Unified Interior Regions

California

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.

States L2 Landing Page Tabs

Filter Total Items: 377
Date published: October 23, 2019
Status: Active

San Francisco Bay Area – SF Peninsula (BALT3) Site near Brisbane, CA

Recent Conditions

The instruments for this site were installed in the summer of 2011 and are used to monitor and detect changes in local conditions.  Soil water content and ground water pressure are monitored at two nests on the same hillslope.  Data for the site include:

  • ...
Contacts: Brian Collins
Date published: October 23, 2019
Status: Active

San Francisco Bay Area – Marin County (BALT2) Site near San Rafael, CA

Recent Conditions

The instruments for this site were installed in the winter of 2010 and are used to monitor and detect changes in local conditions.  Soil water content and ground water pressure are monitored at two nests on the same hillslope.  Data for the site include:

  • ...
Contacts: Brian Collins
Date published: October 23, 2019
Status: Active

Drivers and Impacts of North Pacific Climate Variability

Climate model forecasts indicate an increase in extreme hydrologic events, including floods and droughts, for California and the western U.S. in the future. To better understand what the consequences of this future change in climate may be, USGS scientists are studying the frequency, magnitude, and impacts of past hydroclimate variability and extremes in the region. This project produces well-...

Date published: October 17, 2019
Status: Completed

What if the ShakeAlert Earthquake Early Warning System Had Been Operating During the M6.9 1989 Loma Prieta Earthquake?

How will ShakeAlert® likely perform now on a large earthquake impacting a major urban area? How much warning will you get? To answer this, let’s do a thought experiment...

Date published: October 17, 2019
Status: Active

CoSMoS 3.1: Central California

CoSMoS v3.1 for central California shows projections for future climate scenarios (sea-level rise and storms)

Date published: October 14, 2019
Status: Active

Topobathymetric Elevation Model of San Francisco Bay Area, California

Accurate, high-resolution elevation information is vital to understanding the natural hazards that can impact the highly populated San Francisco Bay area, such as sea-level rise, winter storms, cliff erosion, and other coastal hazards. The San Francisco Bay estuary three-dimensional (3D) topobathymetric digital elevation model (TBDEM) was developed in collaboration between ...

Date published: October 8, 2019
Status: Completed

Earthquake Early Warning – Fine-Tuning for Best Alerts

The goal of an earthquake early warning (EEW) system is to provide an alert to people and automatic systems after an earthquake begins but before the shaking reaches their location. As the USGS and its partners are developing an EEW system, called ShakeAlert®, for the West Coast, the benefits, costs, capabilities, and limitations are being investigated. Two recent studies explored the...

Date published: September 30, 2019
Status: Completed

Could the M7.1 Ridgecrest, CA Earthquake Sequence Trigger a Large Earthquake Nearby?

Release Date: SEPTEMBER 30, 2019

Two of the first questions that come to mind for anyone who just felt an earthquake are, “Will there be another one?” and “Will it be larger?”.

Date published: August 26, 2019
Status: Completed

Loma Prieta Earthquake Professional Papers

The four Loma Prieta Earthquake Professional Papers, which were published as multiple chapters, comprehensively document the magnitude 6.9 earthquake in California that shook the San Francisco and Monterey Bay regions on October 17, 1989. They contain almost 3000 pages written by 401 investigators of the earthquake. The investigations were funded by a special Congressional appropriation to the...

Date published: August 21, 2019
Status: Active

Directions

Information to help you plan your visit to the Earthquake Science Center.

Date published: August 5, 2019
Status: Completed

M7.9 1857 Fort Tejon Earthquake

The Last "Big One" in Southern California.

Date published: August 5, 2019
Status: Completed

M6.9 October 17, 1989 Loma Prieta Earthquake

On October 17, 1989, at 5:04:15 p.m. (PDT), a magnitude 6.9 earthquake severely shook the San Francisco and Monterey Bay regions. The epicenter was located near Loma Prieta peak in the Santa Cruz Mountains, approximately 14 km (9 mi) northeast of Santa Cruz and 96 km (60 mi) south-southeast of San Francisco.

