South Lahontan

Hydroclimate response of spring ecosystems to a two‐stage Younger Dryas event in western North America

Nature Portfolio (Springer Nature) | May 5th, 2022

The Younger Dryas (YD) climate event is the preeminent example of abrupt climate change in the recent geologic past. Climate conditions during the YD were spatially compl

The Younger Dryas (YD) climate event is the preeminent example of abrupt climate change in the recent geologic past. Climate conditions during the YD were spatially complex, and high-resolution sediment cores in the North Atlantic, western Europe, and East Asia have revealed it unfolded in two distinct stages, including an initial stable climatic period between ~ 12.9 and 12.2 ka associated with a weakened Atlantic Meridional Overturning Circulation (AMOC) and a second phase characterized by variable conditions until 11.7 ka as the AMOC recovered. Decades of investigations into the climate of western North America during the YD have failed to identify this stepped phenomenon. Here we present hydroclimate data from paleospring deposits in Death Valley National Park (California, USA) that demonstrate unequivocal evidence of two-stage partitioning within the YD event. High groundwater levels supported persistent and long-lived spring ecosystems between ~ 13.0 and 12.2 ka, which were immediately replaced by alternating wet and dry environments until ~ 11.8 ka. These results establish the mid-YD climate transition extended into western North America at approximately the same time it was recorded by hydrologic systems elsewhere in the Northern Hemisphere and show that even short-lived changes in the AMOC can have profound consequences for ecosystems worldwide.

Hydroclimate volatility on a warming Earth

Nature Portfolio (Springer Nature) | January 9th, 2025

Hydrogeologic Conceptual Model for the Owens Valley Groundwater Basin (6-12), Inyo and Mono Counties

Inyo County Water Department (ICWD) | January 27th, 2016

This report provides a hydrogeologic conceptual model of the Owens Valley Groundwater Basin (OVGB) compiled from numerous sources including the US Geological Survey, Los

This report provides a hydrogeologic conceptual model of the Owens Valley Groundwater Basin (OVGB) compiled from numerous sources including the US Geological Survey, Los Angeles Department of Water and Power, Inyo and Mono Counties, the California Department of Fish and Wildlife, and the California Department of Water Resources. Because groundwater and surface water systems are linked, both systems are described here, prefaced by a summary of the physical setting of the OVGB.

Hydrogeologic Evaluation - Proposed Regional Recharge and Recovery Project Mojave River Chanel Area

Mojave Water Agency (MWA) | August 15th, 2008

Provided in this report are the findings and conclusions of our hydrogeologic evaluation of the proposed Regional Recharge and Recovery Project (known herein as the R3 Pr

Provided in this report are the findings and conclusions of our hydrogeologic evaluation of the proposed Regional Recharge and Recovery Project (known herein as the R3 Project) that is to be located along/near the channel of the Mojave River in the vicinity of Hesperia, San Bernardino County, California. The R3 Project is to ultimately involve the construction of a put-and-take series of wells and transmission pipelines and the use of existing and proposed artificial spreading basins (mainly along the upper reach of the Mojave River).

Hydrogeologic evaluation and numerical simulation of the Death Valley regional ground-water flow system, Nevada and California

U.S. Geological Survey (USGS) | July 1st, 1997

Hydrogeology of Lower Amargosa Valley and Groundwater Discharge to the Amargosa Wild and Scenic River, Inyo and San Bernardino Counties, California, and Adjacent Areas in Nye and Clark Counties, Nevada

U.S. Geological Survey (USGS) | February 7th, 2019

In 2009, Congress designated certain reaches of the Amargosa River in Inyo County, California between the town of Shoshone and Dumont Dunes as a Wild and Scenic River. As

