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Guam

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The Pacific Region has nine USGS Science Centers in California, Nevada, and Hawaii. The Regional Office, headquartered in Sacramento, provides Center oversight and support, facilitates internal and external collaborations, and works to further USGS strategic science directions.

News

Date published: May 22, 2020

USGS Brown Treesnake Research Continues at Guam National Wildlife Refuge

On May 14, Director Reilly signed a Memorandum of Agreement with the Department of the Navy and the U.S. Fish and Wildlife Service. The MOA provides for continuity of operations for the USFWS and the USGS with construction of new office and lab facilities on the Guam National Wildlife Refuge in conjunction with DOD’s construction of a Marine Corps firing range.

Date published: January 23, 2020

New Study Provides Insights for Detecting the Invasive Brown Treesnake

Research by the USGS and Dickinson College reveals why scientists fail to detect brown treesnakes at low densities

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Coral head that looks like lettuce sits on sandy bottom in clear blue water and is surrounded by brightly colored fish.
Date Published: May 8, 2020
Status: Active

Coral Reef Project

Explore the fascinating undersea world of coral reefs. Learn how we map, monitor, and model coral reefs so we can better understand, protect, and preserve our Nation's reefs.

Aerial photograph of Wake Island. The deep ocean water around the atoll is dark blue, the shallow lagoon water is light blue.
Date Published: May 4, 2020
Status: Active

Low-lying areas of tropical Pacific islands

Sea level is rising faster than projected in the western Pacific, so understanding how wave-driven coastal flooding will affect inhabited, low-lying islands—most notably, the familiar ring-shaped atolls—as well as the low-elevation areas of high islands in the Pacific Ocean, is critical for decision-makers in protecting infrastructure or relocating resources and people.

Value of US Coral Reefs for Risk Reduction
Date Published: January 21, 2020
Status: Active

The Value of U.S. Coral Reefs for Risk Reduction

Summary of the report, “Rigorously valuing the role of U.S. coral reefs in coastal hazard risk reduction”

    Contacts: Curt Storlazzi, PhD, Michael Beck
    Underwater view of tropical fish swimming in shallow water above a coral reef which reflects upward to the water surface.
    Date Published: July 15, 2019
    Status: Active

    Coral Reef Project: Guam

    As part of the USGS Coral Reef Project, the USGS is working on the west coast of Guam to help determine the effects of sedimentation in nearshore waters.

    USGS biologists sample fish and macroinvertebrates from Streams in Palau
    Date Published: February 19, 2019
    Status: Active

    Risk Analysis of Invasive Freshwater Fishes in Hawaii and Micronesia

    Invasive species threaten biodiversity around the world, especially on islands. USGS scientists are helping to identify fish species that have the greatest potential to invade the fresh waters of Microneisa. 

    Satellite image of an island showing its terrain, some land features like runways and towns, and the bright shallow waters.
    Date Published: December 10, 2018
    Status: Completed

    Exploring: Reservoir Capacity And Sedimentation Of The Fena Valley Reservoir Guam

    The Fena Valley Reservoir, located in southern Guam, is the primary source of water for the United States Naval Base Guam and nearby village residents. At full capacity, the reservoir surface area extends approximately 0.30 mi2, and drains a watershed area of about 5.88 mi2

    Department of Interior U.S.G.S Guam Magnetic Observatory sign
    Date Published: July 20, 2018
    Status: Active

    Guam (GUA)

    The Guam observatory was established in 1957. The observatory is situated on property owned by the U.S. Air Force according to terms of an agreement with the USGS and the Geomagnetism Program. The facility is shared with the USGS Fort Collins Science Center (FORT) ...

