Publications

Understanding recent historical and projected trends in precipitation and temperature in the Colorado River Basin, and estimating what the projected changes in these climate parameters may mean for groundwater resources in the region, is important for water managers and policymakers to sustainably manage water resources in the basin. Historical (1896–2019) precipitation and temperature...

Assessing chemical loading from streams in remote, difficult-to-access watersheds is challenging. The Grand Canyon area in northern Arizona, an international tourist destination and sacred place for many Native Americans, is characterized by broad plateaus divided by canyons as much as two-thousand meters deep and hosts some of the highest-grade uranium deposits in the U.S. From 2015...

In the arid landscape south of the Grand Canyon, natural springs and seeps are a critical resource for endemic species and Native American tribes. Groundwater is potentially threatened by expanding populations, visitations, and mineral extraction activities. Environmental tracers including noble gases, stable isotopes of hydrogen and oxygen in water, tritium, and carbon-14 were used to

Springs and groundwater seeps along the South Rim of the Grand Canyon serve an important function for the region’s ecosystems, residents (both human and wild animal), and economy. However, these springs and seeps are potentially vulnerable to contamination, increased groundwater extraction, or reduced recharge due to climate change. Protection of South Rim groundwater resources requires...

Better characterization of the geochemical evolution of groundwater south of Grand Canyon, Arizona (USA), is needed to understand natural conditions and assess potential effects from breccia-pipe uranium mining in the region. Geochemical signatures of groundwater at 28 sampling locations were evaluated; baseline concentrations for select trace elements (As, B, Ba, Cr, Li, Mo, Rb, Se, Sr...

Radon (Rnair) was monitored in open air in publicly accessible areas surrounding the Pinenut uranium (U) mine during mining and reclamation activities in 2015–16 to address concerns about mining related effects to areas surrounding Grand Canyon National Park (GCNP) in Arizona, USA. During July 2015, Rnair concentrations associated with the ore storage pile monitoring site were larger...

Floods affected approximately two billion people around the world from 1998–2017, causing over 142,000 fatalities and over 656 billion U.S. dollars in economic losses. Flood data, such as the extent of inundation and peak flood stage, are needed to define the environmental, economic, and social impacts of significant flood events. Ground-based global positioning system (GPS) surveys of...

This is the third and final report in a series that describe the groundwater resources of the Hualapai Indian Reservation. These reports document the findings of a comprehensive groundwater study conducted on the reservation and adjacent areas from 2015 through 2018 by the U.S. Geological Survey in cooperation with the Bureau of Reclamation. The first report described the hydrologic...

This is a summary chapter of a multichapter volume that includes a brief description of the study area and descriptions of the hydrogeologic framework, numerical groundwater-flow model, and estimates of simulated changes to groundwater levels of the Truxton aquifer.

This study was developed to assess if groundwater from the western Hualapai Plateau could be used to supply developments in the Grand Canyon West area of the Hualapai Indian Reservation and to collect hydrogeologic data for future use in a numerical groundwater model for the reservation. Ground-based geophysical surveys; existing well, spring, and other hydrogeologic information from...

The geology of northwestern Arizona is prominently displayed on the canyon and cliff walls that compose the high-desert landscape of the Hualapai Plateau and that border the Truxton basin. The Truxton basin is a small topographic basin filled with Quaternary and Tertiary deposits and volcanic rock (about 1,600 feet thick near Truxton, Arizona) that overlie Proterozoic crystalline...

The volume of available groundwater and the effect of groundwater pumping in an alluvial basin is influenced in part by the shape and depth of the basin boundary, which commonly consists of low-permeability bedrock. To better understand the shape and depth of basin fill in the Truxton valley in Arizona, new gravity data were collected at 149 stations in 2017 and 2018. These data...