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At least 1,117 records · Page 62Linked to original sources

Identifying long term empirical relationships between storm characteristics and episodic groundwater recharge

Shallow aquifers are an important source of water resources and provide base flow to streams; yet actual rates of groundwater recharge are difficult to estimate. While climate change is predicted to increase the frequency and magnitude of extreme precipitation events, the resulting impact on groundwater recharge remains poorly understood. We quantify empirical relations between precipitation characteristics and episodic groundwater recharge for a wide variety of geographic and land use types across North Carolina. We extract storm duration, magnitude, average rate, and hourly weighted intensity from long-term precipitation records over periods of 12–35 years at 10 locations. Using time series of water table fluctuations from nearby monitoring wells, we estimate relative recharge to precipitation ratios (RPR) to identify statistical trends. Increased RPR correlates with increased storm duration, whereas RPR decreases with increasing magnitude, average rate, and intensity of precipitation. Agricultural and urban areas exhibit the greatest decrease in RPR due to increasing storm magnitude, average rate, and intensity, while naturally vegetated areas exhibit a larger increase in RPR with increased storm duration. Though RPR is generally higher during the winter than the summer, this seasonal effect is magnified in the Appalachian and Piedmont regions. These statistical trends provide valuable insights into the likely consequences of climate and land use change for water resources in subtropical climates. If, as predicted, growing seasons lengthen and the intensity of storms increases with a warming climate, decreased recharge in Appalachia, the Piedmont, and rapidly growing urban areas of the American Southeast could further limit groundwater availability.

North Carolina↗

Reassessment of the rates at which oil from natural sources enters the marine environment

Previous estimates of the world-wide input of oil to the marine environment by natural seeps ranged from 0??2 to 6??0 million (metric) tonnes per year with a 'best estimate' of 0??6 million tonnes per year. Based on considerations of the availability of oil for seepage from the world's known and assumed oil resources, we believe that the world-wide natural oil seepage over geological time should be revised to about 0??2 million tonnes per year with a range upward or downward of a factor of ten leading to estimates between 0??02 and 2 million tonnes per year. Our estimate of the amount of oil eroding from the land and being transported to the oceans is about 0??05 million tonnes per year with an order of magnitude uncertainty. Therefore, while the uncertainties are large, we estimate that the total amount of oil entering the marine environment by natural, geological processes, is about 0??25 million tonnes per year, and the estimate may range from about 0??025 to 2??5 million tonnes per year. This rate applies over geological time, but episodic fluctuations in the input of oil to the marine environment may cause the rate to exceed this range in any one year.Previous estimates of the world-wide input of oil to the marine environment by natural seeps ranged from 0. 2 to 6. 0 million (metric) tonnes per year with a 'best estimate' of 0. 6 million tons per year. Based on considerations of the availability of oil for seepage from the world's known and assumed oil resources, the world-wide natural oil seepage over geological time should be revised to about 0. 2 million tons per year with a range upward or downward of a factor of ten leading to estimates between 0. 02 and 2 million tons per year. It is estimated that the amount of oil eroding from the land and being transported to the oceans is about 0. 05 million tons per year with an order of magnitude uncertainty. Therefore, the total amount of oil entering the marine environment by natural, geological processes, is about 0. 25 million tons per year, and the estimate may range from about 0. 025 to 2. 5 million tons per year. Refs.

Marine Environmental Research↗

Water and rock geochemistry, geologic cross sections, geochemical modeling, and groundwater flow modeling for identifying the source of groundwater to Montezuma Well, a natural spring in central Arizona

The National Park Service (NPS) seeks additional information to better understand the source(s) of groundwater and associated groundwater flow paths to Montezuma Well in Montezuma Castle National Monument, central Arizona. The source of water to Montezuma Well, a flowing sinkhole in a desert setting, is poorly understood. Water emerges from the middle limestone facies of the lacustrine Verde Formation, but the precise origin of the water and its travel path are largely unknown. Some have proposed artesian flow to Montezuma Well through the Supai Formation, which is exposed along the eastern margin of the Verde Valley and underlies the Verde Formation. The groundwater recharge zone likely lies above the floor of the Verde Valley somewhere to the north or east of Montezuma Well, where precipitation is more abundant. Additional data from groundwater, surface water, and bedrock geology are required for Montezuma Well and the surrounding region to test the current conceptual ideas, to provide new details on the groundwater flow in the area, and to assist in future management decisions. The results of this research will provide information for long-term water resource management and the protection of water rights.

