USGS Newsroom

Revised Kentucky and Tennessee Maps Reveal New Design

OC_Web@usgs.gov (Office of Communications and Publishing) — Wed, 15 May 2013 12:00:00 EDT

Newly designed maps covering Kentucky and Tennessee are now available online for free download

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.

This new design is launched on new US Topo quadrangles for Kentucky (671 maps) and Tennessee (694 maps), which 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 Store website.

"The new Kentucky and Tennessee US Topo maps demonstrate our commitment to improving the product design to meet our users’ needs", said Mark DeMulder, Director of the USGS National Geospatial Program. "I encourage you to download these maps, compare them against the previous US Topo map and drop us your comments on the US Topo map product. Your input is important to us."

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/

Tennessee Rivers Experiencing Historic Lows

OC_Web@usgs.gov (Office of Communications and Publishing) — Wed, 13 Jun 2012 14:30:00 EDT

NASHVILLE, Tenn. — Spring streamflows throughout the state of Tennessee are some of the lowest on record, according to U.S. Geological Survey streamgages, which measure water levels, streamflow and rainfall throughout the state

Though rainfall during the 2011-2012 winter months was recorded at near normal levels across much of Tennessee, there has been a marked decrease in precipitation since early to mid-March, leading to lower streamgage readings during the month of May.

"One of the great values of the USGS's long-term stream-monitoring programs is our ability to place the current situation within its historical context, and thus help citizens understand what the water situation might mean for communities and wildlife," said USGS Director Marcia McNutt. "At the same time, the USGS has moved forward to develop new tools to deliver up-to-date water information to interested members of the public in useful formats on their mobile devices."

To provide a snapshot of current water conditions throughout the state, USGS scientists assessed readings from 36 gauges on Tennessee’s recreational and commercial rivers, all of which have more than 40 years of continued measurement. More than half of these gauges recorded near record low flows for the month of May. Scientists identified four gauges recording the lowest average May streamflow on record and 16 gauges with near record low readings.

"These record low streamflows are likely attributable to decreased rainfall in the springtime, combined with warmer spring temperatures and an earlier start to growing season, which reduces the amount of available water in streams," said Rodney Knight, a hydrologist with the USGS Tennessee Water Science Center. "Although at this point, the data for May 2012 are still preliminary."

Decreased streamflows are most prominent in central Tennessee along the Duck, Collins, Elk, Obey, and Sequatchie rivers. Streamflow along the Elk River is the lowest in 47 years, resulting in almost a five foot deficit at Tim's Ford Reservoir.

Average May streamflow recorded at the Duck River below Manchester, Tennessee, was the third lowest reading in 63 years of measurement at this site. Statewide or regional droughts in 1941 and 1981 were responsible for the first and second lowest readings recorded at this site.

"Abnormally low spring rainfall this year in the Duck River region kept Normandy Reservoir from reaching summer operating levels, creating an alert to monitor stream flows and run-off more closely," said Doug Murphy, executive director for the Duck River Agency. "Real-time streamflow data from the USGS, combined with reservoir information from the Tennessee Valley Authority help the multi-agency Drought Management Task Force to make decisions quickly and accurately."

Warmer temperatures and dryness are expected to continue statewide, but a transition to an El Nino weather pattern sometime in the second half of this year may bring some needed rainfall late this summer and into the fall, according James LaRosa, meteorologist with the National Weather Service in Nashville.

Real-time streamflow data from 131 USGS monitored streamgages throughout Tennessee are used for flood and drought preparedness tools such as USGS WaterAlert and StreaMail. These tools allow anyone to access information about local streams and rivers via text and email. With these tools, emergency managers, resource managers and the public can stay informed about local conditions.

The USGS is the nation’s primary provider of flow and water level information for our nation's waterways. For more than 125 years, the USGS has monitored selected streams and rivers with about 7,700 streamgaging sites across the nation.

Veterans Hospitals Stay Safe with a Healthy Dose of Earthquake Monitoring

OC_Web@usgs.gov (Office of Communications and Publishing) — Wed, 9 May 2012 16:40:26 EDT

USGS and VA install seismic monitoring systems in medical centers nationwide

Being in a hospital is tough enough without having to worry about how the building will hold up during an earthquake. Now veterans in Memphis, Tenn. can rest assured knowing that their medical center, even though it is located in the most active earthquake zone in the Eastern United States, has the most sophisticated seismic structural monitoring system in the country.

The U.S. Geological Survey and the Department of Veterans Affairs have equipped over 70 VA medical centers across the country with seismic monitoring systems that monitor in real time what happens to buildings during and after earthquakes._Most recently, the agencies installed 36 sensors in two buildings at the Memphis VA Medical Center. These sensors provide information that can be used to see what happens to the buildings during an event, to judge the safety of the buildings afterwards, and to design safer hospitals in the future.

"Modern hospitals are immense investments in state-of-the-art facilities, high-tech equipment, highly-educated medical professionals, as well as recovering patients, all of which need the very best protection in the event of an earthquake," said USGS Director Marcia McNutt. "We are grateful for the partnership of the Department of Veterans Affairs in helping the USGS to record very detailed building performance data that will ultimately reduce risk to life and property from natural hazards."

