SEATTLE, Wash. — More than 1,000 dams have been removed across the United States because of safety concerns, sediment buildup, inefficiency or having otherwise outlived usefulness. A paper published today in Science finds that rivers are resilient and respond relatively quickly after a dam is removed.
“The apparent success of dam removal as a means of river restoration is reflected in the increasing number of dams coming down, more than 1,000 in the last 40 years,” said lead author of the study Jim O’Connor, geologist with the U.S. Geological Survey. “Rivers quickly erode sediment accumulated in former reservoirs and redistribute it downstream, commonly returning the river to conditions similar to those prior to impoundment.”
Dam removal and the resulting river ecosystem restoration is being studied by scientists from several universities and government agencies, including the USGS and U.S. Forest Service, as part of a national effort to document the effects of removing dams. Studies show that most river channels stabilize within months or years, not decades, particularly when dams are removed rapidly.
“In many cases, fish and other biological aspects of river ecosystems also respond quickly to dam removal,” said co-author of the study Jeff Duda, an ecologist with USGS. “When given the chance, salmon and other migratory fish will move upstream and utilize newly opened habitat.”
The increase in the number of dam removals, both nationally and internationally, has spurred the effort to understand the consequences and help guide future dam removals.
“As existing dams age and outlive usefulness, dam removal is becoming more common, particularly where it can benefit riverine ecosystems,” said Gordon Grant, Forest Service hydrologist. “But it can be a complicated decision with significant economic and ecologic consequences. Better understanding of outcomes enables better decisions about which dams might be good candidates for removal and what the river might look like as a result.”
Sponsored by the USGS John Wesley Powell Center for Analysis and Synthesis, a working group of 22 scientists compiled a database of research and studies involving more than 125 dam removals. Researchers have determined common patterns and controls affecting how rivers and their ecosystems respond to dam removal. Important factors include the size of the dam, the volume and type of sediment accumulated in the reservoir, and overall watershed characteristics and history.
Following is a summary of key federal disaster aid programs that can be made available as needed and warranted under President Obama's disaster declaration issued for the Commonwealth of Kentucky.
Assistance for the Commonwealth and Affected Local Governments Can Include as Required:Language English
WASHINGTON, D.C. – The U.S. Department of Homeland Security's Federal Emergency Management Agency announced that federal disaster aid has been made available to the Commonwealth of Kentucky to supplement commonwealth and local recovery efforts in the area affected by the severe winter storms, snowstorms, flooding, landslides, and mudslides during the period of February 15-22, 2015.Language English
DENVER – Thursday, April 30, is America’s PrepareAthon! National Day of Action, a grassroots campaign for action to get families, organizations and whole communities better prepared for emergencies. The campaign offers easy-to-use preparedness guides, checklists, and resources to help individuals prepare for common natural hazards and to take action, including downloading alerts and warnings, holding a drill, or safeguarding critical documents.Language English
WASHINGTON, D.C. – The U.S. Department of Homeland Security's Federal Emergency Management Agency announced that federal disaster aid has been made available to the government of the Federated States of Micronesia under the Compact of Free Association between the government of the United States of America and the government of the Federated States of Micronesia, as amended, due to Typhoon Maysak during the period of March 29 to April 1, 2015.Language English
Sixty Percent of Americans Not Practicing for Disaster: FEMA urges everyone to prepare by participating in National PrepareAthon! Day on April 30
WASHINGTON – A recent Federal Emergency Management Agency (FEMA) survey found that nearly 60 percent of American adults have not practiced what to do in a disaster by participating in a disaster drill or preparedness exercise at work, school, or home in the past year. Further, only 39 percent of respondents have developed an emergency plan and discussed it with their household.Language English
EVERGLADES NATIONAL PARK, Fla.— The largest and longest Burmese Python tracking study of its kind -- here or in its native range -- is providing researchers and resource managers new information that may help target control efforts of this invasive snake, according to a new study led by the U.S. Geological Survey.
Among the findings, scientists have identified the size of a Burmese python’s home range and discovered they share some “common areas” that multiple snakes use.
“These high-use areas may be optimal locations for control efforts and further studies on the snakes’ potential impacts on native wildlife,” said Kristen Hart, a USGS research ecologist and lead author of the study. “Understanding habitat-use patterns of invasive species can aid resource managers in designing appropriately timed and scaled management strategies to help control their spread.”
Using radio and GPS tags to track 19 wild-caught pythons, researchers were able to learn how the Burmese python moved within its home range. The 5,119 days of tracking data led researchers to conclude that python home ranges are an average of 22 square kilometers, or roughly an area 3 miles wide-by-3 miles long, all currently within the park.
The study found pythons were concentrated in slough and coastal habitats, with tree islands being the principal feature of common-use areas, even in areas where they were not the predominant habitat type. The longest movements of individual pythons occurred most often during dry conditions, but took place during “wet” and “dry” seasons.
