Sevier River
Template:Short description Template:Use American English Template:Infobox river
The Sevier River (pronounced "severe") is a Template:Convert-long<ref name=NHD>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> river in the Great Basin of southwestern Utah in the United States. Originating west of Bryce Canyon National Park, the river flows north through a chain of high farming valleys and steep canyons along the west side of the Sevier Plateau before turning southwest and terminating in the endorheic basin of Sevier Lake in the Sevier Desert. It is used extensively for irrigation along its course, with the consequence that Sevier Lake is usually dry.
The Sevier River drainage basin of Template:Convert<ref name="USGS">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> covers more than 13 percent of Utah and includes parts of ten counties, of which the river flows through seven.<ref name="GNIS">Template:Cite gnis</ref> The name of the river is derived from the Spanish Río Severo, "violent river".<ref name="Sevier County history">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name="Utah Place Names">Template:Cite book</ref>Template:Rp The Sevier is the longest river entirely within the state of Utah.
CourseEdit
The Sevier River is formed by the confluence of Minnie Creek and Tyler Creek in Long Valley in Kane County.<ref name="USGS Long Valley Junction">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The headwaters are at an elevation of Template:Cvt between the Markagunt Plateau (on the west) and the Paunsaugunt Plateau.<ref name="Benchmark Utah Atlas">Template:Cite map</ref>Template:Rp The river flows north through a wide valley into Garfield County passing Hatch and Panguitch.<ref name="USGS Hatch">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name="USGS Panguitch">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> It then flows through the narrow, Template:Convert Circleville Canyon<ref name="USGS Bull Rush Peak">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> and enters Piute County at the town of Circleville,<ref name="USGS Circleville">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> and is joined by the East Fork Sevier River at Kingston.<ref name="USGS Junction">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Immediately north of Kingston, it is dammed to form Piute Reservoir.<ref name="USGS Piute Reservoir">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
The Sevier continues north past Marysvale<ref name="USGS Marysvale">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> and through Marysvale Canyon (or Sevier Canyon) into Sevier County.<ref name="USGS Marysvale Canyon">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> At Sevier the river enters the agricultural Sevier Valley, a Template:Convert long basin between the Pavant Range on the west and the Sevier Plateau to the east. In the valley, the Sevier River flows generally northeast, passing the cities and towns of Sevier, Joseph, Elsinore, Monroe, Central Valley, Anabella, Richfield, Glenwood, Venice and Sigurd. Just north of Sigurd, the river is dammed to form Rocky Ford reservoir. The Sevier River then continues north passing the towns of Aurora, Salina and Redmond,<ref name="Benchmark Utah Atlas"/>Template:Rp then flows north into Sanpete County where it picks up the San Pitch River near Gunnison.<ref name="USGS Gunnison">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
In Juab County the Yuba Dam forms Sevier Bridge Reservoir, which also extends into Sanpete County.<ref name="USGS Scipio North">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Below the dam the river flows north then turns abruptly west through Leamington Canyon, between the Canyon Mountains and Gilson Mountains, into Millard County.<ref name="USGS Champlin Peak">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The river flows southwest across the Sevier Desert, where it is used heavily for irrigation in the Delta area, and is dammed at the DMAD and Gunnison Bend reservoirs.<ref name="USGS Delta">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The river is essentially dry for the last Template:Convert below Delta, through its confluence with the also dry Beaver River before reaching the intermittent Sevier Lake bed.<ref name="USGS Red Pass">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Drainage basinEdit
The Sevier River drainage basin is on the border of the Basin and Range Province and the Colorado Plateau; the north and west parts of the basin are defined by long linear mountain ranges such as the Pavant and Canyon Mountains.<ref name="Benchmark Utah Atlas"/>Template:Rp To the east and south rise high plateaus and block-shaped mountain ranges, chief of which are the Wasatch and Sevier Plateaus to the east,<ref name="Benchmark Utah Atlas"/>Template:Rp and the Paunsaugunt and Markagunt Plateaus, the Pink Cliffs and the Tushar Mountains to the south.<ref name="Benchmark Utah Atlas"/>Template:Rp The entire basin is at high elevation, with the highest point at Template:Convert Delano Peak in the Tushar Mountains. There are twelve other peaks in the basin rising more than Template:Convert.<ref name="USWP Introduction">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The lowest point is at Sevier Lake, Template:Convert above sea level.<ref>Template:Cite gnis</ref>
The basin experiences a continental climate ranging in character from semi-arid to alpine. Precipitation – ranging from Template:Convert in the desert valleys to more than Template:Convert in the mountains<ref name="Sevier River System"/> – falls largely as snow during the winter and early spring, and as monsoon thunderstorms in late summer and early fall.<ref name="USWP Introduction"/> As of 1999, there was an estimated annual runoff of Template:Convert in the Sevier River basin, but only about Template:Convert of that reached Sevier Lake, and mostly in wet years.<ref name="USWP Executive Summary">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Even before irrigation, however, not all of this water reached Sevier Lake due to large evaporation losses in the Sevier Desert.