Hospitals are just one piece of the Nation’s critical infrastructure threatened by the shaking that comes with earthquakes. The USGS monitors more than 250 structures nationwide including fire stations, emergency operation centers, major bridges, nuclear power plants, offshore drilling platforms and airports.

These monitoring stations are part of the implementation of the USGS Advanced National Seismic System, which is modernizing and expanding earthquake monitoring around the Nation to improve the overall understanding of earthquakes and their behavior. This allows for better preparation for earthquakes and can minimize damage by designing safer structures that protect vulnerable citizens and resources.

USGS structural monitoring provides information about how buildings act during shaking, and how damage occurs. This can lead to improved earthquake-resistant design techniques, as well as predict how buildings will withstand different levels of shaking. Data from the sensors demonstrate whether the buildings behaved as designed by recording:

the swaying and twisting of the buildings,
the time it takes seismic waves to travel from the foundations to the roofs, and
how the frame of the buildings changed during the earthquake.

Other sensors located away from the building record overall ground shaking to feed USGS Shakemaps. These graphics show ground motion and shaking intensity after significant earthquakes, giving a visual representation of a quake’s behavior and impact for rapid situational awareness.

The USGS Earthquake Hazards Program is part of the four-agency National Earthquake Hazards Reduction Program (NEHRP) led by the National Institute of Standards and Technology (NIST). Earthquakes pose significant risk to 75 million Americans in 39 States. The EHP provides information and products for earthquake loss reduction, including hazard and risk assessment, and comprehensive real-time earthquake monitoring.

Learn more about the Memphis VA Hospital Center’s real-time seismic monitoring system in this USGS Factsheet.

A Big Day for Science: Citizens Have Contributed One Million Observations to Top Nature Database

OC_Web@usgs.gov (Office of Communications and Publishing) — Thu, 3 May 2012 9:00:00 EDT

RESTON, Va. — Thanks to citizen-scientists around the country, the USA National Phenology Network hit a major milestone this week by reaching its one millionth nature observation.

The millionth observation was done by Lucille Tower, a citizen-scientist in Portland, Ore., who entered a record about seeing maple vines flowering. Her data, like all of the entries, came in through USA-NPN’s online observation program, Nature's Notebook, which engages more than 4,000 volunteers across the country to observe and record phenology – the timing of the recurring life events of plants and animals such as when cherry trees or lilacs blossom, when robins build their nests, when salmon swim upstream to spawn or when leaves turn colors in the fall.

Each record not only represents a single data point — the status of a specific life stage of an individual plant or animal on one day – but also benefits both science and society by helping researchers understand how plants and animals are responding to climate change and, in turn, how those responses are affecting people and ecological systems.

"My dream is that through the wonders of modern technology and the National Phenology Network we could turn the more than six billion people on the planet into components of our scientific observing system," said USGS Director Marcia McNutt. "We could make giant leaps in science education, improve the spatial and temporal coverage of the planet, lower the cost of scientific data collection, and all while making ordinary citizens feel a part of the scientific process."

Jake Weltzin, a U.S. Geological Survey scientist and the executive director of USA-NPN, concurs. "Hitting the one millionth observation is exciting because researchers and decision-makers need more information to understand and respond to our rapidly changing planet. More information means better-informed decisions that ensure the continued vitality of our natural areas that we all depend on and enjoy."

For example, said Weltzin, the data in Nature's Notebook are already being used to benefit society, including the development of more accurate indicators of spring, forecasting the onset of allergy seasons or the chances of western wildfires, managing wildlife and invasive plants, and setting goals for habitat restoration. Ultimately, such information can be used for better managing water resources, wildlife and ecosystem management, and even help farmers and ranchers across the nation.

Changes in phenology are among the most sensitive biological indicators of global change. Across the world, many springtime events are occurring earlier — and fall events happening later — than in the past. These changes are happening quickly for some species and more slowly, or not at all, for others, altering relationships and processes that have been dynamically stable for thousands of years. Some wildlife —like caribou and butterflies — are becoming mismatched from their plant food resources, which are responding differently. Migrations for some birds are changing too, as they can now overwinter instead of moving south for the winter, or as they fly north more quickly to keep pace with an advancing front of spring flowering.

Because of this, said Weltzin, scientists need more and better information about the pace and pattern of nature — locally to nationally — to answer important scientific and societal questions, and to build the tools and models needed to help people understand and adapt to the changes.

"So much of our improved understanding about global environmental changes is driven by varied and valuable sources of information that include networks of citizen-scientists," said John Wingfield, National Science Foundation’s assistant director for biological sciences. "The public at large has played an important role collecting observations and data for a hundred years and more. Knowledge and data gained from their work will continue to have a lasting effect on how we understand regularly recurring biological phenomena for hundreds of plant and animal species and contribute to the policy arena."

Gwen Lundburg in Seattle is one citizen-scientist who has contributed hundreds of entries into Nature’s Notebook. "Just noticing small changes like tiny purple lilac buds suddenly turning green has taught me to look more closely at my plants," Lundburg said. "I see things in my garden I never saw before."

With the help of citizen-scientist volunteers, working in concert with professionals, the USA-NPN, which was established in 2007, collects, stores and freely shares phenological data on more than 800 species of plants and animals. The Nature’s Notebook observing program has been in operation since 2009. The coordinating office of the organization is located at 1955 E. 6^th St., Tucson, Ariz., 85721. For more information, visit the USA National Phenology Network, or contact Jake Weltzin at 520-626-3821 or jweltzin@usgs.gov.

