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At least 505 records · Page 28Linked to original sources
USGS2025

Effects of riparian forest thinning on resident salmonid fishes in coastal northern California catchments

Resource managers are interested in whether thinning second-growth forests may be a viable restoration strategy for stream and riparian habitats, but may be concerned about the potential impacts that increases in stream temperature associated with riparian thinning treatments may have on cold-water salmonid fishes. We evaluated the effects of riparian forest thinning on resident populations of coastal cutthroat trout ( Oncorhynchus clarkii clarkii ) in coastal northern California catchments using a manipulative field experiment with a replicated before-after-control-impact design (pre-treatment data collected in 2016, thinning treatments occurred in 2017, and post-treatment data collected in 2018). Experimental thinning treatments reduced riparian shade by 20%–30% along five 150–200 m stream reaches. To provide a process-based evaluation of the implications of riparian thinning for coastal cutthroat trout, we combined seasonal observations of trout density, biomass, and growth with bioenergetics modelling. Cutthroat trout density increased by 8%–31% and biomass increased by 27%–111% in thinned reaches 1 year post-treatment, but responses varied widely across sites and seasons so did not always differ statistically. Growth rates of cutthroat trout varied more among seasons than among reach types (upstream reference, thinned, and downstream), peaking in spring and overwinter relative to summer. Bioenergetics modelling indicated that cutthroat trout responded to thinning-induced increases in stream temperature and shifts in prey energy density via higher consumption rates (i.e., fish fed more frequently) in thinned reaches. Additionally, reach-scale consumption estimates indicated that the energy intake of cutthroat trout increased at the population level in thinned reaches. However, thinned reaches exhibited relatively small changes in consumption, suggesting that riparian thinning was unlikely to enhance growth opportunities for cutthroat trout, supporting our empirical growth observations. Collectively, our field experiment suggests that salmonid fishes may be resilient to thinning second-growth riparian forests when treatments do not substantially increase water temperatures. Moreover, our results highlight that pairing empirical data with bioenergetics modelling can provide valuable insights into the mechanisms driving fish responses to riparian forest restoration.

California↗
USGS2007

Tintina Gold Province Study, Alaska and Yukon Territory, 2002-2007

The Tintina gold province is an arc-shaped 2,000-kilometer-long metallogenic province that extends from northern British Columbia, through the Yukon Territory, and across and into southwestern Alaska. In the United States, the province remains a prime area for gold exploration and includes such large gold deposits as Pogo, Fort Knox-True North, and Donlin Creek. In recent years, gold exploration and development and mining activity have accelerated in the area. Plans have been discussed for public and private projects and infrastructures associated with development. A U.S. Geological Survey study undertaken from 2002 to 2007 provides a context for understanding why and how the mineral resources of the area were formed, why this area is so abundantly endowed, and how the environmental signatures that are characteristic of the area are related to the development of mineral resources. Characterization of natural baseline metal concentrations in the area's watersheds is necessary to address future land-use issues related to mining and/or infrastructure activities. A thorough understanding of water-rock and element-bioavailability processes will help predict the possible environmental impact of development. The five tasks of this study add to the science of defining and understanding an 'intrusion-related gold system.'

Fact Sheet↗
USGS2026

Colocating artificial intelligence data centers with energy infrastructure on Federal public lands—A science synthesis and spatial analysis to inform decision making