The Sevier River basin is bordered to the south by the drainage basins of Virgin River, Kanab Creek, Paria River, and Dirty Devil River, all tributaries of the Colorado River. To the east, it is bordered by the Price and San Rafael River basins, tributaries of the Green River, which flows into the Colorado River. On the north, it is bordered by the Utah Lake–Great Salt Lake basin, and to the west, it is bordered by the Great Salt Lake Desert basins.<ref name="USWP Introduction"/>
Most of the Sevier drainage is rural, composed of small farming communities.<ref name="Sevier River System"/> The largest town is Richfield, with a population of 7,723 as of 2016.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> About 69 percent of the land is federally owned, much of that in national forest lands such as the Manti-La Sal, Fishlake, Dixie, and Uinta National Forests. The basin also includes parts of Bryce Canyon National Park and Cedar Breaks National Monument. About 23 percent of the basin is privately owned and 8 percent is owned by the state of Utah.<ref name="USWP Introduction"/>
The Sevier River corridor is a major transportation route, with U.S. Route 89 closely following the river for over Template:Convert from its headwaters as far as Gunnison, and I-70 paralleling the river for about Template:Convert between Sevier and Salina.<ref name="Benchmark Utah Atlas"/>Template:Rp
GeologyEdit
Surface rock in the Sevier River basin is composed mostly of Tertiary igneous rock and sedimentary rock ranging in age from Jurassic to Quaternary.<ref name="USWP Introduction"/> This is underlain by marine sedimentary rock including thick limestone layers, which accumulated prior to the Jurassic when the western US was part of a shallow sea.<ref name="History of Millard County"/> Uplift during the Jurassic and Cretaceous thrust western Utah above sea level for the first time. Between 100 and 80 million years ago, the Sevier Orogeny created mountains much higher than those found in western Utah today.<ref name="History of Millard County"/> The Sevier Desert was formed starting about 20 million years ago due to crustal stretching that lowered the local terrain.<ref name="History of Millard County"/> Another period of uplift occurred towards the end of the Tertiary, about 12–2 million years ago, creating most of the present-day mountain ranges and plateaus.<ref name="History of Millard County"/>
Significant vertical displacement has occurred on several north–south faults in the basin. The Sevier Fault and Elsinore Fault run mostly parallel to the upper Sevier River above Gunnison, and the Paunsaugunt fault runs in the same general direction further east, passing through Bryce Canyon.<ref name="USWP Introduction"/> The Sevier Valley (and the Sanpete Valley north of it) is a graben or down-thrown block of land between the Sevier and Elsinore faults, with deep alluvial deposits filling the valley bottom.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Groundwater basins occur mostly in the alluvial valleys and have been estimated to hold up to Template:Convert of water.
