U.S. Geological Survey News Feed
ANCHORAGE, Alaska — Greenhouse gas emissions remain the primary threat to the preservation of polar bear populations worldwide. This conclusion holds true under both a reduced greenhouse gas emission scenario that stabilizes climate warming and another scenario where emissions and warming continue at the current pace, according to updated U.S. Geological Survey research models.
Under both scenarios, the outcome for the worldwide polar bear population will very likely worsen over time through the end of the century.
The modeling effort examined the prognosis for polar bear populations in the four ecoregions (see map) comprising their range using current sea ice projections from the Intergovernmental Panel on Climate Change for two greenhouse gas emission scenarios. Both scenarios examined how greenhouse gas emissions may affect polar bears: one looked at stabilization in climate warming by century’s end because of reduced GHG emissions, and the other looked at unabated (unchanged) rates of GHG emissions, leading to increased warming by century’s end.
“Addressing sea ice loss will require global policy solutions to reduce greenhouse gas emissions and likely be years in the making,” said Mike Runge, a USGS research ecologist. “Because carbon emissions accumulate over time, there will be a lag, likely on the order of several decades, between mitigation of emissions and meaningful stabilization of sea ice loss.”
Under the unabated emission scenario, polar bear populations in two of four ecoregions were projected to reach a greatly decreased state about 25 years sooner than under the stabilized scenario. Under the stabilized scenario, GHG emissions peak around 2040, decline through 2080, then decline through the end of the century. In this scenario, USGS projected that all ecoregion populations will greatly decrease except for the Archipelago Ecoregion, located in the high-latitude Canadian Arctic, where sea ice generally persists longer in the summer. These updated modeling outcomes reinforce earlier suggestions of the Archipelago’s potential as an important refuge for ice-dependent species, including the polar bear.
The models, updated from 2010, evaluated specific threats to polar bears such as sea ice loss, prey availability, hunting, and increased human activities, and incorporated new findings on regional variation in polar bear response to sea ice loss.
“Substantial sea ice loss and expected declines in the availability of marine prey that polar bears eat are the most important specific reasons for the increasingly worse outlook for polar bear populations,” said Todd Atwood, research biologist with the USGS, and lead author of the study. “We found that other environmental stressors such as trans-Arctic shipping, oil and gas exploration, disease and contaminants, sustainable harvest and defense of life takes, had only negligible effects on polar bear populations—compared to the much larger effects of sea ice loss and associated declines in their ability to access prey.”
Additionally, USGS researchers noted that if the summer ice-free period lengthens beyond 4 months – as forecasted to occur during the last half of this century in the unabated scenario – the negative effects on polar bears will be more pronounced. Polar bears rely on ice as the platform for hunting their primary prey – ice seals – and when sea ice completely melts in summer, the bears must retreat to land where their access to seals is limited. Other research this year has shown that terrestrial foods available to polar bears during these land-bound months are unlikely to help polar bear populations adapt to sea ice loss.
USGS scientists’ research found that managing threats other than greenhouse gas emissions could slow the progression of polar bear populations to an increasingly worse status. The most optimistic prognosis for polar bears would require immediate and aggressive reductions of greenhouse gas emissions that would limit global warming to less than 2°C above preindustrial levels.
The U.S. Fish and Wildlife Service listed the polar bear as threatened under the Endangered Species Act in 2008 due to the threat posed by sea ice loss. The polar bear was the first species to be listed because of climate change. A plan to address recovery of the polar bear will be released into the Federal Register by the USFWS for public review on July 2, 2015.
The updated forecast for polar bears was developed by USGS as part of its Changing Arctic Ecosystems Initiative, together with collaborators from the U.S. Forest Service and Polar Bears International. The polar bear forecasting report is available online.Polar Bear Ecoregions: In the Seasonal Ice Ecoregion (see map), sea ice melts completely in summer and all polar bears must be on land. In the Divergent Ice Ecoregion, sea ice pulls away from the coast in summer, and polar bears must be on land or move with the ice as it recedes north. In the Convergent Ice and Archipelago Ecoregions, sea ice is generally retained during the summer. (High resolution image)
The amount of water required to hydraulically fracture oil and gas wells varies widely across the country, according to the first national-scale analysis and map of hydraulic fracturing water usage detailed in a new USGS study accepted for publication in Water Resources Research, a journal of the American Geophysical Union. The research found that water volumes for hydraulic fracturing averaged within watersheds across the United States range from as little as 2,600 gallons to as much as 9.7 million gallons per well.This map shows the average water use in hydraulic fracturing per oil and gas well in watersheds across the United States. (High resolution image)
In addition, from 2000 to 2014, median annual water volume estimates for hydraulic fracturing in horizontal wells had increased from about 177,000 gallons per oil and gas well to more than 4 million gallons per oil well and 5.1 million gallons per gas well. Meanwhile, median water use in vertical and directional wells remained below 671,000 gallons per well. For comparison, an Olympic-sized swimming pool holds about 660,000 gallons.
“One of the most important things we found was that the amount of water used per well varies quite a bit, even within a single oil and gas basin,” said USGS scientist Tanya Gallegos, the study’s lead author. “This is important for land and resource managers, because a better understanding of the volumes of water injected for hydraulic fracturing could be a key to understanding the potential for some environmental impacts.”This map shows the percentage of oil and gas wells that use horizontal drilling in watersheds across the United States. (High resolution image)
Horizontal wells are those that are first drilled vertically or directionally (at an angle from straight down) to reach the unconventional oil or gas reservoir and then laterally along the oil or gas-bearing rock layers. This is done to increase the contact area with the reservoir rock and stimulate greater oil or gas production than could be achieved through vertical wells alone.
However, horizontal wells also generally require more water than vertical or directional wells. In fact, in 52 out of the 57 watersheds with the highest average water use for hydraulic fracturing, over 90 percent of the wells were horizontally drilled.
Although there has been an increase in the number of horizontal wells drilled since 2008, about 42 percent of new hydraulically fractured oil and gas wells completed in 2014 were still either vertical or directional. The ubiquity of the lower-water-use vertical and directional wells explains, in part, why the amount of water used per well is so variable across the United States.