Burmese pythons are long-lived, large-bodied constricting snakes native to Southeast Asia. Highly adaptable, these ambush predators can reach lengths greater than 19 feet and produce large clutches of eggs that can range from eight to 107 eggs. Burmese pythons were first observed in South Florida’s Everglades National Park in 1979. Since then, they have spread throughout the park. Although recent research indicates the snakes may be having a significant effect on some populations of mid-sized mammals, it has also shown there is little risk to people who visit Everglades National Park.
Invasive species compete with native wildlife for food, and they threaten native biodiversity across the globe. With nearly 50 percent of the imperiled species in the US being threatened by exotic species, a major concern for land managers is the growing number of exotics that are successfully invading and establishing viable populations.
Florida is home to more exotic animals than any other state. Snakes in particular have been shown to pose a high risk of becoming invasive species. The establishment of Burmese pythons in South Florida poses a significant threat to both the sensitive Everglades ecosystem and native species of conservation concern. For example, in the park, wood storks, Florida panthers and Cape Sable seaside sparrows are all species of conservation concern that have home ranges near the common-use areas of the radio-tracked pythons.
The study, “Home Range, Habitat Use, and Movement Patterns of Non-Native Burmese Pythons in Everglades National Park, Florida, USA,” with authors from the USGS, University of Florida, National Park Service, and Davidson College, was published in the journal Animal Biotelemetry.
DNREC, New Castle Conservation District honored by Water Resources Association of Delaware River Basin for dike restoration project
Diane Noserale ( Phone: 703-648-4333 );
A map showing the many different pieces of Earth’s crust that comprise the nation’s geologic basement is now available from the U.S. Geological Survey. This is the first map to portray these pieces, from the most ancient to recent, by the events that influenced their composition, starting with their origin. This product provides a picture of the basement for the U.S., including Alaska, that can help scientists produce regional and national mineral resource assessments, starting with the original metal endowments in source rocks.
“Traditionally, scientists have assessed mineral resources using clues at or near the Earth’s surface to determine what lies below,” said USGS scientist Karen Lund, who led the project. “This map is based on the concept that the age and origins of basement rocks influenced the nature and location of mineral deposits. It offers a framework to examine mineral resources and other geologic aspects of the continent from its building blocks up,” said Lund.
More than 80 pieces of crust have been added to the nation’s basement since the Earth began preserving crust about 3.6 billion years ago. These basement domains had different ages and origins before they became basement rocks, and this map includes these as key factors that determined their compositions and the original metals that may be available for remobilization and concentration into ore deposits. The map further classifies the basement domains according to how and when they became basement, as these events also influence the specific metals and deposit types that might be found in a region.
Users can identify domains potentially containing specific metals or deposit types. They can configure the companion database to show the construction of the U.S. through time. The map also provides a template to correlate regional to national fault and earthquake patterns. The map is also available on a separate site, where users can combine data and overlay known mineral sites or other features on the domains.
Basement rocks are crystalline rocks lying above the mantle and beneath all other rocks and sediments. They are sometimes exposed at the surface, but often they are buried under miles of rock and sediment and can only be mapped over large areas using remote geophysical surveys. This map was compiled using a variety of methods, including data from national-scale gravity and aeromagnetic surveys.
Crustal rocks are modified several times before they become basement, and these transitions alter their composition. Basement rocks are continental crust that has been modified by a wide variety of plate tectonic events involving deformation, metamorphism, deposition, partial melting and magmatism. Ultimately, continental crust forms from pre-existing oceanic crust and overlying sediments that have been thus modified.
It is not only the myriad processes that result in varying basement rock content but also the time when these processes occurred during the Earth’s history. For example, because the Earth has evolved as a planet during its 4.5 billion year history, early deposit types formed when there was less oxygen in the atmosphere and the thin crust was hotter. The ancient domains are now more stable and less likely to be altered by modern processes that could cause metals to migrate. By contrast, basement rocks that formed out of crust that is less than one billion years old have origins that can be interpreted according to the present-day rates and scales of plate tectonic processes that reflect a more mature planet with a thicker crust.
By incorporating ancient to modern processes, this map offers a more complete and consistent portrait of the nation’s geologic basement than previous maps and presents a nationwide concept of basement for future broad-scale mineral resource assessments and other geologic studies.Map showing basement domains according to generalized original crust types. (High resolution image)
Significant strides in science have been made to better understand potential ground shaking from induced earthquakes, which are earthquakes triggered by man-made practices.
Earthquake activity has sharply increased since 2009 in the central and eastern United States. The increase has been linked to industrial operations that dispose of wastewater by injecting it into deep wells.
The U. S. Geological Survey (USGS) released a report today that outlines a preliminary set of models to forecast how hazardous ground shaking could be in the areas where sharp increases in seismicity have been recorded. The models ultimately aim to calculate how often earthquakes are expected to occur in the next year and how hard the ground will likely shake as a result. This report looked at the central and eastern United States; future research will incorporate data from the western states as well.
