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At least 1,369 records · Page 76Linked to original sources

USGS1994

Selected nutrients in stormwater runoff from Davenport, Iowa, 1992

Flow-weighted composite samples of stormwater runoff from areas of different land use in Davenport, Iowa, were collected in the summer and fall of 1992 and analyzed for selected nutrients. Annual constituent loads were estimated for the area drained by the Davenport storm-sewer network. In all cases, the regression-equation estimate of mean annual load is less than the estimate obtained by using the method of the U.S. Environmental Protection Agency. The largest mean annual loads for total nitrite nitrogen, total nitrate nitrogen, total nitrite and nitrate nitrogen, total organic nitrogen, total ammonia and organic nitrogen, total nitrogen, and total phosphorus are associated with residential land, which covers 67.2 percent of the area drained. Using concentration data from this study, it is estimated that an average storm-producing runoff during the 7-day, 10-year low-flow discharge of the Mississippi River would contribute about 4 percent of the total ammonia and organic nitrogen load in the river. Precipitation-chemistry data indicate that substantial parts of the nitrate nitrogen and ammonia nitrogen contained in the stormwater runoff could be from precipitation.

Iowa↗

USGS2022

Multi-scale patterns in occurrence of an ephemeral pool-breeding amphibian

Species distributions are governed by processes occurring at multiple spatial scales. For species with complex life cycles, the needs of all life stages must be met within the dispersal limitations of the species. Multi-scale processes can be particularly important for these species, where small-scale patterns in specific habitat components can affect the distribution of one life stage, whereas large-scale patterns in land cover might better explain the distribution of other life stages. Using a conditional multi-scale model, we evaluated which aspects of the landscape and local environment are most strongly related to occupancy patterns of western spadefoots ( Spea hammondii ). In northern and central California, the proportion of grassland land cover within 2 km of a site was positively related to the occurrence of the northern clade of the western spadefoot. At the pond scale, we found that western spadefoots were more likely to breed in pools with lower pH. Our results indicate that protecting remaining grasslands for adult spadefoots and ensuring multiple pools with diverse characteristics and hydroperiods so at least some pools result in successful breeding will likely be necessary to conserve western spadefoots, especially with a changing climate. Considering the processes that affect species distributions at multiple life stages and spatial scales is an essential component of effective conservation.

California↗

USGS2022

Water-budget accounting for tropical regions model (WATRMod) documentation

Regional groundwater recharge commonly is estimated using a threshold-type water-budget approach in which groundwater recharge is assumed to occur when water in the plant-root zone exceeds the soil’s moisture storage capacity. A water budget of the plant-soil system accounts for water inputs (rainfall, fog interception, irrigation, septic-system leachate, and other inputs), water outputs (runoff, evaporation, transpiration, and recharge), and changes in stored water during a specified time interval. Water budgets can be computed on any desired interval, including annual, monthly, daily, and subdaily intervals. In general, uncertainty in recharge estimates is expected to be lower using daily or subdaily intervals relative to monthly and annual intervals. Average recharge rates computed over a period of a year or multiple years are commonly determined from water budgets computed using a daily computation interval capable of capturing rainfall and land-cover changes during the period. This report documents the Water-budget Accounting for Tropical Regions Model, or WATRMod, code that can be used to estimate spatially variable, daily water-budget components in tropical-island and other appropriate settings. The purpose of this report is to provide descriptions of WATRMod’s (1) approach to computing a daily water budget, (2) represented processes, (3) limitations, and (4) execution procedure, input requirements, output files, and example files. The model computes a daily water budget for each hydrologically independent subarea within the overall study area. A subarea is defined by its climatic, soil, land-cover, and human-related (for example, adding irrigation or other water) characteristics. The water-budget model can represent processes including rainfall, fog interception, irrigation, septic-system leachate, direct recharge that bypasses the plant-soil system, runoff, canopy evaporation in forested areas, evapotranspiration, and groundwater recharge. The water-budget model can represent either one of the following different accounting orders: (1) accounting for loss of water by evapotranspiration before accounting for recharge, and (2) accounting for recharge before accounting for evapotranspiration. WATRMod’s limitations include: (1) uncharacterized, subdaily transient changes in water inputs and outputs from the plant-soil system, (2) unrepresented precipitation in the form of snow and sublimation, and (3) routing runoff from one subarea to an adjacent subarea that is not directly represented.

