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John Wesley Powell Center for Analysis and Synthesis

Current Powell Center Working Groups

Budyko Framework.jpg from ScienceBase Item
A global synthesis of land-surface fluxes under natural and human-altered watersheds using the Budyko framework
Global hydroclimatic conditions have been significantly altered, over the past century, by anthropogenic influences that arise from warming global climate and also from local/regional anthropogenic disturbances. There has been never been an effort that has systematically analyzed how the spatio-temporal variability of land-surface fluxes vary in natural and human-altered watersheds globally. This synthesis study will adapt and extend the classical Budyko framework to quantify the role of drivers - changing climate and local human disturbances - in altering flow regimes and in creating urban heat island episodes over the globe. An allied goal is to develop parsimonious hydroclimatic models that explain the spatio-temporal variability [...] (Read More)
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Accounting for U.S. ecosystem services at national and subnational scales
Ecosystem services - the benefits that nature provides to society and the economy - are gaining increasing traction worldwide as governments and the private sector use them to monitor integrated environmental and economic trends. When they are well understood and managed, ecosystems can provide these long-term benefits to people - such as clean air and water, flood control, crop pollination, and recreational, cultural, and aesthetic benefits. Within the U.S. government, a memo issued by the White House Council on Environmental Quality in October 2015 charged agencies with incorporating these values in planning, investment, and regulatory processes. Natural capital accounting - a tool being used in dozens of countries globally and by [...] (Read More)
Paleoclimate.jpg from ScienceBase Item
Broader view of North American climate over the past two millennia: Synthesizing paleoclimate records from diverse archives
Regional- to continental-scale paleoclimate syntheses of temperature and hydroclimate in North America are essential for understanding long-term spatiotemporal variability in climate, and for properly assessing risk on decadal and longer timescales. However, existing syntheses rely almost exclusively on tree-ring records, which are known to underestimate low-frequency variability and rarely extend beyond the last millennium. Meanwhile, many additional records from a variety of archives are available and hold the potential of broadening and enhancing our understanding of past climate in North America over the past two thousand years. We propose to bring together a diverse group of with expertise that spans the relevant natural archives [...] (Read More)
Global_Arsenic_Powell (1).jpg from ScienceBase Item
Characterizing global variability in groundwater arsenic
Groundwater contaminated with naturally occurring arsenic is a widespread problem affecting many alluvial and deltaic aquifer systems throughout the world. The human health toll from consuming groundwater with high levels of arsenic is staggering in its proportions. Furthermore, the use of arsenic contaminated groundwater for irrigation is observed to result in diminished crop yields and thus poses a threat to food security in arsenic affected regions. Decades of research at individual field sites have resulted in the collection of many geochemical and geologic datasets. A key feature of alluvial and deltaic aquifer systems is the large degree of spatial variability in groundwater arsenic concentrations from local to regional scales. [...] (Read More)
Biocrusts.jpg from ScienceBase Item
Completing the dryland puzzle: creating a predictive framework for biological soil crust function and response to climate change
Drylands are integral to the Earth system and the present and future of human society. Drylands encompass more than 40% of the terrestrial landmass and support 34% of the world’s human population. Biocrusts are the “living skin” of Earth’s drylands, sometimes dominating the ground cover and figuring prominently in ecosystem structure and function. Biocrusts are a biological aggregate of cyanobacteria, fungi, algae, lichens and mosses in the surface millimeters of soil. By aggregating soil, biocrusts make sediment less erodible. They also strongly influence the water runoff-infiltration balance. In some ecosystems they generate runoff, whereas in other systems they enhance water capture. Vascular plant germination, establishment, [...] (Read More)
USGS_Stream.JPG from ScienceBase Item
Continental-scale overview of stream primary productivity, its links to water quality, and consequences for aquatic carbon biogeochemistry
Streams and rivers have a limited spatial extent, but are increasingly recognized as key components of regional biogeochemical cycles. The collective metabolic processing of organisms, known as ecosystem metabolism, is centrally important to nutrient cycling and carbon fluxes in these environments, but is poorly integrated into emerging biogeochemical concepts. This line of inquiry lags behind other aspects of regional biogeochemistry because of the lack of long-term, regionally-diverse studies of stream metabolism. With a few exceptions, metabolism studies have focused on small headwater catchments using short-term (days to weeks) observation. As a consequence, basic patterns and controls of this fundamental process, such as seasonality, [...] (Read More)