The watersheds where the most water was used to hydraulically fracture wells on average coincided with parts of the following shale formations:
- Eagle Ford (within watersheds located mainly in Texas)
- Haynesville-Bossier (within watersheds located mainly in Texas & Louisiana)
- Barnett (within watersheds located mainly in Texas)
- Fayetteville (within watersheds located in Arkansas)
- Woodford (within watersheds located mainly in Oklahoma)
- Tuscaloosa (within watersheds located in Louisiana & Mississippi)
- Marcellus & Utica (within watersheds located in parts of Ohio, Pennsylvania, West Virginia and within watersheds extending into southern New York)
Shale gas reservoirs are often hydraulically fractured using slick water, a fluid type that requires a lot of water. In contrast, tight oil formations like the Bakken (in parts of Montana and North Dakota) often use gel-based hydraulic fracturing treatment fluids, which generally contain lower amounts of water.
This research was carried out as part of a larger effort by the USGS to understand the resource requirements and potential environmental impacts of unconventional oil and gas development. Prior publications include historical trends in the use of hydraulic fracturing from 1947-2010, as well as the chemistry of produced waters from hydraulically fractured wells.
The report is entitled “Hydraulic fracturing water use variability in the United States and potential environmental implications,” and has been accepted for publication in Water Resources Research. More information about this study and other USGS energy research can be found at the USGS Energy Resources Program. Stay up to date on USGS energy science by signing up for our quarterly Newsletter or following us on Twitter!
Wading bird numbers in the Florida Everglades are driven by water patterns that play out over multiple years according to a new study by the U.S. Geological Survey and Florida Atlantic University. Previously, existing water conditions were seen as the primary driving factor affecting numbers of birds, but this research shows that the preceding years’ water conditions and availability are equally important.
“We’ve known for some time that changes in water levels trigger a significant response by wading birds in the Everglades,” said James Beerens, the study’s lead author and an ecologist at USGS. “But what we discovered in this study is the importance of history. What happened last year can tell you what to expect this year.”
From 2000 to 2009, scientists examined foraging distribution and abundance data for wading bird populations, including Great Egrets, White Ibises, and threatened Wood Storks. To do the research, they conducted reconnaissance flights across the Greater Everglades system, an area that includes Big Cypress National Preserve and Everglades National Park. They found climate and water management conditions going as far back as three years influenced current bird population numbers and distribution.
“We know wading birds depend on small fish and invertebrates for food,” said Dale Gawlik, director of FAU’s Environmental Science Program and study coauthor. “What is interesting is the ‘lag effect’; wet conditions that build up invertebrate and fish numbers may not immediately result in increased bird numbers until after several more wet years.”
This new information has allowed scientists to improve existing wading bird distribution models providing a more accurate tool to estimate wading bird numbers under climate change scenarios and hydrological restoration scenarios proposed for the Everglades.
In the Everglades, food items such as small fish and crayfish are concentrated from across the landscape into pools as water levels recede throughout the dry season. It does not always work that way anymore due to a lack of water and loss of habitat in Everglades marshes. This new research shows that under the right dry season conditions following a water pulse in previous years, wading bird food is even further concentrated in near-perfect water depths, setting off a boom in the numbers of young wading birds that add to the population.
Beerens and computer scientists from the USGS have also developed publically available software as an extension to this work that predicts wading bird numbers in the Everglades based on real-time, current conditions, in addition to historical settings. This new model allows managers to simulate the effect of various management strategies that can have an impact on future bird numbers. The number and distribution of wading birds serve as an important indicator of ecosystem health in the Everglades. Beerens further explained that “increased seasonal water availability in drier areas of the Everglades stimulates the entire ecosystem, as reflected in the wading birds.”
Altered water patterns resulting from land-use and water management changes have reduced wading bird numbers throughout the Everglades by about 90 percent since the turn of the 20th Century. This research shows that current management and use of water is equally important.
“Our findings also suggest that we can continue to improve the Everglades and its wading bird community by restoring water availability to areas that are over drained,” said Beerens. “There is increasing understanding that water availability and proper management make this entire ecological and economic engine work.”
Florida generates more than $3 billion in annual revenue from resident and nonresident wildlife watchers according to estimates from the U.S. Fish and Wildlife Service. Of the 1.9 million people who view wildlife in Florida while ‘away-from-home’ each year, more than 1.3 million watch wading birds and other water-dependent birds.
The study, “Linking Dynamic Habitat Selection with Wading Bird Foraging Distributions across Resource Gradients,” was published in the journal PLOS ONE and can be found online.
Scientists are expecting that this year’s Chesapeake Bay hypoxic low-oxygen zone, also called the “dead zone,” will be approximately 1.37 cubic miles – about the volume of 2.3 million Olympic-size swimming pools. While still large, this is 10 percent lower than the long-term average as measured since 1950.
The anoxic portion of the zone, which contains no oxygen at all, is predicted to be 0.27 cubic miles in early summer, growing to 0.28 cubic miles by late summer. Low river flow and low nutrient loading from the Susquehanna River this spring account for the smaller predicted size.
This is the ninth year for the Bay outlook which, because of the shallow nature of large areas of the estuary, focuses on water volume or cubic miles, instead of square mileage as used in the Gulf of Mexico dead zone forecast announced last week. The history of hypoxia in the Chesapeake Bay since 1985 can be found at EcoCheck, a website from the University of Maryland Center for Environmental Science.
The Bay’s hypoxic and anoxic zones are caused by excessive nutrient pollution, primarily from human activities such as agriculture and wastewater. The nutrients stimulate large algal blooms that deplete oxygen from the water as they decay. The low oxygen levels are insufficient to support most marine life and habitats in near-bottom waters and threaten the Bay’s production of crabs, oysters and other important fisheries.
The Chesapeake Bay Program coordinates a multi-year effort to restore the water and habitat quality to enhance its productivity. The forecast and oxygen measurements taken during summer monitoring cruises are used to test and improve our understanding of how nutrients, hydrology, and other factors affect the size of the hypoxic zone. They are key to developing effective hypoxia reduction strategies.
The predicted “dead zone” size is based on models that forecast three features of the zone to give a comprehensive view of expected conditions: midsummer volume of the low-oxygen hypoxic zone, early-summer oxygen-free anoxic zone, and late-summer oxygen-free anoxic zone. The models were developed by NOAA-sponsored researchers at the University of Maryland Center for Environmental Science and the University of Michigan. They rely on nutrient loading estimates from the U. S. Geological Survey.
"These ecological forecasts are good examples of the critical environmental intelligence products and tools that NOAA is providing to stakeholders and interagency management bodies such as the Chesapeake Bay Program," said Kathryn D. Sullivan, Ph.D., under secretary of commerce for oceans and atmosphere and NOAA administrator. “With this information, we can work collectively on ways to reduce pollution and protect our marine environments for future generations.”