Filter Total Items: 501
Date published: May 4, 2020

CoSMoS (Coastal Storm Modeling System) Central California v3.1 wave-hazard projections: 1-year storm in Santa Cruz County

This data contains maximum model-derived significant wave height (in meters) for the sea-level rise (SLR) and storm condition indicated.
The Coastal Storm Modeling System (CoSMoS) makes detailed predictions (meter-scale) over large geographic scales (100s of kilometers) of storm-induced coastal flooding and erosion for both current and future sea-level rise (SLR) scenar

Date published: May 4, 2020

CoSMoS (Coastal Storm Modeling System) Central California v3.1 water-level projections: average conditions in Santa Cruz County

This data contains model-derived total water levels (in meters) for the sea-level rise (SLR) and storm condition indicated.
The Coastal Storm Modeling System (CoSMoS) makes detailed predictions (meter-scale) over large geographic scales (100s of kilometers) of storm-induced coastal flooding and erosion for both current and future sea-level rise (SLR) scenarios. Projecti

Date published: May 4, 2020

CoSMoS (Coastal Storm Modeling System) Central California v3.1 wave-hazard projections: 100-year storm in Santa Cruz County

This data contains maximum model-derived significant wave height (in meters) for the sea-level rise (SLR) and storm condition indicated.
The Coastal Storm Modeling System (CoSMoS) makes detailed predictions (meter-scale) over large geographic scales (100s of kilometers) of storm-induced coastal flooding and erosion for both current and future sea-level rise (SLR) scenar

Date published: May 4, 2020

CoSMoS (Coastal Storm Modeling System) Central California v3.1 ocean-currents projections: 20-year storm in Santa Cruz County

This data contains maximum model-derived ocean currents (in meters per second) for the sea-level rise (SLR) and storm condition indicated.
The Coastal Storm Modeling System (CoSMoS) makes detailed predictions (meter-scale) over large geographic scales (100s of kilometers) of storm-induced coastal flooding and erosion for both current and future sea-level rise (SLR) scen

Date published: May 4, 2020

CoSMoS (Coastal Storm Modeling System) Central California v3.1 flood depth and duration projections: 1-year storm in Santa Cruz County

This data contains maximum depth of flooding (cm) in the region landward of the present-day shoreline for the sea-level rise (SLR) and storm condition indicated.
The Coastal Storm Modeling System (CoSMoS) makes detailed predictions (meter-scale) over large geographic scales (100s of kilometers) of storm-induced coastal flooding and erosion for both current and future sea-le

Date published: May 4, 2020

CoSMoS (Coastal Storm Modeling System) Central California v3.1 ocean-currents projections: 100-year storm in Santa Cruz County

This data contains maximum model-derived ocean currents (in meters per second) for the sea-level rise (SLR) and storm condition indicated.
The Coastal Storm Modeling System (CoSMoS) makes detailed predictions (meter-scale) over large geographic scales (100s of kilometers) of storm-induced coastal flooding and erosion for both current and future sea-level rise (SLR) scen

Date published: May 4, 2020

CoSMoS (Coastal Storm Modeling System) Central California v3.1 ocean-currents projections: average conditions in Santa Cruz County

This data contains maximum model-derived ocean currents (in meters per second) for the sea-level rise (SLR) and storm condition indicated.
The Coastal Storm Modeling System (CoSMoS) makes detailed predictions (meter-scale) over large geographic scales (100s of kilometers) of storm-induced coastal flooding and erosion for both current and future sea-level rise (SLR) scen

Date published: April 30, 2020

Quaternary faults offshore of California

A comprehensive map of Quaternary faults has been generated for offshore of California. The Quaternary fault map includes mapped geometries and attribute information for offshore fault systems located in California State and Federal waters. The polyline shapefile has been compiled from previously published mapping where relatively dense, high-resolution marine geophysical data exist. The data...

Date published: April 30, 2020

Select borehole data for Anza Valley, Anza, CA

Borehole log number, State Well Number, location, construction information, and any wells tests performed on select wells from the Anza basin, Anza, CA. Also includes a lithologic data for a sub-set of borehole logs identified based on best coverage and representation of data within the study area.