Executive Summary Artificial intelligence (AI) is rapidly transforming industries and economies, creating an urgent need to strategically plan for the energy and infrastructure required to support increasing AI use. U.S. Federal agencies and bureaus have been directed to explore ways to accelerate permitting, development, and deployment of energy resources and AI technologies, including encouraging the colocation of energy infrastructure and data centers. To inform these initiatives, this report synthesizes relevant scientific information and presents a spatial analysis of existing energy infrastructure and data centers on or near U.S. Federal public lands managed by the Bureau of Land Management (BLM). The purpose of this science synthesis and spatial analysis is to provide the BLM with foundational information for considering potential colocation of data centers with energy infrastructure on Federal public lands to support evidence-based decisions. Additionally, this report provides insight into current (2025) and potential future energy demands by providing projections of a range of potential future environmental conditions relevant to maintaining industry-recommended cooling temperature standards necessary for efficient data center operations. As a part of this effort, a rapid response literature review was conducted of the best available science on the topic of data center development and energy infrastructure in July–August 2025, supplemented by additional resources recommended by U.S. Federal agency and bureau subject matter experts (hereafter experts; including the U.S. Department of Energy National Laboratory of the Rockies) and peer reviewers. To better understand current conditions relevant to AI data center development, a spatial analysis was conducted across Alaska and 11 States in the Western United States, Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, and Wyoming, all of which contain extensive BLM-managed surface lands (hereafter referred to as “BLM lands”) that could be considered for the colocation of energy infrastructure and AI data centers. This effort identified BLM lands within 10 miles of existing transmission lines, consistent with methods used in previous BLM programmatic environmental impact statements. This report describes the types of data centers operating within the United States, which vary in ownership, size, technology, and proximity to end users. This report then outlines the primary considerations of data center development, including reliable energy supply, natural resources (such as water availability to support cooling requirements), and relevant policy and regulatory considerations. Energy supply considerations are pivotal for data center operation. Between 2014 and 2018, data centers in the United States accounted for nearly 2 percent of the Nation’s total electricity consumption, and data center energy consumption is projected to increase from 2 to 6.7–12 percent of total U.S. electricity use by 2028. These energy requirements necessitate careful consideration of energy supply when considering potentially suitable locations for data center development. Experts anticipate that an increase in renewable energy generation will likely support most potential future power demand needs, including for data centers, followed by increases in natural gas, nuclear, and geothermal energy production. Additional capacity in the form of battery storage will likely not generate electricity, but may improve the reliability and flexibility of supply, helping to ensure that growing data center loads can be met. However, the U.S. Department of Energy estimates that the United States will need, on average, 57 percent more energy transmission infrastructure by 2035 to account for the growing power demand introduced by development such as data centers. Cooling server equipment in data centers requires large amounts of electricity and water, and this demand can be exacerbated by hot and humid conditions. Energy efficient water-based cooling technologies may reduce electricity consumption onsite but require more water consumption. This additional water demand has the potential to increase water stress and competition with other users. As such, developing data centers will likely need a thorough assessment of current and potential future water availability, as well as consideration of how water demand may change across other sectors. Data center development involves policy and regulatory considerations, as projects must undergo environmental review and authorization processes that can take 18–24 months. Coordinating these environmental reviews and authorizations with other energy development projects, such as building new transmission lines, may cause additional delays. Recent efforts by the U.S. Department of Energy and U.S. Department of the Interior aim to expedite environmental reviews and authorizations and improve coordination across agencies. The spatial analysis identified 771 existing AI data centers and more than 3,300 power plants. The spatial analysis found that 6 percent of AI data centers and 22 percent of power plants in the Western United States were on or within 1 mile of BLM lands, and California had the largest number of facilities. Most existing AI data centers were near high-voltage transmission lines and close to power plants, supporting efficient energy delivery. More than 90,000,000 acres of BLM lands were within 10 miles of existing high-voltage transmission lines, representing 38 percent of BLM lands in the study area. Available transmission infrastructure and the overlap with BLM lands varied by State, and Alaska had limited overlap compared to the rest of the Western United States. To operate most efficiently, data center temperatures must be at or below 80.6 degrees Fahrenheit. This analysis of future temperature and precipitation projections indicated increasing cooling demands for data centers, particularly in Arizona, California, and Nevada, where rising temperatures are expected to increase energy and operational costs while potentially stressing current regional electrical grid infrastructure. This report highlights relevant energy supply, natural resources, and regulatory considerations for data center development on BLM lands. This report does not provide a comprehensive ecological, regulatory, land suitability, or permitting analysis. The factors described here are contextual considerations only and are not intended to identify, rank, quantify, or recommend optimal areas for data center colocation. This spatial analysis focused solely on energy considerations relevant to data centers and did not consider water availability, critical habitats, BLM National Conservation Lands, areas of cultural or historical significance, and other sensitive resources. These topics are recognized as critical but were not within the scope of this science synthesis and spatial analysis.