The hypoxia forecast is based on the relationship between nutrient loading and oxygen. Aspects of weather, including wind speed, wind direction, precipitation and temperature also impact the size of dead zones. For example, in 2014, sustained winds from Hurricane Arthur mixed Chesapeake Bay waters, delivering oxygen to the bottom and dramatically reducing the size of the hypoxic zone to 0.58 cubic miles.
"Tracking how nutrient levels are changing in streams, rivers, and groundwater and how the estuary is responding to these changes is critical information for evaluating overall progress in improving the health of the Bay,” said William Werkheiser, USGS associate director for water. "Local, state and regional partners rely on this tracking data to inform their adaptive management strategies in Bay watersheds."
The USGS provides the nutrient runoff and river stream data that are used in the forecast models. USGS estimates that 58 million pounds of nitrogen were transported to the Chesapeake Bay from January to May 2015, which is 29 percent below average conditions. The Chesapeake data are funded through a cooperative agreement between USGS and the Maryland Department of Natural Resources. USGS operates more than 400 real-time stream gages and collects water quality data at numerous long-term stations throughout the Chesapeake Bay basin to track how nutrient loads are changing over time.
"Forecasting how a major coastal ecosystem, the Chesapeake Bay, responds to decreasing nutrient pollution is a challenge due to year-to-year variations and natural lags," said Dr. Donald Boesch, president of the University of Maryland Center for Environmental Science, "But we are heading in the right direction."
Later this year researchers will measure oxygen levels in the Chesapeake Bay. The final measurement in the Chesapeake will come in October following surveys by the Chesapeake Bay Program's partners from the Maryland Department of Natural Resources (DNR) and the Virginia Department of Environmental Quality. Bimonthly monitoring cruise updates on Maryland Bay oxygen levels can be found on DNR’s Eyes on the Bay website.
Scientists are expecting that this year’s Gulf of Mexico hypoxic zone, also called the “dead zone,” will be approximately 5,483 square miles or about the size of Connecticut — the same as it has averaged over the last several years.
The dead zone in the Gulf of Mexico affects nationally important commercial and recreational fisheries and threatens the region's economy. Hypoxic zones hold very little oxygen, and are caused by excessive nutrient pollution, primarily from activities such as agriculture and wastewater. The low oxygen levels cannot support most marine life and habitats in near-bottom waters.
This year marks the first time the results of four models were combined. The four model predictions ranged from 4,344 to 5,985 square miles, and had a collective predictive interval of 3,205 to 7,645 square miles, which take into account variations in weather and oceanographic conditions.
The NOAA-sponsored Gulf of Mexico hypoxia forecast has improved steadily in recent years, a result of advancements of individual models and an increase in the number of models used for the forecast. Forecasts based on multiple models are called ensemble forecasts and are commonly used in hurricane and other weather forecasts.
The ensemble models were developed by NOAA-sponsored modeling teams and researchers at the University of Michigan, Louisiana State University, Louisiana Universities Marine Consortium, Virginia Institute of Marine Sciences/College of William and Mary, Texas A&M University, North Carolina State University, and the U.S.Geological Survey (USGS). The hypoxia forecast is part of a larger NOAA effort to deliver ecological forecasts that support human health and well-being, coastal economies, and coastal and marine stewardship.
“NOAA, along with our partners, continues to improve our capability to generate environmental data that can help mitigate and manage this threat to Gulf fisheries and economies,” said Kathryn D. Sullivan, Ph.D., under secretary of commerce for oceans and atmosphere and NOAA administrator. “We are adding models to increase the accuracy of our dead zone forecast."
The Gulf of Mexico hypoxia forecast is based on nutrient runoff and river stream data from the USGS. The USGS operates more than 3,000 real-time stream gauges, 50 real-time nitrate sensors, and collects water quality data at long-term stations throughout the Mississippi River basin to track how nutrient loads are changing over time.
The USGS estimates that 104,000 metric tons of nitrate and 19,300 metric tons of phosphorus flowed down the Mississippi and Atchafalaya rivers into the Gulf of Mexico in May 2015. This is about 21 percent below the long-term (1980-2014) average for nitrogen and 16 percent above the long-term average for phosphorus.
"Real-time nitrate sensors are advancing our understanding of how nitrate is transported in small streams and large rivers, including the main stem of the Mississippi River,” said William Werkheiser, USGS associate director for water. “Long-term monitoring is critical for tracking how nutrient levels are changing in response to management actions and for improving modeling tools to estimate which sources and areas are contributing the largest amounts of nutrients to the Gulf. "
The confirmed size of the 2015 Gulf hypoxic zone will be released in early August, following a monitoring survey led by the Louisiana Universities Marine Consortium from July 28 to August 4.
A new GPS survey of Mount McKinley, the highest point in North America, will update the commonly accepted elevation of McKinley’s peak, 20,320 ft. The last survey was completed in 1953.
The USGS, along with NOAA’s National Geodetic Survey (NGS), and the University of Alaska Fairbanks (UAF), are supporting a Global Positioning System (GPS) survey of the Mount McKinley apex. Surveying technology and processes have improved greatly since the last survey and the ability to establish a much more accurate height now exists. With the acquisition of new elevation (ifsar) data in Alaska as part of the 3D Elevation Program, there have been inquiries about the height of the summit. The survey party is being led by CompassData, a subcontractor for Dewberry on a task awarded under the USGS’ Geospatial Products and Services Contract (GPSC).
Using modern GPS survey equipment and techniques, along with better gravity data to improve the geoid model in Alaska, the partners will be able to report the summit elevation with a much higher level of confidence than has been possible in the past. It is anticipated the newly surveyed elevation will be published by the National Geodetic Survey in late August.
An experienced team of four climbers, one from UAF and three from CompassData, will start the precarious trek to the summit with the needed scientific instruments in tow, in the middle part of June. They plan to return on or before July 7 and begin work with the University of Alaska Fairbanks and NGS processing the data to arrive at the new summit elevation.At 20, 320 feet, Mount McKinley is North America’s highest peak. (Photo courtesy of Todd Paris, UAF). (High resolution image) Climbing Mount McKinley, North America’s highest peak, is a daunting task for even the most experienced mountaineers at Denali National Park in Alaska. (Photo courtesy of National Geographic). (High resolution image) The Mount McKinley survey team, and their equipment, are expected to face temperatures well below zero, high winds and frequent snow. Current forecast, courtesy of NOAA. (Photo courtesy of Todd Paris, UAF). (High resolution image)
North America may have once been attached to Australia, according to research just published in Lithosphere and spearheaded by U.S. Geological Survey geologist James Jones and his colleagues at Bucknell University and Colorado School of Mines.