Large mineral deposits occur in various areas of the basin, including coal in the Salina area, beryllium in the Delta area, and gypsum in the Richfield area. The dry Sevier Lake bed as well as deposits in the Redmond area, are a major source of salts, including halites and potassium sulfates.<ref name="USWP Introduction"/> Historically, uranium was mined near Marysvale.<ref name="USWP Introduction"/> Above Marysvale Canyon, the colorful formations of Big Rock Candy Mountain are a widely recognized geological site in central Utah; yellow, red and orange bands are the result of jarosite, hematite and pyrite while white bands result from alunite and kaolinite presence.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
During the Pleistocene Ice Age and other preceding ice ages, the Sevier River flowed into Lake Bonneville, which covered more than Template:Convert of the eastern Great Basin. The Sevier Valley was underwater as far upstream as Richfield. As the lake receded with a drying climate at the end of the ice age, what is now the Sevier Desert became an independent lake, which drained into the Great Salt Lake via a now dry channel in Millard County north of Delta. As Sevier Lake shrank, the Sevier River formed a large delta at its mouth, hence the name of the modern town.<ref name="USWP Introduction"/><ref name="History of Millard County">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Soils become progressively more alkaline and saline closer to Sevier Lake, the result of the river transporting minerals downstream over millennia as the lake receded.<ref name="History of Millard County"/> The largest sand dunes in Utah, found in Little Sahara Recreation Area, were formed from Sevier River delta deposits moved over thousands of years by prevailing winds.<ref name="History of Millard County"/>
There have been relatively recent volcanic activity in the Sevier basin between 1000 and 1500 AD, when basalt flows occurred on the Markagunt and Paunsaugaut Plateaus and in Pahvant Valley.<ref name="USWP Introduction"/> One of these flows dammed a valley and formed Navajo Lake.
Plants and animalsEdit
Valley and stream habitatsEdit
Due to the semi-desert climate, the valleys of the Sevier River basin were historically mostly grassland and shrubland, with the seeds of Oryzopsis hymenoides (Indian ricegrass) being an important food source for Native Americans. Many valley plants, such as greasewood, shadscale and saltgrass are adapted to the higher salt content in the soil. The valleys have been heavily modified for farming and grazing, and much of the remaining native grassland has been taken over by invasive species such as junegrass and the ubiquitous Russian thistle (tumbleweed), as well as native sagebrush whose range has expanded into formerly grassy areas.<ref name="History of Millard County"/>
The Sevier River historically supported large areas of wetland and riparian zones, especially where it formed a delta at the northern end of Sevier Lake. Many of these habitats have been replaced by agriculture, but there are still an estimated Template:Convert of wetland and aquatic habitat extant in the basin, of which about half is located in Millard and Sanpete counties alone.<ref name="USWP Wildlife">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The upper reaches of the river and many mountain tributaries are home to cutthroat trout, brook trout and rainbow trout, of which cutthroat are the only native species.<ref name="USWP Wildlife"/> Much of the lower part of the river is a warm water fishery with brown trout, carp, suckers and channel catfish.<ref name="USWP Wildlife"/> Common fish found in reservoirs are walleye, smallmouth bass, yellow perch and northern pike.<ref name="USWP Wildlife"/>
Because the Sevier River provides some of the only water-based habitats in a large desert area, it is used by abundant migratory waterfowl, including geese, ducks, cranes, and shorebirds. Gunnison Bend Reservoir is visited by thousands of snow geese each spring.<ref name="USWP Wildlife"/> Other birds common to the Sevier basin include pheasants in agricultural and riparian areas; chukars in foothill areas and grouse in the hills and mountains.<ref name="USWP Wildlife"/> There are also multiple raptor species, including bald eagles and peregrine falcons.<ref name="USWP Wildlife"/> Fur-bearing animals such as beaver and river otter were once widespread before being trapped out in the early 1800s, and predators such as kit foxes, coyotes, and cougars still roam less populated areas of the basin.<ref name="USWP Wildlife"/>
Mountain habitatsEdit
In the high mountains and plateaus above Template:Convert elevation, conifer-aspen forest prevails in the alpine zone with forests of white fir, Douglas fir, ponderosa pine, red cedar, spruce and quaking aspen.<ref name="Sevier River System"/> Engelmann spruce, limber pine and the occasional bristlecone pine are found at the highest elevations.<ref name="History of Millard County"/> Precipitation is sufficient to support many perennial streams and springs, which nourish mountain meadows and numerous small high elevation lakes.<ref name="Utah High Plateaus"/> Large wildfires once regularly occurred on the mountains and plateaus, but since the beginning of the 20th century fires have been heavily suppressed.<ref name="Utah High Plateaus"/>