Streamflow Models Evaluated for Reliability and Application to Predicting Fish Health

OC_Web@usgs.gov (Office of Communications and Publishing) — Thu, 19 Apr 2012 11:00:00 EDT

A new USGS study found that streamflow characteristics critical to fish in the Tennessee River basin were estimated more accurately and precisely by a statistical model than a simulated hydrograph produced by a rainfall-runoff model.

Streamflow characteristics are summary statistics that describe timing, magnitude and duration aspects of streamflow. Current conceptual models relating flow to ecology are strongly based on the use of streamflow characteristics. However until now, an evaluation of differing estimation methods, even on a small scale, had yet to be completed.

In this USGS study, 19 ecologically relevant streamflow characteristics calculated from observed daily streamflows were compared to estimates from a statistical model and a rainfall-runoff model. The statistical model was developed for the Tennessee and Cumberland River Valleys and is composed of 19 multivariate regression equations that each predicts a single streamflow characteristic. The rainfall-runoff model was developed for the state of Kentucky and produces a simulated hydrograph from which the 19 streamflow characteristics are calculated. Six sites with observed streamflow data occur within the geographic overlap of these two models – where the Tennessee and Cumberland River basins cross into Kentucky

When predictions from the models were compared to streamflow characteristics calculated from observed data, the statistical model produced more accurate and precise estimates than the rainfall-runoff model. For the rainfall-runoff model, median departures (the median difference between predicted and observed values across all six sites) for 13 of 19 streamflow characteristics were greater than 30 percent. Most of these median departures were between 30 percent and 50 percent and a few were greater than 100 percent. In contrast, for the statistical model, median departures for only two characteristics were greater than 30 percent and 12 characteristics had median departures that were less than 10 percent. Furthermore, the rainfall-runoff model either over or under predicted all six sites for eight streamflow characteristics. Such biases are not as pronounced for the statistical model.

These results suggest that when compared to a rainfall-runoff model, a statistical model is a better predictor of a range of streamflow characteristics, meaning the overall flow regime. The rainfall-runoff model was calibrated on a single streamflow characteristic, mean daily discharge, whereas the statistical model was calibrated individually on all 19 streamflow characteristics. Poor model performance may misrepresent hydrologic conditions, potentially distorting the perceived risk of ecological degradation. Without prior selection of streamflow characteristics, targeted calibration, and error quantification, the widespread application of general hydrologic models to ecological flow studies should be approached with caution.

USGS Identifies Streamflow Characteristics Critical to Tennessee River Basin Fishes

OC_Web@usgs.gov (Office of Communications and Publishing) — Wed, 25 Jan 2012 12:00:00 EDT

Streamflow characteristics critical for fish communities in the Tennessee River basin have been identified, according to recently published U.S. Geological Survey research. Of particular note are three which describe the stability of streamflow, frequency of moderate streamflow, and the rate at which streamflow recedes after rainfall events.

The stability of streamflow from year-to-year is critical to maintaining water-quality conditions suitable for fish, including dissolved oxygen, temperature and basic water chemistry.

The study suggests that the frequency of moderate streamflow – flows at least three times the median annual flow – maintains habitat for sight-feeding fish, such as darters.

The research shows that the rate at which streamflow recedes is linked to stranding fish in off-channel pools as well as increased cloudiness in the water, something that is detrimental to sight-feeding fish.

"As water managers work to balance water availability for people and for ecosystems so that they can continue to provide us valuable natural services, it is important to understand what aspects of stream flow are essential and why," explained USGS director Marcia McNutt. "This study provides valuable new insights on the importance of temporal factors in stream flow that may have otherwise been overlooked."

To better understand how fish communities respond to different streamflow conditions, experts have developed statistical models to predict these three characteristics, along with 16 other streamflow characteristics identified in published research. These tools were developed using climate, land use, and streamflow data on 231 free-flowing streams in the almost 41,000 square mile Tennessee River basin. When taken together, the 19 individual streamflow characteristic models represent a model of the ecological flow regime at a location. By using about 1,000 Tennessee Valley Authority fish community sample sites, researchers will be able to quantify the effect that alteration of the ecological flow regime has on fish community diversity.

The USGS Tennessee Water Science Center, in cooperation with the Tennessee Valley Authority, Tennessee Department of Environment and Conservation, and The Nature Conservancy, has been investigating how fish community diversity is impacted by streamflow alteration in rivers and streams in Tennessee River basin. Initial efforts are aimed at identifying critical streamflow characteristics and developing a set of statistical tools to predict these characteristics.

Groundwater Storage Losses Substantial Across Eight State Aquifer System

OC_Web@usgs.gov (Office of Communications and Publishing) — Thu, 1 Dec 2011 13:10:46 EDT

More than 280 million acre-feet of groundwater has been withdrawn from the Mississippi embayment aquifer system between 1870-2007, according to a new water modeling tool developed by the U.S. Geological Survey.

This cumulative withdrawal, which is the equivalent of five feet of water over 78,000 square miles, contributes to one of the largest losses of groundwater storage anywhere in the United States.

