Search Results

For the first time in the 40-year history of the National Atmospheric Deposition Program / National Trends Network (NADP/NTN), a unique urban-to-rural transect of wet deposition monitoring stations were operated as part of the NTN in 2017 to quantify reactive inorganic nitrogen wet deposition for adjacent urban and rural, montane...

The 2010 MW 7.2 El Mayor‐Cucapah earthquake ruptured a zone of ~120 km in length in northern Baja California. The geographic distribution of this earthquake sequence was well constrained by waveform relocation. The depth distribution, however, was poorly determined as it is near the edge of, or outside, the Southern California Seismic...

Wastewater disposal associated with rapid population growth and development on Cape Cod, Massachusetts, during the past several decades has resulted in widespread contamination of groundwater with nitrogen. As a result, water quality in many of the streams, lakes, and coastal embayments on Cape Cod is impaired by excess nitrogen. To...

We investigate the late Miocene‐Pleistocene offshore sedimentary record of the Yakutat microplate to evaluate the spatial and temporal variations in rock exhumation and sediment routing patterns at the heavily glaciated and actively converging plate boundary in southeast Alaska. We present 1,456 new fission track ages and 1,372...

In tectonically active regions, post-earthquake motions are generally shaped by a combination of continued fault slippage (afterslip) on a timescale of days to months and viscoelastic relaxation of the lower crust and upper mantle on a timescale of days to years. Transient crustal motions have been observed following numerous magnitude >~7 earthquakes in various tectonic...

Soil microorganisms are known to survive periods of aridity and to recover rapidly after wetting events, with the ability to transition between a dormant state in dry conditions and an active state in wet conditions. Though this dynamic behavior has been previously incorporated into soil carbon respiration modeling frameworks, a...

Ahyi seamount, a shallow submarine volcano in the Northern Mariana Islands, began erupting on April 23, 2014. Hydroacoustic eruption signals were observed on the regional Mariana seismic network and on distant hydrophones, and NOAA scuba divers working in the area soon after the eruption began heard and felt underwater explosion...

Atmospheric nitrogen and sulfur pollution increased over much of the United States during the twentieth century from fossil fuel combustion and industrial agriculture. Despite recent declines, nitrogen and sulfur deposition continue to affect many plant communities in the United States, although which species are at risk remains uncertain. We used...

Historically, closed eastern forests transitioned into open savannas and prairies in the US Midwest, but this transition is poorly understood. To investigate the eastern boundary of the prairie-forest ecotone, we conducted a case study of historic and modern vegetation patterns of the Yellow River watershed in northwest Indiana. Historic vegetation...

No abstract available....

Accurate measurements of suspended sediment, a leading water-quality impairment in many rivers, are important for managing and protecting water resources; however, water quality standards for suspended sediment in Minnesota are based on grab field sampling and total suspended solids (TSS) laboratory analysis methods. These methods have underrepresented concentrations of suspended...

The erosional and depositional characteristics of meandering rivers lead to the formation and maintenance of point bars along the inner banks of meander bends. Point bars are composed of sediment layers in patterns resulting from the rate and style of channel migration, hydrodynamics, and sediment transport and deposition within the...

In early November, 2006, an atmospheric river brought heavy rainfall and high freezing levels to the Pacific Northwest. Without snowpack to buffer the hydrologic response, the storm caused widespread landslides and debris flows in drainages sourced from every central Cascades volcano. At Mount St. Helens, in southwestern Washington State, intense...

The purpose of this study is to assess the precision and accuracy of laboratory laser-diffraction particle-size distribution (PSD) analysis in support of an effort to formally adopt the method for routine use in U.S. Geological Survey (USGS) sediment laboratories. USGS sediment laboratories analyze the PSD of sediment in support...

The USGS Water Mission Area’s Sediment Science Program provides leadership, training, and methods development in fluvial sediment science for the USGS and its external partners. Overarching objectives of the USGS Sediment Science Program (which includes the Federal Interagency Sedimentation Project) include: 1) developing and promoting innovative sediment monitoring techniques that result in cost effective,...

Channel dredging and erosion in the Atchafalaya River basin have resulted in changes to the hydraulic connectivity of this floodplain swamp that have not been previously quantified. In this study, analyses were conducted to determine hydraulic and geomorphic factors that have changed since channel closure in 1962. Results indicated changes...

The U.S. Geological Survey (USGS) in cooperation with the U.S. Army Corps of Engineers (USACE), monitored a sediment flush event from Spencer Dam located on the Niobrara River near Spencer, Nebraska, during the fall of 2014. Data collected during the flush was used to validate a one-dimensional sediment transport model...

Along the San Bernardino Valley, the Santa Ana River decreases in slope, increases in width, and deposits particles from boulders to sand as it loses transport capacity. Episodic rainfalls feed very large winter floods, but dry summer and fall periods lead to extensive dry alluvial reaches due to surface water...

The U.S. Geological Survey (USGS) Geomorphology and Sediment Transport Laboratory (GSTL), in collaboration with the U.S. Army Corps of Engineers Cold Regions Research and Engineering Laboratory (CRREL), acquired remotely sensed data from several Alaskan rivers in 2017 and 2018 with the goal of developing a methodology for measuring streamflow from...

Acoustics and other surrogates can be used to accurately and cost-effectively provide time-series estimates of suspended-sediment concentration and load, which is essential for creating informed solutions to many sediment-related environmental, engineering, and agricultural concerns. Interagency efforts in recent years have advanced the testing, methods development, operational guidelines, and training on sediment acoustics. This extended...

The Salinas River is the largest river in California’s Central Coast region. Groundwater resources of the Salinas River basin are used to meet water supply needs, including crop irrigation and municipal water supply. Two large multipurpose reservoirs also supply irrigation and municipal water uses. Historical imbalances between supply and demand...

Scientific questions regarding the impact of anthropomorphic noise in the marine environment have resulted in an increasing number of regulatory requirements and precautionary mitigation strategies to reduce the risks associated with high-resolution marine geophysical surveys performed in waters subjected to government jurisdiction. An example of regulatory frameworks includes the Marine...

The worst drought in California in over 1,200 years occurred between 2012-2017 (Griffin, 2014), depleting surface water and groundwater supply and drying out the soils past wilting point. In the summer of 2015, the Jerusalem and Rocky fires burned roughly 40,000 acres within the Cache Creek watershed. To fully characterize...

Introduced pathogens causing emerging infectious diseases (EIDs) are serious contemporary threats to animal, plant, and ecosystem health. The invasive fungus, Pseudogymnoascus destructans, has established populations of European origin in North America, resulting in mass mortality of several hibernating bat species. Extensive monitoring for this pathogen exists in Europe and North America,...

No abstract available. ...