Scientific Investigations Report↗
USGS2009

Long-duration drought variability and impacts on ecosystem services: A case study from Glacier National Park, Montana

Instrumental climate records suggest that summer precipitation and winter snowpack in Glacier National Park (Glacier NP), Montana, vary significantly over decadal to multidecadal time scales. Because instrumental records for the region are limited to the twentieth century, knowledge of the range of variability associated with these moisture anomalies and their impacts on ecosystems and physical processes are limited. The authors developed a reconstruction of summer (June–August) moisture variability spanning a.d. 1540–2000 from a multispecies network of tree-ring chronologies in Glacier NP. Decadal-scale drought and pluvial regimes were defined as any event lasting 10 yr or greater, and the significance of each potential regime was assessed using intervention analysis. Intervention analysis prevents single intervening years of average or opposing moisture conditions from ending what was otherwise a sustained moisture regime. The reconstruction shows numerous decadal-scale shifts between persistent drought and wet events prior to the instrumental period (before a.d. 1900). Notable wet events include a series of three long-duration, high-magnitude pluvial regimes spanning the end of the Little Ice Age ( a.d. 1770–1840). Though the late-nineteenth century was marked by a series of >10 yr droughts, the single most severe dry event occurred in the early-twentieth century ( a.d. 1917–41). These decadal-scale dry and wet events, in conjunction with periods of high and low snowpack, have served as a driver of ecosystem processes such as forest fires and glacial dynamics in the Glacier NP region. Using a suite of paleoproxy reconstructions and information from previous studies examining the relationship between climate variability and natural processes, the authors explore how such persistent moisture anomalies affect the delivery of vital goods and services provided by Glacier NP and surrounding areas. These analyses show that regional water resources and tourism are particularly vulnerable to persistent moisture anomalies in the Glacier NP area. Many of these same decadal-scale wet and dry events were also seen among a wider network of hydroclimatic reconstructions along a north–south transect of the Rocky Mountains. Such natural climate variability can, in turn, have enormous impacts on the sustainable provision of natural resources over wide areas. Overall, these results highlight the susceptibility of goods and services provided by protected areas like Glacier NP to natural climate variability, and show that this susceptibility will likely be compounded by the effects of future human-induced climate change.

Montana↗
USGS1977

Map showing general availability of ground water in the Kaiparowits coal-basin area, Utah

This is one of a series of maps that describe the geology and related natural resources in the Kaiparowits coal-basin area. This map is based partly on records of water wells, springs, and coal and petroleum exploration holes, partly on unpublished reports of field evaluations of prospective stock-water well sites by personnel of the U.S. Geological Survey, and partly on a 6-day field reconnaissance by the writer in parts of the mapped area. Most of the data used to compile this map were collected by the U.S. Geological Survey in cooperation with State, local, and other Federal agencies. Published sources of data included Phoenix (1963), Iorns, Hembree, and Phoenix (1964), Cooley (1965), Feltis (1966), Goode (1966, 1969), and the final environmental impact statement for the proposed Kaiparowits power project (U.S. Bureau of Land Management, 1976). Few data about the availability or depth of ground water could be obtained for large areas in the Kaiparowits coal basin. In those areas, expected yields of individual wells are inferred from the geology as compiled by Stokes (1964) and Hackman and Wyant (1973), and depths of ground water in wells are inferred largely from the local topography. El Paso Natural Gas Co., Resources Co., Kaiser Engineers, and Southern California Edison Co. provided specific information regarding the availability and depth of ground water in their exploratory holes on the Kaiparowits Plateau. The cooperation of those firms is gratefully acknowledged.