In 2009, Congress designated certain reaches of the Amargosa River in Inyo County, California between the town of Shoshone and Dumont Dunes as a Wild and Scenic River. As part of the management of the Amargosa Wild and Scenic River, the Bureau of Land Management cooperated with the U.S. Geological Survey to assess the surface and groundwater resources of the Tecopa basin. Groundwater is the primary source of water to the perennial reaches of the Amargosa River. The U.S. Geological Survey studied the surface and groundwater systems in the basin, and assessed the sources and volume of groundwater discharging into the perennial reaches of the Amargosa Wild and Scenic River. The springs within the Tecopa basin (and the greater Lower Amargosa Valley Hydrographic Area) can be generally grouped by spring type and geographic location. There are four types of groundwater discharge points in the Tecopa basin—regional carbonate-rock springs and seeps, Tecopa Hills springs and seeps, thermal springs and seeps, and Amargosa Canyon hillslope springs and seeps. Results of chemical analysis indicate that water from all of these springs in the Lower Amargosa Valley and particularly in the Tecopa basin, is sourced in the carbonate-rock aquifer, with a local component of recharge. Groundwater is recharged in the Spring Mountains and moves through and around the Nopah and Resting Spring Ranges and into the Tecopa basin. A small (less than 1 cubic foot per second [ft3/s] or 500 acre‑feet per year) component of flow from the Amargosa Desert moves through the river channel alluvium and basin fill from the north. The location and type of spring appear to be controlled by the geology and geologic structure of the Lower Amargosa Valley. The regional springs (such as Shoshone and Borax Springs) and associated seeps tend to occur along the west side of the basin whereas other carbonate-rock aquifer springs discharge from adjacent mountain ranges, such as the Resting Spring Range, and as a result of low-permeability barriers, such as the Tecopa Hills. The thermal springs and seeps discharge from an area near the town of Tecopa, California. The Amargosa Canyon hillslope springs and seeps discharge directly into the river. Salt-crusted soils adjacent to the river indicate additional areas of diffuse discharge where groundwater is being evaporated. Perennial flow in the main channel of the Amargosa River appears to originate in an area of thermal springs near Tecopa. Persistent groundwater-fed pools begin to appear along the river channel just to the south of the Tecopa Hills. Flow between these pools is evident, but difficult to measure. During the synoptic seepage measurement survey in February 2014, flow in the Amargosa River at the Tecopa streamgage (U.S. Geological Survey site 10251300, Amargosa River at Tecopa, California) was approximately 1 ft3/s. Just to the south of the Tecopa streamgage, a line of cooler water springs (the Amargosa Canyon hillslope springs) emerges east of the river channel and continues for approximately 1 mile along the Amargosa Canyon wall. At the end of the spring reach, the flow in the river increased to just over 4 ft3/s. Flow then decreased to approximately 3 ft3/s at the confluence of Willow Creek, approximately 3.5 miles downstream. Downstream from the confluence of Willow Creek, the river consistently loses water and was dry just north of Dumont Dunes during the February 2014 synoptic seepage measurement survey.

Hydrologic and geologic controls on groundwater recharge along the Mojave River floodplain aquifer

San Diego State University (SDSU) | July 12th, 2016

Groundwater is an extremely important water source for the state of California, particularly in arid regions such as the Mojave Desert. Over-pumping in the Mojave River G

Groundwater is an extremely important water source for the state of California, particularly in arid regions such as the Mojave Desert. Over-pumping in the Mojave River Groundwater Basin has resulted in basin overdraft, and water is imported and artificially recharged to mitigate these effects. Though artificial recharge has helped maintain groundwater-levels, storm flow runoff in the Mojave River is still important and is responsible for more than 80% of natural recharge to the Mojave River floodplain aquifer, the most productive aquifer in the basin. For this reason, it is important to understand processes governing recharge quantity and spatial distribution. The objectives of this study were to determine 1) how total stormflow volume, duration, and peak stormflow control the amount of groundwater recharge at a given distance downstream of where the Mojave River enters the floodplain aquifer, and 2) how geologically-mediated features, including depth to the water table and aquifer and channel morphology, control the amount and spatial distribution of recharge. Univariate and multivariate regressions were run using hydrologic and geologic variables to predict observed water-level rise for ten aquifer segments along the Mojave River, during 6 stormflow events. Results were compared to determine dominant controls on transmission loss and corresponding water-level rise for each segment. Of the two methods used to estimate water-level rise, inverse distance weighting (IDW) results were determined to give a more accurate representation of the system. IDW results indicate that magnitude is the dominant predictor of water-level rise for the entire floodplain aquifer. On a segment basis, recharge to the floodplain aquifer was controlled by different variables going downstream: pre-event water-level (segment 1) near the headwaters, duration (segment 4) and magnitude (segments 5-7) in the middle portion of the river, and peak flow (segments 8-10) towards the outflow of the river. Aquifer and channel variables were statistically significant for 5 out of 6 events. Additionally, a water balance was constructed for the three gaged reaches of the river. By combining reaches 1 & 2, the water budget was balanced with an error within 13% for all but one event. Transmission loss was the largest contributor to groundwater recharge along all three reaches, with artificial recharge and lateral inflow contributing only a very small portion to total observed recharge. Contrary to expectation, the largest water-level rise did not occur in the upstream reaches, where recharge was limited by a combination of channel width, aquifer width, and high pre-event water-levels.