Approximately every 300 million years, the Earth completes a supercontinent cycle wherein continents drift toward one another and collide, remain attached for millions of years, and eventually rift back apart. Geologic processes such as subduction and rifting aid in the formation and eventual break-up of supercontinents, and these same processes also help form valuable mineral resource deposits. Determining the geometry and history of ancient supercontinents is an important part of reconstructing the geologic evolution of Earth, and it can also lead to a better understanding of past and present mineral distributions.
North America is a key component in reconstructions of many former supercontinents, and there are strong geological associations between the western United States and Australia, which is one of the world’s leading mineral producers.
In this study, Jones and others synthesized mineral age data from ancient sedimentary rocks in the Trampas and Yankee Joe basins of Arizona and New Mexico. They found that the ages of many zircon crystals—mineral grains that were eroded from other rocks and embedded in the sedimentary deposits—were approximately 1.6 to 1.5 billion years old, an age range that does not match any known geologic age provinces in the entire western United States.
This surprising result actually mirrors previous studies of the Belt-Purcell basin (located in Montana, Idaho and parts of British Columbia, Canada) and a recently recognized basin in western Yukon, Canada, in which many zircon ages between 1.6 and 1.5 billion years old are common despite the absence of matching potential source rocks of this age.
However, the distinctive zircon ages in all three study locations do match the well known ages of districts in Australia and, to a slightly lesser known extent, Antarctica.
This publication marks the first time a complete detrital mineral age dataset has been compiled to compare the Belt basin deposits to strata of similar age in the southwestern United States. “Though the basins eventually evolved along very different trajectories, they have a shared history when they were first formed,” said Jones. “That history gives us clues as to what continents bordered western North America 1.5 billion years ago.”
The tectonic model presented in this paper suggests that the North American sedimentary basins were linked to sediment sources in Australia and Antarctica until the break up of the supercontinent Columbia. The dispersed components of Columbia ultimately reformed into Rodinia, perhaps the first truly global supercontinent in Earth’s history, around 1.0 billion years ago. Continued sampling and analysis of ancient sedimentary basin remnants will remain a critical tool for further testing global supercontinent reconstructions.
Although record low precipitation has been the main driver of one of the worst droughts in California history, abnormally high temperatures have also played an important role in amplifying its adverse effects, according to a recent study by the U.S. Geological Survey and university partners.
Experiments with a hydrologic model for the period Oct. 2013-Sept. 2014 showed that if the air temperatures had been cooler, similar to the 1916-2012 average, there would have been an 86% chance that the winter snowpack would have been greater, the spring-summer runoff higher, and the spring-summer soil moisture deficits smaller.
To gauge the effect of high temperatures on drought, lead author Shraddhanand Shukla (University of California – Santa Barbara, UCSB) devised two sets of modeling experiments that compared climate data from water year 2014 (Oct. 2013-Sept. 2014) to similar intervals during 1916-2012.
In the first simulation set, Shukla substituted 2014 temperature values with the historical temperatures for each of the study’s 97 years, while keeping the 2014 precipitation values. In the second simulation set, he combined the observed 2014 temperatures with historical precipitation values for each of the preceding years, 1916-2012.
“This experimental approach allows us to model past situations and tease out the influence of temperature in preceding drought conditions,” said Chris Funk, a USGS scientist and a co-author of the investigation. “By crunching enough data over many, many simulations, the effect of temperature becomes more detectable. We can’t do the same in reality, the here and now, because then we only have a single sample.” Funk, an adjunct professor at UCSB, helps coordinate research at the university that supports USGS programs.
High heat has multiple damaging effects during drought, according to the study, increasing the vulnerability of California’s water resources and agricultural industry. Not only does high heat intensify evaporative stress on soil, it has a powerful effect in reducing snowpack, a key to reliable water supply for the state. In addition to decreased snowpack, higher temperatures can cause the snowpack to melt earlier, dramatically decreasing the amount of water available for agriculture in summer when it is most needed.
Although the study did not directly address the issue of long-term climate change, the implications of higher temperatures are clear.
“If average temperatures keep rising, we will be looking at more serious droughts, even if the historical variability of precipitation stays the same,” Shukla said. “The importance of temperature in drought prediction is likely to become only more significant in the future.”
The research was published online in Geophysical Research Letters, a journal of the American Geophysical Union.
For more information about drought in California, visit the USGS California Water Science Center online.Drought effects at Trinity Lake, a major California reservoir located about 60 miles NW of Redding, California. USGS photo, Tim Reed, Feb. 2014. Photo source: CA Water Science Center
Heidi Koontz ( Phone: 303-202-4763 );
Newly released research from the U.S. Geological Survey describes U.S. hydraulic fracturing (frac) sand deposits and their locations, and provides estimates of frac sand production, consumption, and reserves. A companion map of producing and potential frac sand and resin-coated sand source units in the conterminous U.S. is also included.
The United States is the largest producer and consumer of frac sand in the world with nearly 70 percent of 2014 domestic production coming from the Great Lakes Region, primarily Wisconsin and Minnesota. The specialized silica sand, which consists of natural sand grains with strict mineralogical and textural properties, acts as a proppant (a granular substance that props open fractures) when added to fracking fluids that are injected into unconventional oil and gas wells during hydraulic fracturing.
“These new USGS compilations will provide comprehensive information about frac sand to mining companies, the petroleum industry, and land managers,” said USGS scientist Mary Ellen Benson, principal author of “Frac Sand Sources in the United States”.
Hydraulic fracturing in the U.S. significantly increased around 2004, and frac sand production rapidly grew to meet that demand. “Estimates of Hydraulic Fracturing (Frac) Sand Production, Consumption, and Reserves in the United States” by USGS scientist Don Bleiwas, provides an overview of the frac sand industry, including production, consumption, reserves, and resources.
“Frac Sand Sources in the United States,” by USGS geologists Mary Ellen Benson and Anna Burack Wilson, describes the unique physical properties of frac sand and focuses on the geology and spatial relationships of frac sand sources in the U.S. It also tracks recent published efforts to examine the potential for less optimal frac sand sources, reviews current and future sources in Canada, discusses the emergence of alternative proppants, and provides geologic guidelines for identifying potential new sources.