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The high country is home to small mammals such as ground squirrels, red squirrels, snowshoe hare, chipmunks and porcupine. Pika and marmot are found near mountain peaks and flying squirrels can be found in the Navajo Lake area.<ref name="USWP Wildlife"/> Larger mammals include mule deer, pronghorn (antelope), black bear and cougar. Also once found in the area were the Rocky Mountain bighorn sheep, bison, grizzly bear and timberwolves which were all hunted to extinction in the 1800s or early 1900s.<ref name="Utah High Plateaus">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The deer population was nearly extirpated during the era of western settlement, although it has since recovered.<ref name="USWP Wildlife"/>
The foothill and transition zones support a wide variety of vegetation types. Small hardwoods such as gambel oak, serviceberry, mountain mahogany, maple and scrub oak tend to occur at elevations of Template:Convert just below the boundary of the alpine zone, but still high enough to receive significant precipitation.<ref name="Sevier River System"/><ref name="USWP Introduction"/> In the lower foothills, pinyon–juniper "pygmy forest" mixed with areas of grassland and sagebrush occur between Template:Convert in elevation.<ref name="USWP Introduction"/>
HistoryEdit
Native AmericansEdit
Paleo-Indians were present in southwestern Utah as early as 10,000 BC, when the climate was much wetter during the Pleistocene ice age and the Sevier basin was partially occupied by pluvial Lake Bonneville. Wetlands along the shoreline and a much fuller Sevier River provided abundant habitat for fish and wildlife, supporting a larger human population.<ref name="History of Millard County"/> Lake Bonneville had dried up by about 7000 BC, and the aridifying climate limited plant and animal resources. The Desert Archaic culture, characterized by small semi-nomadic bands, succeeded the Paleo-Indians but it is not known whether they are the descendants or an entirely different group.<ref name="History of Millard County"/><ref name="Sevier County"/> The Desert Archaic culture declined around 1500 BC, for reasons that are uncertain but have been attributed to massive flooding at that time.<ref name="History of Millard County"/>
Beginning about 500 AD, people of the Fremont culture inhabited the Sevier basin; a Fremont village site called Nawthis has been discovered in the Salina area dating to the years 800–1150 AD. There is evidence that these early peoples used irrigation for their crops – primarily corn, beans and squash.<ref name="USWP Introduction"/> Fremont remains have also been found in southern Sevier County near Clear Creek. This site is now preserved as Fremont Indian State Park.<ref name="Sevier County">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The Fremont culture disappeared around 1300 AD, possibly due to an extended drought.<ref name="History of Millard County"/>
The ancestors of the Ute, Southern Paiute and Goshute peoples who populated the Sevier River basin immediately prior to European arrival migrated into the area possibly centuries after the decline of the Fremont culture.<ref name="Sevier River UEN"/><ref name="History of Millard County"/> The traditional lands of these three peoples converged on the Sevier River delta in what is now Millard County.<ref name="History of Millard County"/> The Utes dominated most of the area traversed by the Sevier River including the Sevier Valley and the headwaters of the river. Notable sub-groups including the Pahvant Utes who lived around Sevier Lake, the Sanpits Utes from whom the name of Sanpete Valley and Sanpete County is derived from, and the Moanunt Utes who lived on the upper Sevier River.<ref name="History of Millard County"/> The Paiutes lived to the south and west of the delta, and the Goshutes inhabited drier areas to the northwest.<ref name="History of Millard County"/>
Settlers William Wolfskill and George C. Yount noted some Native Americans who called the river the Pooence.<ref name="USWP Introduction"/>
Explorers and tradersEdit
The first Europeans to see the river were the Spanish missionaries Francisco Atanasio Domínguez and Silvestre Vélez de Escalante who led the Domínguez–Escalante expedition of 1776, trying to find a way to Monterey, California from Santa Fe, New Mexico. They arrived at the Sevier River on September 27, two days after leaving the Utah Valley, and camped at a location near the present day town of Mills.<ref name="History of Millard County" /> They named the Sevier River El Río de Santa Isabel and gave the name Laguna de Miera to Sevier Lake.<ref name="Utah Place Names" />Template:Rp However, the expedition was unable to find a way further west across the desert and was forced to turn back to Santa Fe. The expedition's cartographer, Don Bernardo Miera y Pacheco, sketched a map showing an outlet from Sevier Lake to the Pacific Ocean, which may have given rise to the myth of a Buenaventura River draining the Great Basin to the sea.<ref name="History of Millard County" />