Utah↗
USGS2014

Effects of disturbance associated with seismic exploration for oil and gas reserves in coastal marshes

Anthropogenic disturbances in wetland ecosystems can alter the composition and structure of plant assemblages and affect system functions. Extensive oil and gas extraction has occurred in wetland habitats along the northern Gulf of Mexico coast since the early 1900s. Activities involved with three-dimensional (3D) seismic exploration for these resources cause various disturbances to vegetation and soils. We documented the impact of a 3D seismic survey in coastal marshes in Louisiana, USA, along transects established before exploration began. Two semi-impounded marshes dominated by Spartina patens were in the area surveyed. Vegetation, soil, and water physicochemical data were collected before the survey, about 6 weeks following its completion, and every 3 months thereafter for 2 years. Soil cores for seed bank emergence experiments were also collected. Maximum vegetation height at impact sites was reduced in both marshes 6 weeks following the survey. In one marsh, total vegetation cover was also reduced, and dead vegetation cover increased, at impact sites 6 weeks after the survey. These effects, however, did not persist 3 months later. No effects on soil or water properties were identified. The total number of seeds that germinated during greenhouse studies increased at impact sites 5 months following the survey in both marshes. Although some seed bank effects persisted 1 year, these effects were not reflected in standing vegetation. The marshes studied were therefore resilient to the impacts resulting from 3D seismic exploration because vegetation responses were short term in that they could not be identified a few months following survey completion.

Louisiana↗
USGS2002

Impacts of swine manure pits on groundwater quality

Manure deep-pits are commonly used to store manure at confined animal feeding operations. However, previous to this study little information had been collected on the impacts of deep-pits on groundwater quality to provide science-based guidance in formulating regulations and waste management strategies that address risks to human health and the environment. Groundwater quality has been monitored since January 1999 at two hog finishing facilities in Illinois that use deep-pit systems for manure storage. Groundwater samples were collected on a monthly basis and analyzed for inorganic and bacteriological constituent concentrations. The two sites are located in areas with geologic environments representing different vulnerabilities for local groundwater contamination. One site is underlain by more than 6 m of clayey silt, and 7-36 m of shale. Concentrations of chloride, ammonium, phosphate, and potassium indicated that local groundwater quality had not been significantly impacted by pit leakage from this facility. Nitrate concentrations were elevated near the pit, often exceeding the 10 mg N/l drinking water standard. Isotopic nitrate signatures suggested that the nitrate was likely derived from soil organic matter and fertilizer applied to adjacent crop fields. At the other site, sandstone is located 4.6-6.1 m below land surface. Chloride concentrations and ??15N and ??18O values of dissolved nitrate indicated that this facility may have limited and localized impacts on groundwater. Other constituents, including ammonia, potassium, phosphate, and sodium were generally at or less than background concentrations. Trace- and heavy-metal concentrations in groundwater samples collected from both facilities were at concentrations less than drinking water standards. The concentration of inorganic constituents in the groundwater would not likely impact human health. Fecal streptococcus bacteria were detected at least once in groundwater from all monitoring wells at both sites. Fecal streptococcus was more common and at greater concentrations than fecal coliform. The microbiological data suggest that filtration of bacteria by soils may not be as effective as commonly assumed. The presence of fecal bacteria in the shallow groundwater may pose a significant threat to human health if the ground water is used for drinking. Both facilities are less than 4 years old and the short-term impacts of these manure storage facilities on groundwater quality have been limited. Continued monitoring of these facilities will determine if they have a long-term impact on groundwater resources. ?? 2002 Elsevier Science Ltd. All rights reserved.