The new USGS modeling tool was designed to help resource managers find a balance between water supply and demand for future economic and environmental uses. The three-dimensional model provides a holistic picture of how water flows below ground and how it relates to surface-water. The Mississippi embayment aquifer system encompasses approximately 78,000 square miles in Alabama, Arkansas, Illinois, Kentucky, Louisiana, Mississippi, Missouri and Tennessee. A report documenting past and current groundwater conditions, and tools to forecast regional response to human use, climate variability, and land-use changes are all available online.

"Our groundwater aquifers are nature's own natural method for storing water safely long term where it is less vulnerable to loss through evaporation and surface contamination," explained USGS director Marcia McNutt. "We should be as concerned about loss of groundwater as we are about dropping levels in reservoirs behind dams, because in the depths of the worst drought, when the rivers run dry, it is only the groundwater that will sustain us."

"This model can assist water resource managers faced with increasing management challenges and constraints," said USGS hydrologist, Brian Clark. "This model could be used to evaluate regional issues, such as streamflow declines from groundwater pumping or conservation scenarios to lessen water level declines."

The Mississippi embayment aquifer system includes one of the nation’s most productive agricultural regions, with an annual value of $3 billion per year. Two of the region’s most important aquifers lie beneath the Mississippi embayment. The pumping from the Mississippi River Valley alluvial aquifer accounts for more than 12 percent of all groundwater pumped in the United States.

"This model will help officials find ways to better manage the area's present and future groundwater resources," said USGS Arkansas Water Science Center Director, Dave Freiwald. "This is the most recent large-scale, comprehensive assessment of groundwater resources in the area."

This report is a product of a four-year study being funded by the USGS Groundwater Resources Program. Information derived from this and future studies of more than 30 regional aquifers will provide a collective assessment of America's groundwater availability.

To develop the model, scientists examined more than 2,600 geophysical logs, some dating back to the early 1960’s. Researchers examined groundwater and surface-water data from the early 1900’s to 2007, groundwater withdrawal information, and thousands of miles of surface-water bodies to illustrate how the water system works and how supplies have changed.

A comprehensive report detailing the research, “Groundwater Availability of the Mississippi Embayment,” and a factsheet, “A New Tool to Assess Groundwater Resources in the Mississippi Embayment,” are available online.

Map showing the Mississippi embayment aquifer system area. (Larger image)

USGS Releases New Assessment of Gas Resources in the Marcellus Shale, Appalachian Basin

OC_Web@usgs.gov (Office of Communications and Publishing) — Tue, 23 Aug 2011 11:30:00 EDT

The Marcellus Shale contains about 84 trillion cubic feet of undiscovered, technically recoverable natural gas and 3.4 billion barrels of undiscovered, technically recoverable natural gas liquids according to a new assessment by the U. S. Geological Survey (USGS).

These gas estimates are significantly more than the last USGS assessment of the Marcellus Shale in the Appalachian Basin in 2002, which estimated a mean of about 2 trillion cubic feet of gas (TCF) and 0.01 billion barrels of natural gas liquids.

The increase in undiscovered, technically recoverable resource is due to new geologic information and engineering data, as technological developments in producing unconventional resources have been significant in the last decade. This Marcellus Shale estimate is of unconventional (or continuous-type) gas resources.

Since the 1930's, almost every well drilled through the Marcellus found noticeable quantities of natural gas. However, in late 2004, the Marcellus was recognized as a potential reservoir rock, instead of just a regional source rock, meaning that the gas could be produced from it instead of just being a source for the gas. Technological improvements resulted in commercially viable gas production and the rapid development of a major, new continuous natural gas and natural gas liquids play in the Appalachian Basin, the oldest producing petroleum province in the United States.

This USGS assessment is an estimate of continuous gas and natural gas liquid accumulations in the Middle Devonian Marcellus Shale of the Appalachian Basin. The estimate of undiscovered natural gas ranges from 43.0 to 144.1 TCF (95 percent to 5 percent probability, respectively), and the estimate of natural gas liquids ranges from 1.6 to 6.2 billion barrels (95 percent to 5 percent probability, respectively). There are no conventional petroleum resources assessed in the Marcellus Shale of the Appalachian Basin.

These new estimates are for technically recoverable oil and gas resources, which are those quantities of oil and gas producible using currently available technology and industry practices, regardless of economic or accessibility considerations. As such, these estimates include resources beneath both onshore and offshore areas (such as Lake Erie) and beneath areas where accessibility may be limited by policy and regulations imposed by land managers and regulatory agencies.

The Marcellus Shale assessment covered areas in Kentucky, Maryland, New York, Ohio, Pennsylvania, Tennessee, Virginia, and West Virginia.

USGS is the only provider of publicly available estimates of undiscovered technically recoverable oil and gas resources of onshore lands and offshore state waters. The USGS worked with the Pennsylvania Geological Survey, the West Virginia Geological and Economic Survey, the Ohio Geological Survey, and representatives from the oil and gas industry and academia to develop an improved geologic understanding of the Marcellus Shale. The USGS Marcellus Shale assessment was undertaken as part of a nationwide project assessing domestic petroleum basins using standardized methodology and protocol.