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    USGS
    January 1, 2019

    This part of the data release presents projected flooding extent polygon (flood masks) and flooding depth points (flood points) shapefiles based on wave-driven total water levels for the Territory of Guam. There are 8 associated flood mask and flood depth shapefiles: one for each of four nearshore wave energy return periods (rp; 10-, 50-, 100-, and 500-years) and both with %

    USGS
    January 1, 2019

    This part of the data release presents projected flooding extent polygon (flood masks) and flooding depth points (flood points) shapefiles based on wave-driven total water levels for the State of Hawaii (the islands of Hawaii, Kahoolawe, Kauai, Lanai, Maui, Molokai, Niihau, and Oahu). For each island there are 8 associated flood mask and flood depth shapefiles: one for

    USGS
    January 1, 2019

    This part of the data release presents projected flooding extent polygon (flood masks) and flooding depth points (flood points) shapefiles based on wave-driven total water levels for the Territory of Puerto Rico (the islands of Culebra, Puerto Rico, and Vieques). For each island there are 8 associated flood mask and flood depth shapefiles: one for each four nearshore wave energy

    Map of the Pacific Ocean and surrounding continents with boxes drawn around areas to show study locations.
    January 1, 2019

    This data release provides flooding extent polygons (flood masks) and depth values (flood points) based on wave-driven total water levels for 22 locations within the States of Hawaii and Florida, the Territories of Guam, American Samoa, Puerto Rico, and the U.S. Virgin Islands, and the Commonwealth of the Northern Mariana Islands. For each of the 22 locations there are eight ass

    USGS
    January 1, 2018

    Data were collected in association with locations of standard brown treesnake traps on Guam at location prior to suppression or control efforts and after control had occurred. In all cases study sites were closed or semi-closed populations of brown treesnakes. Habitat data focused on type and structure of the habitat within 10-m of the trap.

    USGS science for a changing world
    October 18, 2017

    On an island largely devoid of native vertebrate seed dispersers, we monitored forest succession for seven years following ungulate exclusion from a 5-hectare area and adjacent plots with ungulates still present. 

    USGS
    January 1, 2017

    The stream segments available here were used in the Precipitation Runoff Modeling System (PRMS) of southern Guam documented by Rosa and Hay (2017). A Geographic Information System (GIS) file for the stream segments is provided as a shapefile with attributes ParentSeg, Region, and RegionSeg identifying the numbering convention used in the PRMS_2016 southern Guam model parameter fil

    USGS
    January 1, 2017

    The hydrologic response units (HRUs) available here were used in the Precipitation Runoff Modeling System (PRMS) of southern Guam documented by Rosa and Hay (2017). A Geographic Information System (GIS) file for the HRUs is provided as a shapefile with attributes ParentHRU, Region, and RegionHRU identifying the numbering convention used in the PRMS_2016 southern Guam model par

    USGS
    January 1, 2017

    These tables document grain-size distributions of sediment collected as part of a study on the geomorphic impacts of the March 2014 State Route 530 Landslide near Oso, Washington. This includes samples of material from the landslide deposit itself, covering a range of distinct facies present in the landslide, and samples of sand and gravel at various locations along the North Fork Stillagua

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    Year Published: 2019

    Rigorously valuing the role of U.S. coral reefs in coastal hazard risk reduction

    The degradation of coastal habitats, particularly coral reefs, raises risks by increasing the exposure of coastal communities to flooding hazards. The protective services of these natural defenses are not assessed in the same rigorous economic terms as artificial defenses, such as seawalls, and therefore often are not considered in decision making...

    Storlazzi, Curt D.; Reguero, Borja G.; Cole, Aaron D.; Lowe, Erik; Shope, James B.; Gibbs, Ann E.; Nickel, Barry A.; McCall, Robert T.; van Dongeren, Ap R.; Beck, Michael W.
    Storlazzi, C.D., Reguero, B.G., Cole, A.D., Lowe, E., Shope, J.B., Gibbs, A.E., Nickel, B.A., McCall, R.T., van Dongeren, A.R., and Beck, M.W., 2019, Rigorously valuing the role of U.S. coral reefs in coastal hazard risk reduction: U.S. Geological Survey Open-File Report 2019–1027, 42 p., https://doi.org/10.3133/ofr20191027.

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    Year Published: 2019

    Tropical cyclone projections: Changing climate threats for Pacific Island defense installations

    Potential changing climate threats in the tropical and subtropical North Pacific Ocean were assessed, using coupled ocean-atmosphere and atmosphere-only general circulation models, to explore their response to projected increasing greenhouse gas emissions. Tropical cyclone occurrence, described by their frequency and intensity, near islands...

