Aerial photos of the Elwha River mouth before and during dam removal. Photos show (A) the river mouth wetlands before dam removal, (B) the turbid coastal plume that occurred during much of the dam removal project, and (C) the expansion of the river mouth delta by sediment deposition. Photos provided by Ian Miller of Washington Sea Grant, Jonathan Felis of USGS, and Neal and Linda Chism of LightHawk. (High resolution image)
SEATTLE — The effects of dam removal are better known as a result of several new studies released this week by government, tribal and university researchers. The scientists worked together to characterize the effects of the largest dam removal project in U.S. history occurring on the Elwha River of Washington State. New findings suggest that dam removal can change landscape features of river and coasts, which have ecological implications downstream of former dam sites.
“These studies not only give us a better understanding of the effects of dam removal, but show the importance of collaborative science across disciplines and institutions,” said Suzette Kimball, acting director of the U.S. Geological Survey.
Five peer-reviewed papers, with authors from the U.S. Geological Survey, Reclamation, National Park Service, Washington Sea Grant, NOAA Fisheries, the Lower Elwha Klallam Tribe, and the University of Washington, provide detailed observations and insights about the changes in the river’s landforms, waters and coastal zone during the first two years of dam removal. During this time, massive amounts of sediment were eroded from the drained reservoirs and transported downstream through the river and to the coast.
One finding that intrigued scientists was how efficiently the river eroded and moved sediment from the former reservoirs; over a third of the 27 million cubic yards of reservoir sediment, equivalent to about 3000 Olympic swimming pools filled with sediment, was eroded into the river during the first two years even though the river’s water discharge and peak flows were moderate compared to historical gaging records.
This sediment release altered the river’s clarity and reshaped the river channel while adding new habitats in the river and at the coast. In fact, the vast majority of the new sediment was discharged into the coastal waters of the Strait of Juan de Fuca, where the river mouth delta expanded seaward by hundreds of feet.
“The expansion of the river mouth delta is very exciting, because we are seeing the rebuilding of an estuary and coast that were rapidly eroding prior to dam removal,” said USGS research scientist and lead author of the synthesis paper, Dr. Jonathan Warrick.
Although the primary goal of the dam removal project is to reintroduce spawning salmon runs to the pristine upper reaches of the Elwha River within Olympic National Park, the new studies suggest that dam removal can also have ecological implications downstream of the former dam sites. These implications include a renewal of the sand, gravel and wood supplies to the river and to the coast, restoring critical processes for maintaining salmon habitat to river, estuarine and coastal ecosystems.
“These changes to sediment and wood supplies are important to understand because they affect the river channel form, and the channel form provides important habitat to numerous species of the region,” stated USGS research scientist and river study lead author, Dr. Amy East.
The final stages of dam removal occurred during the summer of 2014. Some sediment erosion from the former reservoirs will likely continue. The Elwha Project and research teams are continuing to monitor how quickly the river returns to its long-term restored condition.
“We look forward to seeing when the sediment supplies approach background levels,” said Reclamation engineer and co-author, Jennifer Bountry, “because this will help us understand the length of time that dam removal effects will occur.”
The five new papers can be found in Elsevier’s peer-reviewed journal, Geomorphology, and they focus on the following topics of the large-scale dam removal on the Elwha River, Washington (web-based publication links using digital object identifiers, doi, are provided in parentheses):
- Erosion of reservoir sediment
- Fluvial sediment load
- River channel and floodplain geomorphic change
- Coastal geomorphic change
- Source-to-sink sediment budget and synthesis
Delaware artists invited to apply for DNREC Watershed Assessment rain barrel painting contest now through March 6
DNREC Division of Watershed Stewardship accepting applications for youth artist rain barrel painting contest now through March 5
Division of Fish and Wildlife to hold Feb 23 public hearing on options to reduce recreational striped bass harvest
Newly released US Topo maps for Nevada now feature selected trails. The data for the trails is provided to the USGS through a nation-wide “crowdsourcing” project managed by the International Mountain Biking Association (IMBA). Several of the 1,785 new US Topo quadrangles for the state now display public trails along with other improved data layers such as land survey information (PLSS), map symbol redesign and new road source data.
"Users of the US Topo maps in our state are excited about the release of these new versions," said Carol Ostergren, The National Map Liaison for Nevada. "Nevada features numerous trails, so the addition of several mountain bike trails will increase the use of the new US Topo maps. Also, adding PLSS will assist many of our users who have been asking for that data for a long time."
