Unified Interior Regions


The Southwest Region includes California, Nevada, and Arizona. The Regional Office, headquartered in Sacramento, provides Center oversight and support, facilitates internal and external collaborations, and works to further USGS strategic science directions.

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Filter Total Items: 140
Date published: April 10, 2017
Status: Active

Spatial and Temporal Distribution of Bacterial Indicators and Microbial Source Tracking within Tumacácori National Historical Park and the Santa Cruz River Watershed

Elevated levels of bacteria have been measured by the USGS, National Park Service, Arizona Department of Environmental Quality (ADEQ), and other agencies, in the Upper Santa Cruz River, including within the reach at Tumacácori National Historical Park (TUMA).  Indicators of pathogens in the river at TUMA are at levels that are of great concern to TUMA personnel responsible for safeguarding two...

Date published: April 10, 2017
Status: Active

Occurrence, fate, transport, and ecological effects of aerially applied herbicides in the effort to control invasive buffelgrass (Pennisetum ciliare syn. Cenchrus ciliaris) in Saguaro National Park

The Sonoran Desert lands that the Saguaro National Park (SAGU) has been tasked to protect are facing an unprecedented threat from buffelgrass (Cenhrus ciliaris), an invasive perennial grass that was added to Arizona’s noxious weed list in 2005. The buffelgrass invasion has been so pervasive that the U.S. Department of Interior issued a declaration in 2010 which highlighted a need for...

Date published: March 29, 2017
Status: Active

C Aquifer Monitoring Program

The Navajo Nation, the City of Flagstaff (COF), and the U.S. Geological Survey (USGS) maintain a cooperative monitoring program with other local and State agencies for groundwater in the C aquifer (Coconino aquifer) in the Little Colorado River Basin. The goal of this program is to determine baseline groundwater conditions in the C aquifer and other water-bearing zones before significant...

Date published: March 15, 2017
Status: Active

Black Mesa Monitoring Program

The U.S. Geological Survey water-monitoring program in the Black Mesa area began in 1971 and provides information about the long-term effects of groundwater withdrawals from the N aquifer for industrial and municipal uses. The monitoring program includes measuring potential recovery in the N aquifer as a result of the reduction in industrial pumpage by Peabody Western Coal Company.

Date published: March 14, 2017
Status: Active

Maricopa County Urban Stormwater Quality

Since 1991, the U.S. Geological Survey (USGS), in cooperation with the Flood Control District of Maricopa County (FCDMC), the city of Phoenix, and the city of Glendale, has been collecting, analyzing, and interpreting urban stormwater information from selected basins throughout the metropolitan Phoenix area. Water-resource managers and policy makers have used this information to determine...

Contacts: Kenneth Fossum
Date published: March 9, 2017
Status: Active

Air Force Plant 44

Industrial activity at Air Force Plant 44 (AFP 44), a manufacturing facility located on property owned by the U.S. Air Force and operated by a major defense contractor, resulted in extensive contamination of groundwater with the industrial solvent trichloroethylene (TCE) and other organic compounds. The sole-source regional aquifer underlying AFP 44 provides potable water for municipal,...

Date published: March 9, 2017
Status: Active

Arizona Water Use

The Arizona Water Use program collects and estimates annual water withdrawals for the categories of irrigation, municipal, mining, thermoelectric-power, and drainage uses. The data for these categories are compiled for the Arizona Department of Water Resources groundwater basins outside of Active Management Areas. 

Contacts: Saeid Tadayon
Date published: February 28, 2017
Status: Active

USGS Data at Risk: Expanding Legacy Data Inventory and Preservation Strategies

As one of the largest and oldest science organizations in the world, USGS has produced more than a century of earth science data, much of which is currently unavailable to the greater scientific community due to inaccessible or obsolescent media, formats, and technology. Tapping this vast wealth of “dark data” requires 1) a complete inventory of legacy data and 2) methods and tools to...

Contacts: Lance Everette, Tara M Bell, Cristiana Falvo
Date published: January 17, 2017

Ecological Drought in Riparian Ecosystems

Drought is killing riparian trees along many rivers in the western United States. The cause can be increasing temperature or decreasing precipitation, flow or water-table elevation. At multiple locations we are relating water availability to physiological measurements of tree survival and water stress, such as ring width, carbon stable isotope ratio and branch hydraulic conductivity. These...

