Unified Interior Regions

Region 8: Lower Colorado Basin

Regions L2 Landing Page Tabs

The Lower Colorad Basin includes Arizona, southern Nevada, and souther California. The Regional Office, headquartered in Sacramento, provides Center oversight and support, facilitates internal and external collaborations, and works to further USGS strategic science directions. Our scientists do a broad array of research and technical assistance throughout the U.S. and across the globe.

News

Date published: November 16, 2021

Uranium in Grand Canyon Region Groundwater Mostly Complies with Federal Health Standards

Nearly 95% of samples collected from 206 locations over 40 years show uranium concentrations less than the U.S. Environmental Protection Agency Maximum Contaminant Level for drinking water, according to a new U.S. Geological Survey report.

Date published: October 28, 2021

Groundwater Flow to Colorado River May Decline by a Third over Next 30 Years

A new study projects that a hot and dry future climate may lead to a 29% decline in Upper Colorado River Basin “baseflow” at the basin outlet by the 2050s, affecting both people and ecosystems.

Date published: September 22, 2021

A Century of Watching the Colorado River

Right where the Colorado River flows into the mouth of the Grand Canyon, an inconspicuous 20-foot-high concrete tower rises from the riverbank.  

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Date published: October 15, 2021
Status: Active

U.S. West Coast and Alaska Marine Geohazards

Marine geohazards are sudden and extreme events beneath the ocean that threaten coastal populations. Such underwater hazards include earthquakes, volcanic eruptions, landslides, and tsunamis.

Devastating earthquakes in Japan (2011) and Chile (2010) that spawned pan-oceanic tsunamis sent a sobering reminder that U.S. coastlines are also vulnerable to natural disasters that originate in...

Date published: September 1, 2021
Status: Active

Coastal Storm Modeling System (CoSMoS)

The Coastal Storm Modeling System (CoSMoS) makes detailed predictions of storm-induced coastal flooding, erosion, and cliff failures over large geographic scales. CoSMoS was developed for hindcast studies, operational applications and future climate scenarios to provide emergency responders and coastal planners with critical storm-hazards information that can be used to increase public safety...

Date published: July 30, 2021
Status: Active

Dynamic coastlines along the western U.S.

The west coast of the United States is extremely complex and changeable because of tectonic activity, mountain building, and land subsidence. These active environments pose a major challenge for accurately assessing climate change impacts, since models were historically developed for more passive sandy coasts.

Date published: July 30, 2021
Status: Active

Seafloor Faults off Southern California

More than 22 million people live along Southern California’s coast, and many more migrate there every year. Faults and earthquake threats in this region have been heavily studied on land. USGS aims to boost our knowledge about faults on the seafloor, so they can be included in hazard assessments.

Contacts: Danny Brothers
Date published: March 26, 2019
Status: Active

Defining Native Ranges of U.S. Inland Fishes

Understanding the native versus non-native range of a species can provide useful information about dispersal, population distribution patterns, and human mediated movement across hydrologic barriers. The USGS Nonindigenous Aquatic Species (NAS) Program is working with partners to define native ranges of inland fishes in the United States to help identify which species should be included in the...

Date published: March 5, 2019
Status: Active

The Nonindigenous Aquatic Species Flood and Storm Tracker (FaST)

Storm-related flooding can lead to the potential spread of nonindigenous (or non-native) aquatic species into waterways they have not been seen in before. The USGS Nonindigenous Aquatic Species program has developed an innovative mapping tool to help natural resource managers with post-storm nonindigenous aquatic species detection and assessment efforts. 

Date published: April 11, 2016
Status: Active

Nonindigenous Aquatic Species (NAS) Program

Welcome to the Nonindigenous Aquatic Species (NAS) information resource for the United States Geological Survey. Located at Gainesville, Florida, this site has been established as a central repository for spatially referenced biogeographic accounts of introduced aquatic species. The program provides scientific reports, online/realtime queries, spatial data sets, distribution maps, and general...