Oppertunities in Earthquake Monitoring.JPG from ScienceBase Item
Future Opportunities in Regional and Global Seismic Network Monitoring and Science
The past decade has seen improvements in computational efficiency, seismic data coverage, and communication technology - driven by societal expectation for timely, accurate information. While aspects of earthquake research have taken advantage of this evolution, the adoption of improvements in earthquake monitoring has not been fully leveraged. In real-time monitoring, earthquakes are characterized in a vacuum, without building upon our knowledge of past events. New data types may help characterize earthquakes more quickly and accurately. New opportunities exist for rapidly communicating information. With these advances, global seismic monitoring can improve the quality and timeliness of information shared with the public. While we [...] (Read More)
GEISHA_WS1 group photo_3 (1).jpg from ScienceBase Item
Global Evaluation of the Impacts of Storms on freshwater Habitat and Structure of phytoplankton Assemblages (GEISHA)
Climate change is expected to cause more intense and frequent extreme weather events, but we only have a basic understanding of how these events might alter freshwater systems. Storms are likely to impact lake systems through delivery of sediments from watersheds and mixing of the water column, both of which could have important consequences for phytoplankton. Phytoplankton are the base of the food web; their community configuration and how the community changes across seasons have large impacts on ecosystem processes such as energy flow, nutrient cycling, and carbon cycling. External disturbances may abruptly alter phytoplankton community dynamics and thus impact ecosystem function. The effects of storms on the physical structure [...] (Read More)
Watershed Storage Controls.jpg from ScienceBase Item
Improved hydrologic forecasting through synthesis of critical storage components and timescales across watersheds worldwide
Models that predict the flow of rivers and streams are critically important for planning flood control, hydropower, and reservoir operations, as well as for management of fish and wildlife populations. As temperatures and precipitation regimes change globally, the need to improve and develop these models for a wider spatial coverage and higher spatial fidelity becomes more imperative. Currently, one of the biggest impediments to developing robust streamflow knowledge is incomplete understanding of the range of timescales over which water is stored (e.g., in snowpack, soils, and groundwater) in watersheds, as well as the processes and factors that control those storage timescales. This working group will address that knowledge gap by [...] (Read More)
IMG_1362.JPG from ScienceBase Item
Integrating GRACE Satellite and Ground-based Estimates of Groundwater Storage Changes
Groundwater storage depletion is a critical issue for many of the major aquifers in the U.S., particularly during intense droughts. The GRACE (Gravity Recovery and Climate Experiment) satellites launched in 2002, with sensors designed to measure changes in the Earth’s gravitational field at large spatial scales (≥ ~200,000 km2). These changes are primarily driven by changes in water storage on the Earth’s surface. Estimates of groundwater storage changes based on these gravity measurements have attracted considerable media attention in the U.S. and globally. However, groundwater storage changes are computed indirectly by subtracting snow, surface water, and soil moisture storage from the total water storage monitored by GRACE, and [...] (Read More)
Estimated probability of arsenic greater than 10 micrograms per liter in domestic wells in the conterminous United States.JPG from ScienceBase Item
Linking environmental and public health data to evaluate health effects of arsenic exposure from domestic and public supply wells
Everyone needs clean drinking water in order to thrive. The US EPA and public water purveyors in the US work together in adherence with the Safe Drinking Water Act to make water safe for public consumption. The recent media coverage of lead in public drinking water supplies in Flint, Michigan, and schools in many cities with aging infrastructure throughout the US has raised public awareness of drinking water as a potential pathway of exposure to toxic chemicals. Epidemiologists and other researchers have conclusively shown that high arsenic levels in drinking water in Bangladesh, Taiwan, and South America cause adverse human health outcomes. However, research in study populations with levels of arsenic exposure relevant to communities [...] (Read More)
Flat Cays_USVI_2012_healthy Acervicornis.jpg from ScienceBase Item
Local-scale ecosystem resilience amid global-scale ocean change: the coral reef example
Coral reefs are massive, wave resistant structures found throughout the tropics, where they have long attracted attention for their beauty, ecological importance, and rich biological diversity. However, in recent years attention to these systems has focused on their downturn in health and the potential that they effectively could disappear within a century. Yet while many coral reefs have deteriorated, a small number have flourished and now represent “oases” with the potential to drive repopulation of the denuded areas that surround them. This working group focuses on the geographic, biological, ecological, and physical features that characterize oases in coral reef communities, and evaluates the potential of these oases to catalyze [...] (Read More)