    Widlansky, Matthew J.; Annamalai, Hariharasubramanian; Gingerich, Stephen B.; Storlazzi, Curt D.; Marra, John J.; Hodges, Kevin I.; Choy, Barry; Kitoh, Akio

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    Year Published: 2015

    Storage capacity of the Fena Valley Reservoir, Guam, Mariana Islands, 2014

    The Fena Valley Reservoir is in southern Guam and is the primary source of water for the U.S. Naval Base Guam and nearby village residents. Since the construction of the Fena Dam in 1951, sediment has accumulated in the reservoir and reduced its storage capacity. The reservoir was surveyed previously in 1973, 1979, and 1990 to estimate the loss in...

    Marineau, Mathieu D.; Wright, Scott A.
    Marineau, M.D., and Wright, S.A, 2015, Storage capacity of the Fena Valley Reservoir, Guam, Mariana Islands, 2014: U.S. Geological Survey Scientific Investigations Report 2015–5128, 31 p., http://dx.doi.org/10.3133/sir20155128.

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    Year Published: 2015

    Climate trends and projections for Guam

    The island of Guam experiences a tropical marine climate, which is warm and humid moderated by seasonal tradewinds and a wet and dry season. The dry season lasts from January to June, while the rainy months are from July to December. Annual rainfall totals 84-116 inches (2133-2946 mm), of which two-thirds fall during the rainy season. Seasonal...

    Gingerich, Stephen B.; Keener, Victoria; Finucane, Melissa L.

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    Year Published: 2013

    The effects of withdrawals and drought on groundwater availability in the Northern Guam Lens Aquifer, Guam

    Owing to population growth, freshwater demand on Guam has increased in the past and will likely increase in the future. During the early 1970s to 2010, groundwater withdrawals from the limestone Northern Guam Lens Aquifer, the main source of freshwater on the island, tripled from about 15 to 45 million gallons per day. Because of proposed military...

    Gingerich, Stephen B.
    The effects of withdrawals and drought on groundwater availability in the Northern Guam Lens Aquifer, Guam; 2013; SIR; 2013-5216; Gingerich, Stephen B.

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    Year Published: 2013

    Estimating hydraulic properties from tidal attenuation in the Northern Guam Lens Aquifer, territory of Guam, USA

    Tidal-signal attenuations are analyzed to compute hydraulic diffusivities and estimate regional hydraulic conductivities of the Northern Guam Lens Aquifer, Territory of Guam (Pacific Ocean), USA. The results indicate a significant tidal-damping effect at the coastal boundary. Hydraulic diffusivities computed using a simple analytical solution for...

    Rotzoll, Kolja; Gingerich, Stephen B.; Jenson, John W.; El-Kadi, Aly I.
    Estimating hydraulic properties from tidal attenuation in the Northern Guam Lens Aquifer, territory of Guam, USA; 2013; Article; Journal; Hydrogeology Journal; Rotzoll, Kolja ; Gingerich, Stephen B.; Jenson, John W.; El-Kadi, Aly I.

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    Year Published: 2013

    Freshwater and drought on Pacific Islands

    Izuka, Scot K.; Keener, Victoria
    Freshwater and drought on Pacific Islands; 2013; Book chapter; Book; Climate Change and Pacific Islands: Indicators and Impacts: Report for the 2012 Pacific Islands Regional Climate Assessment; Scot K Izuka; Keener, Victoria

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    Year Published: 2012

    Seismic hazard assessment for Guam and the Northern Mariana Islands

    We present the results of a new probabilistic seismic hazard assessment for Guam and the Northern Mariana Islands. The Mariana island arc has formed in response to northwestward subduction of the Pacific plate beneath the Philippine Sea plate, and this process controls seismic activity in the region. Historical seismicity, the Mariana megathrust,...

    Mueller, Charles S.; Haller, Kathleen M.; Luco, Nicholas; Petersen, Mark D.; Frankel, Arthur D.
    Seismic hazard assessment for Guam and the Northern Mariana Islands; 2012; OFR; 2012-1015; Mueller, Charles S.; Haller, Kathleen M.; Luco, Nicholas ; Petersen, Mark D.; Frankel, Arthur D.

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    Year Published: 2012

    A water-budget model and estimates of groundwater recharge for Guam

    On Guam, demand for groundwater tripled from the early 1970s to 2010. The demand for groundwater is anticipated to further increase in the near future because of population growth and a proposed military relocation to Guam. Uncertainty regarding the availability of groundwater resources to support the increased demand has prompted an investigation...