The new assessment of the Marcellus Shale may be found online. The previous Marcellus Shale assessment can be found online. To find out more about USGS energy assessments and other energy research, please visit the USGS Energy Resources Program website

USGS Measures Flooding at Morganza Spillway and Across Louisiana

OC_Web@usgs.gov (Office of Communications and Publishing) — Mon, 16 May 2011 17:19:36 EDT

Reporters: Do you want to accompany a USGS field crew as they measure flooding? Please contact Jennifer LaVista at 720-480-7875.

U.S. Geological Survey crews are measuring flooding along the Atchafalaya and Mississippi Rivers, including the Morganza and Bonnet Carre Spillways.

Several USGS streamgages located on the Mississippi and Atchafalaya Rivers are expected to reach the highest levels recorded since 1927.

Learn more in a video featuring USGS scientists studying waterflow in these areas.

USGS scientists are collecting critical streamflow data that are vital for protection of life, property and the environment. This information is used by the U.S. Army Corps of Engineers to manage flood control, the National Weather Service to develop flood forecasts, and various state and local agencies in their flood response activities. A live webcam at the Morganza Spillway and real-time streamflow information from around the state are available on the USGS Louisiana Water Science Center Website.

USGS scientists have installed 64 rapid-deploy, mobile storm surge sensors across Louisiana, in addition to the 12 real-time streamgages already in the affected area. These temporary sensors, originally developed after Hurricanes Katrina and Rita, provide additional monitoring data in critical areas needed for effective forecasting and emergency response.

“When flooding occurs, USGS field crews are among the first to respond,” said George Arcement, USGS Louisiana Water Science Center Director. “We have been measuring streamflow for weeks, and will continue to do so until the floodwaters recede.”

USGS crews are also collecting water quality and sediment samples to examine any changes in the Atchafalaya and Mississippi River Basins. USGS scientists are gathering water quality samples in the Atchafalaya Rivers, Lake Pontchartrain, and the Morganza Spillway to determine whether flooding will have an impact on the health of the river. Sediment samples are being collected at the Morganza and Bonnet Carre Spillways to evaluate how the structure of the delta may change. These projects are being conducting at the request of the U.S. Army Corps of Engineers.

For more than 125 years, the USGS has monitored flow in selected streams and rivers across the U.S. In Louisiana, there are more than 250 USGS-operated streamgages that measure water levels, streamflow and rainfall. The information is routinely used for water supply and management, monitoring floods and droughts, bridge and road design, determination of flood risk, and for many recreational activities.

Access current flood and high flow conditions across the country by visiting the USGS WaterWatch website. Receive instant, customized updates about water conditions in your area via text message or email by signing up for USGS WaterAlert.

Satellite Images Display Extreme Mississippi River Flooding from Space

OC_Web@usgs.gov (Office of Communications and Publishing) — Fri, 13 May 2011 15:24:56 EDT

Recent Landsat satellite data captured by the U.S. Geological Survey and NASA on May 10 show the major flooding of the Mississippi River around Memphis, Tenn. and along the state borders of Tennessee, Kentucky, Missouri, and Arkansas as seen from 438 miles above the Earth.

The flood crest of 47.87 feet on May 10 is the second highest rise in recent history; the highest being 48.7 feet in 1937. Five counties surrounding Memphis have been declared disaster areas, and the costs of the flooding are expected to approach $1 billion. The Mississippi River crest continues to move south and is expected to occur in the Greenville, Miss. area around May 16 to finally crest in New Orleans around May 23.

When natural hazards like flooding occur, the USGS provides the most recent Landsat data to local emergency managers.

“Landsat imagery is crucial in helping to monitor the flood rate and effects of the flooding in the region, and to aid in the decision making process regarding flood control. Such decisions include closing portions of the Mississippi River to shipping and opening flood gates outside of low-lying New Orleans in preparation for the flood wave as it makes its way slowly down the river to the Gulf of Mexico,” said Mark Anderson, Acting Director of the USGS Earth Resources Observation and Science Center.

Remotely sensed data are not the only science endeavors occurring due to floods. The USGS collects river data through its network of about 7,700 stream gages around the Nation. You can receive instant, customized updates about water conditions, including flooding, by subscribing to USGS WaterAlert.

General flood information is available at USGS Science Features and USGS Flood Information

Note to Editors: The associated image pairs show the Mississippi River in the Memphis, Tenn. area and along the state borders of Tennessee, Kentucky, Missouri, and Arkansas. The May 12, 2006 images (left) show the river in a more normal state, while the 2011 images (right) show the massive flooding. In the images, the dark blue tones represent water or flooded areas, the light green is cleared fields, and light tones are clouds.

[Access images for this release at: &amp;lt;a href="http://gallery.usgs.gov/tags/NR2011_05_13" _mce_href="http://gallery.usgs.gov/tags/NR2011_05_13"&amp;gt;http://gallery.usgs.gov/tags/NR2011_05_13&amp;lt;/a&amp;gt;]

USGS Flood Teams in Tennessee

OC_Web@usgs.gov (Office of Communications and Publishing) — Tue, 10 May 2011 14:00:13 EDT

Note to Reporters: To join a USGS flood crew in Tennessee, please call contacts listed.