Date published: December 9, 2016
Status: Active

RAMPS: Restoration Assessment & Monitoring Program for the Southwest

The Restoration Assessment and Monitoring Program for the Southwest (RAMPS) seeks to assist U.S. Department of the Interior (DOI) and other land management agencies in developing successful techniques for improving land condition in dryland ecosystems of the southwestern United States. Invasion by non-native species, wildfire, drought, and other disturbances are growing...

Date published: December 3, 2016
Status: Active

Erosion and Invasive Saltcedar

Formation of arroyos in the late 1800s greatly increased erosion across the southwestern United States. Since the 1930s, however, this erosion has decreased, partly because of bank stabilization by introduced saltcedar. With Isleta Pueblo Indian Nation, the Aquatic Systems Branch developed a new sediment dating method using saltcedar tree rings. We applied the method in a landmark study of...

Date published: December 1, 2016
Status: Active

Riparian Ecology

Riparian ecologists in the AS Branch study interactions among flow, channel change, and vegetation along rivers across the western United States and worldwide. Our work focuses on issues relevant to the management of water and public lands, including dam operation, climate change, invasive species, and ecological restoration. Investigations take place on a range of scales. For example,...

Filter Total Items: 240
August 7, 2013

TESNAR Program: CSAs

TESNAR stands for the Technical training in Support of Native American Relations, and is a program run by the USGS to foster cooperation between tribes and the USGS by providing them with the tools and training to manage their tribal resources, such as water. As shown here, training in the Continuous Slope Area Method can help tribes a great deal, by providing data when

Image: Burned Area Near Yarnell, Arizona
July 19, 2013

Burned Area Near Yarnell, Arizona

Burned area within the Yarnell Hill Fire near Yarnell Arizona.

Attribution: Natural Hazards
June 30, 2013

Animal Interactions at Wind Energy Facilities – Bobcat

In this video, a bobcat approached a desert tortoise (a marked female in the study population) that was sleeping on the apron of her burrow. Bobcats are known predators of various life stages of the desert tortoise. In this case, the bobcat bent down to sniff the tortoise, and then touched its paw to the top of the tortoise's shell. The tortoise then moved into an "all-

June 26, 2013

Earth.Science.Art Project

This collaborative project pairs artists from California's Central Coast and San Francisco Bay Area with scientists from the Santa Cruz-based U.S. Geological Survey's Pacific Marine and Coastal Science Center. The artist create work inspired by scientific research.

June 22, 2013

Animal Interactions at Wind Energy Facilities – American Black Bear

This American black bear and cub duo was seen simply investigating a tortoise burrow, and although it is surprising to see a black bear so low in elevation, it isn't impossible. The study site, Mesa, sits at the intersection of multiple ecosystems (Sonoran Desert, Mojave Desert, montane, and coastal sage scrub). Therefore, the bears could have come down from the montane

June 22, 2013

Animal Interactions at Wind Energy Facilities – Coyotes

Coyotes were the second most frequently observed mammalian predator on the trail cameras. Coyotes are considered one of the primary predators of desert tortoises. In this instance, a coyote is passing by a burrow when it suddenly has a change in attention as it is passing by. It then approaches the burrow and sniffs all around the burrow entrance (including the apron and

USGS and US Forest Service staff installing dust monitoring equipment at a uranium mine near Grand Canyon National Park.
May 31, 2013

USGS and US Forest Service staff installing dust monitoring equipment

USGS and US Forest Service staff installing dust monitoring equipment at a uranium mine near Grand Canyon National Park.

Climate change combined with overlapping high-intensity land uses are likely to create conditions detrimental to the recreation economy, wildlife habitat, water availability and other resources in hyper-arid landscapes, or drylands, in the future

Bureau of Land Management truck sprays herbicide in southwestern Idaho as part of a restoration effort. 
December 31, 2012

Truck sprays herbicide in Idaho as part of a restoration effort.

Bureau of Land Management truck sprays herbicide in southwestern Idaho as part of a restoration effort. 

An examination of long-term data for lands managed by the Bureau of Land Management finds that land treatments in the southwestern United States are increasingly large, expensive and related to fire and invasive species control.

December 11, 2012

Streamflow Gaging Station and Measurement on San Pedro River, AZ

USGS employee, Hanna Coy, talks about stream gauging.