Environmental Pollution↗
USGS2021

Integrated hydrology and operations modeling to evaluate climate change impacts in an agricultural valley irrigated with snowmelt runoff

Applying models to developed agricultural regions remains a difficult problem because there are no existing modeling codes that represent both the complex physics of the hydrology and anthropogenic manipulations to water distribution and consumption. We apply an integrated groundwater – surface water and hydrologic river operations model to an irrigated river valley in northwestern Nevada/northern California, United States to evaluate the impacts of climate change on snow-fed agricultural systems that use surface water and groundwater conjunctively. We explicitly represent individual surface water rights within the hydrologic model and allow the integrated code to change river diversions in response to earlier snowmelt runoff and water availability. Historically under-used supplemental groundwater rights are dynamically activated within the model to offset diminished surface water deliveries. The model accounts for feedbacks between the natural hydrology and anthropogenic stresses, which is a first-of-its-kind assessment of the impacts of climate change on individual water rights, and more broadly on river basin operations. Earlier snowmelt decreases annual surface water deliveries to all water rights, not just the junior water rights, owing to a lack of surface water storage in the upper river basin capable of capturing earlier runoff. Conversely, downstream irrigators with access to reservoir storage benefit from earlier runoff flowing past upstream points of diversion prior to the start of the irrigation season. Despite regional shifts toward greater reliance on groundwater for irrigation, crop consumption (a common surrogate for crop yield) decreases due to spatiotemporal changes in water supply that preferentially impact a subset of growers in the region.

California↗
USGS2021

Critical aquifer overdraft accelerates degradation of groundwater quality in California’s Central Valley during drought

Drought-induced pumpage has precipitated dramatic groundwater-level declines in California’s Central Valley over the past 30 years, but the impacts of aquifer overdraft on water quality are poorly understood. This study coupled over 160,000 measurements of nitrate from ∼6,000 public-supply wells with a 30-year reconstruction of groundwater levels throughout the Central Valley to evaluate dynamic relations between aquifer exploitation and resource quality. We find that long-term rates of groundwater-level decline and water-quality degradation in critically overdrafted basins accelerate by respective factors of 2–3 and 3–5 during drought, followed by brief reversals during wetter periods. Episodic water-quality degradation can occur during drought where increased pumpage draws shallow, contaminated groundwater down to depth zones tapped by long-screened production wells. These data show, for the first time, a direct linkage between climate-mediated aquifer pumpage and groundwater quality on a regional scale.

California↗
USGS2016

Modeling the effects of tile drain placement on the hydrologic function of farmed prairie wetlands

The early 2000s saw large increases in agricultural tile drainage in the eastern Dakotas of North America. Agricultural practices that drain wetlands directly are sometimes limited by wetland protection programs. Little is known about the impacts of tile drainage beyond the delineated boundaries of wetlands in upland catchments that may be in agricultural production. A series of experiments were conducted using the well-published model WETLANDSCAPE that revealed the potential for wetlands to have significantly shortened surface water inundation periods and lower mean depths when tile is placed in certain locations beyond the wetland boundary. Under the soil conditions found in agricultural areas of South Dakota in North America, wetland hydroperiod was found to be more sensitive to the depth that drain tile is installed relative to the bottom of the wetland basin than to distance-based setbacks. Because tile drainage can change the hydrologic conditions of wetlands, even when deployed in upland catchments, tile drainage plans should be evaluated more closely for the potential impacts they might have on the ecological services that these wetlands currently provide. Future research should investigate further how drainage impacts are affected by climate variability and change.

Journal of the American Water Resources Associatio↗
USGS2008

Comparisons of Simulated Hydrodynamics and Water Quality for Projected Demands in 2046, Pueblo Reservoir, Southeastern Colorado