Date published: April 29, 2020

SmeltCam sampling in San Joaquin River and False River near Jersey Island in the Sacramento-San Joaquin River Delta, California, 2016

This dataset includes field data for fishes sampled using mid-water trawls and the SmeltCam during daylight hours in the Sacramento- San Joaquin Delta, California. Sampling took place between February 8, 2016 and March 1, 2016. This data release includes all measured environmental parameters and fish taxa collected during sampling event.

Date published: April 29, 2020

Partitioning of six pyrethroid insecticides at varying salinities

To determine aqueous pyrethroid partitioning across a salinity gradient 20 mL Pyrex beakers were filled with 8 mL of deionized water at varying salinities (0, 0.5, 2, 6 ppt). Salinity was adjusted using a 10 ppt stock solution (made by diluting Instant Ocean into deionized water). The water samples were spiked with pyrethroids (bifenthrin, cyhalothrin, cyfluthrin, cypermethr

Date published: April 28, 2020

Otolith chemistry of fishes in Rodeo Lagoon, Marin County, California, 2016

The dataset includes multiple file types (CSV, ArcGIS shapefiles, and images), data relates to the elemental analysis of fish otoliths. Otoliths examined in this study were from randomly-sampled individual Tidewater Goby (Eucyclogobius newberryi) and Prickly Sculpin (Cottus asper) from the adult population of Rodeo Lagoon and Rodeo Creek, Marin County, California. The fish w

Filter Total Items: 350
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Year Published: 2019

Mapping protected groundwater adjacent to oil and gas fields, San Joaquin Valley, California

Airborne electromagnetic (AEM) surveys are a major component of a regional study of groundwater quality adjacent to oil and gas fields in the San Joaquin Valley of California, USA. AEM resistivity models are being used to delineate groundwater salinity in an effort to locate groundwater adjacent to oil and gas fields that could have future...

Ball, Lyndsay B.; Gillespie, Janice M.; Minsley, Burke; Davis, Tracy; Landon, Matthew K.

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Year Published: 2018

Quantifying post-wildfire hillslope erosion with lidar

Following a wildfire, flooding and debris- flow hazards are common and pose a threat to human life and infrastructure in steep burned terrain. Wildfire enhances both water runoff and soil erosion, which ultimately shape the debris flow potential. The erosional processes that route excess sediment from hillslopes to debris-flow channels in...

Rengers, Francis K.; McGuire, Luke

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Year Published: 2018

Application of the Stream Salmonid Simulator (S3) to the restoration reach of the Trinity River, California—Parameterization and calibration

Executive SummaryIn this report, we constructed and parameterized the Stream Salmonid Simulator (S3) for the 64-kilometer “Restoration Reach” of the Trinity River, just downstream of Lewiston Dam in northern California. S3 is a deterministic life-stage-structured population model that tracks daily growth, movement, and survival of juvenile salmon...

Perry, Russell W.; Jones, Edward C.; Plumb, John M.; Som, Nicholas A.; Hetrick, Nicholas J.; Hardy, Thomas B.; Polos, Joseph C; Martin, Aaron C.; Alvarez, Justin S.; De Juilio, Kyle P.
Perry, R.W., Jones, E.C., Plumb, J.M., Som, N.A., Hetrick, N.J., Hardy, T.B., Polos, J.C., Martin, A.C., Alvarez, J.S., and De Juilio, K.P., 2018, Application of the Stream Salmonid Simulator (S3) to the restoration reach of the Trinity River, California—Parameterization and calibration: U.S. Geological Survey Open-File Report 2018-1174, 64 p., https://doi.org/10.3133/ofr20181174.

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Year Published: 2018

Modeling morphodynamic development in the Alviso Slough system, South San Francisco Bay, California

Alviso Slough area, South San Francisco Bay, California, is the site of an ongoing effort to restore former salt production ponds to intertidal habitat. As restoration proceeds and the levees surrounding the former salt production ponds are breached, the increase in tidal prism and associated sediment scour in the sloughs will remobilize legacy...