Arizona↗

Comparison of watershed disturbance predictive models for stream benthic macroinvertebrates for three distinct ecoregions in western US

The successful use of macroinvertebrates as indicators of stream condition in bioassessments has led to heightened interest throughout the scientific community in the prediction of stream condition. For example, predictive models are increasingly being developed that use measures of watershed disturbance, including urban and agricultural land-use, as explanatory variables to predict various metrics of biological condition such as richness, tolerance, percent predators, index of biotic integrity, functional species traits, or even ordination axes scores. Our primary intent was to determine if effective models could be developed using watershed characteristics of disturbance to predict macroinvertebrate metrics among disparate and widely separated ecoregions. We aggregated macroinvertebrate data from universities and state and federal agencies in order to assemble stream data sets of high enough density appropriate for modeling in three distinct ecoregions in Oregon and California. Extensive review and quality assurance of macroinvertebrate sampling protocols, laboratory subsample counts and taxonomic resolution was completed to assure data comparability. We used widely available digital coverages of land-use and land-cover data summarized at the watershed and riparian scale as explanatory variables to predict macroinvertebrate metrics commonly used by state resource managers to assess stream condition. The “best” multiple linear regression models from each region required only two or three explanatory variables to model macroinvertebrate metrics and explained 41–74% of the variation. In each region the best model contained some measure of urban and/or agricultural land-use, yet often the model was improved by including a natural explanatory variable such as mean annual precipitation or mean watershed slope. Two macroinvertebrate metrics were common among all three regions, the metric that summarizes the richness of tolerant macroinvertebrates (RICHTOL) and some form of EPT (Ephemeroptera, Plecoptera, and Trichoptera) richness. Best models were developed for the same two invertebrate metrics even though the geographic regions reflect distinct differences in precipitation, geology, elevation, slope, population density, and land-use. With further development, models like these can be used to elicit better causal linkages to stream biological attributes or condition and can be used by researchers or managers to predict biological indicators of stream condition at unsampled sites.

Ecological Indicators↗

A science plan for a comprehensive assessment of water supply in the region underlain by fractured rock in Maryland

The fractured rock region of Maryland, which includes land areas north and west of the Interstate 95 corridor, is the source of water supply for approximately 4.4 million Marylanders, or approximately 76 percent of the State's population. Whereas hundreds of thousands of residents rely on wells (both domestic and community), millions rely on surface-water sources. In this region, land use, geology, topography, water withdrawals, impoundments, and other factors affect water-flow characteristics. The unconfined groundwater systems are closely interconnected with rivers and streams, and are affected by seasonal and climatic variations. During droughts, groundwater levels drop, thereby decreasing well yields, and in some cases, wells have gone dry. Low ground-water levels contribute to reduced streamflows, which in turn, can lead to reduced habitat for aquatic life. Increased demand, over-allocation, population growth, and climate change can affect the future sustainability of water supplies in the region of Maryland underlain by fractured rock. In response to recommendations of the 2008 Advisory Committee on the Management and Protection of the State's Water Resources report, the Maryland Department of the Environment's Water Supply Program, the Maryland Geological Survey, the Maryland Department of Natural Resources, Monitoring and Non-Tidal Assessment (MANTA) Division, and the U.S. Geological Survey have developed a science plan for a comprehensive assessment that will provide new scientific information, new data analysis, and new tools for the State to better manage water resources in the fractured rock region of Maryland. The science plan lays out five goals for the comprehensive assessment: (1) develop tools for the improved management and investigation of groundwater and surface-water resources; (2) characterize factors affecting reliable yields of individual groundwater and surface-water supplies; (3) investigate impacts on nearby water withdrawal users caused by groundwater and surface-water withdrawals; (4) assess the role of streamflow and water withdrawals on the ecological integrity of streams; and (5) improve understanding of the distribution of water-quality conditions in fractured rock aquifers. To accomplish these goals, accurate data collection, review, and analysis are needed, including the study of "Research Watersheds" that can provide detailed information about the potential effects that climate change and water withdrawals may have on groundwater, streamflow, and aquatic life. The assessment planning started in 2009 and is being conducted with close interagency coordination. A Fractured Rock Aquifer Information System is currently (2012) undergoing initial development. Other major tasks that will be performed include the development of work plans for each science goal, the estimation of daily streamflow at ungaged streams, and the design and implementation of Research Watersheds. Finally, scenarios will be modeled to evaluate current water allocation permitting methodologies, investigate effects on nearby water withdrawal users caused by groundwater and surface-water withdrawals, and assess the potential impacts of climate change on water resources. Desktop and Web-based tools will be developed in order to meet the diverse research needs of the assessment. These tools, including the Fractured Rock Aquifer Information System will be continuously improved during the assessment to store relevant groundwater and surface-water data in spatially referenced databases, estimate streamflows, locate higher-yielding wells, estimate the impacts of withdrawals on nearby users, and assess the cumulative impacts of withdrawals on the aquatic resource. Tools will be developed to serve the needs of many audiences, including water resource managers, water suppliers, planners, policymakers, and other scientific investigators.