Pueblo Reservoir is one of southeastern Colorado's most valuable water resources. The reservoir provides irrigation, municipal, and industrial water to various entities throughout the region. The reservoir also provides flood control, recreational activities, sport fishing, and wildlife enhancement to the region. The Bureau of Reclamation is working to meet its goal to issue a Final Environmental Impact Statement (EIS) on the Southern Delivery System project (SDS). SDS is a regional water-delivery project that has been proposed to provide a safe, reliable, and sustainable water supply through the foreseeable future (2046) for Colorado Springs, Fountain, Security, and Pueblo West. Discussions with the Bureau of Reclamation and the U.S. Geological Survey led to a cooperative agreement to simulate the hydrodynamics and water quality of Pueblo Reservoir. This work has been completed and described in a previously published report, U.S. Geological Survey Scientific Investigations Report 2008-5056. Additionally, there was a need to make comparisons of simulated hydrodynamics and water quality for projected demands associated with the various EIS alternatives and plans by Pueblo West to discharge treated water into the reservoir. Plans by Pueblo West are fully independent of the SDS project. This report compares simulated hydrodynamics and water quality for projected demands in Pueblo Reservoir resulting from changes in inflow and water quality entering the reservoir, and from changes to withdrawals from the reservoir as projected for the year 2046. Four of the seven EIS alternatives were selected for scenario simulations. The four U.S. Geological Survey simulation scenarios were the No Action scenario (EIS Alternative 1), the Downstream Diversion scenario (EIS Alternative 2), the Upstream Return-Flow scenario (EIS Alternative 4), and the Upstream Diversion scenario (EIS Alternative 7). Additionally, the results of an Existing Conditions scenario (water years 2000 through 2002) were compared to the No Action scenario (projected demands in 2046) to assess changes in water quality over time. All scenario modeling used an external nutrient-decay model to simulate degradation and assimilation of nutrients along the riverine reach upstream from Pueblo Reservoir. Reservoir modeling was conducted using the U.S. Army Corps of Engineers CE-QUAL-W2 two-dimensional water-quality model. Lake hydrodynamics, water temperature, dissolved oxygen, dissolved solids, dissolved ammonia, dissolved nitrate, total phosphorus, algal biomass, and total iron were simulated. Two reservoir site locations were selected for comparison. Results of simulations at site 3B were characteristic of a riverine environment in the reservoir while results at site 7B (near the dam) were characteristic of the main body of the reservoir. Simulation results for the epilimnion and hypolimnion at these two sites also were evaluated and compared. The simulation results in the hypolimnion at site 7B were indicative of the water quality leaving the reservoir. Comparisons of the different scenario results were conducted to assess if substantial differences were observed between selected scenarios. Each of the scenarios was simulated for three contiguous years representing a wet, average, and dry annual hydrologic cycle (water years 2000 through 2002). Additionally, each selected simulation scenario was evaluated for differences in direct- and cumulative-effects on a particular scenario. Direct effects are intended to isolate the future effects of the scenarios. Cumulative effects are intended to evaluate the effects of the scenarios in conjunction with all reasonably foreseeable future activities in the study area. Comparisons between the direct- and cumulative-effects analyses indicated that there were not large differences in the results between most of the simulation scenarios and, as such, the focus of this report was on results for the direct-effects analysis. Addi

Scientific Investigations Report↗
USGS1985

Effects of flow alterations on trout, angling, and recreation in the Chattahoochee River between Buford Dam and Peachtree Creek

In 1974 county governments in the Atlanta vicinity realized that demands on the Chattahoochee River for water supply plus the streamflow required for water quality nearly equaled the minimum flow in the river. Increased demands for water supply in the following years could not be supplied under the then existing flow regime in the river. In response to the anticipated shortage of water, the Atlanta Regional Commission, a multicounty agency responsible for comprehensive regional planning in the Atlanta region, was contracted to prepare water demand projections to the year 2010 and identify alternatives for meeting projected water demands. The results of this study are published in an extensive final report, the Metropolitan Atlanta Area Water Resources Management Study (1981). Requests for copies should be directed to the District Engineer, Savannah District. Many of the identified alternatives to increase future water supply for the Atlanta area would result in modifications to the present flow regime within the Chattahoochee River between Buford Dam (river mile 348.3) and its confluence with Peachtree Creek (river mile 300.5). The present preferred alternative is construction of a reregulation dam at about river mile 342. The proposed reregulation dam would release a much more constant flow than the peaking flows presently released from Buford Dam (generally, a maximum release of approximately 9000 cfs or minimum release of about 550 cfs) by storing the generation releases from Buford Dam for gradual release during non-generation periods. The anticipated minimum release from the rereg dam would he approximately 1U5U cfs (based on contractual obligations to the Southeast Power Administration to supply a minimum of 11 hours of peaking power per week from Buford Dam). The average annual release from the proposed reregulation dam into the Chattahoochee River would be approximately 2000 cfs (based on USGS flow records) and the median release would he approximately 1500 cfs (value obtained from Savannah District). The proposed reregulation dam would have sufficient storage to provide some opportunity for flow management to optimize uses other than water supply and water quality. Flow modifications (and resultant water quality changes) within this reach of the Chattahoochee River to meet increased demands for water supply may have an effect on other beneficial uses of this important natural resource. In addition to supplying a significant proportion of the water supply for metropolitan Atlanta and providing for water quality, the Chattahoochee River also is used extensively for recreation and supports a valuable trout fishery. Altered flows in the channel to meet water supply needs may have an impact on river recreation and trout habitat.