The papers are contained in a special supplement, Frac Sand Insider Resource Guide, in the May 2015 issue of the magazine Rock Products. A USGS Open-File Report expanding on the geology and containing digital data is expected to be released later this year.Map of producing and potential frac sand and resin-coated source units in the conterminous United States. (High resolution image)
Heidi Koontz ( Phone: 303-202-4763 );
Recently, U.S. Geological Survey researchers and partners working in California’s Channel Islands National Park discovered mammoth remains in uplifted marine deposits that date to about 80,000 years ago, confirming a long-held but never proven hypothesis that mammoths may have been on the Channel Islands long before the last glacial period 25,000 to 12,000 years ago.
“These are the first confidently dated fossils from the California Channel Islands showing that mammoths had been on the islands a long time, not just during the last glacial period,” said lead author and USGS research geologist Dan Muhs. “It supports an older hypothesis that mammoths could have swum from the mainland to the islands any time that conditions were favorable for such a journey, when sea level was low.”
This discovery on Santa Rosa Island, detailed in the online and print journal editions of Quaternary Research, shows that mammoths likely ventured to the islands during at least one earlier glacial period, when sea level was lower than present and the swimming distance from the mainland to the islands was minimal.
The older age of mammoths also challenges the hypothesis that climate change and sea level rise at the close of the last glacial period (about 12,000 years ago) were the causes of mammoth extinction on the Channel Islands. Earlier mammoth populations also would have had to contend with climate change and sea level rise, but apparently survived.
The newly discovered fossil mammoth remains are likely Mammuthus exilis, the pygmy mammoth. The Columbian mammoth immigrated to the islands from the California mainland by swimming and the pygmy mammoth evolved on the islands from this ancestral stock. Most mammoth remains previously reported on the Channel Islands date to the last glacial period, about 25,000 to 12,000 years ago.
Mammoths are iconic animals of the Pleistocene Ice Ages, both in North America and Eurasia. Fossil mammoths and other proboscideans (elephants and their relatives) have also been found on many islands of the Mediterranean.
The risk of extinction for the endangered Florida manatee appears to be lower, according to a new U.S. Geological Survey led study.
Based on the data available in 2012, the long-term probability of the species surviving has increased compared to a 2007 analysis, as a result of higher aerial survey estimates of population size, improved methods of tracking survival rates, and better estimates of the availability of warm-water refuges.
USGS scientists, working with colleagues from several other agencies and universities, used the manatee Core Biological Model to analyze the long-term viability of the manatee population in Florida, and to evaluate the threats it faces. A similar analysis completed in 2007 was used by the U.S. Fish and Wildlife Service as part of its 5-year Review of the status of manatees.
“Our analysis using data from 2007 estimated that there was nearly a nine percent chance of Florida manatee numbers falling below 250 adults over the next 100 years on either the Atlantic or Gulf Coast,” said Michael Runge, a USGS research ecologist and lead author of the study. “The current analysis, using data available in 2012, has the estimate dropping to a fraction of one percent, but we need to be cautious in our conclusion, because the analysis did not include several mortality events that have occurred since then.
The mortality events Runge was referencing were cold winters, loss of seagrass in prime habitat, and a red tide event, all of which affected the population.
“Although the estimated status in 2012 was better than in 2007, questions still remain about the population effects of the more recent cold-related mortality events in the winters of 2009-10 and 2010-11,” Runge said. “The 2012 analysis also does not account for the extensive loss of seagrass habitat in Indian River Lagoon in 2011 and 2012 nor the severe red tide event in the Southwest region of Florida in 2013.”
The potential effects of these events will be analyzed in the next update of the Core Biological Model, which is underway in collaboration with Florida Fish and Wildlife Research Institute and Mote Marine Laboratory, and is expected to be complete within the next year.
The major threats to long-term survival of Florida manatees remain boat-related deaths and loss of warm-water winter habitat. In the Southwest region, an increasing frequency of red-tide deaths also warrants concern.
Manatees are large, gentle, herbivorous, slow-moving mammals. They are entirely aquatic, and their range is limited by temperature. Manatees cannot survive for extended periods in water colder than about 17°C (63°F), and prefer temperatures warmer than 22°C (72°F). Manatees live in shallow fresh, brackish, and marine aquatic habitats, traveling readily among them. In Florida, they travel considerable distances during the winter to access warm water refuges, such as artesian springs and the heated discharges of power generating plants. Some individuals also travel long distances during the warm season.
The publication “Status and threats analysis for the Florida Manatee (Trichechus manatus latirostris), 2012,” USGS Open-File Report 2015-1083, by M. C. Runge, C. A. Langtimm, J. Martin, and C. J. Fonnesbeck is available online.
Several of the 812 new US Topo quadrangles for Louisiana now display public trails along with improved data layers. Other significant additions include public land survey system information (PLSS), redesign of map symbols, enhanced railroad information and new road source data.
“I am very excited about the 2015 US Topo maps for Louisiana!” said R. Hampton Peele, GIS Coordinator for the Louisiana Geological Survey. “These maps will provide a great reference for our Cartographic Section as we compile our annual geologic map deliverables for the USGS.”
For Louisiana recreationalists and visitors who want to explore the diverse Gulf coast landscape on a bicycle, hiking, horseback or other means, the new trail features on the US Topo maps will come in handy. During the past two years the IMBA, in a partnership with the MTB Project, has been building a detailed national database of trails. This activity allows local IMBA chapters, IMBA members, and the public to provide trail data and descriptions through their website. The MTB Project and IMBA then verify the quality of the trail data provided, ensure accuracy and confirm the trail is legal. This unique crowdsourcing venture has increased the availability of trail data available through The National Map mobile and web apps, and the revised US Topo maps.
Additionally, a widely anticipated addition to the new Louisiana US Topo maps is the inclusion of Public Land Survey System data. PLSS is a way of subdividing and describing land in the US. All lands in the public domain (lands owned by the federal government) are subject to subdivision by this rectangular system of surveys, which is regulated by the U.S. Department of the Interior.
“The US Topo maps provide an excellent instructional tool in our GIS Certification Program,” said Brent Yantis, Director of the University of Louisiana Lafayette Regional Application Center. “They orient students to their environment and provide a fundamental foundation in the development of geospatial concepts. We look forward to this new release.”
These new maps replace the first edition US Topo maps for the Pelican State and are available for free download from The National Map, the USGS Map Locator & Downloader website , or several other USGS applications.