Maryl↗

Inferring shallow groundwater flow in saprolite and fractured rock using environmental tracers

The Ridge and Valley Province of eastern Tennessee is characterized by (1) substantial topographic relief, (2) folded and highly fractured rocks of various lithologies that have low primary permeability and porosity, and (3) a shallow residuum of medium permeability and high total porosity. Conceptual models of shallow groundwater flow and solute transport in this system have been developed but are difficult to evaluate using physical characterization or short‐term tracer methods due to extreme spatial variability in hydraulic properties. In this paper we describe how chlorofluorocarbon 12, 3 H, and 3 He were used to infer groundwater flow and solute transport in saprolite and fractured rock near Oak Ridge, Tennessee. In the shallow residuum, fracture spacings are <0.05 m, suggesting that concentrations of these tracers in fractures and in the matrix have time to diffusionally equilibrate. The relatively smooth nature of tracer concentrations with depth in the residuum is consistent with this model and quantitatively suggests recharge fluxes of 0.2 to 0.4 m yr −1 . In contrast, groundwater flow within the unweathered rock appears to be controlled by fractures with spacings of the order of 2 to 5 m, and diffusional equilibration of fractures and matrix has not occurred. For this reason, vertical fluid fluxes in the unweathered rock cannot be estimated from the tracer data.

Water Resources Research↗

U.S. Department of the Interior South Central Climate Science Center strategic science plan, 2013--18

The Department of the Interior (DOI) recognizes and embraces the unprecedented challenges of maintaining our Nation’s rich natural and cultural resources in the 21st century. The magnitude of these challenges demands that the conservation community work together to develop integrated adaptation and mitigation strategies that collectively address the impacts of climate change and other landscape-scale stressors. On September 14, 2009, DOI Secretary Ken Salazar signed Secretarial Order 3289 (amended February 22, 2010) entitled, “Addressing the Impacts of Climate Change on America’s Water, Land, and Other Natural and Cultural Resources.” The Order establishes the foundation for two partner-based conservation science entities to address these unprecedented challenges: Climate Science Centers (CSCs and Landscape Conservation Cooperatives (LCCs). CSCs and LCCs are the Department-wide approach for applying scientific tools to increase understanding of climate change and to coordinate an effective response to its impacts on tribes and the land, water, ocean, fish and wildlife, and cultural-heritage resources that DOI manages. Eight CSCs have been established and are managed through the U.S. Geological Survey (USGS) National Climate Change and Wildlife Science Center (NCCWSC); each CSC works in close collaboration with their neighboring CSCs, as well as those across the Nation, to ensure the best and most efficient science is produced. The South Central CSC was established in 2012 through a cooperative agreement with the University of Oklahoma, Texas Tech University, Louisiana State University, the Chickasaw Nation, the Choctaw Nation of Oklahoma, Oklahoma State University, and NOAA’s Geophysical Fluid Dynamics Lab; hereafter termed the ”Consortium” of the South Central CSC. The Consortium has a broad expertise in the physical, biological, natural, and social sciences to address impacts of climate change on land, water, fish and wildlife, ocean, coastal, and cultural resources. The South Central CSC will provide scientific information, tools, and techniques that managers and other parties interested in land, water, wildlife, and cultural resources can use to anticipate, monitor, and adapt to climate change, actively engaging LCCs and other partners in translating science into management decisions. This document is the first Strategic Science Plan for the South Central CSC (2013-18). Using the January 2011 DOI guidance as a model, this document (1) describes the role and interactions of the South Central CSC among partners and stakeholders including Federal, State, and non-governmental organizations throughout the region; (2) describes a concept of what the center will provide to its partners; (3) defines a context for climate impacts in the south central United States; and (4) establishes the science priorities the center will address through research. Science priorities are currently organized as immediate or future research needs; however, this document is intended to be reevaluated and modified as partner needs change and as scientific work progresses.

