Author: Office of Communications and Publishing

Key factors have been identified that help determine the vulnerability of public-supply wells to contamination. A new USGS report describes these factors, providing insight into which contaminants in an aquifer might reach a well and when, how and at what concentration they might arrive.

About one-third of the U.S. population gets their drinking water from public-supply wells.

“Improving the understanding of the vulnerability of public-supply wells to contamination is needed to safeguard public health and prevent future contamination,” said Suzette Kimball, acting USGS Director. “By examining ten different aquifers across the nation, we have a more thorough and robust understanding of the complexities and factors affecting water quality in our public supplies.”

The study explored factors affecting public-supply-well vulnerability to contamination in ten study areas across the Nation. The study areas include Modesto, Calif., Woodbury, Conn., near Tampa, Fla., York, Nebr., near Carson City and Sparks, Nev., Glassboro, N. J., Albuquerque, N. Mex., Dayton, Ohio, San Antonio, Tex., and Salt Lake City, Utah.

Measures that are crucial for understanding public-supply-well vulnerability include: 1) the sources of the water and contaminants in the water that infiltrate the ground and are drawn into a well; 2) the geochemical conditions encountered by the groundwater; and 3) the range of ages of the groundwater that enters a well.

 “Common sense might say that wells located near known contaminant sources would be the most vulnerable, but this study found that even where contaminant sources are similar, there are differences in public-supply-well vulnerability to contamination,” said Sandra Eberts, the study team leader.

The study found that conditions in some aquifers enable contaminants to remain in the groundwater longer or travel more rapidly to wells than conditions in other aquifers. Direct pathways, such as fractures in rock aquifers or wellbores of non-pumping wells, frequently affect groundwater and contaminant movement, making it difficult to identify which areas at land surface are the most important to protect from contamination. An unexpected finding is that human-induced changes in recharge and groundwater flow caused by irrigation and high-volume pumping for public supply changed aquifer geochemical conditions in numerous study areas. Changes in geochemical conditions often release naturally occurring drinking-water contaminants such as arsenic and uranium into the groundwater, increasing concentrations in public-supply wells.

Knowledge of how human activities change aquifer conditions that control which contaminants are released to groundwater and how persistent those contaminants are once in the groundwater can be used by water managers to anticipate future water quality and associated treatment costs.

The quality of drinking water from the Nation’s public water systems is regulated by the U.S. Environmental Protection Agency under the Safe Drinking Water Act.  The USGS studies are intended to complement drinking water monitoring required by federal, state and local programs.

This new report, Factors affecting public-supply-well vulnerability to contamination: understanding observed water quality and anticipating future water quality, was done by the USGS National Water-Quality Assessment Program. NAWQA conducts regional and national assessments of the Nation’s water quality to provide an understanding of water-quality conditions, where conditions are getting better or worse over time, and how natural features and human activities affect those conditions.

Learn more about the transport of contaminants to public-supply wells:

• Fact sheet
• Frequently Asked Questions

From Fire Science to Climate Change and Invasive Rodents

About 4,000 people are expected to attend the annual meeting of the Ecological Society of America in Minneapolis from Aug. 4 to 9, 2013. The theme of this year’s conference is Sustainable Pathways: Learning from the Past and Shaping the Future.

Forest Drought Stress in Southwest May Exceed Most Severe Droughts in Last Thousand Years: Severe wildfires and drought-induced tree deaths have increased greatly over the past two decades in the southwestern United States. Historical ecological sources about Southwest fire regimes and forest patterns over the past 10,000 years provide context for recent fire and vegetation trends. Specifically, these sources show that regional forest landscapes are greatly affected by interactive changes among human land management, climate and disturbances. Such linkages are further emphasized through the newly developed  forest drought-stress index (FDSI) for the Southwest, which uses extremely robust relationships among historical tree-ring growth, warm-season temperature and cold-season precipitation  to reconstruct the FDSI back to AD 1000 from a massive archive of tree-ring growth data. This research by USGS, Los Alamos National Laboratory, University of Arizona, and other university partners shows very strong relationships between FDSI and regional forest productivity, tree mortality, bark-beetle outbreaks and wildfire. Moving forward, if temperatures increase as projected, background levels of southwestern forest drought-stress by the 2050s will exceed that of the most severe droughts in the past 1,000 years, which almost certainly means imminent changes in forest structure and composition.  Overall, interactions among climate, land-use history and disturbance processes are driving the current pulse of major forest transitions in the Southwest. In the face of such rapid changes, it is imperative to explore adaptation strategies to foster ecosystem resilience. This work is addressed in two presentations:   1) Land cover change in the Southwest: wildfire risk, drought-induced tree mortality, and the convergence of climate, land management, and disturbance trends in regional forests and woodlands, will be in room 101c on Aug. 9 at 8:40 a.m.  Contact Craig Allen, [email protected], 505-795-1571; and 2)  A forest is not a pan of water: temperature and vapor-pressure deficit as potent drivers of regional forest drought stress, will be in room 101A on Aug. 6 at 9:50 a.m. Contact Park Williams, [email protected], 505-667-6551.

Response of North American Desert Plants to Climate Change: Forecasts for Management and Planning: Forecasted climate warming and changes in precipitation patterns in North American deserts can have a strong impact on plant species already stressed by low water availability. Accurate forecasts of climate-induced changes to desert plant assemblages are needed by managers because dryland ecosystems are prone to abrupt and potentially irreversible degradation and reductions in productivity. To help managers mitigate and adapt to climate change impacts, USGS researchers have synthesized over a century (1906-2012) of climate and vegetation monitoring results from more than 1,500 vegetation plots across the Colorado Plateau, and the Sonoran, Chihuahuan and Mojave deserts. In all of these deserts, dominant plant species and plant diversity responded to drought and elevated temperature.

On the Colorado Plateau, large declines of cool-season perennial bunchgrasses occurred, primarily driven by high temperatures. In the Sonoran Desert, increases in cacti occurred with hotter temperatures, and decreases in warm-season perennial grasses and sub-shrubs occurred with less annual precipitation. Tree and shrub species in the Sonoran Desert were less responsive to changing climatic conditions than other species, but some woody species were sensitive to warmer temperatures and less winter precipitation, especially on south-facing slopes. In the Chihuahuan Desert, many grasses and forbs had large responses to summer precipitation, whereas most woody vegetation showed small responses to winter precipitation. In the Mojave Desert, winter drought was related to declines of shrubs at some sites. USGS research also highlights “climate pivot points” that mark important shifts from increases to decreases in plant abundance along climatic gradients. These results are being used to assist with management decisions, improve monitoring protocols and inform climate change vulnerability assessments for land managers. This presentation (OOS 16-4), Regional signatures of plant response to climate across North American deserts: Forecasts for management and planning, will take place in room 101B on Aug. 7 at 9 a.m. Contact Seth Munson, [email protected], work cell, 303-810-4896.

​Large, Invasive Rodents: Are They Heading Your Way? The nutria  is a large, prolific and water-loving invasive rodent that has become established in many parts of the world after being introduced for the fur industry,  including in the Southeast and the Pacific Northwest regions of the United States. In the Southeast and elsewhere, they wreak havoc in coastal marshes and bald cypress swamps by feeding on the tender roots of plants, seedlings and saplings, completely stripping vegetation in areas where the animals are concentrated. Historically nutria ranges have expanded regionally  northward following milder winters and contracted southward following more severe winters. This USGS study examined the current and potential distribution of nutria in the Pacific Northwest. Due to a string of relatively mild winters nutria populations have been expanding northward in the United States, suggesting that nutria populations could extend their range substantially both in the Pacific Northwest, the Mississippi Valley and the Eastern Seaboard in the future since  climate change models predict milder winter temperatures though the USA. Large-scale management of the species requires knowledge of its current and potential distribution. This presentation, Using a combined hydrologic network-climate model of the invasive nutria (Myocastor coypus) to understand current distributions and range expansion potential under climate change scenarios, will be in room 101H on Aug. 9 at 10:50 a.m.  Contact Catherine Jarnevich, [email protected], 970-226-9439.

In a related study, USGS scientists investigated  the activity patterns of urban nutria populations in Lafayette, La., and Portland, Ore., since little is known about this subject. The study found that daily as well as seasonal activity patterns differed in the two geographic areas, leading to current efforts to explore the role that alternative factors might play in the differing activity patterns. This presentation, Comparison of activity patterns of nutria (Myocastor coypus) between urban pond complexes in Lafayette, Louisiana, USA and Portland, Oregon, USA, will be in Room L100B on Aug. 5 at 1:30 p.m.  Contact Jacoby Carter, [email protected], 337-266-8620. 

People, Cameras, and Action! Teaming Up to Better Understand Phenology: The implications and impacts of climate change on the earth’s phenology – the timing of plant and animal life-cycle events – are increasingly well documented.  Two continental-scale observation networks, PhenoCam and the USA National Phenology Network, which is managed by the USGS, are collaborating with the National Ecological Observatory Network (NEON) to develop more refined phenological monitoring processes and to explore new opportunities for collaborative research. While PhenoCam  quantifies plant phenology by using high-frequency camera monitoring of plant canopies, the USA-NPN contributes ground-based plant and animal data through its crowd-sourcing phenology program, Nature’s Notebook. Both organizations are collaborating with NEON, a continental-scale ecological observing system, to enhance and codify best practices for phenological data collection and to collect and integrate phenological data across multiple spatial scales. The joint efforts of these programs will bridge major knowledge gaps in the field of phenology: not only will cameras provide new techniques for validating satellite-derived land-surface phenology products, but multi-faceted phenology datasets will aid in investigations of the feedback between ecosystem phenology and carbon/water/energy fluxes between the biosphere and atmosphere. This presentation, Integrating Phenocam and USA National Phenology Network continental-scale approaches into NEON phenology data products, will be in room L100I on Aug. 6 at 4:30 p.m. Contact Jake Weltzin, [email protected] (cell: 703-485-5138) or the lead author Michael Toomey, [email protected], 860-986-3804.