Georgia↗
USGS2021

Enhancing the application of Earth observations for improved environmental decision-making using the Early Warning eXplorer (EWX)

The mitigation of losses due to extreme climate events and long-term climate adaptation requires climate informed decision-making. In the past few decades, several remote sensing and modeled-based Earth observations (EOs) have been developed to provide an unprecedented global overview and routine monitoring of climate and its impacts on vegetation and hydrologic conditions, with the goal of supporting informed decision-making. However, their usage in decision-making is particularly limited in climate-risk vulnerable and in situ data-scarce regions such as sub-Saharan Africa, due to lack of access to EOs. Here, we describe the Early Warning eXplorer (EWX), which was developed to address this crucial limitation and facilitate the application of EOs in decision-making, particularly in the food and water-insecure regions of the world. First, the EWX's core framework, which includes (i) the Viewer, (ii) GeoEngine, and (iii) Support Applications, is described. Then, a comprehensive overview of the Viewer, which is a web-based interface used to access EOs, is provided. This includes a description of (i) the maps and associated features to access gridded EO data and anomalies for different temporal averaging periods, (ii) time series graphs and associated features to access EOs aggregated over polygons such as administrative boundaries, and (iii) commonly used EOs served by the EWX that provide assessments of climate and vegetation conditions. Next, examples are provided to demonstrate how EWX can be used to monitor development, progression, spatial extent, and severity of climate-driven extreme events to support timely decisions related to mitigation of food insecurity and flooding impacts. Finally, the value of a regional implementation of EWX at the Regional Centre for Mapping of Resources for Development (RCMRD) in Nairobi, Kenya, is highlighted. Regional implementation of the EWX facilitates access to regionally focused EOs and their availability at polygon boundaries most relevant to the local decision-makers. Similar instances of EWX implemented in other regions, especially those susceptible to food and water security, will likely further enhance the application of EOs for informed decision-making.

Frontiers in Climate↗
USGS2012

Target loads of atmospheric sulfur and nitrogen deposition for protection of acid sensitive aquatic resources in the Adirondack Mountains, New York

The dynamic watershed acid-base chemistry model of acidification of groundwater in catchments (MAGIC) was used to calculate target loads (TLs) of atmospheric sulfur and nitrogen deposition expected to be protective of aquatic health in lakes in the Adirondack ecoregion of New York. The TLs were calculated for two future dates (2050 and 2100) and three levels of protection against lake acidification (acid neutralizing capacity (ANC) of 0, 20, and 50 eq L -1). Regional sulfur and nitrogen deposition estimates were combined with TLs to calculate exceedances. Target load results, and associated exceedances, were extrapolated to the regional population of Adirondack lakes. About 30% of Adirondack lakes had simulated TL of sulfur deposition less than 50 meq m -2 yr to protect lake ANC to 50 eq L -1. About 600 Adirondack lakes receive ambient sulfur deposition that is above this TL, in some cases by more than a factor of 2. Some critical criteria threshold values were simulated to be unobtainable in some lakes even if sulfur deposition was to be decreased to zero and held at zero until the specified endpoint year. We also summarize important lessons for the use of target loads in the management of acid-impacted aquatic ecosystems, such as those in North America, Europe, and Asia. Copyright 2012 by the American Geophysical Union.