Hawaii↗

USGS2024

Novel approach for ranking DEMs: Copernicus DEM improves one arc second open global topography

We present a practical approach to intercompare a range of candidate digital elevation models (DEMs) based on predefined criteria and a statistically sound ranking approach. The presented approach integrates the randomized complete block design (RCBD) into a novel framework for DEM comparison. The method presented provides a flexible, statistically sound, and customizable tool for evaluating the quality of any raster—in this case, a DEM—by means of a ranking approach, which takes into account a confidence level and can use both quantitative and qualitative criteria. The users can design their own criteria for the quality evaluation in relation to their specific needs. The application of the RCBD method to rank six 1′′ global DEMs, considering a wide set of study sites, covering different morphological and land cover settings, highlights the potentialities of the approach. We used a suite of criteria relating to the differences in the elevation, slope, and roughness distributions compared to reference DEMs aggregated from 1- to 5-m light detection and ranging (LiDAR)-derived DEMs. Results confirmed the significant superiority of Copernicus DEM (CopDEM) 1′′ and its derivative forests and buildings removed DEM (FABDEM) as the overall best 1′′ global DEMs. They are slightly better than Advanced Land Observing Satellite (ALOS) and clearly outperform NASADEM and SRTM, which are, in turn, much better than advanced spaceborne thermal emission and reflection radiometer (ASTER).

IEEE Transactions on Geoscience and Remote Sensing↗

USGS2022

Fifty years of Landsat science and impacts

Since 1972, the Landsat program has been continually monitoring the Earth, to now provide 50 years of digital, multispectral, medium spatial resolution observations. Over this time, Landsat data were crucial for many scientific and technical advances. Prior to the Landsat program, detailed, synoptic depictions of the Earth's surface were rare, and the ability to acquire and work with large datasets was limited. The early years of the Landsat program delivered a series of technological breakthroughs, pioneering new methods, and demonstrating the ability and capacity of digital satellite imagery, creating a template for other global Earth observation missions and programs. Innovations driven by the Landsat program have paved the way for subsequent science, application, and policy support activities. The economic and scientific value of the knowledge gained through the Landsat program has been long recognized, and despite periods of funding uncertainty, has resulted in the program's 50 years of continuity, as well as substantive and ongoing improvements to payload and mission performance. Free and open access to Landsat data, enacted in 2008, was unprecedented for medium spatial resolution Earth observation data and substantially increased usage and led to a proliferation of science and application opportunities. Here, we highlight key developments over the past 50 years of the Landsat program that have influenced and changed our scientific understanding of the Earth system. Major scientific and programmatic impacts have been realized in the areas of agricultural crop mapping and water use, climate change drivers and impacts, ecosystems and land cover monitoring, and mapping the changing human footprint. The introduction of Landsat collection processing, coupled with the free and open data policy, facilitated a transition in Landsat data usage away from single images and towards time series analyses over large areas and has fostered the widespread use of science-grade data. The launch of Landsat-9 on September 27, 2021, and the advanced planning of its successor mission, Landsat-Next, underscore the sustained institutional support for the program. Such support and commitment to continuity is recognition of both the historic impact the program, and the future potential to build upon Landsat's remarkable 50-year legacy.

Remote Sensing of Environment↗

USGS2019

Factors influencing anuran wetland occupancy in an agricultural landscape

Habitat disturbance is an important cause of global amphibian declines, with especially strong effects in areas of high agricultural use. Determining the influence of site characteristics on amphibian presence and success is vital to developing effective conservation strategies. We used occupancy analysis to estimate presence of four anuran species at wetlands in northern Iowa as a function of eight environmental covariates hypothesized to affect occupancy: fish and salamander abundance, invertebrate density, aquatic vegetative cover, wetland area, atrazine concentration in water, surrounding agricultural land use, and an overall wetland health score (wetland condition index [WCI]). We surveyed 27 wetlands multiple times in 2015 and 2016. Leopard Frogs ( Lithobates pipiens ) and American Toads ( Anaxyrus americanus ) were observed at 100% of the sites, Boreal Chorus Frogs ( Pseudacris maculata ) at 96%, and Gray Treefrogs ( Hyla spp.) at 81%. Wetland site occupancy for all species in our study ranged from 0.23 ( Hyla spp. tadpoles) to 0.95 ( L. pipiens adults), indicating that agricultural wetlands can provide refuge or habitat for amphibians. Fish abundance, percentage of cropland cover within 500 m of the wetland, and salamander abundance were among the variables best supported by our models although their estimated effects were weak. Wetland area, atrazine concentration, vegetative cover, and WCI also influenced occupancy probability, but for only a small number of species and life stages. The direction of predicted effects varied by species and life stage. Despite only weak evidence that the environmental factors we measured influenced anuran occupancy, our results provide insights for managers seeking to understand how amphibians use landscapes modified by agriculture.