Crowd-Sourcing Needed to Take the Pulse of Our Planet: The USA National Phenology Network serves science and society by collecting and organizing valuable data on plant and animal activity across the United States, and by setting global standards for integrated monitoring of plant and animal seasonal activity to understand impacts of climate change on ecological systems.  Most data entered into the Network’s national database are submitted by citizen scientists through the national-scale, multi-taxa phenology observation program, Nature’s Notebook. With 2,500 active participants and more than 2.3 million contributions since the program went live in 2008, volunteers and professional scientists work side by side to observe and record the important phases in the annual life cycles of plants and animals.  This presentation will provide a broad overview of the Network and its partners and participants, but will focus on recent successes embodied in local- to national-scale projects including detection of invasive species, recent and historical trends in phenology, and potential future changes in phenology in the eastern deciduous forest. This presentation, The National Phenology Database: A multi-taxa, continental-scale dataset for scientific inquiry, will be in room LL101 on Aug. 8 at 4 p.m. Contact Jake Weltzin, [email protected], 703-485-5138.

Climate Science Centers: Sparking Collaboration through Research & Resource Management: This special session will introduce participants to the Department of Interior Climate Science Centers (CSCs) and their unique position to unite researchers with cultural and natural resource managers to facilitate a full-cycle approach to the use of research in support of management decisions. A panel composed of leaders from the CSCs, members of the University Consortia and Landscape Conservation Cooperatives, and other collaborators/clients will provide an overview of the approaches used to support the CSC mission: to serve the scientific needs of managers of fish, wildlife, habitats, and ecosystems as they plan for a changing climate by providing scientific support for climate-adaptation identification and implementation of climate-adaptation strategies  across a full range of natural and cultural resources. Participants will benefit from an overview of the CSC support capacities, research solicitation and funding processes with hopes to spark future collaborations. This presentation, Climate Science Centers: now supporting resource management with science at a location near you!, will be in room 101A on Aug. 5 at 10:15 a.m. Contact Stephen Gray ([email protected]), 907-301-7830.

Actionable Climate Change Science Strategically Tying Research to Management and Policy Needs: Prompt access to climate adaptation science for policymakers and managers is vital to effectively plan for climate change in a timely manner.  Up until this point, the scientific community has employed a largely ineffective “conveyor-belt” approach to this process, in which managers both define scientific needs and assign projects to scientists. To streamline this process, the Department of the Interior Climate Science Centers have designed a new approach in which this procedure is executed in a more integrated and promptly actionable method. Using strategic decision-based approaches, the CSCs are creating a series of pilot projects that will focus on developing science outcomes that are tied to strategic management decisions.  Unlike previous models, these teams, consisting of scientists, managers, decision-makers and stakeholders, will work collaboratively throughout the project to assure science outputs are consistent with management needs. These CSC pilot projects will form the basis for a national science agenda that will support climate adaptation decision-making processes. This presentation, Actionable science in an era of rapid climate change, tying observations and predictions to policies and action, will be in Auditorium room 3 on Aug. 8 at 4:10 p.m. Contact Doug Beard,[email protected], 571-265-4623

Bridging the Gap between Science and Decisions:  Climate-science researchers and resource-management decision-makers inhabit different professional worlds, but those worlds must come together to ensure scientifically informed management decisions.   Effective cooperation and interaction between these groups are essential, yet hampered by professional and institutional barriers.  Despite these disconnects, numerous case studies exist in which research has been applied effectively to climate-change management decisions.  These case studies provide a foundation for identifying best practices for both researchers and decision-makers.  These best practices include patient, persistent engagement among relevant parties.  If climate-change research is to be used effectively in decision-making, researchers will need to step outside traditional comfort zones, listen carefully to decision-makers, and maintain continuing dialogue.  New professional models must be encouraged, in which effective engagement and actionable science become part of the professional reward structure in research institutions. This presentation, Seeking Leopold’s Quadrant: how do we foster research that addresses needs of resource-management decision-makers?, will be in room 101C on Aug. 9 at 9:50 a.m. Contact Stephen T. Jackson, [email protected], 307-760- 0750.

U.S. Engagement in the Global Shift in Biodiversity and Ecosystem Services: The Intergovernmental Platform on Biodiversity and Ecosystem Services is in full swing with  109 member countries; its  first IPBES plenary conference took place in Bonn, Germany (also the site of its Secretariat), in January 2013. The United States scientific community should be engaged as full participants in the IPDS  process. The session speakers will discuss the changing landscape in global environmental science initiatives, present the latest updates in the IPBES process, share current and future opportunities for input, and discuss ways to broadly engage the U.S scientific community and other stakeholders in preparation for the December 2013 second IPBES plenary. This presentation, Biodiversity and ecosystem services on the global stage: IPBES and you, will be in room L100F on Aug. 7 at 8:00 p.m. Contact Doug Beard, [email protected], 571-265-4623.

Study will help biologists track wild polar bears’ response to climate change

PORTLAND, Ore. — Tasul, an Oregon Zoo polar bear, recently landed her first white-collar job: research assistant for the U.S. Geological Survey. Her assignment: wearing a high-tech collar to help solve a climate change mystery. 

“Scientists and wildlife managers need to understand how polar bears are responding as sea ice retreats,” said Amy Cutting, Oregon Zoo curator. “But polar bears are notoriously difficult to study in the wild. Direct behavioral observations are nearly impossible.”

Enter Tasul. 

Within her USGS-issued collar is an accelerometer — a device found in most smart phones — that detects minute changes in motion and direction of movement. The device turns Tasul’s everyday behaviors like walking, eating, sleeping and swimming into electronic signals. By recording video of her wearing the collar and matching the behavior to the signal, researchers will create a sort of digital fingerprint for polar bear behavior. 

Once the signals are calibrated, similar collars can be placed on free-roaming bears in the Arctic, allowing researchers to monitor their behavior without having to observe them directly. These collars will be equipped with quick-release mechanisms so scientists can open them remotely and let them drop off the bears after the necessary data has been obtained. 

“Our research shows that polar bears are being displaced from sea ice habitats they formerly used,” said Anthony Pagano, a wildlife biologist with the USGS Alaska Science Center leading this study. “This collaborative project with the Oregon Zoo will help us understand the implications between going to land or staying with the ice as it retreats hundreds of kilometers north into the Arctic Basin.” 

To train Tasul to wear her “techcessory,” keepers slowly acclimated the bear to different types of neckwear over several months, using a special training module that allows close — but safe — access. Zoo visitors may see Tasul wearing the collar periodically throughout the summer. 

“Tasul was the perfect candidate for this study because she already participates in many health-care behaviors voluntarily, as opposed to requiring tranquilization,” Cutting said. “She doesn’t mind wearing the collar and actively cooperates. She is a very curious bear and seems interested in all the extra attention from keepers.” 

The training sessions also gave zoo staffers a chance to get a bear’s-eye view of Tasul’s daily activities by attaching a small GoPro camera to her training collar. Footage from the “Tasul-cam,” is available on the Oregon Zoo website. 

“There’s a lot we need to learn about how climate change is affecting polar bears,” Cutting said, “so it’s very rewarding to see Tasul offering researchers a chance to study this threatened species in a new way.”

This project is part of the U.S. Geological Survey’s Changing Arctic Ecosystems initiative, which includes research on the effects of climate change on polar bears.

The zoo is a service of Metro and is dedicated to its mission of inspiring the community to create a better future for wildlife. Committed to conservation, the zoo is currently working to save endangered California condors, Oregon silverspot and Taylor’s checkerspot butterflies, western pond turtles and Oregon spotted frogs. Other projects include studies on Asian elephants, polar bears, orangutans and giant pandas. Celebrating 125 years of community support, the zoo relies in part on donations through the Oregon Zoo Foundation to undertake these and many other animal welfare, education and sustainability programs. 

The zoo opens at 9 a.m. daily and is located five minutes from downtown Portland, just off Highway 26. 

Newly designed maps covering Indiana, Iowa, North Carolina, Pennsylvania, and Virginia are now available online for free download

To keep pace with a rapid schedule and increasing demand, the USGS has posted new US Topo quadrangles covering Indiana(640 maps), Iowa (1,011 maps), North Carolina (833 maps), Pennsylvania (798 maps) and Virginia (596 maps). These new quads replace the first edition US Topo maps for those states. The replaced maps will be added to the USGS Historical Topographic Map Collection and are also available for free download from The National Map and the USGS Map Locator & Downloader website.

 “The newly redesigned US Topo maps are visually appealing, especially with the addition of the shaded relief layer”, explained Bob Davis, the new US Topo Project Manager. “The addition of shaded relief and other design components demonstrate our commitment to improving the product to meet our users’ needs. I encourage you to download these maps, compare them against previous US Topo maps and drop us your comments. We value your input.”

US Topo maps now have a crisper, cleaner design – enhancing readability of maps for online and printed use. Map symbols are easier to read over the digital aerial photograph layer whether the imagery is turned on or off. Improvements to symbol definitions (color, line thickness, line symbols, area fills), layer order, and annotation fonts are additional features of this supplemental release. Users can now adjust the transparency for some features and layers to increase visibility of multiple competing layers.

US Topo maps are updated every three years, with the initial round completed last September. Maps for Hawaii are currently in production with Alaska production starting later this year.