    Johnson, Adam G.
    A water-budget model and estimates of groundwater recharge for Guam; 2012; SIR; 2012-5028; Johnson, Adam G.

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    Year Published: 2010

    Groundwater availability study for Guam; goals, approach, products, and schedule of activities

    An expected significant population increase on Guam has raised concern about the sustainability of groundwater resources. In response, the U.S. Geological Survey (USGS), in collaboration with the University of Guam's Water and Environmental Research Institute of the Western Pacific (WERI) and with funding from the U.S. Marine Corps (USMC), is...

    Gingerich, Stephen B.; Jenson, John W.
    Groundwater availability study for Guam; goals, approach, products, and schedule of activities; 2010; FS; 2010-3084; Gingerich, Stephen B.; Jenson, John W.

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    Year Published: 2008

    Ground Water on Tropical Pacific Islands - Understanding a Vital Resource

    To a casual observer, tropical Pacific islands seem idyllic. Closer scrutiny reveals that their generally small size makes them particularly vulnerable to economic and environmental stresses imposed by rapidly growing populations, increasing economic development, and global climate change. On these islands, freshwater is one of the most precious...

    Tribble, Gordon
    Ground Water on Tropical Pacific Islands - Understanding a Vital Resource; 2008; CIR; 1312; Tribble, Gordon

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    Year Published: 2005

    Rainfall-Runoff and Water-Balance Models for Management of the Fena Valley Reservoir, Guam

    The U.S. Geological Survey's Precipitation-Runoff Modeling System (PRMS) and a generalized water-balance model were calibrated and verified for use in estimating future availability of water in the Fena Valley Reservoir in response to various combinations of water withdrawal rates and rainfall conditions. Application of PRMS provides a physically...

    Yeung, Chiu W.
    Rainfall-Runoff and Water-Balance Models for Management of the Fena Valley Reservoir, Guam; 2005; SIR; 2004-5287; Yeung, Chiu W.

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    Aerial imagery of islands are marked to show different data about each island's coast.
    January 1, 2020

    Guam and CNMI Coral Reefs and Coastal Hazard Risk Reduction

    Rigorously Valuing the Role of Guam’s Coral Reefs and the Commonwealth of the Northern Mariana Islands’s Coral Reefs in Coastal Hazard Risk Reduction

    Estimated Annual Benefits

    Maps of Guam and the the Commonwealth of the Northern Mariana Islands showing the distribution of the value of averted direct building damages, indirect economic activity losses, and

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    Brown treesnake
    May 22, 2020

    On May 14, Director Reilly signed a Memorandum of Agreement with the Department of the Navy and the U.S. Fish and Wildlife Service. The MOA provides for continuity of operations for the USFWS and the USGS with construction of new office and lab facilities on the Guam National Wildlife Refuge in conjunction with DOD’s construction of a Marine Corps firing range.

    Simulated change in rainfall on Guam
    October 7, 2019

    Guam’s water demands are anticipated to increase. Potential impacts of sea-level rise and a changing climate on surface-water and groundwater resources are assessed. 

    Close up photo of juvenile brown treesnake on branch.
    March 3, 2016

    Two recent reports of two brown treesnakes on Saipan is prompting federal and state officials to urge citizens of Hawaii, Guam and other Pacific Islands to report any sightings of these invasive snakes to authorities. Snakes can be reported by calling (671) 777-HISS or (670) 28-SNAKE.

    USGS science for a changing world logo
    October 1, 2015

    SANTA CRUZ, Calif. — A new study shows that the combined effect of storm-induced wave-driven flooding and sea level rise on island atolls may be more severe and happen sooner than previous estimates of inundation predicted by passive “bathtub” modeling for low-lying atoll islands, and especially at higher sea levels forecasted for the future due to climate change.

    Image: Severe Coastal Erosion During an El Niño Storm
    September 21, 2015

    SANTA CRUZ, Calif. — The projected upsurge of severe El Niño and La Niña events will cause an increase in storm events leading to extreme coastal flooding and erosion in populated regions across the Pacific Ocean, according to a multi-agency study published today in Nature Geoscience.

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