Water Resources Research↗
USGS2023

A watershed moment for western U.S. dams

The summer of 2023 is a notable time for water-resource management in the western United States: Glen Canyon Dam, on the Colorado River, turns 60 years old while the largest dam-removal project in history is beginning on the Klamath River. This commentary discusses these events in the context of a changing paradigm for dam and reservoir management in this region. Since the era of large dam building began to wane six decades ago, new challenges have arisen for dam and reservoir management owing to climate change, population increase, reservoir sedimentation, declining safety of aging dams, and more environmentally focused management objectives. Today we also better understand dams' benefits, costs, and environmental impacts, including some that were unforeseen and took decades to become apparent. Where dams have become unsafe, obsolete (e.g., due to excessive reservoir sedimentation), and uneconomical beyond saving, dam removal has become common. The science and practice of dam removal are accelerating rapidly, and some long-term physical and biological response studies are now available. Removal of four hydroelectric dams on the Klamath River will be a larger and more complex project than any previous dam removal. The imminency of this project reflects a very different situation for dam and reservoir management than 60 years ago. Looking forward, dam and reservoir management in the western United States and worldwide will require continued collaboration and innovative thinking to meet a wide range of objectives and to manage water resources sustainably for future generations.

Water Resources Research↗
USGS2019

Long-term annual aerial surveys of submersed aquatic vegetation (SAV) support science, management, and restoration

Aerial surveys of coastal habitats can uniquely inform the science and management of shallow, coastal zones, and when repeated annually, they reveal changes that are otherwise difficult to assess from ground-based surveys. This paper reviews the utility of a long-term (1984-present) annual aerial monitoring program for submersed aquatic vegetation (SAV) in Chesapeake Bay, its tidal tributaries, and nearby Atlantic coastal bays, USA. We present a series of applications that highlight the program’s importance in assessing anthropogenic impacts, gauging water quality status and trends, establishing and evaluating restoration goals, and understanding the impact of commercial fishing practices on benthic habitats. These examples demonstrate how periodically quantifying coverage of this important foundational habitat answers basic research questions locally as well as globally, and provides essential information to resource managers. New technologies are enabling more frequent and accurate aerial surveys at greater spatial resolution and lower cost. These advances will support efforts to extend the applications described here to similar issues in other areas

Chesapeake Bay↗
USGS2014

Assessment of dissolved-solids loading to the Colorado River in the Paradox Basin between the Dolores River and Gypsum Canyon, Utah

Salinity loads throughout the Colorado River Basin have been a concern over recent decades due to adverse impacts on population, natural resources, and regional economics. With substantial financial resources and various reclamation projects, the salt loading to Lake Powell and associated total dissolved-solids concentrations in the Lower Colorado River Basin have been substantially reduced. The Colorado River between its confluence with the Dolores River and Lake Powell traverses a physiographic area where saline sedimentary formations and evaporite deposits are prevalent. However, the dissolved-solids loading in this area is poorly understood due to the paucity of water-quality data. From 2003 to 2011, the U.S. Geological Survey in cooperation with the U.S. Bureau of Reclamation conducted four synoptic sampling events to quantify the salinity loading throughout the study reach and evaluate the occurrence and impacts of both natural and anthropogenic sources. The results from this study indicate that under late-summer base-flow conditions, dissolved-solids loading in the reach is negligible with the exception of the Green River, and that variations in calculated loads between synoptic sampling events are within measurement and analytical uncertainties. The Green River contributed approximately 22 percent of the Colorado River dissolved-solids load, based on samples collected at the lower end of the study reach. These conclusions are supported by water-quality analyses for chloride and bromide, and the results of analyses for the stable isotopes of oxygen and deuterium. Overall, no significant sources of dissolved-solids loading from tributaries or directly by groundwater discharge, with the exception of the Green River, were identified in the study area.

Utah↗