Iowa↗

USGS2021

Evaluating the impact of watershed development and climate change on stream ecosystems: A Bayesian network modeling approach

A continuous-variable Bayesian network (cBN) model is used to link watershed development and climate change to stream ecosystem indicators. A graphical model, reflecting our understanding of the connections between climate change, weather condition, loss of natural land cover, stream flow characteristics , and stream ecosystem indicators is used as the basis for selecting flow metrics for predicting macroinvertebrate-based indicators. Selected flow metrics were then linked to variables representing watershed development and climate change. We fit the model to data from two river basins in southeast US and the resulting model was used to simulate future stream ecological conditions using projected future climate and development scenarios. The three climate models predicted varying ecological condition trajectories, but similar worst-case ecological conditions. The established modeling approach couples mechanistic understanding with field data to develop predictions of management-relevant variables across a heterogeneous landscape. We discussed the transferability of the modeling approach.

North Carolina, South Carolina, Virginia↗

USGS2003

Global forest cover mapping for the United Nations Food and Agriculture Organization forest resources assessment 2000 program

Many countries periodically produce national reports on the status and changes of forest resources, using statistical surveys and spatial mapping of remotely sensed data. At the global level, the Food and Agriculture Organization (FAO) of the United Nations has conducted a Forest Resources Assessment (FRA) program every 10 yr since 1980, producing statistics and analysis that give a global synopsis of forest resources in the world. For the year 2000 of the FRA program (FRA2000), a global forest cover map was produced to provide spatial context to the extensive survey. The forest cover map, produced at the U.S. Geological Survey (USGS) EROS Data Center (EDC), has five classes: closed forest, open or fragmented forest, other wooded land, other land cover, and water. The first two forested classes at the global scale were delineated using combinations of temporal compositing, modified mixture analysis, geographic stratification, and other classification techniques. The remaining three FAO classes were derived primarily from the USGS global land cover characteristics database (Loveland et al. 1999). Validated on the basis of existing reference data sets, the map is estimated to be 77% accurate for the first four classes (no reference data were available for water), and 86% accurate for the forest and nonforest classification. The final map will be published as an insert to the FAO FRA2000 report.

Forest Science↗

USGS2004

An automated approach to mapping corn from Landsat imagery

Most land cover maps generated from Landsat imagery involve classification of a wide variety of land cover types, whereas some studies may only need spatial information on a single cover type. For example, we required a map of corn in order to estimate exposure to agricultural chemicals for an environmental epidemiology study. Traditional classification techniques, which require the collection and processing of costly ground reference data, were not feasible for our application because of the large number of images to be analyzed. We present a new method that has the potential to automate the classification of corn from Landsat satellite imagery, resulting in a more timely product for applications covering large geographical regions. Our approach uses readily available agricultural areal estimates to enable automation of the classification process resulting in a map identifying land cover as ‘highly likely corn,’ ‘likely corn’ or ‘unlikely corn.’ To demonstrate the feasibility of this approach, we produced a map consisting of the three corn likelihood classes using a Landsat image in south central Nebraska. Overall classification accuracy of the map was 92.2% when compared to ground reference data.

Computers and Electronics in Agriculture↗

USGS1995

Land use, organochlorine compound concentrations, and trends in benthic-invertebrate communities in selected stream basins in Chester County, Pennsylvania

Land use was analyzed for the drainage areas of 26 stream sites in Chester County, Pa., that cover a total area of 227 square miles or about 30 percent of the country. The most significant land-use changes during 1967-87 were decreased agricultural land use, increased residential land use, and increased commercial and industrial land use. Bulk samples of stream-bottom materials were collected at 42 sites in the study area from October 1985 through November 1987 and analyzed for content of organochlorine pesticides and polychlorinated biphenyls (PCB's). Organochlorine compounds and (or) PCB's were detected in streambed materials collected at 40 of the 42 sites sampled. The most enriched compounds (greater than 15 micrograms per kilogram) were PCB's, chlordane, and DDT plus its breakdown products. Data suggest that chlordane residues are closely associated with residential land use. PCB residues are closely associated with industrial and commercial land use. Cores of labeled sediments from the site of Icedale Lake, a drained reservoir on the West Branch Brandywine Creek, indicate that DDT was the first organochlorine pesticide to enter the Brandywine Creek; concentrations peaked in the late 1940's and early 1950's. As DDT influx subsequently decreased, influxes of chlordane and dieldrin increased and peaked in the mind-1960's, before the Chester County biological monitoring program. Influx of all pesticides appears to have decreased significantly since the 1960's. Contingency analyses showed that the relation between the Kendall slope estimator for trend and the increases in residential land use of 12 percent or greater were significant at the 95-percent confidence level. The contingency tables also showed that the relation between diversity indices of less than 2.25 and organochlorine-compound concentrations greater than 45 micrograms per kilogram was significant at the 95-percent confidence level.