The river was a major trade corridor during the late 18th and early 19th centuries, in no small part due to the route from Santa Fe opened up by Domínguez and Escalante. The Spanish traded manufactured goods and guns for furs, hides, horses and slaves from the Native Americans. Most of these slaves were Southern Paiutes that had been captured by more aggressive Ute bands.<ref name="History of Millard County" /> The river's present name probably originated in 1813 with Spanish traders Moricio Arce and Lagos García, who ran into trouble with the Utes (supposedly when they rejected an offer by the Utes to sell them slaves)<ref name="Duncan">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> and escaped to a stream they called Río Severo, Spanish for "violent".<ref name="Sevier River UEN">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
In 1821, the Sevier River basin became Mexican territory following the Mexican Revolution. Mountain man William H. Ashley explored the area in 1825 in search of beaver; the river was dubbed the "Ashley River" by Jedediah Smith in Ashley's honor.<ref name="Utah Place Names" />Template:Rp Smith is credited with blazing a connection between existing Native American trails through the Sevier basin in 1826; this became part of the northern branch of the Old Spanish Trail, following the middle and upper parts of the river.<ref name="Sevier River UEN" /> John C. Frémont traveled along the Sevier River on his 1844 exploration of the Great Basin, which confirmed that the Sevier and other Great Basin streams had no ocean outlet and the rumor of a "Buenaventura River" was no more than a myth.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> During the 1830s and 1840s the fur trade was in full force with thousands of beaver and otter taken from the Sevier River and its tributaries; most trappers were Native Americans although there were also many of British, French and Spanish origin.<ref name="Duncan" /> The slave trade also remained a major if controversial business and only ended after the Mexican–American War in 1848, after which the Sevier River became part of Utah Territory.
19th-century settlersEdit
The first Mormon settlers arrived in the Sevier Valley in late 1849 under the direction of Brigham Young, but they and other whites passing through the region soon clashed with Native Americans.<ref name="Sevier River UEN"/> Sometime in early October 1853 a party of California-bound emigrants opened fire on a group of Pahvant Utes who had come to their camp to trade, killing one. In retaliation, on October 26, 1853, the Pahvants attacked a railroad survey crew led by Captain John W. Gunnison, killing eight members of the party near what is now the town of Delta.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Despite the massacre, immigration continued with 30 Mormon families settling in the Richfield area in 1864, followed by 100 more the next year, further straining relations with the tribes.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Between 1865 and 1872 more than 150 violent confrontations occurred between Mormon settlers and various Native American groups including the Utes, Paiutes, Apache and Navajo, a period now known as the Black Hawk War after Timpanogos chief Antonga Black Hawk.<ref name="Sevier County history"/> Livestock grazing had decimated the local grasses whose seeds were a staple food for Native Americans, forcing them to raid white settlements and steal cattle for food. By June 1866 most of the settlements had been abandoned as the fighting increased.<ref name="bryce">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> One of the bloodiest single episodes was the Circleville Massacre near the upper Sevier River, in which 26 Paiutes were killed by white settlers after an earlier attack by Ute warriors, despite the fact that the Paiutes and Utes were enemies.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> In total, at least 70 whites and an unknown number of Native Americans were killed.<ref name="bryce"/>
The tribes were ultimately defeated with the intervention of the US government in 1870, although minor confrontations and skirmishes continued until about 1872. Most Native Americans in the area were moved to the Uintah Reservation in northeastern Utah.<ref name="Duncan"/> Many resisted the move, with several Ute bands traveling back to the Sanpete Valley early in 1872. Their presence alarmed Mormon settlers, as the Utes expressed discontent with conditions at the reservation. After the federal government sent additional supplies to the Uintah reservation, the Utes retreated.<ref name="Duncan"/>
By summer 1872 many towns in the area had been resettled, and the white population increased rapidly for a number of years. During this time, Richfield grew into the largest city in the Sevier Valley, sometimes referred to as "the hub of Central Utah".<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The Deseret Telegraph was extended from Salt Lake City as far as Monroe in 1872.<ref name="Sevier County history"/> Development was slower to reach the upper Sevier country south of Marysvale Canyon, which was mostly ranching country although it would soon be the location of significant mineral strikes. Notorious outlaw Butch Cassidy grew up on a ranch near Circleville during the 1870s, where he "learned to be a cowboy first and, later, how to put his brand on other peoples' livestock."<ref>Template:Cite news</ref>