Re-design enhancements and new features:

• Crisper, cleaner design improves online and printed readability while retaining the look and feel of traditional USGS topographic maps
• New functional road classification schema has been applied
• A slight screening (transparency) has been applied to some features to enhance visibility of multiple competing layers
• Updated free fonts that support diacritics
• New PDF Legend attachment
• Metadata formatted to support multiple browsers
• New shaded relief layer for enhanced view of the terrain
• Military installation boundaries, post offices and cemeteries

US Topo maps are created from geographic datasets in The National Map, and deliver visible content such as high-resolution aerial photography, which was not available on older paper-based topographic maps. The new US Topo maps provide modern technical advantages that support wider and faster public distribution and on-screen geographic analysis tools for users.

The new digital electronic topographic maps are delivered in GeoPDF image software format and may be viewed using Adobe Reader, available as a no cost download.

For more information, go to: http://nationalmap.gov/ustopo/

Proposed US Topo map production graphic showing; states that were updated in 2012, in yellow; states that have, or will be updated in 2013, in red; and states are scheduled to be updated in 2014, in blue. (High resolution image)

A Pacific chorus frog (Pseudacris regilla) in a meadow located in Lassen Volcanic National Park. (High resolution image)

A Pacific chorus frog (Pseudacris regilla) in a meadow located in Point Reyes National Seashore. (High resolution image)

A Pacific chorus frog (Pseudacris regilla) in a meadow located in Yosemite National Park. (High resolution image)

USGS scientist collecting water samples for pesticide analysis. (High resolution image)

SACRAMENTO, Calif. — A study on frogs in remote Sierra Nevada mountain habitats including Yosemite National Park and Giant Sequoia National Monument, detected concentrations of pesticides in frog tissue that potentially came from California’s Central Valley sources. 

“Our results show that current-use pesticides, particularly fungicides, are accumulating in the bodies of Pacific chorus frogs in the Sierra Nevada,” says Kelly Smalling, a research hydrologist with the U.S. Geological Survey and lead author of the study. “This is the first time we’ve detected many of these compounds, including fungicides, in the Sierra Nevada. The data generated by this study support past research on the potential of pesticides to be transported by wind or rain from the Central Valley to the Sierras.”

“Having experts such as hydrologists, chemists, and biologists working together on our staff is part of what USGS can uniquely bring to address complex environmental problems,” said USGS Pacific Region Director, Mark Sogge.

Researchers sampled seven sites across Lassen Volcanic National Park, Lake Tahoe, Yosemite National Park, Stanislaus National Forest and Giant Sequoia National Monument. They collected and analyzed water and sediment samples and frogs for more than 90 different types of pesticides. The Pacific chorus frog (Pseudacris regilla) was chosen because it is commonly found in water bodies across the Sierra Nevada, allowing researchers to compare results across locations.

Two fungicides, commonly used in agriculture, pyraclostrobin and tebuconazole, and one herbicide, simazine, were the most frequently detected compounds, and this is the first time these compounds have ever been reported in wild frog tissue. DDE, a byproduct of the pesticide DDT, was another compound frequently found in frogs collected — though this is not surprising since DDE is one of the most widely detected compounds globally, even decades after DDT was banned in the United States. 

 “One notable finding was that among sites where pesticides were detected in frog tissue, none of those compounds were detected in the water samples and only a few were detected in the sediment samples,” adds Smalling. “This suggests that frogs might be a more reliable indicator of environmental accumulation for these types of pesticides, than either water or soil.”

Pesticides continue to be a suspected factor in the decline of amphibian species across the U.S. and the world, but much remains to be learned about how pesticides impact amphibians, and whether pesticide exposure could influence other amphibian decline factors like the deadly chytrid fungus.

“Documenting the presence of environmental contaminants in amphibians found in our protected federal lands is an important first step in finding out whether the frogs are experiencing health consequences from such exposure,” says Patrick Kleeman, a USGS amphibian ecologist who collected the frog samples. “Unfortunately, these animals are often exposed to a cocktail of multiple contaminants, making it difficult to parse out the effects of individual contaminants.”

The research was conducted by the USGS California Water Science Center and USGS Western Ecological Research Center and was published today in the journal “Environmental Toxicology and Chemistry.” A PDF version of this report along with additional information on this and similar research is available online.

Select Pesticide Types Detected in Study
Compound	Pesticide Type	Lassen Volcanic NP – Reading Peak	Lake Tahoe Page Meadow	Stanislaus NF – Spicer Sno-Park	Stanislaus NF – Ebbetts Pass	Yosemite NP – Summit Meadow*	Yosemite NP – Tioga Pass*	Giant Sequoia NM – Rabbit Meadow
Tebucanoazole	Fungicide	Detected	Detected	Detected	Detected	Not Detected	Detected	Detected
Simazine	Herbicide	Not Detected	Detected	Not Detected	Detected	Not Detected	Not Detected	Detected
Pyraclostrobin	Fungicide	Detected	Detected	Detected	Detected	Not Detected	Detected	Detected
DDE	Insecticide degradate	Detected	Detected	Detected	Detected	Detected	Not Detected	Detected
Data collected during 2009 and 2010 sampling. Asterisk denotes sampling only took place in 2010.

ARCATA, Calif. — Climate change is expected to amplify both droughts and wildfires across the western United States. A new study shows that the effects of drought and fire work in combination, such that forests experiencing drought will see more dead trees in the aftermath of wildfires.

“There is a lot of research showing that climate change is already increasing wildfire frequency and fire spread,” says forest ecologist Phillip van Mantgem of the U.S. Geological Survey and lead author of the study. “But what this study shows is that there is an additional risk to warming trends — namely that trees already stressed by drought may be more likely to die from fires.”

The study was published this week in the journal Ecology Letters, and was a collaborative effort of U.S. Geological Survey, National Park Service and U.S. Forest Service.

Researchers studied conifer forests in areas that had recently experienced prescribed fire across Arizona, California, Colorado, Montana, New Mexico, Oregon, and Utah, examining data from 1984 to 2005 for more than 7,000 individual coniferous trees, including familiar species such as ponderosa pine, white fir, and Douglas fir.

They used this information to estimate the risk factors involved in tree mortality, and they found more trees dying at sites where high temperatures were lengthening the duration of summer drought.

“Our results imply that if current warming trends continue, we can expect to see more frequent tree deaths following fire, which can lead to substantial changes in forests,” says van Mantgem. “Such changes could ultimately affect habitat suitability for wildlife species, aggravate erosion and increase the amounts of carbon dioxide released into the atmosphere from fires.”

The analysis did not consider other factors that could also exacerbate climatic warming effects on tree deaths. For example, warmer temperatures may increase the activity of tree pathogens and insect pests. Also, the forest data were solely drawn from prescribed fire events. Researchers hope to address these factors in future research, and include data from unplanned wildfires.

Nevertheless, the new study offers some valuable insights for forest managers.

“Understanding the relationship between climatic water deficit and tree mortality from fires adds some important wrinkles to how we manage forests,” says Eric Knapp, a research ecologist with U.S. Forest Service’s Pacific Southwest Research Station and a study co-author. “If the goal is to minimize tree mortality while removing accumulated fuels, managers may wish to conduct prescribed burns at times when trees are not already under stress from drought or other problems. However, if the objective is to reduce the density of an overstocked forest, prescribed burning might actually be more effective when done during dryer than normal periods.”

The study was conducted by researchers from the USGS Western Ecological Research Center, NPS National Interagency Fire Center, USFS Pacific Southwest Research Station and the USGS California Water Science Center, with support from the U.S. Joint Fire Science Program.

Locations and tree species included in the data for the van Mantgem et al. 2013 study
Locations	Approximate Tree Species Composition of Forests Plots Studied
Bandelier National Monument, N.M.	ponderosa pine 89%, white fir 6%, Douglas fir 4%
Bryce Canyon National Park, Utah	white fir 49%, Douglas fir 23%, ponderosa pine 22%, limber pine 5%, Rocky Mountain juniper 2%
El Malpais National Monument, N.M.	ponderosa pine 92%, Colorado pinyon 6%, one-seed juniper 1%, Douglas fir 1%
Lubrecht Forest, Mont.	ponderosa pine 62%, Douglas fir 35%, lodgepole pine 2%, western larch 1%
Glacier National Park, Mont.	lodgepole pine 40%, ponderosa pine 39%, Douglas fir 10%, western larch 9%, Engelmann spruce 1%
Golden Gate National Recreation Area, Calif.	coast redwood 77%, Douglas fir 23%
Grand Canyon National Park, Ariz.	ponderosa pine 70%, white fir 10%, Colorado pinyon 10%, Utah juniper 7%, Engelmann spruce 2%, Rocky Mountain fir 1%, Douglas fir 1%
John Day Fossil Beds National Monument, Ore.	western juniper 100%
Lava Beds National Monument, Calif.	ponderosa pine 100%
Lassen Volcanic National Park, Calif.	white fir 50%, ponderosa pine 28%, lodgepole pine 12%, California incense cedar 5%, Jeffrey pine 4%
Pinnacles National Park, Calif.	gray pine 100%
Redwood National Park, Calif.	coast redwood 90%, grand fir 10%
Rocky Mountain National Park, Colo.	lodgepole pine 71%, ponderosa pine 24%, Douglas fir 6%
Sequoia and Kings Canyon National Parks, Calif.	white fir 44%, California incense cedar 17%, sugar pine 15%, giant sequoia 13%, ponderosa pine 9%, silvertip fir 2%
Whiskeytown National Recreation Area, Calif.	knobcone pine 41%, white fir 26%, ponderosa pine 17%, sugar pine 13%, California incense cedar 1%, Douglas fir 1%
Yosemite National Park, Calif.	white fir 39%, California incense cedar 21%, ponderosa pine 21%, silvertip fir 8%, sugar pine 8%, Jeffrey pine 1%, Douglas fir 1%

New research by the U.S. Geological Survey has found that many wetlands created for habitat do very little to improve water quality problems in streams and rivers. Collectively, these wetland design practices represent a missed opportunity to improve the general ecological health of watersheds and wetland ecosystems. 