To compare change over time, scans of legacy USGS topo maps, some dating back to the late 1800s, can be downloaded from the USGS Historical Topographic Map Collection.
For more information on US Topo maps: http://nationalmap.gov/ustopo/Updated 2015 version of Saint Landry quadrangle with orthoimage turned on. (1:24,000 scale) (high resolution image 1.3 MB) Updated 2015 version of the Saint Landry quadrangle with the orthoimage turned off to better see the contour intervals. (1:24,000 scale) (high resolution image 1.1 MB) Scan of the 1935 USGS quadrangle of the Turkey Creek area (which covers the Saint Landry map) from the USGS Historic Topographic Map Collection. (1:62, 500 scale) (high resolution image 1.6 MB)
Water contamination by hormone-disrupting pollutants is a concern for water quality around the world. Existing research has determined that elevated concentrations of Bisphenol-A (BPA), a chemical used in consumer products such as plastic food storage and beverage containers, have been deposited directly into rivers and streams by municipal or industrial wastewater. Now, researchers from the University of Missouri and the U.S. Geological Survey have assessed Missouri water quality near industrial sites permitted to release BPA into the air. As a result, scientists now believe that atmospheric releases may create a concern for contamination of local surface water leading to human and wildlife exposure.
“There is growing concern that hormone disruptors such as BPA not only threaten wildlife, but also humans,” said Chris Kassotis, a doctoral candidate in the Division of Biological Sciences in the College of Arts and Science at MU. “Recent studies have documented widespread atmospheric releases of BPA from industrial sources across the United States. The results from our study provide evidence that these atmospheric discharges can dramatically elevate BPA in nearby environments.”
Water sampling sites were selected based on their proximity to the Superfund National Priorities List (NPL) or locations with reported atmospheric discharges of BPA as identified by the Environmental Protection Agency. Current or historical municipal wastewater treatment sites, which have been shown in the past to contribute hormonally active chemicals to surface water from urban or industrial sources, were also tested. Finally, relatively clean sites were chosen to serve as the control group.
The water then was analyzed for concentrations of BPA, Ethinyl estradiol (EE2), an estrogen commonly used in oral contraceptive pills, and several wastewater compounds. Scientists also measured the total estrogen and receptor activities of the water. This approach is used to measure all chemicals present in the water that are able to bind to and activate (or inhibit) the estrogen or androgen receptors in wildlife and humans. Levels of chemicals were highest in samples with known wastewater treatment plant discharges.
“In addition, we were surprised to find that BPA concentrations were up to 10 times higher in the water near known atmospheric release sites,” said Don Tillitt, adjunct professor of biological sciences at MU, and biochemistry and physiology branch chief with the USGS Columbia Environmental Research Center. “This finding suggests that atmospheric BPA releases may contaminate local surface water, leading to greater exposure of humans or wildlife.”
Concentrations of BPA measured in surface water near these sites were well above levels shown to cause adverse health effects in aquatic species, Kassotis said.
The study, “Characterization of Missouri surface waters near point sources of pollution reveals potential novel atmospheric route of exposure for bisphenol A and wastewater hormonal activity pattern,” was published in the journal, Science of the Total Environment, with funding from MU, the USGS Contaminants Biology Program (Environmental Health Mission Area), and STAR Fellowship Assistance Agreement awarded by the U.S. EPA.
WELLSBORO, Pa. — A piece of the restoration puzzle to save populations of endangered freshwater mussels may have been found, according to a recent U.S. Geological Survey led study. Local population losses in a river may not result in irreversible loss of mussel species; other mussels from within the same river could be used as sources to restore declining populations.
Though they serve a critical role in rivers and streams, freshwater mussels are threatened by habitat degradation such as dams, alteration to river channels, pollution and invasive species. Mussels filter the water and provide habitat and food for algae, macroinvertebrates, and even fish, which are necessary components of aquatic food webs.
“Few people realize the important role that mussels play in the ecosystem," said USGS research biologist Heather Galbraith, lead author of the study. "Streams and rivers with healthy mussel populations tend to have relatively good water quality which is good for the fish and insects that also inhabit those systems."
Mussels in general are poorly understood and difficult to study. Because of this lack of knowledge, population genetics has become a useful tool for understanding their ecology and guiding their restoration.
More than 200 of the nearly 300 North American freshwater mussel species are imperiled, with rapidly dwindling populations. Researchers are providing information to resource managers, who are working to reverse this trend. USGS led research suggests that re-introducing mussels within the same river could reverse population declines without affecting the current genetic makeup of the population.
The research shows that patterns in the genetic makeup of a population occurs within individual rivers for freshwater mussels; and that in the study area, mussels from the same river could be used for restoration.
“That genetic structuring is occurring within individual rivers is good news, because it may be a means of protecting rare, threatened and endangered species from impending extinction,” said Galbraith. “Knowing the genetic structure of a freshwater mussel population is necessary for restoring declining populations to prevent factors such as inbreeding, high mutation rates and low survivorship.”
Knowing that mussels in the same river are similar genetically opens up opportunities for augmenting declining populations or re-introducing mussels into locations where they were historically found. The genetics also highlight the importance of not mixing populations among rivers without additional studies to verify the genetic compatibility of mussels within those rivers.
The international team of researchers from Canada and the United States working to understand mussel genetics found similar genetic patterns among common and endangered mussel species. This is important information for mussel biologists because studying endangered species can be difficult, and researchers may be able to study the genetic structure of common mussels and generalize the patterns to endangered mussels.
Although understanding the genetic structure of mussel populations is important for restoration, genetic tools do have limitations. Researchers found that despite drastic reductions in freshwater mussel populations, there was little evidence of this population decline at the genetic level. This may be due to the extremely long lifespan of mussels, some of which can live to be more than 100 years old.
“Genetics, it turns out, is not a good indicator of population decline; by the time we observe a genetic change, it may be too late for the population,” said Galbraith.
By way of comparison, in fruit flies, which have short lifespans, genetic changes show up quickly within a few generations. Mussels, on the other hand, are long lived animals; therefore it may take decades to see changes in their genetic structure within a population.
The study examined six species of freshwater mussels in four Great Lakes Tributaries in southwestern Ontario. The species are distributed across the eastern half of North America and range in status from presumed extinct to secure. The six mussels were the snuffbox, Epioblasma triquetra; kidneyshell, Ptychobranchus fasciolaris; mapleleaf, Quadrula quadrula; wavy-rayed lampmussel, Lampsilis fasciola; Flutedshell Lasmigona costata; and the threeridge mussel Amblema plicata.