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Year Published: 2021

Geologic and geophysical maps of the Santa Maria and part of the Point Conception 30'×60' quadrangles, California

This report presents digital geologic, gravity, and aeromagnetic maps for the onshore parts of the Santa Maria and Point Conception 30'x60' quadrangles at a compilation scale of 1:100,000. The map depicts the distribution of bedrock units, surficial deposits, paleontological data, geophysical data and structural features in the Santa Maria basin...

Sweetkind, Donald S.; Langenheim, Victoria E.; McDougall-Reid, Kristin; Sorlien, Christopher C.; Demas, Shiera C.; Tennyson, Marilyn E.; Johnson, Samuel Y.
Sweetkind, D.S., Langenheim, V.E., McDougall-Reid, K., Sorlien, C.C., Demas, S.C., Tennyson, M.E., and Johnson, S.Y., 2021, Geologic and geophysical maps of the Santa Maria and part of the Point Conception 30'×60' quadrangles, California: U.S. Geological Survey Scientific Investigations Map 3472, 1 sheet, scale 1:100,000, 58-p. pamphlet, https://doi.org/10.3133/sim3472. [Supersedes USGS Open-File Reports 95–25 and 92–189.]

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Year Published: 2021

Colored shaded-relief bathymetry, acoustic backscatter, and selected perspective views of the northern part of the California Continental Borderland, southern California

The California Continental Borderland is the complex continental margin in southern California that extends from Point Conception southward into northern Baja California (Fisher and others, 2009). This colored shaded-relief bathymetry map of the northern continental borderland in southern California was generated primarily from multibeam-...

Dartnell, Peter; Roland, Emily C.; Raineault, Nicole A.; Castillo, Christopher M.; Conrad, James E.; Kane, Renato; Brothers, Daniel S.; Kluesner, Jared; Walton, Maureen A. L.
Dartnell, P., Roland, E.C., Raineault, N.A., Castillo, C.M., Conrad, J.E., Kane, R., Brothers, D.S., Kluesner, J., and Walton, M.A.L., 2021, Colored shaded-relief bathymetry, acoustic backscatter, and selected perspective views of the northern part of the California Continental Borderland, southern California: U.S. Geological Survey Scientific Investigations Map 3473, 3 sheets, scale 1:250,000, https://doi.org/10.3133/sim3473.

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Year Published: 2021

Multiple climate change-driven tipping points for coastal systems

As the climate evolves over the next century, the interaction of accelerating sea level rise (SLR) and storms, combined with confining development and infrastructure, will place greater stresses on physical, ecological, and human systems along the ocean-land margin. Many of these valued coastal systems could reach “tipping points,” at which hazard...

Barnard, Patrick L.; Dugan, Jenifer; Page, Henry M. ; Wood, Nathan J.; Finzi Hart, Juliette A.; Cayan, Daniel; Erikson, Li H.; Hubbard, David A.; Myers, Monique; Melack, John M.; Iacobellis, Samuel F.

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Year Published: 2021

Global-scale changes to extreme ocean wave events due to anthropogenic warming

Extreme surface ocean waves are often primary drivers of coastal flooding and erosion over various time scales. Hence, understanding future changes in extreme wave events owing to global warming is of socio-economic and environmental significance. However, our current knowledge of potential changes in high-frequency (defined here as having return...

Morim, Joao; Vitousek, Sean; Hemer, Mark; Reguero, Borja; Erikson, Li H.; Casas-Prat, Merce; Wang, Xiaolan L.; Semedo, Alvaro; Mori, Nobuhito; Shimura, Tomoya; Mentaschi, Lorenzo; Timmerman, Ben

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Year Published: 2021

Twenty-first-century projections of shoreline change along inlet-interrupted coastlines

Sandy coastlines adjacent to tidal inlets are highly dynamic and widespread landforms, where large changes are expected due to climatic and anthropogenic influences. To adequately assess these important changes, both oceanic (e.g., sea-level rise) and terrestrial (e.g., fluvial sediment supply) processes that govern the local sediment budget must...