CSZ_image2.jpg from ScienceBase Item
Margin-wide geological and geophysical synthesis to understand the recurrence and hazards of great subduction zone earthquakes in Cascadia
The Cascadia Subduction Zone, located in the U.S. Pacific Northwest and southwestern British Columbia, has hosted magnitude ≥8.0 megathrust earthquakes in the geologic past, a future earthquake is imminent, and the potential impacts could cripple the region. Subduction zone earthquakes represent some of the most devastating natural hazards on Earth. Despite substantial knowledge gained from decades of geoscience research, the size and frequency of Cascadian earthquakes remain controversial, as do the physics of earthquake rupture, the effects of earthquake shaking, and the effect of resultant tsunamis. This translates into major uncertainties in earthquake hazard assessments that can lead to ineffective preparedness measures. Reducing [...] (Read More)
mercury collage.jpg from ScienceBase Item
Mercury cycling, bioaccumulation, and risk across western North America: a landscape scale synthesis linking long-term datasets
Mercury (Hg) is a serious environmental problem that is impacting ecological and human health on a global scale. However, local and regional processes are largely responsible for producing methylmercury, which drives ecological risk. This is particularly true in western North America where the combination of diverse landscapes, habitat types, climates, and Hg sources may disproportionally impact the region relative to other areas in North America. Even with decades of regional Hg research and monitoring, there is still no holistic synthesis of the spatiotemporal patterns of Hg in abiotic and biotic resources across the region, nor has there been a formal, simultaneous analysis of the landscape, ecological and climatological factors [...] (Read More)
100_0027.jpg from ScienceBase Item
North American Analysis and Synthesis on the Connectivity of "Geographically Isolated Wetlands" to Downstream Waters
Geographically Isolated Wetlands (GIWs) occur along gradients of hydrologic and ecological connectivity and isolation, even within wetland types (e.g., forested, emergent marshes) and functional classes (e.g., ephemeral systems, permanent systems, etc.). Within a given watershed, the relative positions of wetlands and open-waters along these gradients influence the type and magnitude of their chemical, physical, and biological effects on downgradient waters. In addition, the ways in which GIWs connect to the broader hydrological landscape, and the effects of such connectivity on downgradient waters, depends largely upon climate, geology, and relief, the heterogeneity of which expands with increasing scale. Developing an understanding [...] (Read More)
Nitrogen Fixation - landscape (1).jpg from ScienceBase Item
Novel multi‐scale synthesis of nitrogen fixation rates and drivers across the terrestrial biosphere
Biological nitrogen fixation (BNF) is a critical biogeochemical process that converts inert atmospheric N2 gas into biologically usable forms of the essential nutrient nitrogen. A variety of free-living and symbiotic organisms carry out BNF, and in most regions worldwide, BNF is the largest source of nitrogen that fuels terrestrial ecosystems. As a result, BNF has far reaching effects on ecosystem properties (water quality, carbon storage), sustainability (plant growth, soil fertility), and the global climate system. Despite this cross-cutting importance, existing syntheses of BNF have major gaps, with particular challenges in upscaling local measurements across large areas. These gaps, and a corresponding lack of information on environmental [...] (Read More)
Powell_Center_to_RMNP_51.jpg from ScienceBase Item
Operational Earthquake Forecasting – Implementing a Real-Time System for California
It is well know that every earthquake can spawn others (e.g., as aftershocks), and that such triggered events can be large and damaging, as recently demonstrated by L’Aquila, Italy and Christchurch, New Zealand earthquakes. In spite of being an explicit USGS strategic-action priority (; page 32), the USGS currently lacks an automated system with which to forecast such events and official protocols for disseminating the potential implications. This capability, known as Operational Earthquake Forecasting (OEF), could provide valuable situational awareness to emergency managers, the public, and other entities interested in preparing for potentially damaging earthquakes. With the various ingredients in [...] (Read More)
MVIMG_20180620_122539.jpg from ScienceBase Item
Optimizing satellite resources for the global assessment and mitigation of volcanic hazards
A vast number of the world’s volcanoes are unmonitored by ground-based sensors, yet constitute an important hazard to nearby residents and infrastructure, as well as air travel and the global economy. Satellite data provide a cost-effective means of tracking activity at such volcanoes. Unfortunately, satellite acquisitions are not optimized for application to volcano hazards, in part because clear relations between satellite-monitored unrest and eruptive activity are lacking. We aim to bridge this gap by developing linked global databases of satellite observations of volcanic activity, with the goal of relating surface change and volcanic emissions to eruption style and impact. This database (or databases) will be used to design [...] (Read More)