A photo of a female mountain bluebird with mistletoe.
November 28, 2012

WERC Mountain Bluebird Eating Mistletoe Berry

A mountain bluebird eats a giant mistletoe berry in an ash tree in Sedona, Arizona (Oak Creek).  These bluebirds, and many other types of birds, rely on mistletoe berries for sustenance. As a result, they also help distribute the mistletoe seeds.

Image: Sandbar growth Grand Canyon following controlled flood
October 31, 2012

Sandbar growth Grand Canyon following controlled flood

Picture showing the increased size of the sandbar after the November 2012 controlled flood from the Glen Canyon Dam. This location is 65 miles downstream from Lees Ferry and the view is looking downstream. These and additional photographs depicting the results of the recent controlled floods can be viewed online.


Image: Sandbar in Grand Canyon
September 30, 2012

Sandbar in Grand Canyon

Picture showing the size of the sandbar before the November 2012 controlled flood from the Glen Canyon Dam. This location is 65 miles downstream from Lees Ferry and the view is looking downstream. These and additional photographs depicting the results of the recent controlled floods can be viewed online.


Filter Total Items: 192
USGS science for a changing world logo
February 15, 2011

Forests should be managed according to their respective, specific fire ecology — not whole-scale fire suppression or one-size-fits-all plans — to optimize forest growth and stabilize carbon storage.

December 12, 2010

The U.S. Geological Survey (USGS) is celebrating the success of three distinguished researchers who are recipients of the Presidential Early Career Award for Scientists and Engineers (PECASE). This award is the highest recognition granted by the United States government to scientists and engineers in the early stages of their research careers.

December 2, 2010

TUCSON, Ariz. -- A new book on the methods and applications of repeat photography that showcases its international usage in monitoring landscape change on five continents has been released. 

November 15, 2010

FLAGSTAFF, Ariz. — The U.S. Geological Survey has named Kate Kitchell the director of its Southwest Biological Science Center. Kitchell, who served as the acting center director for the previous 16 months, assumed the role permanently November 6, 2010. 

October 15, 2010

TEMPE, Ariz. — Climate change and growing human demands for water are leaving an indelible mark on rivers and streams, shortening food chains and eliminating some top predators like large-bodied fish, according to a new study led by Arizona State University and co-authored by a U.S. Geological Survey scientist.

February 18, 2010

Flagstaff, Ariz. — As part of the Department of the Interior’s evaluation of whether to segregate nearly 1 million acres of federal lands near the Grand Canyon from new uranium claims, the United States Geological Survey today released a report on uranium resources and uranium mining impacts in the area.

February 2, 2010

Flagstaff, Ariz. —Resources along the Colorado River in Glen Canyon National Recreation Area and Grand Canyon National Park generally benefited from a high-flow experiment conducted in March 2008 from Glen Canyon Dam, near Page, Ariz., according to research findings released today by the U.S. Geological Survey.

USGS science for a changing world logo
November 4, 2009

Greater sage-grouse populations have declined substantially in many areas in the West, though populations in some locations remain relatively stable, according to a comprehensive publication written by federal, state, and non-governmental organizations. The population assessment is one of numerous sage-grouse topics covered in the 24 chapters released today.

USGS science for a changing world logo
September 14, 2009

Intersex in smallmouth and largemouth basses is widespread in numerous river basins throughout the United States is the major finding of the most comprehensive and large-scale evaluation of the condition, according to U.S. Geological Survey (USGS) research published online in Aquatic Toxicology.

USGS science for a changing world logo
August 10, 2009

A report on long-term glacier measurements released today by Secretary of the Interior Ken Salazar shows that glaciers are dramatically changing in mass, length and thickness as a result of climate change.

USGS science for a changing world logo
July 20, 2009

U.S. Geological Survey scientists and cartographers played an important but relatively unknown role during the Apollo 11 moon landing 40 years ago this week. USGS astrogeologists trained the Apollo astronauts in the science and strategy of field geology.

USGS science for a changing world logo
June 18, 2009

Critical science support for NASA's Lunar Reconnaissance Orbiter (LRO), launched today from Cape Canaveral, Florida, will help pave the way for further human and robotic exploration of the Moon. U.S. Geological Survey scientists are providing unique knowledge and skills as members of the science teams operating instruments on LRO.