This report also identifies issues that must be resolved to develop a final hazard model, which is scheduled for release at the end of the year after the preliminary models are further examined. These preliminary models should be considered experimental in nature and should not be used for decision-making.
USGS scientists identified 17 areas within eight states with increased rates of induced seismicity. Since 2000, several of these areas have experienced high levels of seismicity, with substantial increases since 2009 that continue today. This is the first comprehensive assessment of the hazard levels associated with induced earthquakes in these areas. A detailed list of these areas is provided in the accompanying map, including the states of Alabama, Arkansas, Colorado, Kansas, New Mexico, Ohio, Oklahoma, and Texas.
Scientists developed the models by analyzing earthquakes in these zones and considering their rates, locations, maximum magnitude, and ground motions.
“This new report describes for the first time how injection-induced earthquakes can be incorporated into U.S. seismic hazard maps,” said Mark Petersen, Chief of the USGS National Seismic Hazard Modeling Project. “These earthquakes are occurring at a higher rate than ever before and pose a much greater risk to people living nearby. The USGS is developing methods that overcome the challenges in assessing seismic hazards in these regions in order to support decisions that help keep communities safe from ground shaking.”
In 2014, the USGS released updated National Seismic Hazard Maps, which describe hazard levels for natural earthquakes. Those maps are used in building codes, insurance rates, emergency preparedness plans, and other applications. The maps forecast the likelihood of earthquake shaking within a 50-year period, which is the average lifetime of a building. However, these new induced seismicity products display intensity of potential ground shaking from induced earthquakes in a one-year period. This shorter timeframe is appropriate because the induced activity can vary rapidly with time and is subject to commercial and policy decisions that could change at any point.
These new methods and products result in part from a workshop hosted by the USGS and the Oklahoma Geological Survey. The workshop, described in the new report, brought together a broad group of experts from government, industry and academic communities to discuss the hazards from induced earthquakes.
Wastewater that is salty or polluted by chemicals needs to be disposed of in a manner that prevents contaminating freshwater sources. Large volumes of wastewater can result from a variety of processes, such as a byproduct from energy production. Wastewater injection increases the underground pore pressure, which may lubricate nearby faults thereby making earthquakes more likely to occur. Although the disposal process has the potential to trigger earthquakes, most wastewater disposal wells do not produce felt earthquakes.
Many questions have been raised about whether hydraulic fracturing—commonly referred to as “fracking”—is responsible for the recent increase of earthquakes. USGS’s studies suggest that the actual hydraulic fracturing process is only occasionally the direct cause of felt earthquakes.
Read the newly published USGS report, “Incorporating Induced Seismicity in the 2014 United States National Seismic Hazard Model—Results of 2014 Workshop and Sensitivity Studies.”Cumulative number of earthquakes with a magnitude of 3.0 or larger in the central and eastern United States, 1973-2014. The rate of earthquakes began to increase starting around 2009 and accelerated in 2013-2014. (high resolution image) Research has identified 17 areas in the central and eastern United States with increased rates of induced seismicity. Since 2000, several of these areas have experienced high levels of seismicity, with substantial increases since 2009 that continue today. (high resolution image)
Fish & Wildlife Natural Resources Police investigation into persons prohibited from weapons possession nets four arrests, large cache of evidence
USGS scientists have updated the hydrogeologic framework for the Floridan aquifer system that underlies Florida and parts of Georgia, Alabama, and South Carolina.
The Floridan aquifer system is the principal source of freshwater for agricultural irrigation, industrial, mining, commercial, and public supply in Florida and southeast Georgia. The extensive underground reservoir currently supplies drinking water to about 10 million people residing across the area as well as 50% of the water that is used for agricultural irrigation in the region.
By describing the hydrologic and geologic setting of an aquifer, a hydrogeologic framework enables appropriate authorities and resource managers to monitor an aquifer more accurately, improving their ability to protect these critical resources and determine the near- and long-term availability of groundwater.
As the first update of the framework for the aquifer in over 30 years, the revision incorporates new borehole data into a detailed conceptual model that describes the major and minor units and zones of the system. Its increased accuracy is made possible by data collected in the intervening years by the USGS; the Geological Surveys of Alabama, Florida, Georgia, and South Carolina; the South Florida, Southwest Florida, St Johns River, Suwannee River, and Northwest Florida Water Management Districts; and numerous other state and local agencies.
The USGS is releasing two reports as part of its current assessment of groundwater availability of the Floridan aquifer system.
The first report documents the revised framework.
Williams, L.J., and Kuniansky, E.L., 2015, Revised hydrogeologic framework of the Floridan aquifer system in Florida and parts of Georgia, Alabama, and South Carolina: U.S. Geological Survey Professional Paper 1807, 140 p., 23 pls.
The second report provides datasets that describe the surfaces and thicknesses of selected hydrogeologic units of the Floridan aquifer system. The data depict the top and base of the aquifer system, its major and minor hydrogeologic units and zones, geophysical marker horizons, and th