Water-Resources Investigations Report↗

USGS2026

Amphibian use of recently created wetlands in the Palouse region of northern Idaho, USA

Human development has resulted in the loss of natural wetlands in many regions and thus has led to amphibian habitat loss. Human-constructed wetlands are increasingly prevalent, particularly in human-modified landscapes, and can be used as breeding habitats by amphibians. It is important to identify factors influencing amphibian use of constructed wetlands to guide future wetland creation efforts. We examined wetland- and landscape-level factors influencing the presence and reproduction of native amphibians in 33 recently created (2–11 yold) wetlands within an urban-agricultural interface in northern Idaho, USA. We recorded wetland age, perimeter vegetation, and percentage of surrounding land cover as covariates and modeled detection and occupancy using Bayesian Multi-scale Occupancy Models for the three species we detected: Sierran Treefrog ( Pseudacris sierra ), Colombia Spotted Frog ( Rana luteiventris ), and Long-Toed Salamander ( Ambystoma macrodactylum ). Our results indicate that these three species can rapidly colonize recently created wetlands in an urban-agricultural interface. The effects of wetland- and landscape-scale features varied across species. Colombia Spotted Frog occupancy was greatest in older wetlands with some evidence for a negative association with more urbanized landscapes. Long Toed Salamanders and Sierran Treefrogs were not associated with wetland age but also showed some evidence of negative associations with urbanization. Long-Toed Salamanders showed evidence of using less vegetated wetlands while Sierran Treefrogs showed evidence of using more vegetated wetlands. Our results are consistent with multiple studies showing that wetlands in human-modified landscapes can provide amphibian breeding habitat, and they suggest that including vegetation plantings within recently created wetlands may promote amphibian colonization. Anecdotal observations also indicate that designing wetlands with sufficient hydroperiod for metamorphoses may be important for ensuring that newly created wetlands benefit amphibian populations.

Idaho↗

USGS2010

Status and trends of selected resources in the Upper Mississippi River System

Like other large rivers, the Upper Mississippi River System (UMRS) serves a diversity of roles. The UMRS provides commercial and recreational fishing, floodplain agriculture, drinking water for many communities, an important bird migration pathway, a variety of recreational activities, and a navigation system that transports much of the country's agricultural exports. These multiple roles present significant management challenges. Regular assessment of the condition of the river is needed to improve management plans and evaluate their effectiveness. This report provides a summary of the recent status (mean and range of conditions) and trends (change in direction over time) for 24 indicators of the ecological condition of the Upper Mississippi and Illinois Rivers using data collected through the Long Term Resource Monitoring Program (LTRMP). The 24 indicators were grouped into seven categories: hydrology, sedimentation, water quality, land cover, aquatic vegetation, invertebrates, and fish. Most of the data used in the report were collected between about 1993 and 2004, although some older data were also used to compare to recent conditions.Historical observations and current LTRMP data clearly indicate that the UMRS has been changed by human activity in ways that have diminished the ecological health of the river. The data indicate that status and trends differ among regions, and we expect that regional responses to various ecological rehabilitation techniques will differ as well. The continuing role of the LTRMP will be to provide the data needed to assess changes in river conditions and to determine how those changes relate to management actions, natural variation, and the overall ecological integrity of the river system.

Long Term Resource Monitoring Program Technical Re↗

USGS2020

Linking monitoring and data analysis to predictions and decisions for the range-wide eastern black rail status assessment

The US Fish and Wildlife Service has initiated a re-envisioned approach for providing decision makers with the best available science and synthesis of that information, called the Species Status Assessment (SSA), for endangered species decision making. The SSA report is a descriptive document that provides decision makers with an assessment of a species’ current status and predicted future status. These analyses support all manner of decisions under the US Endangered Species Act, such as listing, reclassification, recovery planning, etc. Novel scientific analysis and predictive modeling in SSAs could be an important part of rooting species conservation decisions in current data and cutting edge analytical and modeling techniques. Here we describe a novel analysis of available data to assess current condition of eastern black rail across its range in a dynamic occupancy analysis. We used the results of the analysis to develop a site occupancy projection model where the model parameters (initial occupancy, site persistence, colonization) were linked to environmental covariates, such as land management and land cover change (sea-level rise, development, etc.). We used the projection model to predict future conditions under multiple sea-level rise and habitat management scenarios. Occupancy probability and site colonization were low in all analysis units and site persistence was also low, suggesting low resiliency and redundancy currently. Extinction probability was high for all analysis units in all simulated scenarios except one with significant effort to preserve existing habitat, suggesting low future resiliency and redundancy. With results of these data analyses and predictive modeling, the US Fish and Wildlife Service concluded that protections of the Endangered Species Act were warranted for this subspecies.