IrrigationEdit
The first irrigation along the Sevier River was established in the spring of 1850, on the Sanpete County stretch of the river. Irrigation in Millard County began in 1859.<ref name="Sevier River UEN"/> The first storage reservoir in the Sevier basin was Scipio Reservoir, constructed in 1860. In 1865 in Sevier County, Mormon settlers dug the Richfield Irrigation Canal in just five weeks using only hand tools.<ref name="USWP Introduction"/> Other farming towns were established along the river particularly after the Black Hawk war ended in 1872. A more ambitious project was the Tropic Ditch, which diverted water Template:Convert from the East Fork of the Sevier River through what is now Bryce Canyon National Park to the town of Tropic.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Agriculture was made difficult by frequent flooding of the Sevier River. In June 1909 heavy snowmelt broke the Gunnison Bend Dam and flooded the town of Deseret under Template:Convert of water.<ref name="flooding">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> It was not until about 1912 when the river was finally controlled by major reservoirs upstream.<ref name="Sevier River UEN"/> The division of water rights became an issue as the population increased, due to limited water supplies during the dry season. In one particularly dry year some residents in Millard County "were so angry they hired a posse in an unsuccessful attempt to remove upstream dams."<ref name="Sevier River System"/> In 1900 the Higgins Decree established a commission to allocate water in the lower Sevier River. The 1936 Cox Decree established allocations for the entire Sevier basin.<ref name="Sevier River UEN"/>
Heavy water use led to the drying up of Sevier Lake as early as 1880; dust blowing off the dry lake bed has become a persistent source of particulate pollution as far as Salt Lake City.<ref>Template:Cite news</ref> However, the river and lake can still fill after major floods. In the especially wet season of 1982–1983, the melting of a record snowpack overwhelmed the reservoir system which had not been designed for flood control. Bridges, roads and diversion structures were washed out, and the DMAD and Gunnison Bend dams were partially breached.<ref name="flooding"/> By May 1984 more than 1.5 million acre feet (1.9 billion m3) of water had flowed into Sevier Lake, temporarily inundating the dry lake bed Template:Convert deep.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Mining, transport and powerEdit
Along with agriculture, the Sevier basin has had a long history of mining and resource extraction, which continues in some areas of the basin today. Coal, rock salts and other minerals have been mined from the Salina area since the 1870s.<ref name="USWP Introduction"/> In 1871 Mormon settlers reportedly found "anthracite coal in almost inexhaustible quantities" in Salina Canyon.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> In 1891 the Sevier Railroad, a branch of the Denver and Rio Grande Western Railroad (D&RGW), reached Salina, and the town soon became the shipping point for both coal and agricultural products from the Sevier Valley. Much of the coal mined in the area is nowadays shipped to the Intermountain Power Plant, which was completed near Delta in 1986. The 1,900 megawatt power station consumes two million tons of coal and draws Template:Convert of cooling water from the Sevier River each year.<ref name="Sevier River System"/><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> In 2017 the Intermountain Power Agency announced it would be converting the plant to natural gas operations.<ref>Template:Cite news</ref>
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Gold was mined at several places along the river starting in the late 19th century. In 1896 the Sevier Railroad was extended to the gold mining area of Belknap and in 1900 tracks were laid through Marysvale Canyon to reach the diggings around Marysvale, with the line thereafter known as the "Marysvale Branch".<ref name="Marysvale Branch">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The boom town of Kimberly in the Tushar Mountains was one of the largest gold mining camps in Utah. Other boom towns of the period included Bullion City, Webster and Alunite, the latter of which produced significant quantities of aluminum ore.<ref name="Piute County history">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Uranium was first discovered in Piute County in 1948.<ref name="Piute County history"/> During the height of the Cold War in the 1950s and 1960s, large amounts of uranium were mined along the upper Sevier River near Marysvale.<ref name="USWP Introduction"/> The Marysvale district was fraught with health and environmental issues since early on; in 1951-52 inspectors in a Marysvale mine found radiation level 1,500 times above what was considered safe.<ref name="Spangler"/> Many of the miners were Navajo people who were often sent to work without any protective clothing or masks.<ref>Template:Cite news</ref> In the following decades, many former uranium miners died of emphysema or various forms of cancer.<ref name="Spangler">Template:Cite news</ref> The state of Utah later spent $500,000 closing down two hundred mines in the district.<ref name="Spangler"/>