Van der Wegen, Mick; Reyes, Johan; Jaffe, Bruce; Foxgrover, Amy

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Year Published: 2018

Emigration and transportation stress of juvenile Chinook salmon relative to their reintroduction upriver of Shasta Dam, California, 2017–18

The Bureau of Reclamation supports the Shasta Dam Fish Passage Evaluation (SDFPE; Yip, 2015) program, and in 2016 set out to determine the feasibility of reintroducing winter-run and spring-run Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss) to tributaries upstream of Shasta Dam. Ideally, reintroduction strategy includes...

Adams, Noah S.; Liedtke, Theresa L.; Plumb, John M.; Weiland, Lisa K.; Hansen, Amy C.; Evans, Scott D.
Adams, N.S., Liedtke, T.L., Plumb, J.M., Hansen, A.C., Evans, S.D., and Weiland., L.K., 2018, Emigration and transportation stress of juvenile Chinook salmon relative to their reintroduction upriver of Shasta Dam, California, 2017–18: U.S. Geological Survey Open-File Report 2018-1144, 60 p., https://doi.org/10.3133/ofr20181144.

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Year Published: 2018

Reported investments in earthquake mitigation top $73 to $80 billion in the San Francisco Bay Area, California, since the 1989 Loma Prieta earthquake

The purpose of this report is to provide a compilation of structural retrofits and replacements of older buildings and infrastructure in the San Francisco Bay Area that have either been completed since 1989 or that are in progress as of October 2018. For the purposes of this report, all or parts of nine Bay Area counties were included:...

Brocher, Thomas M.; Gefeke, Kerri; Boatwright, John; Knudsen, Keith L.
Brocher, T.M., Gefeke, K., Boatwright, J., and Knudsen, K.L., 2018, Reported investments in earthquake mitigation top \$73 to \$80 billion in the San Francisco Bay Area, California, since the 1989 Loma Prieta earthquake: U.S. Geological Survey Open-File Report 2018–1168, 18 p., https://doi.org/10.3133/ofr20181168.

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Year Published: 2018

Aeromagnetic map of Mountain Pass and vicinity, California and Nevada

Magnetic investigations of Mountain Pass and vicinity were begun as part of an effort to study regional crustal structures as an aid to understanding the geologic framework and mineral resources of the eastern Mojave Desert. The study area, which straddles the state boundary between southeastern California and southern Nevada, encompasses Mountain...

Ponce, David A.; Ponce, David A.; Denton, Kevin M.
Ponce, D.A., and Denton, K.M. (D.A. Ponce, ed.), 2018, Aeromagnetic map of Mountain Pass and vicinity, California and Nevada: U.S. Geological Survey Scientific Investigations Map 3412–B, scale 1:62,500, https://doi.org/10.3133/sim3412B.

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Year Published: 2018

Isostatic gravity map of Mountain Pass and vicinity, California and Nevada

Gravity investigations of Mountain Pass and vicinity were begun as part of an effort to study regional crustal structures as an aid to understanding the geologic framework and mineral resources of the eastern Mojave Desert. The study area, which straddles the state boundary between southeastern California and southern Nevada, encompasses Mountain...

Ponce, David A.; Ponce, David A.; Denton, Kevin M.
Ponce, D.A., and Denton, K.M. (D.A. Ponce, ed.), 2018, Isostatic gravity map of Mountain Pass and vicinity, California and Nevada: U.S. Geological Survey Scientific Investigations Map 3412–A, scale 1:62,500, https://doi.org/10.3133/sim3412A.

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Year Published: 2018

Geophysical and geologic maps of Mountain Pass and vicinity, California and Nevada

U.S. Geological Survey Scientific Investigations Map 3412 is a series of products that consists of geophysical and geologic maps of Mountain Pass and vicinity, California. Maps A and B (red outline in above map image) are gravity and aeromagnetic maps, respectively. The map series was begun as part of an effort to study regional crustal structures...

Ponce, David A.