Open-File Report↗

Description of Existing Data for Integrated Landscape Monitoring in the Puget Sound Basin, Washington

This report summarizes existing geospatial data and monitoring programs for the Puget Sound Basin in northwestern Washington. This information was assembled as a preliminary data-development task for the U.S. Geological Survey (USGS) Puget Sound Integrated Landscape Monitoring (PSILM) pilot project. The PSILM project seeks to support natural resource decision-making by developing a 'whole system' approach that links ecological processes at the landscape level to the local level (Benjamin and others, 2008). Part of this effort will include building the capacity to provide cumulative information about impacts that cross jurisdictional and regulatory boundaries, such as cumulative effects of land-cover change and shoreline modification, or region-wide responses to climate change. The PSILM project study area is defined as the 23 HUC-8 (hydrologic unit code) catchments that comprise the watersheds that drain into Puget Sound and their near-shore environments. The study area includes 13 counties and more than four million people. One goal of the PSILM geospatial database is to integrate spatial data collected at multiple scales across the Puget Sound Basin marine and terrestrial landscape. The PSILM work plan specifies an iterative process that alternates between tasks associated with data development and tasks associated with research or strategy development. For example, an initial work-plan goal was to delineate the study area boundary. Geospatial data required to address this task included data from ecological regions, watersheds, jurisdictions, and other boundaries. This assemblage of data provided the basis for identifying larger research issues and delineating the study-area boundary based on these research needs. Once the study-area boundary was agreed upon, the next iteration between data development and research activities was guided by questions about data availability, data extent, data abundance, and data types. This report is not intended as an exhaustive compilation of all available geospatial data, rather, it is a collection of information about geospatial data that can be used to help answer the suite of questions posed after the study-area boundary was defined. This information will also be useful to the PSILM team for future project tasks, such as assessing monitoring gaps, exploring monitoring-design strategies, identifying and deriving landscape indicators and metrics, and visual geographic communication. The two main geospatial data types referenced in this report - base-reference layers and monitoring data - originated from numerous and varied sources. In addition to collecting information and metadata about the base-reference layers, the data also were collected for project needs, such as developing maps for visual communication among team members and with outside groups. In contrast, only information about the data was typically required for the monitoring data. The information on base-reference layers and monitoring data included in this report is only as detailed as what was readily available from the sources themselves. Although this report may appear to lack consistency between data records, the varying degree of details contained in this report are merely a reflection of varying source detail. This compilation is just a beginning. All data listed also are being catalogued in spreadsheets and knowledge-management systems. Our efforts are continual as we develop a geospatial catalog for the PSILM pilot project.

Open-File Report↗

Multireaction equilibrium geothermometry: A sensitivity analysis using data from the Lower Geyser Basin, Yellowstone National Park, USA