Bamunawala, Janaka; Ranasinghe, Roshanka; Dastgheib, Ali; Nichols, Robert .J.; Murray, A. Brad; Barnard, Patrick L.; Sirisena, T. A. J. G.; Duong, Trang Minh; Hulscher, Suzanne J. M. H.; van der Spek, Ad

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Year Published: 2021

Approaches for assessing long-term annual yields of highway and urban runoff in selected areas of California with the Stochastic Empirical Loading and Dilution Model (SELDM)

The California Department of Transportation, commonly known as CalTrans, and other municipal separate storm sewer system permittees in California as well as other State departments of transportation nationwide need information about potential loads and yields (loads per unit area) of constituents of concern in stormwater runoff and discharges from...

Granato, Gregory E.; Friesz, Paul J.
Granato, G.E., and Friesz, P.J., 2021, Approaches for assessing long-term annual yields of highway and urban runoff in selected areas of California with the Stochastic Empirical Loading and Dilution Model (SELDM): U.S. Geological Survey Scientific Investigations Report 2021–5043, 37 p., https://doi.org/10.3133/sir20215043.

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Year Published: 2021

Carbonate-hosted microbial communities are prolific and pervasive methane oxidizers at geologically diverse marine methane seep sites

At marine methane seeps, vast quantities of methane move through the shallow subseafloor, where it is largely consumed by microbial communities. This process plays an important role in global methane dynamics, but we have yet to identify all of the methane sinks in the deep sea. Here, we conducted a continental-scale survey of seven geologically...

Marlow, Jeffrey J.; Hoer, Daniel; Jungbluth, Sean; Reynard, Linda; Gartman, Amy; Chavez, Marko S.; El-Naggar, Mohamed Y.; Tuross, Noreen; Orphan, Victoria; Girguis, Peter R.

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Year Published: 2021

Recency of faulting and subsurface architecture of the San Diego Bay pull-apart basin, California, USA

In southern California, plate boundary motion between the North American and Pacific plates is distributed across several sub-parallel fault systems. The offshore faults of the California Continental Borderland (CCB) are thought to accommodate ~10-15% of the total plate boundary motion, but the exact distribution of slip and the mechanics of slip...

Singleton, Drake Moore; Maloney, Jillian M.; Brothers, Daniel; Klotsko, Shannon; Driscoll, Neal W.; Rockwell, Thomas K.

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Year Published: 2021

USGS National Water Quality Monitoring Network

What is the U.S. Geological Survey National Water Quality Monitoring Network?Understanding the water quality of U.S. streams and rivers requires consistent data collection and analysis over decades. The U.S. Geological Survey’s (USGS) National Water Quality Network (NWQN) was established to facilitate national-scale understanding of surface-water...

Riskin, Melissa L.; Lee, Casey J.
Lee, C.J., and Riskin, M.L., 2021, USGS National Water Quality Monitoring Network: U.S. Geological Survey Fact Sheet 2021–3019, 2 p., https://doi.org/10.3133/fs20213019.

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Year Published: 2021

Landscape evolution in eastern Chuckwalla Valley, Riverside County, California

This study investigates sedimentary and geomorphic processes in eastern Chuckwalla Valley, Riverside County, California, a region of arid, basin-and-range terrain where extensive solar-energy development is planned. The objectives of this study were to (1) measure local weather parameters and use them to model aeolian sediment-transport potential...

East, Amy E.; Gray, Harrison J.; Redsteer, Margaret Hiza; Ballmer, Matthew
East, A.E., Gray, H.J., Redsteer, M.H., and Ballmer, M., 2021, Landscape evolution in eastern Chuckwalla Valley, Riverside County, California: U.S. Geological Survey Scientific Investigations Report 2021–5017, 46 p., https://doi.org/10.3133/sir20215017.

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Year Published: 2021

Evaluation and application of the Purge Analyzer Tool (PAT) to determine in-well flow and purge criteria for sampling monitoring wells at the Stringfellow Superfund site in Jurupa Valley, California, in 2017

The U.S. Geological Survey and U.S. Environmental Protection Agency are developing analytical tools to assess the representativeness of groundwater samples from fractured-rock aquifers. As part of this effort, monitoring wells from the Stringfellow Superfund site in Jurupa Valley in Riverside County, California, approximately 50 miles east of Los...