“Wetlands provide many significant benefits for ecosystems and for people,” said Jerad Bales, acting USGS Associate Director for Water. “While wetlands provide important and unique habitat for great numbers of plants and animals, they also are valuable to humans for flood protection, water quality improvement, and recreation, to name just a few of their benefits. Understanding and improving the contributions of created wetlands to the larger goal of healthy watersheds is a valuable scientific insight.” 

Wetlands are often created for mitigating impacts to wetlands elsewhere. “Restored wetland,” “mitigation wetland,” and “replacement wetland” are similar terms for created wetlands.  Created wetlands typically range from several acres to tens of acres in size and are usually built with berms to regulate water levels precisely.  

These wetland creation practices prevent the exchange of water with adjacent streams and rivers. This lack of hydrologic connectivity to streams then has the consequence of limiting inputs of pollutants (sediment, nitrogen, and phosphorus) to both created and natural wetlands where the detrimental effects of these pollutants could be mitigated. In the watershed of the Chesapeake Bay, reducing sediment, nitrogen, and phosphorus pollution is a focus of large efforts to restore rivers and the Bay. 

USGS ecologist Greg Noe observed, “Unless a wetland can intercept the large amounts of pollutants in streams and rivers, it doesn’t have a chance to remove any of the pollution.” 

Improving habitat for wildlife is one of many reasons for wetland creation and restoration. In some cases, this specific goal may be best managed by limiting nutrient and sediment inputs through limited stream hydrologic connectivity.  However, created wetlands may have poor quality soils which limit the development of these young wetlands and consequently lead to poor habitat.    

USGS scientists, working in collaboration with George Mason University, also found that increasing inputs of sediment, nitrogen, and phosphorus by increasing connectivity to streams stimulated nutrient availability. It is through this process that increased hydrologic connectivity can create more mature wetland systems faster. 

“If you want to maximize the overall water quality benefits of wetland creation,” said Noe, “then design the wetland so that it exchanges water with a stream or river.” 

Learn more

• Research article in Journal of Environmental Quality
• USGS Chesapeake Bay Activities
• USGS National Wetlands Research Center 
• USGS National Research Program

 

Have you ever dropped a stick into a river and wondered where it might go if it floated all the way downstream? Now you can trace its journey using Streamer – a new on-line service from the National Atlas of the United States^®.

Streamer is an online map service that lets anyone trace downstream along America’s major rivers and streams simply by picking a point on a stream.  Streamer will map the route the stream follows.

You can also trace upstream using Streamer. Imagine that you’re standing along the Mississippi River in New Orleans. You’re wondering not only where the river began but also which other streams drained into the Mississippi River before it made its way to your location.  With Streamer you can also:

• locate your area of interest by specifying stream or place names; by entering latitude and longitude coordinates,
• enter the identification number for a U.S. Geological Survey streamflow gaging station,
• find out the names of streams and waterbodies by clicking on them,
• print maps of your downstream and upstream traces,
• create concise or detailed reports for your upstream and downstream traces,
• learn about current or historic streamflow at thousands of locations along America’s streams, and
• find out about the places your stream trace passes through with just a few mouse clicks.

Streamer is fueled by digital hydrographic data for America at one million-scale (an inch is approximately 15.8 miles on the land surface).  These streams and water bodies are generalized from the highly detailed National Hydrography Dataset from The National Map

Streamer lets you navigate rivers in the United States the way other interactive maps help you drive your vehicle from one place to another.  Unlike our nation’s road network, which provides many choices for traveling between two locations, America’s surface waters are somewhat like a network of one-way streets.  You can certainly navigate upstream, but all water flows one way:  downhill.  Use Streamer to trace downstream along that downhill path or use Streamer to trace upstream to highlight rivers at higher elevations that flow to your starting point.

You could stand by the Mississippi River and wonder, “Where did this water come from? Where is it flowing?”  Or with Streamer you can launch your sense of wonder and discovery up and down any of America’s major rivers with a Web connection from your favorite computer or tablet.

For more information: http://nationalatlas.gov/streamer/

The National Atlas of the United States of America^® is a cooperative effort to make geographic information collected by the United States government easier to find, get, and use. Its development is led by the National Geospatial Program of the USGS.  “The National Atlas of the United States of America^®” and “National Atlas of the United States^®” are registered trademarks of the United States Department of the Interior.

Follow the National Atlas on Twitter @nationalatlas

Map generated by Streamer highlighting a downstream trace along three major streams in Georgia and Florida that empty into the Gulf of Mexico. (Larger image)	Map made by Streamer tracing upstream from the Mississippi River near New Orleans, Louisiana, highlighting more than 7,000 large streams that drain to the Gulf of Mexico. (Larger image)

VANCOUVER, Wash. – Scientists and technicians who work at volcano observatories in nine countries are visiting Mount St. Helens and the U.S. Geological Survey Volcano Science Center’s Cascades Volcano Observatory this week to learn techniques for monitoring active volcanoes. Organized by the Center for the Study of Active Volcanoes at the University of Hawaiʻi, Hilo, with support from the VSC-managed joint USGS-USAID Volcano Disaster Assistance Program, the annual program has been training foreign scientists for 22 years. This year’s class includes volcano scientists from Ecuador, Colombia, Peru, Costa Rica, El Salvador, Canada, Indonesia, Italy, and Papua New Guinea.

The International Training Program in Volcano Hazards Monitoring is designed to assist other nations in attaining self-sufficiency in monitoring volcanoes and reducing the risks from eruptions. Through in-class instruction at two USGS volcano observatories, and field exercises in Hawaiʻi and at Mount St. Helens, U.S. scientists are providing training on monitoring methods, data analysis and interpretation, and volcanic hazard assessment, and participants are taught about the use and maintenance of volcano monitoring instruments. Additionally, participants learn about focusing on forecasting and rapid response during volcanic crises, and how to work with governing officials and the news media to save lives and property.

“Science diplomacy, building friendships, and collaboration between the U.S. and other nations through joint scientific work and training can ultimately save many thousands of lives in nations with active volcanoes,” said USGS geologist and VDAP chief, John Pallister. “Avoiding a major volcano disaster through mitigation and advance training is not only better for humanitarian reasons, but it can also be more cost effective than providing foreign aid after a disaster.”

The annual summer course usually takes place only on the Island of Hawaiʻi at the University in Hilo, the USGS VSC Hawaiian Volcano Observatory, and in the field on the slopes of Kīlauea Volcano. This year, in an added component to the course, students are visiting the USGS Cascades Volcano Observatory in Vancouver, Wash. and doing field work at Mount St. Helens to give them the experience of working with a geologically different (more explosive) type of volcano.

“Bringing the class to CVO and including field sessions at Mount St. Helens to complement the Hawaiʻi experience takes advantage of two superb natural laboratories for the study of active volcanism,” said Don Thomas, director of CSAV. “Mount St. Helens has a strong legacy and reputation worldwide as a teaching volcano.” One of this year’s participants noted that he is among the second generation from his country to visit and study modern monitoring techniques at Mount St. Helens.

Providing critical training to international scientists began at HVO, leading to the creation of CSAV to continue the legacy. Since 1990 roughly 200 scientists and civil workers from 25 countries have received training in volcano monitoring methods through CSAV. HVO continues to provide instructors and field experiences for the courses, and VDAP has a long-term partnership with CSAV, providing instructors and co-sponsoring participants from developing countries. VDAP scientists are based at CVO in Washington, so with CSAV course instructors visiting CVO for the first time, there is an opportunity for professional scientific exchanges among researchers who don’t often have a chance to collaborate face to face. For many of the students, attending this training is a rare chance to share their experiences and challenges with other participants from around the world.

VDAP is supported by the U.S. Agency for International Development, Office of Foreign Disaster Assistance. Since 1985, VDAP has worked to reduce fatalities and economic losses in countries experiencing volcano emergencies. At the request of host countries, and working through USAID, an experienced team of USGS scientists can rapidly respond to developing volcanic crises worldwide, and provide consultation, assistance with forecasting, remote sensing data, and monitoring equipment. VDAP teams work in the background, providing support to their hosts who are the responsible parties for hazard communication. Between crises, VDAP scientists work with international partners to build and improve volcano-monitoring systems and to conduct joint activities, including workshops and on-the-job training, to reduce volcanic risk and improve understanding of volcanic hazards. 

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Description: (for ALL photos): Participants in the 2013 summer “International Training Program in Volcano Hazards Monitoring” organized by the Center for the Study of Active Volcanoes at the University of Hawaiʻi, Hilo, with support from the USGS-USAID Volcano Disaster Assistance Program, visit the USGS Cascades Volcano Observatory after having just spent time at the USGS Hawaiian Volcano Observatory.

USGS volcano scientist, Andy Lockhart discusses telemetry options with Syegi Kunrat of Indonesia.(Larger image)	Domenico Mangione (Italy) and Celina Kattan (El Salvador) assemble the framework of a telemetry station in the parking lot of the USGS Cascades Volcano Observatory.(Larger image)
The CSAV International training group practices assembling telemetry stations at the USGS Cascades Volcano Observatory.(Larger image)	International members of the 2013 CSAV volcano monitoring summer training class pose at the USGS Cascades Volcano Observatory sign.(Larger image)
Mikhail Herry from Papua New Guinea, (wearing a CSAV shirt) watches as McChesney demonstrates how to test a battery in the field.(Larger image)

Long-Range Nesting Patterns Reveal New Habitats and Risks

DAVIE, Fla.– Threatened loggerhead sea turtles in the northern Gulf of Mexico can travel distances up to several hundred miles and visit offshore habitats between nesting events in a single season, taking them through waters impacted by oil and fishing industries. 