A multireaction chemical equilibria geothermometry (MEG) model applicable to high-temperature geothermal systems has been developed over the past three decades. Given sufficient data, this model provides more constraint on calculated reservoir temperatures than classical chemical geothermometers that are based on either the concentration of silica (SiO 2 ), or the ratios of cation concentrations. A set of 23 chemical analyses from Ojo Caliente Spring and 22 analyses from other thermal features in the Lower Geyser Basin of Yellowstone National Park are used to examine the sensitivity of calculated reservoir temperatures using the GeoT MEG code (Spycher et al. 2013, 2014) to quantify the effects of solute concentrations, degassing, and mineral assemblages on calculated reservoir temperatures. Results of our analysis demonstrate that the MEG model can resolve reservoir temperatures within approximately ±15°C, and that natural variation in fluid compositions represents a greater source of variance in calculated reservoir temperatures than variations caused by analytical uncertainty (assuming ~5% for major elements). The analysis also suggests that MEG calculations are particularly sensitive to variations in silica concentration, the concentrations of the redox species Fe(II) and H 2 S, and that the parameters defining steam separation and CO 2 degassing from the liquid may be adequately determined by numerical optimization. Results from this study can provide guidance for future applications of MEG models, and thus provide more reliable information on geothermal energy resources during exploration.

Idaho, Montana, Wyoming↗

Comparison of groundwater flow in Southern California coastal aquifers

Development of the coastal aquifer systems of Southern California has resulted in overdraft, changes in streamflow, seawater intrusion, land subsidence, increased vertical flow between aquifers, and a redirection of regional flow toward pumping centers. These water-management challenges can be more effectively addressed by incorporating new understanding of the geologic, hydrologic, and geochemical setting of these aquifers. Groundwater and surface-water flow are controlled, in part, by the geologic setting. The physiographic province and related tectonic fabric control the relation between the direction of geomorphic features and the flow of water. Geologic structures such as faults and folding also control the direction of flow and connectivity of groundwater flow. The layering of sediments and their structural association can also influence pathways of groundwater flow and seawater intrusion. Submarine canyons control the shortest potential flow paths that can result in seawater intrusion. The location and extent of offshore outcrops can also affect the flow of groundwater and the potential for seawater intrusion and land subsidence in coastal aquifer systems. As coastal aquifer systems are developed, the source and movement of ground-water and surface-water resources change. In particular, groundwater flow is affected by the relative contributions of different types of inflows and outflows, such as pump-age from multi-aquifer wells within basal or upper coarse-grained units, streamflow infiltration, and artificial recharge. These natural and anthropogenic inflows and outflows represent the supply and demand components of the water budgets of ground-water within coastal watersheds. They are all significantly controlled by climate variability related to major climate cycles, such as the El Ni&ntilde;o&ndash;Southern Oscillation and the Pacific Decadal Oscillation. The combination of natural forcings and anthropogenic stresses redirects the flow of groundwater and either mitigates or exacerbates the potential adverse effects of resource development, such as declining water levels, sea-water intrusion, land subsidence, and mixing of different waters. Streamflow also has been affected by development of coastal aquifer systems and related conjunctive use. Saline water is the largest water-quality problem in Southern California coastal aquifer systems. Seawater intrusion is a significant source of saline water, but saline water is also known to come from other sources and processes. Seawater intrusion is typically restricted to the coarse-grained units at the base of fining-upward sequences of terrestrial deposits, and at the top of coarsening upward sequences of marine deposits. This results in layered and narrow intrusion fronts. Maintaining the sustainability of Southern California coastal aquifers requires joint management of surface water and groundwater (conjunctive use). This requires new data collection and analyses (including research drilling, modern geohydrologic investigations, and development of detailed computer groundwater models that simulate the supply and demand components separately), implementation of new facilities (including spreading and injection facilities for artificial recharge), and establishment of new institutions and policies that help to sustain the water resources and better manage regional development.

California↗

Droughts, epic droughts and droughty centuries - lessons from a California paleoclimatic record: a PACLIM 2001 meeting report