CactusMoth_Larvae.jpg from ScienceBase Item
Predicting the next high-impact insect invasion: Elucidating traits and factors determining the risk of introduced herbivorous insects on North American native plants
Non-native insect invasions increasingly cause widespread ecological and economic damage in natural and agricultural ecosystems. Non-native insects specialized for feeding on specific plant groups are particularly problematic as they can potentially eliminate an entire genus of native plant species across a wide area. For example, emerald ash borer has killed hundreds of millions of ash trees in North America since its accidental introduction from Asia, including more than 99% of all trees in forests near the epicenter of the invasion. However, most introduced insects do not become high-impact pests. Our goal is to develop a framework that allows us to predict whether non-native herbivorous insects in natural ecosystems will cause [...] (Read More)
IMG_8833.JPG from ScienceBase Item
River Corridor hot spots for biogeochemical processing: a continental scale synthesis
Rivers are the veins of the landscape, providing environmental benefits that are disproportionately high relative to their aerial extent; shedding flood waters, hosting aquatic ecosystems, transporting solutes and energy-rich materials, and storing and transforming pollutants into less harmful forms. From uplands to the coasts, rivers facilitate key biogeochemical reactions that cumulatively influence water quality. Many of the reactions are optimized outside the main channel, in hyporheic zones, riparian zones, and floodplain areas, where riverine water is in close contact with geochemically and microbially-active sediments. However, little is known about the distribution, intermittency, and overall effectiveness of biogeochemical [...] (Read More)
etowahae.jpg from ScienceBase Item
Synthesizing Multiple Long-Term Datasets to Test Flow Ecology Relationships for Fishes - Workshop
River ecosystems support a wide diversity of biota, including thousands of fish species, which are variously adapted to the dynamic environments provided by flowing-water habitats. One of the primary ways that human activities diminish the biological capacity of rivers is by altering the natural hydrologic variability of river systems through regulation and diversion of streamflow for other uses. Managers may be able to avoid some of the worst effects of flow management on aquatic biota if we understand the mechanisms by which streamflow components, such as unusually high and low flow events, affect populations (e.g., by influencing recruitment and mortality). Numerous past studies have described correlative associations of flow [...] (Read More)
tsunami-working-group-web-image.jpg from ScienceBase Item
Tsunami Source Standardization for Hazards Mitigation in the United States
The goal of this Powell Center Working Group is to produce a collection of vetted and standardized earthquake and landslide tsunami sources that can be used to produce the meaningful hazard assessment products required for effective tsunami hazard mitigation and risk reduction. The need for a set of realistic and consistent tsunami sources was identified as a high priority at a 2016 workshop between USGS scientists and the National Tsunami Hazards Mitigation Program (NTHMP). The Powell Center Working Group will include scientists from the USGS, NOAA, the NTHMP, academia, and consulting companies. Tsunamis are extreme events that have caused devastation worldwide over the past several decades. The tsunami from the 2004 Indonesian [...] (Read More)
Wetland flux - Mayberry.jpg from ScienceBase Item
Wetland fluxnet synthesis for methane: understanding and predicting methane fluxes at daily to interannual timescales
Wetlands provide many important ecosystem services, including wildlife habitat, water purification, flood protection, and carbon metabolism. Our ability to manage these services and predict the long-term health of wetlands is strongly linked to their carbon fluxes, of which methane (CH4) is a key component. Natural wetlands emit approximately 30% of global CH4 emissions, as their waterlogged soils create ideal conditions for CH4 production. They are also the largest, and potentially most uncertain, natural source of CH4 to the atmosphere. To understand and predict CH4 fluxes across wetlands globally, we propose the first synthesis of CH4 flux tower data accompanying a global database of CH4 emissions. By taking advantage of the continuous [...] (Read More)
EastRiverValley.jpeg from ScienceBase Item
What lies below? Improving quantification and prediction of soil carbon storage, stability, and susceptibility to disturbance.
Soils are a vast reservoir of organic carbon (C), rendering the fate of soil C an important control on the global climate system. Widespread changes in soil C storage capacity present a potentially strong feedback to global change. Yet, a comprehensive understanding of how soil C will respond to climate and/or land use disturbance remains illusive, resulting in major uncertainties in global climate models. Our working group will synthesize information on the processes controlling soil C storage across different spatial scales and develop new procedures to translate local measurements to the regional and global scale datasets used by models. These activities will improve our ability to map the vulnerability of soil C and constrain [...] (Read More)

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