Evidence from a U.S. Geological Survey study challenges the widely-held view that sea turtles remain near one beach throughout the nesting season and suggests the threatened species may require broader habitat protection to recover. The findings also cast new uncertainties on current estimates of the size of the species’ Gulf of Mexico subpopulation. 

“This is the first study to locate and quantify in-water habitat use by female loggerheads in the Northern Gulf of Mexico subpopulation during their reproductive periods,” said lead author Kristen Hart, a USGS research ecologist. “Our tracking results show they depend on a much broader range of habitat during this critical part of their lives than was previously thought to be required.” 

The study reveals detailed loggerhead movements during “inter-nesting” periods, showing patterns that vary for individual turtles. Generally, this period begins when a female returns from open seas around May and lasts roughly until September. Up until now, efforts to protect the species generally centered on beaches with high nesting activity under the assumption that once turtles had nested on those beaches, they either remained in their immediate vicinity or migrated back out to sea. 

“The satellite data and our observations on the ground tell the same story: loggerheads in this subpopulation nest at multiple beaches, sometimes hundreds of miles apart,” said Hart. “Some of the females we captured and tagged on beaches in Alabama traveled over 250 miles to nest in Florida, where we recaptured them. Likewise, we also captured some females in Alabama that had previously been tagged at the Florida site in earlier breeding years.”  

Researchers used the same statistical technique for analyzing their movements that enabled them to pinpoint loggerhead feeding hotspots at sea last year and, more recently, locate Kemp’s ridley feeding grounds in the Northern Gulf by differentiating between behavioral modes. They analyzed where 39 adult female sea turtles went after they nested on beaches in Alabama and Florida between 2010 and 2012 to learn where they spent time in the water during the breeding season before migrating back to sea. 

“We were surprised to find a lot of variation in their behavior,” said co-author and USGS biologist Meg Lamont.  “On average, the tagged turtles visited areas about 33 kilometers (20 miles) from shore and moved about 28 kilometers (17 miles) to nest at another beach. Several of them journeyed more than 200 kilometers (124) miles to nest at additional beaches, while others simply cruised back out to sea after the first nest.”  

The results of the study explain a mystery that had puzzled Lamont, who has 16 years of data from the St. Joseph Peninsula in Florida showing that few of the nesting loggerheads they tagged returned to nest again on the Peninsula. “We didn’t know whether they were dying or simply nesting elsewhere,” explained Lamont, “Now we know they aren’t as faithful to one nesting site as was once thought.”  

One of the turtles that Lamont tagged in 2002 appeared at Hart’s site in Alabama, nearly a decade later. In fact, the researchers saw several turtles nesting both in Alabama and the St. Joseph Peninsula (roughly 250 miles apart) within a period of just two weeks.  

“These data show it is not sufficient to just protect habitat around high density nesting beaches – such as the St. Joseph Peninsula – because many turtles that nest on the Peninsula use the entire region from the eastern Florida Panhandle to Louisiana,” said Lamont.

There could also be fewer female loggerheads nesting in the northern Gulf of Mexico than current estimates suggest because they are calculated using nest numbers. “Our research shows that the same turtle could easily deposit eggs in Alabama and Florida if nests are separated by about 2 weeks,” said Hart. “Population numbers based on nest counts may therefore be biased upwards if nests at the two sites were assumed to have come from two different females.”  

The study also noted that the areas the loggerheads used during the inter-nesting period overlapped with human uses, such as shrimp trawling and oil and gas platforms. A map showing sea turtle habitat use in relation to these activities can be found in the article, “Movements and Habitat-Use of Loggerhead Sea Turtles in the Northern Gulf of Mexico during the Reproductive Period,” which was published July 3 in the journal PLOS One.

“We are working towards defining areas where sea turtles concentrate their activities at sea, effectively building a map of in-water turtle hotspots,” said Hart. “The more we know about their habitat use, the more questions are raised about their behavior and ability to adapt. We hope to build a better understanding of how frequently turtles return to these same locations, and whether or not they move to new habitats when those locations are impacted. This type of information would be extremely valuable for developing management strategies to help in population recovery.”

Lesser prairie-chicken nest survival may decrease to a level considered too low to sustain the current population by 2050, according to a new report by Texas Tech University and the U.S. Geological Survey. 

The publication assesses the effects of temperature and precipitation change on lesser prairie-chicken reproduction on the Southern High Plains. The authors noted that these findings do not suggest that the prairie chicken will become extinct, but rather indicate potential for population declines in New Mexico and West Texas if no actions are taken. The study can be used by resource managers to identify and offset effects of changes in climate on the lesser prairie-chicken.

Scientists looked at modeled predictions of climate change and reproductive data from lesser prairie-chickens from 2001-2011 to determine how weather conditions affect reproductive success in the Southern High Plains. Scientists focused on prairie chicken habitat in the southwestern part of their distribution in New Mexico and West Texas. The study assessed the potential changes in number of eggs laid in a nest, incubation start date and nest survival for 2050 and 2080. The full peer-reviewed report is available online.

“Results from this study are based on current climate projections, and it doesn’t necessarily mean that lesser prairie-chickens will experience a population decline,” said Blake Grisham, Texas Tech University scientist and lead author of the study. “It is very possible that improving connectivity and quality of existing habitats over the next few decades may offset the negative effects of a changing climate.”

Scientists conducted 1,000 model simulations using future weather variables to predict future reproductive parameters for this species. Climate forecasts indicate that the Southern High Plains will become drier with more frequent extreme heat events and decreased precipitation. Increased temperatures and reduced humidity may lead to lesser prairie-chicken egg death or nest abandonment. The research showed that warm winter temperatures had the largest negative effect on reproductive success. Scientists suggest that above-average winter temperatures were correlated with La Niña events, which were ultimately a good predictor of drought that reduced available nesting cover in the spring.

“Lesser prairie-chicken survival relies on the combination of habitat and climate, and larger areas of habitat provide more opportunities for them to survive a difficult climate,” said USGS scientist and study co-author Clint Boal. “Larger expanses of habitat means that more chickens will live and nest there, allowing for better odds that some nests will be successful.”

The lesser prairie-chicken has experienced widespread declines in abundance and distribution, with some estimates suggesting greater than a 90 percent decrease of the population. The species is currently proposed as threatened under the U.S. Endangered Species Act and is a priority species under the Great Plains Landscape Conservation Cooperative.  

This is the first study to examine how seasonal weather affects reproductive conditions of the lesser prairie-chicken. One aspect that was not incorporated into this modeling is predicted future frequencies of extreme weather events. This model uses average temperatures and does not take into account how a record hot or cold day might affect nest survival.    

This study was conducted by the Texas Cooperative Fish and Wildlife Research Unit in collaboration with the Texas Parks and Wildlife Department, Wildlife Plus Consulting, Grasslans Charitable Foundation, the Kansas Cooperative Fish and Wildlife Research Unit, the Great Plains Landscape Conservation Cooperative and the Nature Conservancy.

 

A new USGS report describes how the health of our Nation’s streams is being degraded by streamflow modifications and elevated levels of nutrients and pesticides.

The national assessment of stream health was unprecedented in the breadth of the measurements—including assessments of multiple biological communities as well as streamflow modifications and measurements of over 100 chemical constituents in water and streambed sediments.

“Healthy streams are an essential part of our natural heritage. They are important to everyone — not only for recreation and for public water supply and public health, but also for economic growth,” said USGS acting Director Suzette Kimball. “A broad understanding of the complex factors that affect stream health across the Nation will aid us in making efficient, long term decisions that support healthy streams.”

 

The ability of a stream to support algal, macroinvertebrate, and fish communities is a direct measure of stream health. USGS image. (High resolution image)

To assess ecological health, USGS scientists examined the relationship of the condition of three biological communities (algae, macroinvertebrates, and fish) to man-made changes in streamflow characteristics and water quality. The ability of a stream to support these biological communities is a direct measure of stream health.

Stream health was reduced at the vast majority of streams assessed in agricultural and urban areas. In these areas, at least one of the three aquatic communities was altered at 83 percent of the streams assessed.

In contrast, nearly one in five streams in agricultural and urban areas was in relatively good health, signaling that it is possible to maintain stream health in watersheds with substantial land and water-use development.

“Understanding the interacting factors that impact multiple aquatic communities is essential to developing effective stream restoration strategies,” said Daren Carlisle, USGS ecologist and lead scientist of this study.

Streamflow modification is a critical factor in stream health because the life cycles of many native fish species are synchronized with—and therefore dependent upon—the timing and variation in natural streamflow patterns.

Annual low and high streamflows were modified in 86 percent of the streams assessed. Over 70,000 dams and diversions contribute to modified streamflows across the Nation. Flood control structures in the East and groundwater withdrawals for irrigation and drinking water in the arid West also contribute to streamflow modification.

Biological alteration associated with elevated nutrient concentrations was most pronounced for algal communities. The occurrence of altered algal communities increased by as much as 40 percent above baseline in streams with elevated nitrogen and phosphorus concentrations.

Macroinvertebrate communities were altered by as much as 40 percent above baseline conditions in streams with elevated pesticide toxicity. Although concentrations of insecticide mixtures, such as chlorpyrifos, carbaryl, and diazinon, in streams are highly variable seasonally and from year to year, they can reach levels that are harmful to aquatic life, particularly in agricultural and urban streams.