During the early 1990s (but echoing studies by S.T. Harding at the University of California, from as early as the 1930s), several lines of paleoclimate evidence in and around the Sierra Nevada Range have provided the water community in California with some real horror stories. By studying ancient tree stumps submerged in Lake Tahoe and Tenaya Lake, stumps that were emerging from Mono Lake during its recent decline, and stumps that were exhumed in the Walker River bed during the floods of 1997, paleoclimatologists like Scott Stine of California State University, Hayward, assembled a picture of epic droughts in the central Sierra Nevada during the medieval period. These droughts had to be severe to drop water levels in the lakes and rivers low enough for the trees to grow in the first place, and then had to last for hundreds of years to explain tree-ring counts in these sizeable stumps. Worse yet, the evidence suggested at least two such epic droughts, one ending close to 1100 and the other close to 1350. These epic droughts challenged paleoclimatologists, as well as modern climatologists and hydrologists, to understand and, ultimately, to determine the likelihood that such droughts might recur in the foreseeable future. The first challenge, however, was to verify that such droughts were more than local events and as extreme as suggested. At this year&rsquo;s Pacific Climate (PACLIM) Workshop, held March 18&ndash;21, 2001, at Asilomar (Pacific Grove, Calif.), special sessions brought together scientists to compare paleoclimatic reconstructions of ancient droughts and pluvial (wet) epidodes to try to determine the nature of decadal and centennial climate fluctuations in western North America, with emphasis on California. A companion session brought together modern climatologists to report on the latest explanations (and evidence) for decadal climate variations during the instrumental era of the 20th century. PACLIM is an annual workshop that, since 1983, has brought together specialists from diverse fields, including physical, social, and biological sciences, to discuss and investigate climate and climate effects in the eastern Pacific and western America. This year&rsquo;s PACLIM was sponsored by the U.S. Geological Survey, NOAA Office of Global Programs, California Department of Water Resources, and, for the first time, the CALFED Science Program. In addition to the presentations summarized here, sessions at this year&rsquo;s PACLIM covered topics as varied as the North American monsoon system; recent economic and political effects of California&rsquo;s climate variations, including a presentation on climate and CALFED by Sam Luoma (U.S. Geological Survey, Menlo Park); and research into daily-to-seasonal weather variations.

Interagency Ecological Program Newsletter↗

Kinetic analysis of strontium and potassium sorption onto sands and gravels in a natural channel

A kinetic, first-order mass transfer model was used to describe the sorption of strontium onto sand- and gravel-sized streambed sediments. Rate parameters, empirically determined for strontium, allowed for the prediction of potassium sorption with moderate success. The model parameters varied significantly with particle size. The sorption data were collected during an experimental injection of several elements into a small mountain pool-and-riffle stream. The sorption process onto sand- and gravel-sized sediment was relatively slow compared to changes in the dissolved concentrations.

Water Resources Research↗

The effects of management practices on grassland birds

Since the mid-1960s, populations of grassland birds have been declining more precipitously than any other group of birds in North America. These long-term declines highlight the need to better understand the habitat requirements of grassland birds and how management practices affect individual species and their habitats. Although resource managers have long recognized that every management approach contains inherent advantages and disadvantages, depending on the species in question, they are often faced with making critical management decisions armed with little or no information. The need for information on management and its effects on grassland birds was identified by the U.S. Prairie Pothole Joint Venture, a part of the North American Waterfowl Management Plan, in support of its objective to stabilize or increase populations of declining grassland- and wetland-associated wildlife species in the Prairie Pothole Region. In 1996, scientists from the U.S. Geological Survey’s Northern Prairie Wildlife Research Center began a long-term, collaborative effort to review and synthesize literature on the effects of management practices on grassland bird species. Major funding for this effort was provided by the Prairie Pothole Joint Venture, U.S. Fish and Wildlife Service, and the U.S. Geological Survey; additional funding was provided by the U.S. Forest Service, The Nature Conservancy, and the Plains and Potholes Landscape Conservation Cooperative. This compendium on “The Effects of Management Practices on Grassland Birds” is a culmination of that work. More than 6,000 published and unpublished publications have been consulted and several thousand publications have been incorporated and synthesized in species accounts for 40 North American grassland bird species. The 40 species represent a taxonomically diverse group that includes grouse, shorebirds, owls, diurnal raptors, and many songbirds. The focus of this effort is on management of breeding habitat, with an emphasis on the Great Plains. The accounts provide land managers with a summary of information on the effects of specific management practices on grassland birds and help to identify the most critical research gaps in our understanding of grassland bird ecology, habitat needs, and responses to management practices. This compendium is organized into three primary sections: an introduction, species accounts, and a concluding chapter. The introduction provides an overview of grasslands, the processes under which grasslands formed, the influence of anthropogenic changes to grasslands, the effects of those changes on grassland bird populations, and the management tools available to land managers. The bulk of this compendium is the individual species accounts, covering 40 species of North American grassland birds arranged in taxonomic order. Each species account includes information on species range, suitable breeding habitat, area requirements and landscape associations, breeding-season phenology, species’ response to management, and management recommendations. Information on rates of brood parasitism by the Brown-headed Cowbird ( Molothrus ater ) in grassland bird nests is summarized in a chapter at the end of this report. The final chapter includes concluding remarks concerning habitat requirements and management effects on grassland birds.