Harte, Philip T.; Perina, Tomas; Becher, Kent; Levine, Herb; Rojas-Mickelson, Daewon; Walther, Lesley; Brown, Anthony
Harte, P.T., Perina, T., Becher, K., Levine, H., Rojas-Mickelson, D., Walther, L., and Brown, A., 2021, Evaluation and application of the Purge Analyzer Tool (PAT) to determine in-well flow and purge criteria for sampling monitoring wells at the Stringfellow Superfund site in Jurupa Valley, California, in 2017: U.S. Geological Survey Scientific Investigations Report 2020–5140, 54 p., https://doi.org/10.3133/sir20205140.

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Year Published: 2021

Potential use of the benthic foraminifers Bulimina denudata and Eggerelloides advenus in marine sediment toxicity testing

The benthic foraminifers Bulimina denudata and Eggerelloides advenus are commonly abundant in offshore regions in the Pacific Ocean, especially in waste-discharge sites. The relationship between their abundance and standard macrofaunal sediment toxicity tests (amphipod survival and sea urchin fertilization) as well as sediment...

McGann, Mary

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November 19, 2021

Image of the Week - Historic Lows at Lake Powell

Image of the Week: Historic Lows at Lake Powell

Lake Powell on the border of Utah and Arizona supplies water to millions across the southwestern United States.

Long-term dry conditions put the reservoir at a historic low in 2021. Landsat 8 imagery from 2017 shows the water's elevation at 3,628 feet. The reservoir on that day was at 60.3% of full capacity. 4

Map of uranium concentration in groundwater sites in the Grand Canyon region
November 15, 2021

Uranium concentration in groundwater sites in the Grand Canyon region

Map of maximum uranium concentration at 206 spring and well sites in the Grand Canyon region.

August 26, 2021

HLS: Magnum Fire, Arizona

 

Harmonized Landsat and Sentinel-2 (HLS) data are here!

The LP DAAC and the HLS Science Team are pleased to announce the release of Harmonized Landsat and Sentinel-2 (HLS) version 2.0 surface reflectance products. HLS data are composed of observations from Landsat 8 and Sentinel-2 and provide a set of seamless data products that can be utilized as if all

A table full of grasses in a greenhouse.
August 6, 2021

Greenhouse study comparing plant provenance for restoration

RestoreNet is partnering with the Gornish lab at the University of Arizona to better understand how a plant’s source location (provenance) influences its performance in a restoration setting. This greenhouse experiment will be conducted by PhD student, Sierra Lauman. Sierra will use locally collected and commercially purchased seeds of eight commonly used restoration

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A woman monitors plants alongside a transect or measuring tape placed on the ground.
July 31, 2021

Pre-construction monitoring of vegetation for the Gemini Solar Array

The United States is developing renewable energy resources, especially solar, at a rapid rate. Although renewable energy development is widely perceived by the public as “green technology,” construction, operation, maintenance, and eventual decommissioning of facilities all have known and potential negative impacts to natural resources, including plant communities and

...
Bins of plants lines up outside a greenhouse
June 11, 2021

Greenhouse study comparing plant performance during drought.

Greenhouse study comparing plant performance during drought will help land managers choose plant species for restoring degraded lands. To find out more, follow the Restoration Assessment and Monitoring Program of the Southwest, housed at the Southwest Biolobigical Science Center. www.ugs.gov/sbsc/ramps

A woman stands in front of a table full of grasses in a greenhouse.
June 2, 2021

Drought experiments shed light on plant responses to climate change.

Greenhouse study comparing plant performance during drought will help land managers choose plant species for restoring degraded lands. To find out more, follow the Restoration Assessment and Monitoring Program of the Southwest, housed at the Southwest Biolobigical Science Center. www.ugs.gov/sbsc/ramps

A man captures insects using a net.
May 13, 2021

Powerlines & Pollinators

Connecting powerline rights-of-way vegetation management to improve pollinator habitat. A USGS RAMPS technician samples pollinating insects along the Salt River Project powerline that crosses through Apache-Sitgreaves and Tonto National Forests. This fall, baseline plots were established in areas that will be treated with mechanical and chemical vegetation management 

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A man monitors plants alongside a transect or measuring tape placed on the ground.
April 21, 2021