Ecological Health in the Nation’s Streams, 1993-2005 (USGS Circular 1391, 132 pp.) is available online.

Learn more about the ecological health of the Nation’s streams from related USGS reports, a fact sheet, and a video. The site also features educational illustrations of natural, agricultural, and urban stream ecosystems (PDF format, suitable for posters).

This study was done by the USGS National Water-Quality Assessment Program, which conducts regional and national assessments of the nation’s water quality to provide an understanding of water-quality conditions, whether conditions are getting better or worse over time, and how natural processes and human activities affect those conditions.

The USGS also continuously monitors water levels and streamflows at thousands of the nation’s streams on a real-time basis. These data are available at USGS Current Streamflow Conditions. Water-quality data from more than 1,300 locations, much of it in real-time, are available through USGS Water Quality Watch.

Finds surprising growth patterns in the Florida Keys

Report is available on-line via open access at the publisher. View the abstract on the SpringerLink website.

Photo of SCUBA diver working on a clacification station at Fowey Rocks, Biscayne National Park, Florida: Photo credit: Carlie Williams (USGS). (High resolution image)

ST. PETERSBURG, Fla. — A new more sensitive weight-based approach for monitoring coral growth in the wild has been developed by U.S. Geological Survey researchers leading to more definitive answers about the status of coral reefs.

Corals and other marine organisms build their skeletons and shells through calcification, the biological process of secreting calcium carbonate obtained from ocean water. This new approach to measuring corals can provide finer-scale resolution than traditional linear measurements of coral growth. 

“A coral may grow two millimeters in height on the left side of the colony and five millimeters on the right, so linear measurements are inherently variable and require sampling hundreds of corals to detect changes in growth over time… our method requires only 10 corals per site,” said Ilsa Kuffner, USGS scientist and lead author of the study.

Using the weight-based approach, Kuffner’s team discovered that colonies of the Massive Starlet coral calcified about 50 percent faster in the remote Dry Tortugas National Park compared to three sites along the rest of the island chain from Miami to Marathon, Fla. The reasons behind this surprising pattern are not clear, leaving a mystery sure to pique the interest of many reef managers.

The new approach could be highly useful to managers because it can detect small changes over space and time due to its high level of precision. Also, the method uses inexpensive and easy-to-find materials, and no corals are harmed in the process.  

“This tool provides the kind of scientific information needed to manage coral reefs at the ecosystem scale by looking at the relationships between coral health, climate change, and water-quality. It provides partners and reef managers with better, more sensitive metrics to assess coral growth, identify the most important variables, and prioritize strategies to protect and preserve these valuable ecosystems,” said Acting USGS Director, Suzette Kimball. “It is also one of the ways USGS science is advancing the National Ocean Policy by supporting a number of on-the-ground priority actions.”

A next step in understanding declines in coral growth is discerning the different components of water-quality that are driving calcification rates, and this can only be achieved through the cooperation of reef managers and scientists around the world. The real power in the new approach will be realized if it is applied across many reefs that naturally have different temperature regimes, water quality, and pH conditions. 

“The study results suggest that we should pay more attention to different aspects of water-quality if we hope to understand and predict what will happen to coral reefs as oceans continue to change,” said Kuffner. 

According to Kuffner, managers already know coral reefs are in decline, but they want to know why. They need a linkage between cause and effect that explains why reefs are not growing like they used to or are not recovering from disease or die-off events. Correlating finely measured coral growth rates with water quality and other environmental information is an important step to making these linkages so they can inform management decisions. 

Photo of coral: Massive Starlet coral, Siderastrea siderea Photo credit: Ilsa B. Kuffner (USGS) (High resolution image)

Coral reefs are in decline globally with the National Oceanic and Atmospheric Administration currently proposing to list 66 reef-building coral species under the Endangered Species Act. Identifying the cause of the decline is not straightforward. Oceanographic instruments have confirmed that the ocean is warming, acidifying, and changing in other aspects of water quality. The first two are a direct result of altered carbon distribution due to burning of fossil fuels; the latter stems largely from land-use changes. Laboratory studies demonstrate that all three of these environmental stressors can hinder coral growth, but linking the causative agents to reef decline in the natural environment requires dependable, precise methods to detect change over time. 

This study is part of a larger USGS Coral Reef Ecosystem Studies project aimed at understanding the status, construction, and resilience of shallow-water reef environments and forecasting future change to inform reef management strategies. Current areas of research include the Dry Tortugas, U.S. Virgin Islands and Biscayne National Parks, and selected areas of the Florida Keys National Marine Sanctuary.

To learn more about the Coral Reef Ecosystem Studies Project, please visit the website.

USGS Reports To Help Community Planners, Emergency Managers

ST. PETERSBURG, Fla. — The probability of hurricane-induced coastal change on sandy beaches from Florida to New York has been assessed for the first time in two U.S. Geological Survey studies released today. 

The two reports — one assessing the coastline from Florida to North Carolina, the other from Virginia to New York — can function as part of a “virtual toolkit” for U.S. Atlantic coast community planners and emergency managers as they make decisions on how to best address coastline vulnerabilities.

The reports show that even during the weakest hurricane, a category 1 with winds between 74 and 95 miles per hour, 89 percent of the dune-backed beaches from Florida to New York coast are very likely to experience dune erosion during a direct landfall.  But scientists involved say the strength of the studies is in their ability to predict coastal change in specific areas. 

The online mapping tool, based on a USGS state-of-the-art model, will allow community planners and emergency managers to focus on a specific storm category and see the predicted coastal change in their area.  The information may help them with decisions ranging from changes to building codes and locations for new construction, to determining the best evacuation routes for future storms.

“The USGS has been working on identifying storm-driven coastal change hazards for more than a decade,” said Hilary Stockdon, a USGS research oceanographer and co-author of the studies. “The data collected and modeling capabilities developed during that period are what’s enabled us to complete these regional assessments of predicted coastal change, providing key information to decision makers working to build more resilient communities and take actions to protect lives and property before storms hit.”

For the entire study area, the modeling also shows that during a category 1 hurricane, storm waves are expected to increase water levels at the shoreline by approximately 150 percent above storm surge levels. This means in a category 1 storm that waves alone would raise water levels at the shoreline by approximately 2.6 to 3.3 meters (8.5 to 10.8 feet), depending on the region.  Results show that waves play a significant role in elevating water levels during lower category storms, while storm surge is the major contributor to high water levels in stronger storms.

In an assessment of dune height from Florida to New York, the researchers found the southeast coasts, because of their lower dune elevations, more likely to experience overwash, or the landward movement of beach sand, than coastlines farther north.  Dune heights from Delaware to New York are 1.4 meters (4.6 feet) higher, on average, than the dunes from Maryland south to Florida.  The South Carolina coast, where average dune elevations are only 2.9 meters (9.5 feet), is the most vulnerable to overwash of the beaches studied. Ninety-six percent of coastal locations in the state are likely to overwash if a category 1 hurricane makes landfall there.

Prior to Hurricane Sandy, dunes on New York’s south shore were among the highest on the Atlantic coast, and as such during a category 1 storm only 9 percent of coastal areas were likely to overwash.  Still, these high dunes were vulnerable to extreme erosion during a category 1 hurricane, with 76 percent of the dunes very likely to be experience erosion.  This was observed during Hurricane Sandy, which made landfall as an extra-tropical cyclone but pounded the beach with hurricane waves and surge. The protective sand dunes along barrier islands in New Jersey and New York were completely eroded in places, increasing vulnerability to more extreme erosion during future storms.  

But vulnerability doesn’t just come down to dune height; scientists credit the continuity of the dunes as being one of the key reasons coastal vulnerabilities vary greatly along the coast.    

“Large areas of the South Carolina coast are very likely to erode during hurricanes due to long, continuous stretches of low dunes.  In other areas, such as Delaware and New York, the mix of high and low dune elevations creates a more complex picture of vulnerabilities where relatively safe areas are adjacent to areas that are likely to be inundated,” said Stockdon.

“Inundation” is a process by which an entire beach system is submerged and, in extreme cases, can result in island breaching.  Only 9 percent of the entire study region is very likely to be inundated in a category 1 storm, although the percent is significantly higher in some regions.  If a category 1 storm makes landfall on the South Carolina coast, for example, 34 percent of the beaches and dunes there are very likely to be inundated. 

Beaches serve as a natural buffer between the ocean and inland communities, ecosystems, and natural resources.  However, these dynamic environments move and change in response to winds, waves, and currents.  During extreme storms, changes to beaches can be large, and the results are sometimes catastrophic.  Lives may be lost, communities destroyed, and millions of dollars spent on rebuilding.

These reports and the mapping tool can serve as an important resource for coastal planners and emergency managers as they work to protect their communities from future storms.

Both publications and internet mapping services are available online. 

National assessment of hurricane-induced coastal erosion hazards: Mid-Atlantic Coast: U.S. Geological Survey Open-File Report 2013–1131, Doran, K.S., Stockdon, H.F., Sopkin, K.L., Thompson, D.M., and Plant, N.G.

National assessment of hurricane-induced coastal erosion hazards: Southeast Atlantic Coast: U.S. Geological Survey Open-File Report 2013-1130, Stockdon, H.F., Doran, K.J., Thompson, D.M., Sopkin, K.L., and Plant, N.G., 2013

An assessment of the Gulf Coast vulnerability to hurricanes was released in May 2012. A news release was issued announcing the results.

ANCHORAGE, Alaska — Low-pathogenic avian influenza viruses with Eurasian genes have been found among birds in the Yukon-Kuskokwim Delta of western Alaska, supporting the theory that the area is a potential point of entry for foreign animal diseases such as the more highly pathogenic H5N1 strain, according to a new study by U.S. Geological Survey scientists.