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Year Published: 2018

Improving earthquake rupture forecasts using California as a guide

This article discusses ways in which earthquake rupture forecast models might be improved. Because changes are most easily described in the context of specific models, the third Uniform California Earthquake Rupture Forecast (UCERF3) and its presumed successor, UCERF4, is used as a basis for discussion. Virtually all of the issues and possible...

Field, Edward H.
Field, E. H. (2018). Improving Earthquake Rupture Forecasts Using California as a Guide, Seismological Research Letters, https://doi.org/10.1785/0220180151.

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Year Published: 2018

Increasing earthquake insurance coverage in California via parametric hedges

California has the highest earthquake risk of any state in the United States. The Federal Emergency Management Agency (FEMA) reported in 2017 that 73% of the nation’s annual losses to earthquakes were expected to be concentrated in California and the Pacific Northwest. California alone constitutes 61% ($3.7 billion out of an estimated $6.1 billion...

Franco, Guillermo; Tirabassi, G; Lopeman, M; Wald, David J.; Siembieda, W.J.

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Year Published: 2018

State transportation agencies partner to deploy and enhance ShakeCast

The California Department of Transportation (Caltrans) is organizing and leading a three-year Transportation Pooled Fund (TPF) project, Connecting the Dots: Implementing ShakeCast Across Multiple State Departments of Transportation for Rapid Post-Earthquake Response. Ten state Departments of Transportation (DOT)—CA, ID, MO, MS, OK, OR, SC, TX, UT...

Turner, L.; Wald, David J.; Lin, Kuo-wan; Chiou, Brian; Slosky, Daniel

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November 14, 2019

Wintering Waterfowl at Sacramento National Wildlife Refuge

In this video, you can hear the honks and quacks of geese and ducks ring through the air, as birds fly in every direction above a wetland. This video was captured at Sacramento National Wildlife Refuge in November 2019, not long after geese and ducks began to arrive to spend the winter in the California Central Valley.

Flyer with images of sea-level rise with ocean waves
November 6, 2019

2019 November Public Lecture

2019 November Public Lecture Flyer

Sea-Level Rise, Extreme Water Levels, and Coastal Erosion ... How bad could it possibly be?

By Sean Vitousek, USGS Research Oceanographer

  • Sea-level rise represents an unprecedented civil engineering challenge.
  • Small amounts of sea-level rise can disproportionately increase the frequency
...
An instrument rests on the deck of a ship, its cables suspended above it, while a scientist looks on.
October 22, 2019

Chirp rests on the deck of R/V Bold Horizon

This instrument, the Edgetech SB-516 or "chirp", emits acoustic signals that penetrate the sediment on the seafloor. The reflected sound is recorded and is used to create a cross-section image, or profile, of the sub-bottom.

View from up high on a coastal cliff looking down along a beach where a river meets the ocean.
October 17, 2019

Klamath River mouth

A view of the mouth of the Klamath River where it meets the Pacific Ocean in northern California. The river runs from Oregon to California. Four dams along the Klamath are pending removal. USGS is studying coastal watershed response to dam removal, including long-term before-after/control-impact (BACI) studies.

October 17, 2019

Initial Observations of Cypress Structure Collapse, Oakland, CA 1989

Retrospective interview with USGS Geophysicist Susan Hough about the collapse of the Nimitz Freeway (known as the Cypress Structure) in Oakland, CA, during the October 17, 1989 Loma Prieta Earthquake and how the first responders reacted to the event.
 

October 17, 2019

Sight Response and Cypress Structure Collapse, Oakland, CA 1989

Retrospective interview with USGS Geophysicist Susan Hough about her early earthquake work during the 1989 Loma Prieta earthquake. The interview covers how the Cypress Structure collapse in Oakland, CA, served as a site response study for seismic research.
 

October 17, 2019

The Great California ShakeOut (2019) Role Play Exercise - Biola Univ.