The USGS Tennessee Water Science Center is working this week in cooperation with FEMA, U.S. Army Corps of Engineers, National Weather Service, and local agencies to provide emergency real-time surface-water stage gages at critical locations in Shelby County. The emergency gages include a replacement gage on the Mississippi River at Memphis and three other critical locations. Information from the gages will be available to the National Weather Service and the Emergency Management agencies to assist in flood forecasts as the crest of the Mississippi river flooding approaches and passes Memphis, Tennessee.

The USGS Tennessee Water Science Center will have four additional crews deployed to the FEMA emergency designated areas, Stewart, Lake, Dyer, and Shelby Counties in Tennessee this week to document high-water levels in the flooded areas. Six transducers have also been deployed to monitor the flood rise, peak levels, and recession. The combination of the high-water marks, transducers, and the emergency gaging will be used to develop flood inundation maps for FEMA

Before, during and after storms and floods, USGS field crews install additional streamgages as needed, work to keep streamgages operating, and verify the accuracy of streamgage information. Field crews continue to work as waters recede, gathering high water marks for post flood analysis. This information is important because it is used by the National Weather Service to issue flood warnings. It is also used by emergency responders and planners to mitigate current and future flood hazards.

For more than 125 years, the USGS has monitored flow in selected streams and rivers across the U.S. The information is routinely used for water supply and management, monitoring floods and droughts, bridge and road design, determination of flood risk, and for many recreational activities.

The USGS operates a network of about 7500 streamgages throughout the U.S. The gages provide critical information within minutes to many users including the National Weather Service, which issues flood warnings.

USGS Water Science Centers are located in each state. They can provide more detailed information on stream conditions and on the USGS response to local events.

Challenges identified in using models to predict snake and other animal invasions

OC_Web@usgs.gov (Office of Communications and Publishing) — Wed, 9 Feb 2011 17:00:00 EDT

FORT COLLINS, Colo. — New research published today has identified challenges in using computer models to predict the potential of pythons or other invasive vertebrate species to spread across portions of the United States, according to the U.S. Geological Survey.

The study, published in PLoS One, assesses the accuracy and limitations of the MaxEnt modeling program for climate matching when applied to predicting the potential risk of vertebrate invasions in the U.S., especially pythons.

Climate matching for invasive species is the process of using climate data from a species’ native range to identify areas that are climatically similar outside of that range and which could be at potential risk for invasion.

A previous paper by USGS researchers Gordon Rodda, Catherine Jarnevich and Robert Reed published online in 2008 in the journal Biological Invasions used a rule-based model and had estimated climatic suitability for Burmese pythons to extend roughly over the southern third of the U.S.

After the Biological Invasions article was published, another group of scientists (Pyron et al.), from the City University of New York (PLoS One, 2008) used MaxEnt, a different climate-matching system, to re-assess the potential for invasion in the U.S. Their results contradicted the USGS 2008 conclusions by asserting that Burmese pythons posed a risk only to the area already occupied by this invasive species in southern Florida.

However, the new USGS research published today concluded that the Pyron et al. study incorrectly applied the MaxEnt modeling program and used some erroneous data. USGS researchers found that when Pyron et al. used MaxEnt's default (pre-set) settings, the model results predicted only very limited climate suitability for the species in Florida and in extreme south Texas. However, when USGS researchers (2011) ran the model again using more appropriate settings (such as limiting the number of parameters and limiting background data to the native range rather than global), it showed a greatly expanded area at risk, including much larger portions of the southern United States from California to South Carolina and many island territories.

USGS authors realized that Pyron et al. accidentally introduced errors such as using a dataset that included erroneous records for a different species of python. When the USGS authors removed these records and repeated the Pyron et al. analysis, different results were obtained, indicating the instability of the model when used in this manner.

Pyron et al. also used about 60 parameters in their models, although the most current guidance for doing these kinds of predictive models recommends that only about 10 parameters should have been used.

“When a model is excessively complex, it has a poor ability to accurately predict invasion risk,” said Gordon Rodda, the lead author of the study. “An excessive number of parameters means that each additional one acts as a filter, and using too many filters means that many sites that are truly at risk of python establishment get filtered out. In this case,” he added, “Pyron et al. incorrectly rejected many sites in the United States that may well have climate suitable for Burmese pythons.”

The new research also highlights the need for scientists to consider that factors other than climate – such as predators, disease or habitat -- may – and often do -- limit a species’ distribution. For example, said Rodda, when a potential invader is released in a new country, predators, diseases and other factors that limit the species’ population numbers in its homeland may not be present in the new place.

“This means the invader’s population may be able to expand into a larger area,” Rodda noted. “As a result, the areas at risk of invasion often extend to climate specifics not found in the native range boundaries. For example, the finding that heavy monsoons are present in the native range does not necessarily mean that a species requires monsoonal downpours to thrive.”

Adhering to the guidelines laid out in this paper and others for using MaxEnt produces more reasonable models. MaxEnt, when used appropriately, can produce useful models. The models for this paper were produced at the Resource for Advanced Modeling (RAM) at the USGS. Expertise at the RAM provides an environment for scientists and managers to carefully implement models such as MaxEnt and assess invasion risk.

The new study, Challenges in identifying sites climatically matched to the native ranges of animal invaders, is authored by Rodda, G.H., C.S. Jarnevich, and R.N. Reed. To see the article please go to PLoS ONE at http://dx.plos.org/10.1371/journal.pone.0014670.