The Yukon-Kuskokwim Delta is an important breeding ground for many bird species and is located where multiple migratory flyways converge, providing opportunities for avian pathogens to spread. Among these pathogens are H5N1 avian influenza, which occurs in both low-pathogenic and the more dangerous highly pathogenic forms.  

After the outbreak of the highly pathogenic H5N1 strain of avian influenza in wild birds of China in 2005, the USGS and the U.S. Fish and Wildlife Service, in cooperation with the Yukon-Kuskokwim Health Corporation,  the Kawerak Tribal Corporation and other partners, conducted four years of testing wild migratory birds in western Alaska for the highly pathogenic H5N1 strain.  

In a paper published by the USGS and the USFWS scientists no highly pathogenic forms of avian influenza were found in more than 24,000 samples tested from 82 species on the Yukon-Kuskokwim Delta from 2006 to 2009, however, 90 low-pathogenic strains of the virus were obtained from these Alaskan samples.  Low-pathogenic avian influenza viruses are common among wild birds and do not cause mortalities to the degree often seen with highly pathogenic forms of the virus, said USGS research geneticist Andrew Reeves, lead author of the paper. The significance of this study is that it demonstrates that viruses with genes of Eurasian origin can enter North America via migratory birds. 

In addition, researchers discussed how low pathogenic virus samples from birds further from Asia contained fewer genes attributable to Eurasian strains.  

“This finding supports a ‘dilution-by-distance’ idea we’ve hypothesized in other studies,” Reeves said. “Birds sampled further from Asia, such as in the lower-48 United States, very rarely contain avian influenza viruses with Eurasian genes, but in Alaska they are more common.”  

“Many of the bird samples used in the study were provided by subsistence hunters in 11 villages throughout the Yukon-Kuskokwim Delta who collected samples from many species, including ducks, geese, swans and shorebirds,” said Kim Trust of the USFWS.  

“Without our partners in western Alaska, we would not have the robust data set that supports the findings in this paper,” Trust said.  

Reeves added that the current study provides support for retaining the Yukon-Kuskokwim Delta as a high-priority region for the surveillance of potentially harmful avian pathogens. 

The paper in the Journal of Wildlife Diseases, “Genomic analysis of avian influenza viruses from waterfowl in western Alaska, USA,” by Andrew Reeves, John Pearce, Andrew Ramey, Craig Ely, Joel Schmutz, Paul Flint, Dirk Derksen and Hon Ip of the USGS and Kimberly Trust of the USFWS, is available online. 

WASHINGTON — NASA transferred operational control Thursday of the Landsat 8 satellite to the U.S. Geological Survey (USGS) in a ceremony in Sioux Falls, S.D.

The event marks the beginning of the satellite’s mission to extend an unparalleled four-decade record of monitoring Earth’s landscape from space. Landsat 8 is the latest in the Landsat series of remote-sensing satellites, which have been providing global coverage of landscape changes on Earth since 1972. The Landsat program is a joint effort between NASA and USGS.

NASA launched the satellite Feb. 11 as the Landsat Data Continuity Mission (LDCM). Since then, NASA mission engineers and scientists, with USGS collaboration, have been putting the satellite through its paces — steering it into its orbit, calibrating the detectors, and collecting test images. Now fully mission-certified, the satellite is under USGS operational control.

“Landsat is a centerpiece of NASA’s Earth Science program,” said NASA Administrator Charles Bolden in Washington. “Landsat 8 carries on a long tradition of Landsat satellites that for more than 40 years have helped us to learn how Earth works, to understand how humans are affecting it and to make wiser decisions as stewards of this planet.”

Beginning Thursday, USGS specialists will collect at least 400 Landsat 8 scenes every day from around the world to be processed and archived at the USGS Earth Resources Observation and Science Center in Sioux Falls. The newest satellite joins Landsat 7, which launched in 1999 and continues to collect images. Since 2008, USGS has provided more than 11 million current and historical Landsat images free of charge to users over the Internet.

“We are very pleased to work with NASA for the good of science and the American people,” said U.S. Interior Secretary Sally Jewell in Washington. “The Landsat program allows us all to have a common, easily accessible view of our planet. We are especially proud that Landsat images have not only been the starting points for some of the world’s best commercial innovations in earth imagery, but also are available free of charge.”

Remote-sensing satellites such as the Landsat series help scientists observe the world beyond the power of human sight, monitor changes to the land that may have natural or human causes, and detect critical trends in the conditions of natural resources.

The 41-year Landsat record provides global coverage at a scale that impartially documents natural processes such as volcanic eruptions, glacial retreat and forest fires and shows large-scale human activities such as expanding cities, crop irrigation and forest clear-cuts. The Landsat Program is a sustained effort by the United States to provide direct societal benefits across a wide range of human endeavors including human and environmental health, energy and water management, urban planning, disaster recovery, and agriculture.

With Landsat 8 circling Earth 14 times a day, and in combination with Landsat 7, researchers will be able to use an improved frequency of data from both satellites. The two observation instruments aboard Landsat 8 feature improvements over their earlier counterparts while collecting information that is compatible with 41 years of land images from previous Landsat satellites. 

Turtles dine in waters affected by oil spills, fishing and oxygen depletion

CORPUS CHRISTI, Texas – The favored feeding grounds of the endangered Kemp’s ridley sea turtle coincide with some Gulf of Mexico waters that are subject to oil spills, extensive commercial fishing and oxygen depletion.

These first-of-their kind details on foraging locations and migration patterns of the Kemp’s ridley sea turtle are from a new National Park Service and U.S. Geological Survey study, providing resource managers new information on how best to manage the species.

Scientists do not know why the turtles feed where they do, how human influences may affect turtle health or behavior, or whether human impacts on their chosen feeding areas might change their future foraging behavior. 

The researchers identified the feeding grounds of the Kemp’s ridley, considered the most endangered and smallest hard-shelled sea turtle in the world, by analyzing 13 years of satellite-tracking data.  The researchers tagged turtles at nesting sites between 1998 and 2011 and tracked them as they went on to foraging locations throughout the Gulf. Turtles from two major nesting sites in the study fed at specific locations off the coasts of Louisiana and Mississippi and at other locations in the Gulf.  

Donna Shaver, chief of the National Park Service’s Sea Turtle Science and Recovery Division at Padre Island National Seashore, said,  “Protecting feeding grounds for adult female sea turtles is important for the recovery of the species and this new information is important for future planning and restoration decisions.”

Cooperative efforts between Mexico and several U.S. agencies have helped increase the population of this species of sea turtle. Species support includes protection of nesting turtles and their eggs on nesting beaches and reducing threats from fishing. The number of Kemp’s ridleys nesting in the region has increased from 702 nests in 1985 to about 22,000 in 2012.

The research, in which dozens of adult female sea turtles were tagged after they nested on the beach at Padre Island National Seashore offers a “first glimpse” of how and when the turtles feed, said Kristen Hart, a research ecologist for the USGS Southeast Ecological Science Center. “We were able to decipher Kemp’s ridleys foraging behavior in space and time using a combination of satellite telemetry and new statistical techniques.”

Previous tracking studies generally showed Kemp’s ridley migration from nesting beaches along the Gulf of Mexico coastline to northern Texas and Louisiana with some turtles migrating as far as peninsular Florida. Until the current study, it was not known whether turtles displayed movement behavior indicative of foraging or migration at a particular location. The modeling done as part of the study has allowed scientists to pinpoint where these turtles may be feeding, a key finding in terms of identifying important at-sea habitats for these imperiled turtles.  

In addition to tagging turtles at Padre Island, Shaver said the researchers tagged turtles at nesting sites in Rancho Nuevo, Mexico, about 200 miles south of Padre Island. Shaver added, “This is the first time we’ve tracked the Mexican turtles to habitats in the Northern Gulf of Mexico.”

The feeding habitat discovery came when scientists differentiated time the sea turtles spent in feeding or breeding mode from the time spent migrating. Once scientists located when and where the turtles were feeding, they were also able to coarsely profile what type of habitat offered the best feeding grounds for Kemp’s ridleys.

“We have a lot more to learn about how and why Kemp’s ridleys use their foraging sites,” Hart said.  “We don’t know enough about individual turtles yet to draw conclusions about their behavioral responses to conditions at foraging grounds, and we are just beginning to understand differences among different sea turtles species. For example, Kemp’s ridleys appear to migrate, then feed, and then migrate to a final feeding destination. Loggerheads, in contrast, seem to head straight for feeding hotpots.”

Hart added, “We plan to continue fleshing out the major scientific gaps that managers need addressed in order to develop long-term survival and recovery plans for Kemp’s ridleys.”

Read the study, “Foraging area fidelity for Kemp’s ridleys in the Gulf of Mexico,” in the journal Ecology and Evolution.

About Kemp’s Ridley sea turtles

The Kemp”s ridley turtles are considered the smallest sea turtle in the world, with adults reaching about 2 feet long and weighing up to 100 pounds. They are found in the Gulf of Mexico and the Atlantic seaboard and feed primarily on crab species living on the sea floor (or benthos) of shallow waters. Their name comes from a fisherman named Richard Kemp of Key West, Florida, who provided the specimen used to describe the species in 1880. They are related to olive ridleys, another small sea turtle found around the world.

Kemp’s ridley sea turtles are listed in the U.S. and internationally as endangered throughout their range due to dramatic population declines in the 20^th century. The vast majority of Kemp’s ridleys converge on three major sites in the state of Tamaulipas, Mexico every year to nest. In the early 1960s, a film was discovered that showed an estimated 40,000 females nesting at one particular site – Rancho Nuevo – on one day.