Pre-construction monitoring of vegetation for the Gemini Solar Array

The United States is developing renewable energy resources, especially solar, at a rapid rate. Although renewable energy development is widely perceived by the public as “green technology,” construction, operation, maintenance, and eventual decommissioning of facilities all have known and potential negative impacts to natural resources, including plant communities and

...
Map of U.S. mainland showing temperate, transitional and tropical temperature patterns
March 16, 2021

U.S. regions in the tropical-to-temperate transition

A map showing North America's tropical-to-temperate transition zone. Red, orange, and yellow depict the more tropical zones, and blues depict the more temperate zones, based on to the coldest recorded temperature for each area between 1980 and 2009. Photos show some cold-sensitive plants and animals with northern range limits governed by winter cold temperature extremes.

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March 15, 2021

B-Roll of Lees Ferry

A collection of video for use in products related to the USGS's streamgage at Lees Ferry. The USGS installed the Lees Ferry gauge 100 years ago, and the data collected since have become critical to monitoring water availability in the West.

Shot List:

  • 0:00 Title slide
  • 0:25 Lees Ferry streamgage wide shot and pan
  • 0:33 Lees Ferry
A school of snook, large subtropical game fish, in a Florida spring
March 15, 2021

Subtropical snook gather at a warm Florida springhead in winter

 Winter temperature extremes control the distributions of subtropical fishes. Common snook (Centropomus undecimalis), aggregate at a spring in northern Florida during winter. Snook are warm saltwater game fish, common in Florida, that have been moving further northward as extreme cold spells become less frequent and less intense.

 

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Photo of a water fall, Havasu Falls.
November 16, 2021

Nearly 95% of samples collected from 206 locations over 40 years show uranium concentrations less than the U.S. Environmental Protection Agency Maximum Contaminant Level for drinking water, according to a new U.S. Geological Survey report.

San Miguel River, Colorado, Fall 2020
October 28, 2021

A new study projects that a hot and dry future climate may lead to a 29% decline in Upper Colorado River Basin “baseflow” at the basin outlet by the 2050s, affecting both people and ecosystems.

Image: Suspended Scientists
September 22, 2021

Right where the Colorado River flows into the mouth of the Grand Canyon, an inconspicuous 20-foot-high concrete tower rises from the riverbank.  

An infographic summarizing activities of the RAMPS program.
September 20, 2021

Restoration Assessment and Monitoring Program for the Southwest (RAMPS)

A Program of the Southwest Biological Science Center & Ecosystems Mission Area

To subscribe to our newsletter, please visit: https://listserv.usgs.gov/mailman/listinfo/ramps

An infographic summarizing activities of the RAMPS program.
May 27, 2021

Restoration Assessment and Monitoring Program for the Southwest (RAMPS)

A Program of the Southwest Biological Science Center & Ecosystems Mission Area

To subscribe to our newsletter, please visit: https://listserv.usgs.gov/mailman/listinfo/ramps

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Aerial photography of Grand Canyon with vegetation change data
May 24, 2021

The USGS will collect high-resolution aerial imagery over Grand Canyon National Park for approximately one week beginning Saturday, May 29, to document, observe and track long-term ecosystem changes in the Colorado River. Visitors along the Colorado River in Glen Canyon National Recreation Area and Grand Canyon National Park may see and hear aircraft more frequently during this time.

2021 March Public Lecture Flyer
March 24, 2021

The U.S. Geological Survey public lecture series is back and virtual. News reporters are invited to attend to learn how USGS scientists are helping protect one of the only jaguars that lives in the U.S.

Sunlight on red cliffs and river
February 8, 2021

Streamflow in the Southwestern U.S. is projected to decrease by as much as 36–80% by the end of this century, reports a new study by the U.S. Geological Survey. Decreases of this magnitude would challenge our ability to meet future water demand in this region and could jeopardize compliance with interstate and international water-sharing agreements.

An infographic summarizing activities of the RAMPS program.
February 4, 2021

Restoration Assessment and Monitoring Program for the Southwest (RAMPS)

A Program of the Southwest Biological Science Center & Ecosystems Mission Area

To subscribe to our newsletter, please visit: https://listserv.usgs.gov/mailman/listinfo/ramps

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