Geology topics

Research about Humboldt River basin

Source-linked reports with geographic coverage including Humboldt River basin.

17 recordsLinked to original sources

USGS2020

Analysis of aquifer framework and hydraulic properties of Lovelock Valley, Lovelock, Nevada

Multiple aquifer tests were conducted in Lovelock, Nevada, to determine hydraulic conductivity and storage properties to be used with the numerical groundwater flow model of the lower Humboldt River Basin while accounting for the influence of surface features with a modeling component. The numerical model will ultimately provide the Nevada Division of Water Resources (NDWR) with information regarding the impacts of groundwater pumping on the Humboldt River, allowing the Nevada State Engineer to make informed decisions in the conjunctive management of the State’s groundwater and surface water resources. Seven slug tests, one single-well pumping test, and two multi-well pumping tests were conducted to evaluate properties of shallow Lahontan clays and silts; shallow fluvial deposits; and coarser, water-bearing deposits of the younger alluvium. Aquifer tests were conducted between March 2017 and April 2018. Results indicate aquifers in the Lovelock Valley have transmissivity ranging between 0.0001 and 95,000 feet squared per day (ft 2 /day). The results of these tests provide constraints on hydraulic properties for a numerical groundwater flow model being developed for a capture study in the lower Humboldt River Basin.

Nevada↗

USGS2003

Leaching, transport, and methylation of mercury in and around abandoned mercury mines in the Humboldt River basin and surrounding areas, Nevada

Mercury and methylmercury concentrations were measured in mine wastes, stream sediments, and stream waters collected both proximal and distal from abandoned mercury mines to evaluate mercury contamination and mercury methylation in the Humboldt River system. The climate in the study area is arid, and due to the lack of mine-water runoff, water-leaching laboratory experiments were used to evaluate the potential of mine wastes to release mercury. Mine-waste calcine contains mercury concentrations as high as 14,000 µg/g. Stream-sediment samples collected within 1 km of the mercury mines studied contain mercury concentrations as high as 170 µg/g, but sediments collected from the Humboldt River and regional baseline sites have much lower mercury contents, less than 0.44 µg/g. Similarly, methylmercury concentrations in mine-waste calcine are locally as high as 96 ng/g, but methylmercury contents in stream sediments collected downstream from the mines and from the Humboldt River are lower (<0.05–0.95 ng/g). Stream-water samples collected below two mines studied contain mercury concentrations ranging from 6 to 2,000 ng/L, whereas mercury contents in Humboldt River and Rye Patch Reservoir water were generally lower, ranging from 2.1 to 9.0 ng/L. Methylmercury concentrations in Humboldt River system water were the lowest in this study (<0.02– 0.27 ng/L). Although mercury and methylmercury concentrations were elevated in some mine-waste calcine and mercury concentrations were locally high in mine-waste leachate samples, data show significant dilution of mercury and lower mercury methylation down gradient from the mines, especially in the sediments and water collected from the Humboldt River, which is more than 8 km from any mercury mines. Data show only minor, local transference of mercury and methylmercury from mine-waste calcine to stream sediment, and then onto the water column, and indicate little transference of mercury from the mine sites to the Humboldt River system.

Nevada↗

USGS2003

Historic mills and mill tailings as potential sources of contamination in and near the Humboldt River basin, northern Nevada

Reconnaissance field studies of 40 mining districts in and near the Humboldt River basin have identified 83 mills and associated tailings impoundments and several other kinds of mineral-processing facilities (smelters, mercury retorts, heap-leach pads) related to historic mining. The majority of the mills and tailings sites are not recorded in the literature. All tailings impoundments show evidence of substantial amounts of erosion. At least 11 tailings dams were breached by flood waters, carrying fluvial tailings 1 to 15 km down canyons and across alluvial fans. Most of the tailings sites are dry most of the year, but some are near streams. Tailings that are wet for part of the year do not appear to be reacting significantly with those waters because physical factors such as clay layers and hard-pan cement appear to limit permeability and release of metals to surface waters. The major impact of mill tailings on surface- water quality may be brief flushes of runoff during storm events that carry acid and metals released from soluble mineral crusts. Small ephemeral ponds and puddles that tend to collect in trenches and low areas on tailings impoundments tend to be acidic and extremely enriched in metals, in part through cycles of evaporation. Ponded water that is rich in salts and metals could be acutely toxic to unsuspecting animals. Rare extreme storms have the potential to cause catastrophic failure of tailings impoundments, carry away metals in stormwaters, and transport tailings as debris flows for 1 to 15 km. In most situations these stormwaters and transported tailings could impact wildlife but probably would impact few or no people or domes-tic water wells. Because all identified historic tailings sites are several kilometers or more from the Humboldt River and major tributaries, tailings probably have no measurable impact on water quality in the main stem of the Humboldt River.

Nevada↗

USGS2003

Overview of mine drainage geochemistry at historical mines, Humboldt River basin and adjacent mining areas, Nevada

Reconnaissance hydrogeochemical studies of the Humboldt River basin and adjacent areas of northern Nevada have identified local sources of acidic waters generated by historical mine workings and mine waste. The mine-related acidic waters are rare and generally flow less than a kilometer before being neutralized by natural processes. Where waters have a pH of less than about 3, particularly in the presence of sulfide minerals, the waters take on high to extremely high concentrations of many potentially toxic metals. The processes that create these acidic, metal-rich waters in Nevada are the same as for other parts of the world, but the scale of transport and the fate of metals are much more localized because of the ubiquitous presence of caliche soils. Acid mine drainage is rare in historical mining districts of northern Nevada, and the volume of drainage rarely exceeds about 20 gpm. My findings are in close agreement with those of Price and others (1995) who estimated that less than 0.05 percent of inactive and abandoned mines in Nevada are likely to be a concern for acid mine drainage. Most historical mining districts have no draining mines. Only in two districts (Hilltop and National) does water affected by mining flow into streams of significant size and length (more than 8 km). Water quality in even the worst cases is naturally attenuated to meet water-quality standards within about 1 km of the source. Only a few historical mines release acidic water with elevated metal concentrations to small streams that reach the Humboldt River, and these contaminants and are not detectable in the Humboldt. These reconnaissance studies offer encouraging evidence that abandoned mines in Nevada create only minimal and local water-quality problems. Natural attenuation processes are sufficient to compensate for these relatively small sources of contamination. These results may provide useful analogs for future mining in the Humboldt River basin, but attention must be given to matters of scale: larger volumes of waste and larger volumes of water could easily overwhelm the delicate balance of natural attenuation described here.

Nevada↗

USGS2003