Arizona Water Science Center
Findings and lessons learned from the assessment of the Mexico-United States transboundary San Pedro and Santa Cruz aquifers: The utility of social science in applied hydrologic research
Study RegionThis study region encompasses the Transboundary San Pedro and Santa Cruz aquifers which are shared between the states of Sonora (Mexico) and Arizona (US). Special regional considerations include a semi-arid climate, basin-fill aquifers with predominantly montane recharge areas, economic drivers in the mining, trade, and military...Callegary, James B.; Megdal, Sharon B.; Tapia Villaseñor, Elia María; Petersen-Perlman, Jacob D.; Minjárez Sosa, Ismael; Monreal, R.; Gray, F.; Grijalva Noriega, Francisco
Assessment of environmental flows in the middle Verde River watershed, Arizona
This report summarizes analyses of middle Verde River watershed environmental flows detailed in U.S. Geological Survey Scientific Investigations Report 2017-5100, “Preliminary synthesis and assessment of environmental flows in the middle Verde River watershed, Arizona," by N.V. Paretti, A.M.D. Brasher, S.L. Pearlstein, D.M. Skow, B. Gungle, and B....Gungle, Bruce W.; Paretti, Nicholas V.
Changes in Earth’s gravity reveal changes in groundwater storage
Changes in the amount of water stored in underground aquifers cause small changes in Earth’s gravitational field. The U.S. Geological Survey’s Southwest Gravity Program has developed methods for measuring terrestrial gravity changes with part-per-billion precision. The measurements allow scientists to map changes in groundwater storage and to...Kennedy, Jeffrey R.
Conceptual and numerical models of dissolved solids in the Colorado River, Hoover Dam to Imperial Dam, and Parker Dam to Imperial Dam, Arizona, California, and Nevada
Conceptual and numerical models were developed to understand and simulate monthly flow-weighted dissolved-solids concentrations in the Colorado River at Imperial Dam. The ability to simulate dissolved-solids concentrations at this location will help the Bureau of Reclamation satisfy the binational agreement on the volume and salinity of Colorado...Anning, David W.; Coes, Alissa L.; Mason, Jon P.
Effect of spatial and temporal scale on simulated groundwater recharge investigations
Hydrologic model input datasets such as climate, land use, elevation, soil, and geology information are available in a range of scales for use in water resources investigations. Smaller spatial and temporal scale input data allow groundwater recharge models to simulate more physically realistic processes and presumably result in more accurate...Tillman, Fred; Pruitt, Tom; Gangopadhyay, Subhrendu
Brackish groundwater and its potential as a resource in the southwestern United States
Secure, reliable, and sustainable water resources are fundamental to food production, energy independence, and the health of humans and ecosystems. But the large-scale development of fresh groundwater resources has stressed aquifers in some areas, causing declines in the amount of groundwater in storage and decreases in discharge to surface-water...Anning, David W.; Beisner, Kimberly R.; Paul, Angela P.; Stanton, Jennifer S.; Thiros, Susan A.
Geochemical characterization and modeling of regional groundwater contributing to the Verde River, Arizona between Mormon Pocket and the USGS Clarkdale gage
We use synoptic surveys of stream discharge, stable isotopes, and dissolved noble gases to identify the source of groundwater discharge to the Verde River in central Arizona. The Verde River more than doubles in discharge in Mormon Pocket over a 1.4 km distance that includes three discrete locations of visible spring input to the river and other...Beisner, Kimberly R.; Gardner, W. Payton; Hunt, Andrew G.
Managing salinity in Upper Colorado River Basin streams: Selecting catchments for sediment control efforts using watershed characteristics and random forests models
Elevated concentrations of dissolved-solids (salinity) including calcium, sodium, sulfate, and chloride, among others, in the Colorado River cause substantial problems for its water users. Previous efforts to reduce dissolved solids in upper Colorado River basin (UCRB) streams often focused on reducing suspended-sediment transport to streams, but...Tillman, Fred; Anning, David W.; Heilman, Julian A.; Buto, Susan G.; Miller, Matthew P.
Preliminary synthesis and assessment of environmental flows in the middle Verde River watershed, Arizona
A 3-year study was undertaken to evaluate the suitability of the available modeling tools for characterizing environmental flows in the middle Verde River watershed of central Arizona, describe riparian vegetation throughout the watershed, and estimate sediment mobilization in the river. Existing data on fish and macroinvertebrates were analyzed...Paretti, Nicholas V.; Brasher, Anne M. D.; Pearlstein, Susanna L.; Skow, Dena M.; Gungle, Bruce W.; Garner, Bradley D.
Assessment of geochemical and hydrologic conditions near Old Yuma Mine in Saguaro National Park, Arizona, 2014–17
The Old Yuma Mine is an abandoned copper, lead, zinc, silver, and gold mine located within the boundaries of Saguaro National Park, Tucson Mountain District, Arizona. This study analyzed the geochemistry of sediments associated with the Old Yuma Mine and assessed hydrologic and geochemical conditions of groundwater to evaluate the area surrounding...Beisner, Kimberly R.; Gray, Floyd
Collection methods and quality assessment for Escherichia coli, water quality, and microbial source tracking data within Tumacácori National Historical Park and the upper Santa Cruz River, Arizona, 2015-16
Tumacácori National Historical Park protects the culturally important Mission, San José de Tumacácori, while also managing a portion of the ecologically diverse riparian corridor of the Santa Cruz River. This report describes the methods and quality assurance procedures used in the collection of water samples for the analysis of Escherichia...Paretti, Nicholas V.; Coes, Alissa L.; Kephart, Christopher M.; Mayo, Justine
The geomorphic legacy of water and erosion control structures in a semiarid rangeland watershed
Control over water supply and distribution is critical for agriculture in drylands where manipulating surface runoff often serves the dual purpose of erosion control. However, little is known of the geomorphic impacts and legacy effects of rangeland water manipulation infrastructure, especially if not maintained. This study investigated the...Nichols, Mary H.; Magirl, Christopher S.; Sayre, N.F.; Shaw, Jeremy R.