Tattered Wings: Bats Grounded by White-Nose Syndrome's Lethal Effects on Life-Support Functions of Wings

OC_Web@usgs.gov (Office of Communications and Publishing) — Wed, 15 Dec 2010 11:47:54 EDT

Madison, Wisconsin—Damage to bat wings from the fungus associated with white-nose syndrome (WNS) may cause catastrophic imbalance in life-support processes, according to newly published research.

This imbalance may be to blame for the more than 1 million deaths of bats due to WNS thus far, proposes Carol Meteyer, a pathologist with the U.S. Geological Survey’s National Wildlife Health Center and a lead author of the research published in BMC Biology.

Physiological problems caused by the novel fungus, may, in fact, represent a completely new disease paradigm for mammals, Meteyer and her colleagues wrote. Other skin infections in mammals due to fungi (ringworm, athlete’s foot) remain superficial and do not invade living tissue—typically they only affect the surface of skin, hair and nails.

Not so for the aptly named Geomyces destructans.

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“This fungus is amazingly destructive — it digests, erodes, and invades the skin — particularly the wings — of hibernating bats,” said Meteyer. “The ability of this fungus to invade bats’ wing skin is unlike that of any known skin fungal pathogen in land mammals.”

The authors examined nearly 200 bats that had died from WNS, and also reviewed the critical function and physiology of bat wings during hibernation. As a result, they propose that G. destructans may cause unsustainable dehydration in hibernating bats, triggering thirst-associated arousals. In addition to the direct damage to the wings that would alter flight control, the erosion and invasion of skin may also cause significant changes in circulation, body-temperature regulation and respiratory function.

Since signs of the disease were first observed in New York during the winter of 2006-07, the fungus has spread through 11 states and 2 Canadian provinces, resulting in the first sustained high-mortality disease affecting bats in recorded history. Biologists assume that as the disease spreads to new areas, cave-hibernating bats in those areas will also be at risk, including some that are endangered.

“The high number of bat deaths and range of species being affected far exceeds the rate and magnitude of any previously known natural or human-caused mortality event in bats, and possibly in any other mammals,” said Paul Cryan, a lead author of the paper and a USGS bat ecologist at the Fort Collins Science Center.

Although the powdery white muzzles of affected bats gave the disease its name, the authors believe that the skin of bat wings is the most significant, though often less obvious, target of the fungus.

The order of bats is called Chiroptera, Greek for “hand-wing,” appropriately named since bat wings are essentially modified arms. Imagine, for a moment, your human hand with its fingers spread apart. Then imagine your fingers are 6 feet long, and the whole skeletal affair is covered with two layers of thin, somewhat transparent membranes attached to the sides of your torso and legs. Sandwiched between the membranes are blood and lymphatic vessels, delicate nerves, muscles and special connective tissues that help you fly and help keep you physiologically healthy.

“The disproportionately large areas of exposed skin that make up bat wings play critical roles in maintaining safe internal body conditions during hibernation,” noted Cryan. “Healthy wings are essential for day-to-day survival, even during winter when bats are mostly just hanging around. Wings damaged by the fungus may not always look so bad to the naked eye, but under the microscope things get ugly fast.”

When Meteyer examined wings of diseased bats microscopically, she discovered wing damage was often so severe that it led her and her colleagues to suggest multiple life-threatening effects on hibernating bats.

“A bat’s wings,” said Meteyer, “are obviously critical for flying, but they also play a vital part in essential functions such as body temperature, blood pressure, water balance and blood and gas circulation and exchange.”

Healthy bats occasionally rouse themselves from hibernation, probably to change roosts, drink, mate and even overcome sleep deprivation, biologists think. But bats afflicted with WNS arouse much more often. In fact, a characteristic of hibernation sites with WNS is daytime flights of affected bats outside caves.

“The prevailing hypothesis is that daytime winter flight is a last-ditch effort for starving bats to find insect prey,” Cryan said. “What we propose is that thirst, and maybe not always hunger, is driving these arousals. Unusual thirst during hibernation may result from water essentially leaking out of wings damaged by the fungus.”

Anecdotally, bats at hibernacula affected by WNS are sometimes seen flying over and drinking from water surfaces or eating snow, highlighting the plausibility of this hypothesis, the authors noted.

Hibernation itself is one reason this emerging disease is so successful. During hibernation, a bat’s immune function and metabolism are dramatically reduced, and body temperature drops significantly. Also, some of the worst-affected bat species roost in humid areas in dense clusters to conserve energy and decrease moisture loss.

“These ideal environmental conditions, combined with the hibernating bat’s suppressed immune system, likely allow the fungus to invade body tissues for nutrients without resistance, making the hibernating bat a most accommodating host for this new disease,” Meteyer said.

The researchers compare the ability of this novel bat fungus to destabilize internal functions with the electrolyte imbalance that occurs in frogs infected by chytrid fungus, which, like G. destructans, is a novel disease of vertebrates. Chytrid infection impairs the ability of frog skin to regulate hydration and internal equilibrium, causing electrolyte imbalance and ultimately cardiac arrest.