For Nevada residents and visitors who want to explore the stunning desert landscape on a bicycle seat or hiking shoes, 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 mountain bike trails. This activity allows local IMBA chapters, IMBA members and the public to provide trail data and descriptions through their website. MTB Project and IMBA then verify the quality of the trail data provided and ensure accuracy and confirm that 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.
Another important addition to the new Nevada US Topo maps is the inclusion of Public Land Survey System data. PLSS is a way of subdividing and describing land in the United States. All lands in the public domain are subject to subdivision by this rectangular system of surveys, which is regulated by the U.S. Department of the Interior.
These new maps replace the first edition US Topo maps for Nevada 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 Boulder City, Nevada quadrangle with orthoimage turned on. (1:24,000 scale. (high resolution image 1.1 MB) Vintage 1886 quadrangle covering the Boulder City, Nevada and Camp Majove, Arizona area from the USGS Historic Topographic Map Collection. 1:25,000 scale. (high resolution image 1.6 MB) Updated 2015 version of Boulder City, Nevada quadrangle with orthoimage turned off to better see the trail network. (1:24,000 scale) (high resolution image 610 KB)
A new U.S. Geological Survey study shows how plants’ vulnerability to drought varies across the landscape; factors such as plant structure and soil type where the plant is growing can either make them more vulnerable or protect them from declines.
Recent elevated temperatures and prolonged droughts in many already water-limited regions throughout the world, including the southwestern U.S., are likely to intensify according to future climate model projections. This warming and drying can negatively affect vegetation and could lead to the degradation of wildlife habitat and ecosystems. It is critical for resource managers and other decision-makers to understand where on the landscape vegetation will be affected so they can prioritize restoration and conservation efforts, and plan for the future.
To better understand the potential detrimental effects of climate change, USGS scientists developed a model to evaluate how plant species will respond to increases in temperature and drought. The model integrates knowledge about how plant responses are modified by landscape, soil and plant attributes that are integral to water availability and use. The model was tested using fifty years of repeat measurements of long-living, or perennial, plant species cover in large permanent plots across the Mojave Desert, one of the most water-limited ecosystems in North America. The report, published in the Journal of Ecology, is available online.
“The impacts of drought are not going away, and sound science to understand how water-limited ecosystems will respond is important for managers to plan climate adaptation strategies,” said Seth Munson, USGS scientist and lead author of the study. “By using monitoring results that scientists and managers have diligently reported for the last several decades, our study helps forecast the future state of drylands.”
Results show that plants respond to climate differently based on the physical attributes of where they are growing in the Mojave Desert. For example, deep-rooted plants were not as vulnerable to drought on soils that allowed for deep-water flow. Also, shallow-rooted plants were better buffered from drought on soils that promoted water retention near the surface. This information may be helpful for resource managers to minimize disturbance in areas that are likely vulnerable to water shortages.
Water moves horizontally and vertically through the landscape, which affects the amount of water plants can take up through their roots. There is more to plant water availability and use than the precipitation that falls out of the sky. Understanding how water moves through ecosystems is critical in regions that already have marginal water available for plant growth. Predicting climate change impacts in these areas requires more than an understanding of climate alone.
This study was done in cooperation with the University of Arizona, the Fort Irwin Directorate of Public Works, Utah State University, University of Nevada, California Polytechnic State University, Ohio State University, California State University and the National Park Service.
RESTON, Va.-- Aftershocks from the 2011 Virginia earthquake have helped scientists identify the previously unknown fault zone on which the earthquake occurred. The research marked one of the few times in the Eastern United States that a fault zone on which a magnitude-5-or-more earthquake occurred was clearly delineated by aftershocks, and is just one finding in a 23-chapter book with new information on the Virginia earthquake and eastern seismic hazards.
Research by the U.S. Geological Survey along with its partners and collaborators defined the newly recognized fault zone, which has been named the “Quail” fault zone. USGS and others worked cooperatively in an effort to capture the accurate locations of hundreds of aftershocks by deploying portable seismic instruments after the earthquake. Most of these aftershocks were in the Quail fault zone, and outlying clusters of shallow aftershocks helped researchers to identify and locate other active faults. Knowing where to look for the active faults helped to focus geologic mapping, geophysical imaging and other technologies to better understand earthquakes in the Central Virginia Seismic Zone and Eastern U.S.