The study, “Comparative analysis of riverscape genetic structure in rare, threatened and common freshwater mussels” is available online in the journal Conservation Genetics.
For more information on freshwater mussels please visit Stranger than Fiction: The Secret Lives of Freshwater Mussels.
Mining companies, land managers, and regulators now have a wealth of tools to aid in reducing potential mining impacts even before the mine gets started. USGS and various research partners released a special edition of papers specifically targeted at providing modern environmental effect research for modern mining techniques.
Minerals play an important role in the global economy, and, as rising standards of living have increased demand for those minerals, the number and size of mines have increased, leading to larger potential impacts from mining.
“Approaches to protecting the environment from mining impacts have undergone a revolution over the past several decades,” said USGS mineral and environmental expert Bob Seal. “The sustainability of that revolution relies on an evolving scientific understanding of how mines and their waste products interact with the environment.”
Many research conclusions are contained in the special issue, and some of the primary findings are listed here:
- USGS evaluated several tools for predicting pre-mining baseline conditions at a mine, even if no baseline was established. This will make it easier to remediate the mine after it closes.
- USGS also took tools used to screen mine waste for contaminants and tested them for predicting potential sources for contaminants before the mine even got started.
Mitigating while Mining
- Because slag is the byproduct of mineral processing, its physical and chemical properties depend a lot on what the original mined mineral material was.
- Slag from copper, zinc, or nickel may be less attractive for reuse, since it has a higher potential to negatively impact the environment than slag that came from iron or steel production.
- Gold mining runs a lower risk of contaminating the environment with cyanide if mines give enough time for it to safely evaporate and be broken down by sunlight.
- Mine drainage is incredibly complicated. It doesn’t come from a single source, but rather complex interactions between water, air, and micro-organisms like bacteria.
- Mine drainage is not just acid mine drainage—it can be basic, neutral, or even high in salts. All of these drainage types have their own impacts.
- Mine drainage concentrations in streams can actually change based on the time of day.
- USGS tested many of the existing techniques for figuring out what toxic contaminants wind up in stream sediments so managers know the right one for the right job.
- USGS also evaluated a new technique for predicting how toxic certain metals will be in aquatic environments.
The research papers are contained in a special issue of the journal Applied Geochemistry. This research was conducted by scientists from USGS and several collaborating organizations, including the Geological Survey of Canada, InTerraLogic, Montana Bureau of Mines and Geology, Montana Tech, SUNY Oneonta, the University of Maryland, the University of Montana, and the University of Waterloo.
USGS minerals research can help to identify problems before they become problems, or at the very least, help address the impacts that do exist. Learn more about USGS minerals research here, or follow us on www.twitter.com/usgsminerals.
A pine siskin stands on the branch of a northern conifer tree. Photo, USFWS National Digital Library. (High resolution image)
Weaving concepts of ecology and climatology, recent interdisciplinary research by USGS and several university partners reveals how large-scale climate variability appears to connect boom-and-bust cycles in the seed production of the boreal (northern conifer) forests of Canada to massive, irregular movements of boreal birds.
These boreal bird “irruptions” — extended migrations of immense numbers of birds to areas far outside their normal range — have been recorded for decades by birders, but the ultimate causes of the irruptions have never been fully explained.
“This study is a textbook example of interdisciplinary research, establishing an exciting new link between climate and bird migrations” said USGS acting Director Suzette Kimball. “A vital strength of our organization is our ability to pursue scientific issues across the boundaries of traditional academic disciplines.”
The investigation was based on statistical analysis of two million observations of the pine siskin (a finch, Spinus pinus) recorded since 1989 by Project FeederWatch, a citizen science program managed by the Cornell Lab of Ornithology. By methodically counting the birds they see at their feeders from November through early April, FeederWatchers help scientists track continent-wide movements of winter bird populations.
One of several nomadic birds that breed during summer in Canadian boreal forests, pine siskins feed on seed crops of conifers and other tree species. When seed is abundant locally, pine siskins also spend the autumn and winter there. In other years, they may irrupt, migrating unpredictably hundreds or even thousands of kilometers to the south and east in search of seed and favorable habitat. “Superflights” is the term applied to winters (e.g.1997-1998, 2012-2013) when boreal species have blanketed bird feeders across the U.S.
The irruptions of pine siskins and other boreal species follow a lagging pattern of intermittent, but broadly synchronous, accelerated seed production (“masting”) by trees in the boreal forest. Widespread masting in pines, spruces, and firs is driven primarily by favorable climate during the two or three consecutive years required to initiate and mature seed crops. Leading up to masting events, the green developing cones and the promise of abundant seed stimulate higher reproductive rates in birds.
However, seed production is expensive for trees and tends to be much reduced in the years following masting. Consequently, meager seed crops in the years following masting drive boreal birds to search elsewhere for food and overwintering habitat.
The key finding of the new research is that the two principal pine siskin irruption modes – North to South and West to East – correlate closely with spatial patterns of climate variability across North America that are well understood by climatologists. Not surprisingly, severely cold winters tend to drive birds south during the irruption year.
More subtly, the researchers found that favorable and unfavorable climatic conditions of regularly juxtaposed regions called “climate dipoles” two years prior to the irruption also appear to push and pull bird migrations across the continent.
USGS co-author Julio Betancourt commented, “Our study underscores the value of continent-wide biological monitoring. In this case, avid birders across the U.S. and Canada have contributed sustained observations of birds at the same broad geographic scale in which weather and climate have also been observed and understood.”
The research study, authored by Court Strong (University of Utah), Ben Zuckerberg (University of Wisconsin-Madison), Julio Betancourt (USGS-Reston), and Walt Koenig (Cornell University), was published May 11 online in the Proceedings of the National Academy of Sciences.
Storage tanks for produced water from natural gas drilling in the Marcellus Shale gas play of western Pennsylvania. USGS photo, Doug Duncan. (High resolution image)
In a study of 13 hydraulically fractured shale gas wells in north-central Pennsylvania, USGS researchers found that the microbiology and organic chemistry of the produced waters varied widely from well to well.
The variations in these aspects of the wells followed no discernible spatial or geological pattern but may be linked to the time a well was in production. Further, the study highlighted the presence of some organic compounds (e.g. benzene) in produced waters that could present potential risks to human health, if the waters are not properly managed.
