muddy UPPER GREEN Upper Green-Flaming Gorge Reservoir WHITE-YAMPA WHITE-YAMPA Lower White 33 Northern Great Salt Lake Desert, Pilot-Thousand Springs, Mountains and on the north by the Great Salt Lake and Pine Valley, Rush-Tooele Valleys, Skull Valley, Southern the Wasatch Range. The basin encompasses 2,502,664 Great Salt Lake Desert, and Tule Valley sub-basins. The acres, all within Utah. Great Salt Lake Basin extends west from the House Range, Wah Wah Mountains, Oquirrh Mountains, and Promon- This basin covers the most urbanized portion of Utah tory Mountains east to the Snake Range, Mount Morah, with at least 10 percent of the total land area classified as Kern Mountains, Goshute Mountains, the Pilot Range, urban development. The natural land cover consists pre- and the Goose Creek Mountains. The northern boundary dominantly of upland zone types, such as Gambel oak, is the Grouse Creek Mountains and Raft River Moun- big sagebrush, and pinyon-juniper. Since this basin ranges tains, and the southern limit is the Needle Range and In- from a low elevation of approximately 4,200 feet to a high dian Peak Mountains. The basin encompasses 14,508,116 of 11,900 feet, the vegetation cover also includes conifers, acres, with 11,596,392 acres in Utah. aspen, mountain meadows, and tall shrublands. Precipita- tion averages 25 inches per year; therefore, the subsequent Although it is the largest basin in Utah, the Great Salt water production is slightly less per unit area than the We- Lake Basin is one of the least populated areas, with ap- ber River Basin, with approximately the same allocation proximately 1.8 percent of the total population in the between natural land cover, agriculture, and human use. state. Eighty-eight percent of this population occupies One significant difference between the Jordan River Basin only 7 percent of the land in the basin. The lack of human and the other basins in Utah is the influx of water through population is due to the relatively harsh nature of this ba- the Central Utah Water Project, which pipes water from sin. It is composed of salty playa bottoms and the Great the High Uintas to the central part of the state. Salt Lake, and it includes some of the most arid lands in the western United States. WEBER RIVER BASIN – The Weber River Basin is lo- cated within the Great Salt Lake Sub-region. The basin The dominant vegetation cover is salt desert shrub and occurs in Box Elder, Davis, Morgan, Summit, and Weber greasewood. Big sagebrush and pinyon-juniper are found counties in Utah and in Uinta County, Wyoming. The ba- at higher elevations on the “island mountains” that are sin contains two sub-basins, including the Lower Weber typical of Basin and Range topography. The mountains and the Upper Weber. The basin is bordered on the east provide much of the water, through snowmelt, needed for by the Uinta Mountains and the Monte Cristo Range and natural vegetation growth.