The book includes contributions by Virginia Tech, the Virginia Department of Mines, Minerals, and Energy and the U.S. Nuclear Regulatory Commission among many others.
“Studies of the Virginia earthquake have improved our understanding of earthquakes and seismic hazards in Eastern North America,” said USGS geologist Wright Horton. “The Virginia earthquake served as a ‘wakeup call’ for many residents of the Eastern U.S., where the probability of major earthquakes is fairly low, but many buildings are vulnerable to damage during earthquakes.”
The new book, “The 2011 Mineral, Virginia, Earthquake, and Its Significance for Seismic Hazards in Eastern North America”, is a collection of articles that covers a broad range of subjects relating to the 2011 earthquake. Highlights from the book include:
- Earthquake shaking and its effects, such as widespread changes in groundwater levels, occurred at greater distances from the source in this and other Eastern U.S. earthquakes as opposed to those of comparable magnitude on the West Coast
- Shaking intensities and related damage were more severe along the northeast trend of the Appalachians than in northwestward directions across this trend
- Evidence that the earthquake ground motion was amplified in parts of D.C. and other areas around the Chesapeake Bay with thicker coastal plain sediments or artificial fill is stimulating further studies to determine how much seismic shaking is amplified by local geological conditions
- Analysis of data on residential property damage in the epicentral area delineates a “bulls eye” distribution of shaking intensities and also confirms that damage is influenced by the age and construction of homes
- Damage to unreinforced masonry buildings in D.C., as far as 80 miles from the epicenter, highlights the seismic risk to buildings in Eastern North American cities. Ground motions occur at farther distances from the epicenter on the East Coast than other parts of the U.S., and buildings are not as well designed to sustain these motions as in other locations
- Seismic reflection imaging—which is similar to medical sonograms—and geophysical flight surveys of the Earth’s magnetic and gravity fields were used to image geologic structures down to about 5 miles underground where the earthquake occurred
- Airborne laser swath mapping using lidar, and radiometric flight surveys—which mapped radioactive elements in rocks and soils within a few feet of the land surface—identified and accurately located preexisting linear features including faults associated with aftershock clusters for detailed surface geologic mapping and trenching studies
- New geologic mapping and trenching reveal previously unknown faults and evidence that the faults were active more than once in the past
- Recorded ground motions from the Virginia earthquake were consistent with previous USGS estimates for the region, and they are helping to improve the assessments of potential earthquake ground motions used to design buildings that will be better able to withstand strong earthquakes
Earthquakes in Eastern North America are not as frequent or as well understood as those along Earth's tectonic plate boundaries, such as on the West Coast. The magnitude 5.8 Virginia earthquake was the largest to occur in the eastern U.S. since the 1886 earthquake near Charleston, South Carolina, and it may have been felt by more people than any other earthquake in U.S. history. It was felt over much of the Eastern U.S. and Southeastern Canada, triggered the automatic safe shutdown of a nuclear power plant and caused significant damage from Central Virginia to the National Capital Region. The earthquake provided a wealth of modern scientific and engineering data to better understand earthquakes and seismic hazards in Eastern North America.
DENTON, Texas – The Federal Emergency Management Agency has awarded more than $1.4 million to Louisiana for repairs to Touro Infirmary in New Orleans in the aftermath of Hurricane Isaac.
Wind and rain from the storm damaged multiple buildings and structures in the hospital system: the main hospital; the Quaife building; the St. Charles garage; the Gumbel building; the Medical Arts Building; and the Buckman Building/Garage.Language English
DENTON, Texas – More than $465,000 was recently awarded to the state of Texas from the Federal Emergency Management Agency for repairs to two lift stations; multiple sewer manhole covers; a city of Austin water supply pipe; and the removal of more than 40,000 cubic yards of debris in the aftermath of the 2013 Halloween flooding.
The damage from the flooding includes:Language English
WASHINGTON – On January 30, the President issued an Executive Order 13690, “Establishing a Federal Flood Risk Management Standard and a Process for Further Soliciting and Considering Stakeholder Input.” Prior to implementation of the Federal Flood Risk Management Standard, additional input from stakeholders is being solicited and considered on how federal agencies will implLanguage English
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 State of Vermont.
Assistance for the State 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 State of Vermont to supplement state and local recovery efforts in the area affected by a severe winter storm during the period of December 9-12, 2014.Language English