Professional Paper↗

Operation of a landslide warning system during the California storm sequence of January and February 1993

From 1986 to late December 1995, the U.S. Geological Survey and the National Weather Service operated a landslide warning system for debris flows triggered by intense rainstorms in the San Francisco Bay region. The Landslide Warning System tracked storm systems as they approached the region, determined actual rainfall with a network of radio-telemetered rain gauges, compared the rainfall to thresholds for initi-ation of debris flows, and issued the appropriate public advisories. A series of intense rainstorms during January 1993 created hazards from landslid-ing and flooding over much of California. In the San Francisco Bay region, January rainfall was over 200% of normal, triggering debris flows on natural hillslopes and road cuts across Marin, San Mateo, Alameda, Santa Clara, and Santa Cruz Counties. The warning system issued Flash Flood/Debris Flow Watches during the most intense storms on January 13 and 15,1993. Most debris flows in this area were small and widely scattered, so damage was largely limited to several blocked roadways in mountainous areas. Storm damage was much heavier in southern California, where rainfall amounts were over 350% of normal for January, triggering flash floods and many landslides. This damage prompted inquiries about developing a landslide warning system for southern California. A number of elements for a landslide warning system already exist in southern Cal-ifornia, including quantitative rainfall forecasting and a network of radio-telemetered rain gauges. Regional rainfall thresholds for debris flow initiation, consistent with the climate, topography, and geology of the region, remain to be developed. Such thresholds could probably be developed with a modest investment of research effort and resources.

California↗

Editorial: Enabling people-centered risk communication for geohazards

In the field of natural hazards, communicating science with the public and stakeholders (i.e., interested parties) involves entering the challenging and complex world of hazard and risk communication, the ultimate purpose of which is to reduce the impact of impending hazards on people and property at risk. Hazard and risk communication are adequate if they reach people with the information that they need, at the right time, and in a form that they can use. This task appears to be particularly difficult when decisions by the public and stakeholders have to be made in the presence of uncertainty about what could happen, as is often the case with geohazards. Moreover, decision-making is complex when there are time pressures, human and economic resources are limited, and multiple sources of information need to be considered. This poses several challenges for the development of two-way and people-centered risk communication for geohazards. The “Enabling People-Centered Risk Communication for Geohazards” Research Topic analyses these challenges and identifies innovative pathways to address them. More precisely, it draws together 13 state-of-the-art articles from around the world on improving communication practices, strategies, and understandings relating to a range of various geohazards and weather-related hazards.

Frontiers in Earth Science↗

Spatial and temporal variation in marine birds in the north Gulf of Alaska: The value of marine bird monitoring within Gulf Watch Alaska

