User:Gh006944/Humboldt River

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The Humboldt River is an extensive river drainage system located in north-central Nevada. It extends in a general east-to-west direction from its headwaters in the Jarbidge, Independence, and Ruby Mountains in Elko County, to its terminus in the Humboldt Sink, approximately 225 direct miles away in northwest Churchill County. Most estimates put the Humboldt River at 300 miles (480 km) to 330 miles (530 km) long however, due to the extensive meandering nature of the river, its length may be more closely estimated at 380 miles (612 km). It is located within the Great Basin Watershed and is the third longest river in the watershed behind the Bear River at 355 miles (570 km) and the Sevier River at 325 miles (523 km). The Humboldt River Basin is the largest sub-basin of the Great Basin encompassing an area of 16,840 square miles (43,615 km2). It is the only major river system wholly contained within the state of Nevada.

It is the only natural transportation artery across the Great Basin and has historically provided a route for westward migration. Additionally, two major railroad routes loosely follow its path. Interstate 80 follows the river's course from its source to its mouth. The river is named for the German naturalist Alexander von Humboldt.

Ecology
The Lahontan cutthroat trout (Oncorhynchus clarki henshawi) is an inland subspecies of cutthroat trout endemic to northern Nevada, eastern California, and southern Oregon. In 1970 the U.S. Fish and Wildlife Service (USFWS) listed the Lahontan cutthroat trout (LCT) as “endangered”. In 1975 it reclassified LCT as “threatened” to facilitate management and to allow regulated fishing. Genetic and meristic studies of LCT indicate that the Humboldt River Basin LCT is a unique subspecies of cutthroat trout.

North American beaver (Castor canadensis) seem to have been making a comeback in Elko County possibly due to less fur trapping combined with reduced consumption of riparian willow and other vegetation by cattle. Maggie and Susie Creeks, which enter the Humboldt River near Carlin, have benefited from 20 years of work by ranchers, agencies, mines, and non-profit groups via improvements in grazing techniques and specific projects. A remote sensing project found 107 beaver dams along 20 miles (32 km) of Maggie Creek in 2006, which rose to 271 dams in 2010. Beaver dams are accelerating the recovery of riparian vegetation and widening the riparian zone as they slow the water and collect sediment that used to be lost downstream. In five years, beaver ponds have increased the amount of impounded water on Maggie Creek from 9 miles (14 km) of the stream to 16 miles (26 km). The impounded water is seeping into the ground and raising the water table. Newmont's shallow groundwater monitoring wells along Maggie Creek have shown about a 2-foot (0.6 m) rise over the past 17 years along Maggie Creek. Stream flows are more perennial, making more water available for wildlife and livestock and protecting populations of native trout. Maggie Creek has a Beaver Creek tributary which flows from Beaver Peak in the Tuscarora Mountains.

Environmental Aspects
The Humboldt River and its surrounding areas have raised some concern about the increasing levels of toxic elements such as arsenic and mercury. These elements are showing up in fish and other wildlife that consume the water. The quantity being absorbed by fish specifically is not of concerning levels though. Brumbaugh and May took samples of fish from the south fork of the Humboldt River. They determined mercury levels within the fish were between 0.061 and 0.082 micrograms per gram of flesh. This is well below the EPA's guideline of 0.30 micrograms per gram.