Produced water is the term specialists use to describe the water brought to the land surface during oil, gas, and coalbed methane production. This water is a mixture of naturally occurring water and fluid injected into the formation deep underground to enhance production. A USGS Fact Sheet on produced water provides more background information and terminology definitions.
Although the USGS investigators found that the inorganic (noncarbon-based) chemistry of produced waters from the shale gas wells tested in the Marcellus region was fairly consistent from well to well and meshed with comparable results of previous studies (see USGS Energy Produced Waters Project), the large differences in the organic geochemistry (carbon-based, including petroleum products) and microbiology (e.g. bacteria) of the produced waters were striking findings of the study.
“Some wells appeared to be hotspots for microbial activity,” observed Denise Akob, a USGS microbiologist and lead author of the study, “but this was not predicted by well location, depth, or salinity. The presence of microbes seemed to be associated with concentrations of specific organic compounds — for example, benzene or acetate — and the length of time that the well was in production.”
The connection between the presence of organic compounds and the detection of microbes was not, in itself, surprising. Many organic compounds used as hydraulic fracturing fluid additives are biodegradable and thus could have supported microbial activity at depth during shale gas production.
The notable differences in volatile organic compounds (VOCs) from the produced waters of the tested wells could play a role in the management of produced waters, particularly since VOCs, such as benzene, may be a health concern around the well or holding pond. In wells without VOCs, on the other hand, disposal strategies could concentrate on issues related to the handling of other hazardous compounds.
Microbial activity detected in these samples could turn out to be an advantage by contributing to the degradation of organic compounds present in the produced waters. Potentially, microbes could also serve to help mitigate the effects of organic contaminants during the disposal or accidental release of produced waters. Additional research is needed to fully assess how microbial activity can best be utilized to biodegrade organic compounds found in produced waters.
The research article can be found in the most recent edition of Applied Geochemistry, Special Issue on Shale Gas Geochemistry.
If invasive bighead carp and silver carp spread into Lake Erie, there would be enough food available for these species of Asian carp to survive, according to a new study by the U.S. Geological Survey.
This information is critical in helping resource managers mitigate effects of an Asian carp invasion. If bighead and silver carp were to populate Lake Erie, they have the potential to damage native fish populations and the Great Lakes economy.
USGS scientists used satellite imagery of Lake Erie showing algae on the surface to determine how much food would be available for Asian carp. Green algae and blue-green algae, specifically floating algal blooms that can be seen on the surface, are a preferred food source for Asian carp. The water temperatures and algal concentrations detected in Lake Erie from 2002-2011 show that the bighead and silver carps could not only live in this environment, but could continue to grow. The full report is available online.
“Remote sensing imagery shows that Lake Erie has huge areas of available food that are often several times more concentrated than necessary for Asian carp growth, particularly in the western basin,” said USGS scientist Karl Anderson.
Food availability and water temperature are the greatest sources of uncertainty for predicting fish growth potential. Water temperature is a big factor in determining how much bighead and silver carps need to eat. Models developed by USGS scientists helped determine how much algae bighead and silver carps need to eat to survive.
For the past 10 years, algal blooms in Lake Erie have been increasing. Remote sensing images showed that the amount of algae doubled, and in some places quadrupled, from 2002-2011. Throughout the lake, algal blooms encompass several hundred to several thousands square kilometers. Specifically, the western part of Lake Erie has algal concentrations that are several times greater than what is needed for bighead or silver carp to survive.
RESTON, Va.-- The latest tool designed to help manage the threatened piping plover is only a download away; iPlover is the first smartphone data collection application developed by the U.S. Geological Survey and will help those managing plover populations.
iPlover supports a long-established network of partners working to address ongoing impacts on plover populations, such as habitat gain or loss due to storms.
More importantly, data from the app is used to develop models that address long-term management concerns for habitat availability. It also improves the overall quality of coastal geologic information available to effectively manage this species.
The piping plover is a small shorebird that depends on open coastal beaches to breed and raise its young. Listed as threatened along the Atlantic coast in 1986, the piping plover’s conservation has been mandated by the Endangered Species Act. Although Atlantic Coast piping plover numbers have more than doubled since their listing nearly 30 years ago, they are still at risk. Recent estimates place the population at fewer than 2000 pairs, and climate change has introduced new threats to their coastal habitat.
Coastal beaches are dynamic systems and managing them for beach-dependent species like the piping plover requires collecting data on physical and biological characteristics that will be affected by sea level rise. Given the extensive Atlantic breeding range of the piping plover – spanning from North Carolina to Newfoundland – biologists have a lot of ground to cover.
The iPlover app supports the need for coordinated, synchronized data collection. It is a powerful new tool to help scientists and coastal resource managers consistently measure and assess the birds’ response to changes to their habitat. Rather than compiling data from multiple sources and formats, the app gives trained resource managers an easy-to-use platform where they can collect and instantly share data across a diverse community of field technicians, scientists, and managers. iPlover improves scientists’ data gathering and analysis capabilities by simplifying and facilitating consistent data collection and management that interfaces with models of shoreline change and beach geomorphology.
“The data come in from all of our study sites basically in real-time,” said Rob Thieler, USGS scientist and lead developer of the app. “It's already formatted, so data can be quickly plugged into our research models. This should really shorten the time between collecting the data, doing the science, and turning it into actionable information for management.”
“The USGS worked with diverse project partners to incorporate specific data collection needs and enable important stakeholders and partners to contribute data from hundreds of field observations within the plover’s U.S. Atlantic coastal breeding range,” said Andrew Milliken, coordinator of the North Atlantic Landscape Conservation Cooperative. “This included getting inputs from the U.S. Fish and Wildlife Service, National Park Service, state agencies and non-governmental organizations.”
“The app highlights the synergies and benefits of interagency and interdisciplinary science that advances conservation,” Milliken added. “The information collected will not only greatly improve our understanding of impacts from sea level rise, storms and beach management on piping plovers but also how managing for plovers can benefit other beach-dependent species, such as the American oystercatcher.”
Funding for iPlover was provided through the Department of Interior North Atlantic Landscape Conservation Cooperative as part of its Hurricane Sandy response. The app was developed by the USGS’ Woods Hole Coastal and Marine Science Center and the Center for Integrated Data Analytics.
“iPlover is a great example of the USGS’ ability to build and deliver a variety of science applications that use modern technology,” said Nate Booth, USGS Chief of Office of Water Information and former Lead Architect for the USGS Center for Integrated Data Analytics. “It offers research teams great gains in data collection efficiency so that more time can be spent on analyzing the data rather than managing it."
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.