“The skin plays a critical role in the physiology of both amphibians and bats,” Meteyer said. “We suggest that a similar, but less subtle, disturbance could be occurring in the wing membranes of bats with WNS.”

The journal article can be accessed online.

[Access images for this release at: &amp;lt;a href="http://gallery.usgs.gov/tags/NR2010_12_14" _mce_href="http://gallery.usgs.gov/tags/NR2010_12_14"&amp;gt;http://gallery.usgs.gov/tags/NR2010_12_14&amp;lt;/a&amp;gt;]

Cumberland River Crest Highest in 73 Years

OC_Web@usgs.gov (Office of Communications and Publishing) — Thu, 13 May 2010 8:21:00 EDT

Flooding in Tennessee

Rivers throughout middle Tennessee crested at record high levels last week. They exceeded previous highs at many streamgages by as much as 14 feet, according to preliminary estimates released today by the U.S. Geological Survey (USGS). The highest flood levels were recorded on May 2 and 3, from Nashville west toward Jackson, extending about 40-miles north and south of Interstate 40, and affecting major tributaries to the Cumberland and Tennessee Rivers.

The flood peak on the Cumberland River in downtown Nashville ranks as only the tenth highest in more than 200 years of record at that site. This peak was, however, the highest observed during the past 73 years in which much of the basin upstream of Nashville was regulated by several large flood-control reservoirs.

At least four major tributaries to the lower Cumberland River met or exceeded warning levels established by the National Weather Service (NWS) for major flooding conditions last week. Flood peaks on the Harpeth River at Bellevue exceeded the NWS stage for major flooding by more than 5 feet, and exceeded the USGS record at that site (measured in 1948) by more than 9 feet. The Harpeth River near Kingston Springs exceeded the NWS major flood stage by almost 16 feet and was 14 higher than the previous recorded peak from 1946.

Flood levels on Mill Creek near Nolensville exceeded major flood stage by more than 3 feet and downstream at Antioch exceeded major flood stage by more than 6 feet. Peak flood levels for Mill Creek further downstream at Thompson Lane in Nashville were somewhat lower, but still exceeded by less than 1 foot both the historic high and NWS stage for major flood.

“Most tributaries to the lower Cumberland River had flows with only a 1 in 500 chance in any given year, causing the lower Cumberland to flood with a severity that was almost entirely unexpected,” according to Rodney Knight, surface-water specialist with the USGS Tennessee Water Science Center. “That a regulated river like the Cumberland could have such high flooding is unusual and is a testament to the severity of this event. The extreme rainfall in tributaries that enter the Cumberland River downstream from the flood storage area made this a very difficult event to regulate.”

The USGS operates streamgages across the Nation in cooperation with other Federal, state, and local agencies. This information is important because it is used by the NWS to issue flood warnings. It is used by FEMA and the U.S. Army Corps of Engineers to characterize flood hazards.

Graphs and tables showing the real-time streamflow data collected at USGS gages in Tennessee for the last 120 days are available online. The USGS May 2010 flood information website includes graphs that compare this event to other historical floods.

High Flows in Tennessee Rivers Estimated

OC_Web@usgs.gov (Office of Communications and Publishing) — Thu, 6 May 2010 10:41:44 EDT

The May 1-2 storm that brought heavy rains to the southeastern U.S. resulted in record high flows for many rivers in middle Tennessee, according to preliminary estimates released today by the U.S. Geological Survey (USGS).

Rivers in middle Tennessee crested May 2-3, breaking records at many USGS-operated streamgages. The highest streamflows were observed from Nashville west toward Jackson, extending about 40-miles north and south of Interstate 40 and affecting major tributaries to the Cumberland and Tennessee Rivers.

Flows on the Harpeth River exceeded 46,000 cubic feet per second (cfs) on May 3, the day after the stream peaked at a level 4 feet higher. This breaks the previous record of 40,000 cfs, set in 1948. The Duck River near Hurricane Mills flowed at 138,000 cfs on May 4, exceeding the previous high by 17,000 cfs.

Flood peaks on the Harpeth near Bellevue, Piney River at Vernon, and Duck River at Hurricane Mills appear to have exceeded levels expected with only a 0.2 percent probability (1 in 500 chance) in any given year. Elsewhere in the area, peaks on the Red River at Port Royal and Buffalo River near Flatwoods and at Lobelville exceeded those expected with only a 0.5 percent probability (1 in 200) and peaks at Mill Creek at Thompson Lane and Big Sandy River at Bruceton exceeded those expected with 1 percent probability (1 in 100).

“The flows on these rivers were much greater than anticipated based on previous experience and exceeded those observed in both the 1975 and 1927 floods,” according to Rodney Knight, surface-water specialist with the USGS Tennessee Water Science Center. “Several of these estimates were based on the last observations received by satellite before our streamgages were submerged,” according to Knight.

During and after storms and floods, USGS hydrologic technicians measure the flow and height of rivers to verify gage readings. During extreme flooding, USGS crews work to keep gages operating, and collect high-water-mark data at ungaged sites and where gages are submerged. This information is important because it is used by the National Weather Service to issue flood warnings. It is used by FEMA and the U.S. Army Corps of Engineers to characterize flood hazards.

Graphs and tables showing the real-time streamflow data collected at USGS gages in Tennessee for the last 120 days and general flood information can be found online.