Hydrologic and hydrochemical framework, south-central Great Basin, Nevada-California, with special reference to the Nevada Test Site

U.S. Geological Survey (USGS) | July 1st, 1975

Intensely fractured Precambrian and Paleozoic carbonate and clastic rocks and block-faulted Cenozoic volcanic and sedimentary strata in the Nevada Test Site are divided

Intensely fractured Precambrian and Paleozoic carbonate and clastic rocks and block-faulted Cenozoic volcanic and sedimentary strata in the Nevada Test Site are divided into 10 hydrogeologic units. Three of these the lower clastic aquitard, the lower carbonate aquifer, and the tuff aquitard control the regional movement of ground water. The coefficients of fracture transmissibility of these rocks are, respectively, less than 1,000, 1,000 to 900,000, and less than 200 gallons per day per foot; interstitial permeability is negligible. Solution caverns are locally present in the carbonate aquifer, but regional movement of water is controlled by variations in fracture transmissibility and by structural juxtaposition of the aquifer and the lower clastic aquitard. Water circulates freely to depths of at least 1,500 feet beneath the top of the aquifer and up to 4,200 feet below land surface. Synthesis of hydrogeologic, hydrochemical, and isotopic data suggests that an area of at least 4,500 square miles (including 10 intermontane valleys) is hydraulically integrated into one ground-water basin, the Ash Meadows basin, by interbasin movement of ground water through the widespread carbonate aquifer. Discharge from this basin a minimum of about 17,000 acre-feet annually occurs along a fault-controlled spring line at Ash Meadows in east-central Amargosa Desert. Intrabasin movement of water between Cenozoic aquifers and the lower carbonate aquifer is controlled by the tuff aquitard, the basal Cenozoic hydrogeologic unit. Such movement significantly influences the chemistry of water in the carbonate aquifer. Ground-water velocity through the tuff aquitard in Yucca Flat is less than 1 foot per year. Velocity through the lower carbonate aquifer ranges from an estimated 0.02 to 200 feet per day, depending upon geographic position within the flow system. Within the Nevada Test Site, ground water moves southward and southwestward toward Ash Meadows.

Hydrologic Components for Model Development, Chapter C of Death Valley Regional Ground-Water Flow System, Nevada and California—Hydrogeologic Framework and Transient Ground-Water Flow Model

U.S. Geological Survey (USGS) | July 1st, 2004

Hydrology of the Valley-Fill and Carbonate-Rock Reservoir, Pahrump Valley, Nevada-California

U.S. Geological Survey (USGS) | July 1st, 1967

This is the second appraisal of the water supply of Pahrump Valley, made 15 years after the first cooperative study. In the first report the average recharge was estima

This is the second appraisal of the water supply of Pahrump Valley, made 15 years after the first cooperative study. In the first report the average recharge was estimated to be 23,000 acre-feet per year, only 1,000 acre-feet r^ore than the estimate made in this report. All this recharge was considered to be available for development. Because of the difficulty in salvaging the subsurface outflow from the deep carbonate-rock reservoil', this report concludes that the perennial yield may be only 12,000 acre-feet. In 1875, Bennetts and Manse Springs reportedly discharged a total of nearly 10,000 acre-feet of water from the valley-fill reservoir. After the construction of several flowing wells in 1910, the spring discharge began to decline. In the mid-1940's many irrigation wells were drilled, and large-capacity pumps were installed. During the 4-year period of this study (1959-62), the net pumping draft averaged about 25,000 acre-feet per year, or about twice the estimated yield. In 1962 Bennetts Spring was dry, and the discharge from Marse Spring was only 1,400 acre-feet. During the period February 1959-February 1962, pumping caused an estimated storage depletion of 45,000 acre-feet, or 15,000 acre-feet per year. If the overdraft is maintained, depletion of stored water will continue and pumping costs will increase. Water levels in the vicinity of the Pahrump, Manse, and Fowler Ranches declined more than 10 feet in response to the pumping during this period, and they can be expected to continue to decline at the projected rate of more than 3 feet per year. The chemical quality of the pumped water has been satisfactory for irrigation and domestic use. Recycling of water pumped for irrigation, however, could result in deterioration of the water quality with time.