Each year the State of California promotes a ShakeOut event where local citizens practice earthquake response and preparedness. This video shows footage from the 2019 Great California ShakeOut, which was hosted at Biola University in La Mirenda, CA. Video includes footage of the initial ShakeAlert announcement that blared across campus. Additional footage includes first

map of 6 wells & hydrographs showing groundwater-level responses to the July 2019 Ridgecrest earthquakes
October 15, 2019

Groundwater-level Response to the July 2019 Ridgecrest, CA Earthquakes

Locations of the July 2019 earthquake epicenters and six USGS groundwater-monitoring sites. The hydrographs show the response of groundwater levels to the earthquakes.  Sites shown are California (1) 

...
People stand on the deck of a ship while guiding a large seafloor coring device off the stern, mountains in background.
October 12, 2019

Rossfelder P-5 Vibracorer

USGS science crew from Pacific Coastal and Marine Science Center work together to get the vibracorer coring device in position to collect sediment core samples off San Francisco, California.

Photo of the stern of a ship on the water with equipment tied down to the deck and coastal cliffs in the background.
October 12, 2019

Vibracorer on deck

The Rossfelder P-5 vibracorer, with its polybuterate liner visible, is secured on the deck of the research vessel Bold Horizon, awaiting deployment off the coast of California just north of San Francisco. More liners are stored in a cage off to the side.

View from the stern of a ship with a large A-frame boom with pullies and ropes attached to a coring device sitting on deck.
October 11, 2019

Vibracorer on deck in San Francisco

The USGS uses the Rossfelder P-5 vibracorer to collect deep-water sediment samples from the seafloor. Here, they are heading out offshore of San Francisco with the Golden Gate Bridge in the background.

October 10, 2019

October 17, 1989 (Part 4)

On October 17, 1989, at 5:04 pm a magnitude M6.9 earthquake struck near Loma Prieta, California. It was a tragic reminder of the destructive power of earthquakes. However, it was also a watershed moment in seismic research. 30 years later, we revisit the earthquake through the eyes of the scientists who experienced it. And studied it. These are their stories. In Part 4 (of

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Screenshot Location of Coso volcanic field
July 6, 2019

An earthquake swarm started on the evening of July 5 at the southern margin of Coso Volcanic Field in Inyo County, California.

Giant gartersnake (Thamnophis gigas)
June 24, 2019

SACRAMENTO – A new study shows how giant gartersnakes use Central Valley rice fields

USGS Scientists taking sediment core at Six Gill Slough restored marsh.
June 6, 2019

California Water Science Center Research Hydrologist Dr. Judith Drexler and others have published an article in the journal Restoration Ecology, observing the progress of a restored salt marsh in southern Puget Sound, Washington.

SEDHYD Conference Image
May 17, 2019

California Water Science Center (CAWSC) hydrologists Joseph Hevesi, Scott Wright, Alexandra Etheridge, Mathieu Marineau, and Michelle Stern will discuss their research at the 2019 Federal Interagency Sedimentation and Hydrologic Modeling (SEDHYD) Conference in Reno, Nevada.

A scene showing the harbor and surrounds at Monaco, Monte Carlo
May 16, 2019

Dr. Christina Kellogg (Research Microbiologist, SPCMSC) is a member of the judging panel that will award winners of the $7 million dollar Shell Ocean Discovery XPRIZE during the final award announcement at the Musée Océanographique de Monaco on May 31.

A huge canyon surrounded by deep-set cliffs opens to reveal a sunny gorge and part of the Colorado River.
April 11, 2019

A new study shows that mysterious cycles in salinity in the lower Colorado River are a result of precipitation patterns in the headwaters of the upper basin more than a thousand river miles away. The salinity levels generally repeat about every 10 years.

Rear-arc basalt lava outcrop
April 2, 2019

Scientists at the volcano observatories of the U.S. Geological Survey pay close attention to volcanoes of the Cascade Range, Alaskan Peninsula and Aleutian Arc.

waves cross a coastal road
March 29, 2019

In less than 30 years the combination of sea-level rise plus an extreme storm along California’s coast could flood more than 150,000 residents and impact over $30 billion in property value. By 2100, up to 600,000 people and $150 billion in property could be at risk from coastal flooding.

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