Threats to Kemp’s ridleys once included egg collection, overhunting, and unintentional capture during fisheries operations.  Today, most of their nesting occurs on protected lands. Nonetheless, nesting habitat is still sometimes disturbed by natural and human events such as hurricanes, oil spills, or erosion. Also, activities that affect the seafloor (what scientists call benthic habitat) can disturb their feeding habitat. This includes bottom trawling and dredging. Another known threat is incidental capture, or unintentional by-catch, in fishing gear.

Although conservation efforts began in the 1960s, the number of nesting females continued to decline. By 1978, the U.S. and Mexico started a multi-agency effort to safeguard Kemp’s ridleys from extinction by encouraging nesting at Padre Island National Seashore in Texas. Biologists have since been monitoring nesting activity, and there has been an increase in the number of nests since 1985.

END

About the National Park Service: More than 20,000 National Park Service employees care for America’s 401 national parks and work with communities across the nation to help preserve local history and create close-to-home recreational opportunities. Learn more at www.nps.gov.

CORVALLIS, Ore. — The first-ever estimate of how fast frogs, toads and salamanders in the United States are disappearing from their habitats reveals they are vanishing at an alarming and rapid rate.

According to the study released today in the scientific journal PLOS ONE, even the species of amphibians presumed to be relatively stable and widespread are declining. And these declines are occurring in amphibian populations everywhere, from the swamps in Louisiana and Florida to the high mountains of the Sierras and the Rockies.

The study by USGS scientists and collaborators concluded that U.S. amphibian declines may be more widespread and severe than previously realized, and that significant declines are notably occurring even in protected national parks and wildlife refuges.

“Amphibians have been a constant presence in our planet’s ponds, streams, lakes and rivers for 350 million years or so, surviving countless changes that caused many other groups of animals to go extinct,” said USGS Director Suzette Kimball. “This is why the findings of this study are so noteworthy; they demonstrate that the pressures amphibians now face exceed the ability of many of these survivors to cope.”

On average, populations of all amphibians examined vanished from habitats at a rate of 3.7 percent each year. If the rate observed is representative and remains unchanged, these species would disappear from half of the habitats they currently occupy in about 20 years. The more threatened species, considered “Red-Listed” in an assessment by the global organization International Union for Conservation of Nature, disappeared from their studied habitats at a rate of 11.6 percent each year. If the rate observed is representative and remains unchanged, these Red-Listed species would disappear from half of the habitats they currently occupy in about six years.

“Even though these declines seem small on the surface, they are not,” said USGS ecologist Michael Adams, the lead author of the study. “Small numbers build up to dramatic declines with time. We knew there was a big problem with amphibians, but these numbers are both surprising and of significant concern.”

For nine years, researchers looked at the rate of change in the number of ponds, lakes and other habitat features that amphibians occupied. In lay terms, this means that scientists documented how fast clusters of amphibians are disappearing across the landscape.

In all, scientists analyzed nine years of data from 34 sites spanning 48 species. The analysis did not evaluate causes of declines.

The research was done under the auspices of the USGS Amphibian Research and Monitoring Initiative, which studies amphibian trends and causes of decline. This unique program, known as ARMI, conducts research to address local information needs in a way that can be compared across studies to provide analyses of regional and national trends.

Brian Gratwicke, amphibian conservation biologist with the Smithsonian Conservation Biology Institute, said, “This is the culmination of an incredible sampling effort and cutting-edge analysis pioneered by the USGS, but it is very bad news for amphibians. Now, more than ever, we need to confront amphibian declines in the U.S. and take actions to conserve our incredible frog and salamander biodiversity.”

The study offered other surprising insights. For example, declines occurred even in lands managed for conservation of natural resources, such as national parks and national wildlife refuges.

“The declines of amphibians in these protected areas are particularly worrisome because they suggest that some stressors – such as diseases, contaminants and drought – transcend landscapes,” Adams said. “The fact that amphibian declines are occurring in our most protected areas adds weight to the hypothesis that this is a global phenomenon with implications for managers of all kinds of landscapes, even protected ones.”

Amphibians seem to be experiencing the worst declines documented among vertebrates, but all major groups of animals associated with freshwater are having problems, according to Adams. While habitat loss is a factor in some areas, other research suggests that things like disease, invasive species, contaminants and perhaps other unknown factors are related to declines in protected areas.

“This study,” said Adams, “gives us a point of reference that will enable us to track what’s happening in a way that wasn’t possible before.”

Read FAQs about this research

The publication, Trends in amphibian occupancy in the United States, is authored by  Adams, M.J., Miller, D.A., Muths, E., Corn, P.S., Campbell Grant, E.H., Bailey, L., Fellers, G.M., Fisher, R.N., Sadinski, W.J., Waddle, H., and Walls, S.C., and is available to the public.

Read a USGS blog, Front-row seats to climate change, about 3 other recent USGS amphibian studies. For more information about USGS amphibian research, visit http://armi.usgs.gov/

 

Citizen volunteers are making significant additions to the U.S. Geological Survey’s ability to provide accurate information to the public. Using crowd sourcing techniques, the USGS project known as The National Map Corps (TNMC) encourages citizen volunteers to collect manmade structure data in an effort to provide accurate and authoritative spatial map data for the National Geospatial Program’s web-based The National Map.

These structures can include schools, hospitals, post offices, police stations and other important public places along with data from other sources, the data currently being collected by volunteers become part of TNM Structures dataset which is made available to users free of charge.

In an effort to recognize the important work being done by volunteers, TNMC has created a recognition program based on the number of points a volunteer contributes. Levels of recognition are displayed in the form of icons or badges of antique catalog drawings of different and increasingly sophisticated pieces of surveying equipment. Each badge comes with a description of the item and encouragement to achieve the next level. As a volunteer attains each level, a congratulations email is sent, and the accomplishments are recognized via The National Map Twitter site (#TNMCorps) and the USGS Facebook page. 

Recognition Categories:

Recognition Category	Number of points
Order of the Surveyor’s Chain	25 – 49
Society of the Steel Tape	50 – 99
Pedometer Posse	100 – 199
Circle of the Surveyor’s Compass	200 – 499
Stadia Board Society	500 – 999
Alidade Alliance	1000 – 1999
Theodolite Assemblage	2000+

 

Order of the Surveyor’s Chain award. (Larger image)	Theodolite Assemblage award. (Larger image)

 

 

 

 

 

 

 

 

 

 

 

 

 

Becoming a volunteer for TNMC is easy; go to The National Map Corps project site to learn more and to sign up as a volunteer. If you have access to the Internet and are willing to dedicate some time editing map data, we hope you will consider participating.

While some familiarity with the area that a volunteer chooses is helpful, you do not have to live near a particular place to contribute. The tools on TNMC website, along with ancillary information available on the Internet, are generally sufficient to edit a distant area. There are presently nineteen states available for volunteers to choose to update structures in.

See for yourself how much fun participating can be. Go to The National Map Corps home page, give it a try and before you know it you’ll be hanging out with the Pedometer Posse!

A new U.S. Geological Survey study documents that the Nation’s aquifers are being drawn down at an accelerating rate. 

Groundwater Depletion in the United States (1900-2008) comprehensively evaluates long-term cumulative depletion volumes in 40 separate aquifers (distinct underground water storage areas) in the United States, bringing together reliable information from previous references and from new analyses. 

“Groundwater is one of the Nation’s most important natural resources. It provides drinking water in both rural and urban communities. It supports irrigation and industry, sustains the flow of streams and rivers, and maintains ecosystems,” said Suzette Kimball, acting USGS Director. “Because groundwater systems typically respond slowly to human actions, a long-term perspective is vital to manage this valuable resource in sustainable ways.” 

To outline the scale of groundwater depletion across the country, here are two startling facts drawn from the study’s wealth of statistics. First, from 1900 to 2008, the Nation’s aquifers, the natural stocks of water found under the land, decreased (were depleted) by more than twice the volume of water found in Lake Erie. Second, groundwater depletion in the U.S. in the years 2000-2008 can explain more than 2 percent of the observed global sea-level rise during that period.   

Since 1950, the use of groundwater resources for agricultural, industrial, and municipal purposes has greatly expanded in the United States. When groundwater is withdrawn from subsurface storage faster than it is recharged by precipitation or other water sources, the result is groundwater depletion. The depletion of groundwater has many negative consequences, including land subsidence, reduced well yields, and diminished spring and stream flows. 

While the rate of groundwater depletion across the country has increased markedly since about 1950, the maximum rates have occurred during the most recent period of the study (2000–2008), when the depletion rate averaged almost 25 cubic kilometers per year. For comparison, 9.2 cubic kilometers per year is the historical average calculated over the 1900–2008 timespan of the study. 

One of the best known and most investigated aquifers in the U.S. is the High Plains (or Ogallala) aquifer. It underlies more than 170,000 square miles of the Nation’s midsection and represents the principal source of water for irrigation and drinking in this major agricultural area. Substantial pumping of the High Plains aquifer for irrigation since the 1940s has resulted in large water-table declines that exceed 160 feet in places. 

The study shows that, since 2000, depletion of the High Plains aquifer appears to be continuing at a high rate. The depletion during the last 8 years of record (2001–2008, inclusive) is about 32 percent of the cumulative depletion in this aquifer during the entire 20th century. The annual rate of depletion during this recent period averaged about 10.2 cubic kilometers, roughly 2 percent of the volume of water in Lake Erie. 

Learn more

• Groundwater Depletion in the United States (1900-2008)
• USGS Groundwater Information
• USGS High Plains Groundwater Availability Study
• Contribution of global groundwater depletion since 1900 to sea‐level rise (journal article)