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Changes in sand storage in the Colorado River in Grand Canyon National Park from July 2017 through June 2020

Changes in the quantity of sand stored within river segments can affect aquatic and riparian habitat, archeological resources, and recreation. Since summer to fall of 2002, gaging stations on the Colorado River in Grand Canyon National Park and on its major tributaries and selected lesser tributaries have measured the mass of sand transported past each station, which allows for changes in the mass
Ronald E. Griffiths, David J. Topping, Joel A. Unema

Resurvey of cross sections on the Yampa and Little Snake Rivers in Lily and Deerlodge Parks, Colorado

Resurveys of seven geomorphologic cross sections located in the Lily Park and Deerlodge Park, Colorado, reaches of the Yampa and Little Snake Rivers were conducted in October 2017. These cross sections extend from Lily Park, at the confluence of the two rivers, to Deerlodge Park within Dinosaur National Monument. Four cross sections were first surveyed in 1983 and then resurveyed in 1997. The rema
Ronald E. Griffiths, David J. Topping, Christina Leonard, Joel A. Unema

Anthropogenic influence on groundwater geochemistry in Horn Creek Watershed near the Orphan Mine in Grand Canyon National Park, Arizona, USA

Breccia pipe deposits of the Grand Canyon region contain ore grade copper and uranium. Horn Creek is located near the Orphan Mine mineralized breccia pipe deposit and groundwater emerging from the bedrock in the headwaters of Horn Creek has the highest uranium concentrations in the region. Uranium decreases an order of magnitude between the groundwater at the top of the watershed and the groundwat
Kimberly R. Beisner, Collin Davidson, Fred D. Tillman

Hydrologic framework and characterization of the Little Colorado River alluvial aquifer near Leupp, Arizona

The Little Colorado River alluvial aquifer near Leupp, Arizona, was investigated as a possible source of irrigation water for the Leupp and Birdsprings Chapters of the Navajo Nation. The physical, chemical, and hydraulic characteristics of the alluvial aquifer were studied using geophysical surveys, installation of observation wells, water-level measurements, chemical analyses, groundwater pumping
Jon P. Mason, Jeffrey R. Kennedy, Jamie P. Macy, Bruce Gungle

Utilizing anthropogenic compounds and geochemical tracers to identify preferential structurally controlled groundwater pathways influencing springs in Grand Canyon National Park, Arizona, USA

Study region: This study focuses on the Colorado River watershed in the area along the South Rim of the Grand Canyon. Study focus: This study utilizes anthropogenic chemical tracers to investigate the fate of treated wastewater effluent discharged within Grand Canyon National Park. Anthropogenic chemical tracers were used to discern preferential structurally controlled pathways in a complex region
Kimberly R. Beisner, Nicholas V. Paretti, Jeramy Jasmann, Larry Barber

Arsenic in groundwater in the Grand Canyon region and an evaluation of potential pathways for arsenic contamination of groundwater from breccia pipe uranium mining

The Grand Canyon in northern Arizona is an international tourist destination, a home or sacred place to many Native Americans, and hosts some of the highest-grade uranium deposits in the United States. Although potential contamination of water resources by uranium from mining activities is a concern, other elements commonly associated with these uranium deposits may pose a greater risk to human po
Fred D. Tillman, Kimberly R. Beisner, Casey J.R. Jones

Salinity and total dissolved solids measurements for natural waters: An overview and a new salinity method based on specific conductance and water type

The total concentration of dissolved constituents in water is routinely quantified by measurements of salinity or total dissolved solids (TDS). However, salinity and TDS are operationally defined by their analytical methods and are not equivalent for most waters. Furthermore, multiple methods are available to determine salinity and TDS, and these methods have inherent differences. TDS is defined a
R. Blaine McCleskey, Charles A. Cravotta, Matthew P. Miller, Fred D. Tillman, Paul Stackelberg, Katherine J. Knierim, Daniel Wise

Heavy: Software for forward-modeling gravity change from MODFLOW output

Fortran software, named Heavy, was developed to simulate gravity change due to water-storage change in MODFLOW groundwater models. Heavy is compatible with MODFLOW-2005 and MODFLOW-NWT models using the layer-property flow or upstream weighting packages. All of the necessary information for the gravity calculation—the geometry of the model cells, the storage coefficient, and head change—is present
Jeffrey Kennedy, Joshua Larsen

Measuring basin-scale aquifer storage change and mapping specific yield in Albuquerque, New Mexico, USA, with repeat microgravity data

Study RegionThe groundwater basin underlying the City of Albuquerque, New Mexico, USA.Study FocusThe study focuses on changes in groundwater storage and how those changes relate to groundwater-level changes. Groundwater storage change was measured using repeat microgravity at 35 stations from 2016 to 2021. Usually, storage is monitored by converting groundwater-level changes to storage changes usi
Jeffrey Kennedy, Meghan T. Bell

Benchmarking high-resolution hydrologic model performance of long-term retrospective streamflow simulations in the contiguous United States

Because use of high-resolution hydrologic models is becoming more widespread and estimates are made over large domains, there is a pressing need for systematic evaluation of their performance. Most evaluation efforts to date have focused on smaller basins that have been relatively undisturbed by human activity, but there is also a need to benchmark model performance more comprehensively, including
Erin Towler, Sydney Foks, Aubrey L Dugger, Jesse E. Dickinson, Hedeff I. Essaid, David Gochis, Roland J. Viger, Yongxin Zhang

Aquifer storage change, 2018–2021, in the Big Chino Subbasin, Yavapai County, Arizona

This report updates groundwater-storage and groundwater-level trends presented in U.S. Geological Survey (USGS) Scientific Investigations Report 2019–5060, in the Big Chino Subbasin, Yavapai County, Arizona. This earlier geophysical investigation of groundwater-storage change in the Big Chino Subbasin was conducted by the U.S. Geological Survey, in cooperation with the City of Prescott, the Town o
Jeffrey R. Kennedy

Determining seasonal recharge, storage changes, and specific yield using repeat microgravity and water-level measurements in the Mesilla Basin alluvial aquifer, New Mexico, 2016–2018

Increasing water demand and multi-year drought conditions within the Mesilla/Conejos-Médanos Basin near the New Mexico-Texas- Chihuahua border have resulted in diminished surface-water supplies and increased groundwater withdrawals. To better understand recharge to the shallow aquifer, the spatial and temporal groundwater storage changes, and the variability of specific yield (Sy) in the aquifer,
Andrew J. Robertson, Jeffrey Kennedy, Libby M. Kahler, Meghan T. Bell, Erek H. Fuchs, Alex Rinehart, Irene Fernald