Trains stopped running regularly on the Marysvale Branch in 1972, and in 1983 heavy flooding washed out much of the tracks along the Sevier River. That year the Thistle mudslide near Spanish Fork severed the northern end of the line, which was subsequently abandoned by the D&RGW.<ref name="Marysvale Branch"/>
Reservoirs and damsEdit
The Sevier River is extensively dammed and diverted to serve more than Template:Convert of farmland.<ref name="USWP Executive Summary"/> Most of the basin is used for beef production, although there is a major turkey industry in Sanpete County.<ref name="USWP Executive Summary"/> For the purpose of water distribution the basin is divided into upper and lower sections, with the dividing point at Vermillion Diversion Dam near Richfield.<ref name="Sevier River System">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> There are 175 irrigation companies in the Sevier River basin, with 72 of them serving over Template:Convert each.<ref name="USWP Executive Summary"/> The Sevier River Water Users Association is responsible for regulating water use in the river system, and monitors reservoir storage levels, canal diversions and stream flows.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Total water use in the basin is more than 1 million acre feet (1.2 billion m3) annually, with more than 60 percent dedicated to agriculture.<ref name="Sevier River System"/> This figure is higher than the naturally available water supply since most of the water is used more than once.<ref name="USWP Executive Summary"/> Due to the repeated reuse of agricultural return flows, salinity is a chronic issue in the lower Sevier River.<ref name="USWP Executive Summary"/> As annual precipitation tends to vary greatly up to Template:Convert of water can be stored in surface reservoirs, with the largest three – Sevier Bridge, Piute and Otter Creek – accounting for 75 percent of that capacity.<ref name="Sevier River System"/>
Otter Creek ReservoirEdit
Although small reservoirs such as Scipio, Panguitch and Gunnison Bend had been built starting in the 1860s, water demand was so high by the 1890s that planning began for much bigger dams and reservoirs. Otter Creek Reservoir was constructed between 1897 and 1901 by a consortium of ten irrigation companies in the Sevier Valley.<ref name="USWP Introduction"/> The reservoir impounds Otter Creek, a tributary of the East Fork Sevier River, and also stores water diverted from the East Fork through a short canal. It has a storage capacity of Template:Convert.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Piute ReservoirEdit
Piute Dam was constructed on the Upper Sevier River between 1908 and 1914, forming Piute Reservoir. The reservoir holds up to Template:Convert of water for use in the Sevier Valley.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Water released from Piute Reservoir is diverted at the Sevier Valley Diversion Dam into the Template:Convert-long Sevier Valley-Piute Canal. It is one of the longest man-made waterways in Utah, irrigating Template:Convert along the western side of the valley in Sevier and Sanpete Counties.<ref name="Sevier River System"/>
Sevier Bridge ReservoirEdit
By the early 1900s, the Lower Sevier often dried up below the Juab area, both due to heavy irrigation in the Upper Sevier and a series of drought years. The Deseret Irrigation Company began constructing Yuba Dam at the Sevier Bridge site in 1902, and work continued through 1907. "Nearly every available man and boy in Deseret, Oasis and Hinckley worked at the dam."<ref name="USWP Introduction"/> The dam was originally completed to a height of Template:Convert, and was raised to Template:Convert between 1913 and 1916.<ref name="USWP Introduction"/> Water rights were sold to three other irrigation districts in the Lower Sevier.<ref name="USWP Introduction"/> Sevier Bridge Reservoir has a capacity of Template:Convert, making it the fourth biggest man-made lake in Utah.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
RecreationEdit
Parts of the Upper Sevier, and its higher tributaries and feeder lakes, are good trout waters, particularly in National Forest lands.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The basin has native cutthroat trout, and many streams contain introduced brook, brown and rainbow trout. A Template:Convert stretch of the East Fork in Black Canyon, above Tropic Reservoir, is classified as a Blue Ribbon trout fishery. This stretch was restored by the Utah Division of Wildlife Resources between 1992 and 2006 due to damage from the 1983 flooding.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Marysvale Canyon is also known for its trout during the non-irrigation (low water) season, being located in the tailwater of Piute Dam.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Fishing is generally poor downstream of Marysvale Canyon due to the warm silty water, numerous diversion structures and degradation of riparian habitat.<ref name="USWP Wildlife"/>
Whitewater rafting is available on the Sevier through Marysvale Canyon.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>