Birds offer useful insights into marine ecosystems. Marine birds are responsive to spatial and temporal variation in the environment, that often originates with fluctuations in oceanographic and climatic drivers and permeates up through food webs to conspicuous top predators such as seabirds (Coyle and Pinchuk 2005, Speckman et al. 2005, Gonzales-Solis et al. 2009, Cushing et al., this report). In that way, marine birds are excellent assimilators, samplers, and indicators of the status of marine environments (Montevecchi 1993, Piatt et al. 2007b, Zador et al. 2013). Marine bird responses to dynamic marine ecosystems can be detected in a variety of metrics, including abundance, distribution, and productivity. For example, in the northern Gulf of Alaska (GOA), decadal-scale variation in oceanographic conditions has been associated with dramatic shifts in prey composition and abundance (Anderson and Piatt 1999). In turn, these shifts were more closely correlated with changes in abundance of fish-eating birds of Prince William Sound (PWS), such as pigeon guillemots (Golet et al. 2002) and marbled and Kittlitz’s murrelets (Kuletz et al. 2011a, 2011b), than in the abundance of species that primarily consume plankton or benthic prey (Agler et al. 1999, Cushing et al., this report). Birds also are responsive to anthropogenic influences in marine environments, including commercial fishing, contamination, introduction of non-native species, coastal development, offshore resource extraction, and vessel traffic. A major anthropogenic perturbation in the northern GOA was the 1989 Exxon Valdez oil spill, in which marine birds suffered high immediate mortality (Piatt and Ford 1996). Additionally, several species showed long-term evidence of declines in the oiled areas of PWS (Lance et al. 2001), as well as impacts to reproductive success years later (Golet et al. 2002). However, the degree of direct impact and vulnerability to chronic injury, which was related to exposure to lingering oil, varied widely among species (see Esler et al., this report). Research and monitoring directed at documenting the timelines and mechanisms of wildlife recovery following the Exxon Valdez oil spill led to an unprecedented understanding of oil spill effects on marine birds, as well as previously unknown information about marine bird ecology in the northern GOA. Quantifying effects of anthropogenic influences requires an understanding of variation in marine bird abundance, distribution, and productivity, in relation to naturally occurring dynamics in marine environments continued marine bird work as part of Gulf Watch Alaska will facilitate this. In addition to their value as indicators of marine conditions and anthropogenic influences, marine birds are protected under the Migratory Bird Treaty Act and are managed by the U.S. Fish and Wildlife Service (USFWS). Marine birds have high societal value from a wide variety of interests (e.g., tourism, bird watching, hunting, mythology), and are an important source of subsistence foods in Alaska (Naves and Braem 2014). Because of the conservation interest in marine birds, as well as their value for indicating the status of marine ecosystems, monitoring of marine birds is an important component of many ocean monitoring programs, including Gulf Watch Alaska.

Alaska↗

Landscape transcriptomics as a tool for addressing global change effects across diverse species

Landscape transcriptomics is an emerging field studying how genome-wide expression patterns reflect dynamic landscape-scale environmental drivers, including habitat, weather, climate, and contaminants, and the subsequent effects on organismal function. This field is benefitting from advancing and increasingly accessible molecular technologies, which in turn are allowing the necessary characterization of transcriptomes from wild individuals distributed across natural landscapes. This research is especially important given the rapid pace of anthropogenic environmental change and potential impacts that span levels of biological organization. We discuss three major themes in landscape transcriptomic research: connecting transcriptome variation across landscapes to environmental variation, generating and testing hypotheses about the mechanisms and evolution of transcriptomic responses to the environment, and applying this knowledge to species conservation and management. We discuss challenges associated with this approach and suggest potential solutions. We conclude that landscape transcriptomics has great promise for addressing fundamental questions in organismal biology, ecology, and evolution, while providing tools needed for conservation and management of species.

Molecular Ecology Resources↗

Climate Change Science Activities of the U.S. Geological Survey in New England

The U.S. Geological Survey (USGS) has actively pursued research in the effects of climate change on the hydrology of New England. Ongoing focus areas of climate change science activities of the USGS in New England include the following: &bull; Hydrologic climate-response data (initiating or expanding long-term hydrologic climate-response data collection networks to detect and monitor climate-related changes in hydrology) &bull; Relations between historical climatic and hydrologic variation (investigating historic relations between long-term climatic variation and hydrologic variation and connecting these relations to future conditions as forecasted by the Interagency Panel on Climate Change (Nakićenović and others, 2000) &bull; Hydrologic change on natural and human (incorporating climate change scenarios into assessments of how flows in streams or water levels in aquifers may change) &bull; Relations between climatic and hydrologic variation (characterizing impacts of climate change on floods and droughts, the long-term availability of water supplies for societal and natural uses in response to climate changes) &bull; Developing tools to forecast ecosystem change and water resources management (developing regionally consistent tools for forecasting ecosystem change and resource management) This fact sheet presents recent climate change investigations of the USGS in New England using selected recent publications. These publications highlight the broad spectrum of expertise and commitment to understanding the relations of climate change and water resources in New England.

New England↗