Endangered Species Research↗

USGS2019

Spatial patterns of meadow sensitivities to interannual climate variability in the Sierra Nevada

Conservation of montane meadows is a high priority for land and water managers given their critical role in buffering the effects of climate variability and their vulnerability to increasing temperatures and evaporative demands. Recent advances in cloud computing have provided new opportunities to examine ecological responses to climate variability over the past few decades, and at large spatial scales. In this study we characterized the sensitivities (magnitude and direction of the slope) of meadow vegetation responses to interannual variations in climate. We calculated sensitivity as the regression slope between a 35-year (1985-2016) time series of Landsat-derived vegetation indices characterizing late-season vegetation vigor and water balance variables from the Basin Characterization Model. We identified April 1 snowpack as the climate variable the majority of meadows were most sensitive to. We assessed how vegetation sensitivities to snowpack varied with hydrogeomorphic context (e.g., climate, geology, soils, watershed geometry and land cover) across the Sierra Nevada mountain range using factor analysis to reduce the dimensionality of the hydrogeomorphic data, and multiple linear regression to model sensitivity responses. We found that meadow sensitivities to snowpack varied with long-term average meadow climate, indicators of watershed subsurface water storage capacity, and indicators of meadow vegetation composition. Alpine and sub-alpine meadows with high average annual precipitation, but limited catchment subsurface storage exhibited the largest sensitivities. Our results provide a novel regional perspective on spatial patterns of meadow sensitivities to climate variability and the landscape-scale hydrogeomorphic factors that influence late-season water availability in meadow ecosystems in the Sierra Nevada.

Sierra Nevada↗

USGS2024

Key breeding habitats of threatened golden eagles across Eastern Canada identified using a multi-level, multi-scale habitat selection approach

Context In a conservation context, identifying key habitats suitable for reproduction, foraging, or survival is a useful tool, yet challenging for species with large geographic distributions and/or living in remote regions. Objectives The objective of this study is to identify selected habitats at multiple levels and scales of the threatened eastern North American population of golden eagles ( Aquila chrysaetos ). We studied habitat selection at three levels: landscape (second order of selection), foraging (third order of selection), and nesting (fourth order of selection). Methods Using tracking data from 30 adults and 366 nest coordinates spanning over a 1.5 million km 2 area in remote boreal and Arctic regions, we modelled the three levels of habitat selection with resource selection functions using seven environmental features (aerial, topographical, and land cover). We then calculated the relative probability of selection in the study area to identify regions with higher probabilities of selection. Results Eagles selected more for terrain ruggedness index and relative elevation than land cover (i.e., forest cover, distance to water; mean difference in relative selection strength: 1.2 [0.71; 1.69], 95% CI) at all three levels. We also found that the relative probability of selection at all three levels was ~ 25% higher in the Arctic than in the boreal regions. Eagles breeding in the Arctic travelled shorter foraging distances with greater access to habitat with a high probability of selection than boreal eagles. Conclusion Here we found which aerial and topographical features were important for several of the eagles’ life cycle needs. We also identified important areas to monitor and preserve this threatened population. The next step is to quantify the quality of habitat by linking our multi-level, multi-scale approach to population demography and performance such as reproductive success.

Landscape Ecology↗

USGS2016

Fire in the Earth System: Bridging data and modeling research

Significant changes in wildfire occurrence, extent, and severity in areas such as western North America and Indonesia in 2015 have made the issue of fire increasingly salient in both the public and scientific spheres. Biomass combustion rapidly transforms land cover, smoke pours into the atmosphere, radiative heat from fires initiates dramatic pyrocumulus clouds, and the repeated ecological and atmospheric effects of fire can even impact regional and global climate. Furthermore, fires have a significant impact on human health, livelihoods, and social and economic systems. Modeling and databased methods to understand fire have rapidly coevolved over the past decade. Satellite and ground-based data about present-day fire are widely available for applications in research and fire management. Fire modeling has developed in part because of the evolution in vegetation and Earth system modeling efforts, but parameterizations and validation are largely focused on the present day because of the availability of satellite data. Charcoal deposits in sediment cores have emerged as a powerful method to evaluate trends in biomass burning extending back to the Last Glacial Maximum and beyond, and these records provide a context for present-day fire. The Global Charcoal Database version 3 compiled about 700 charcoal records and more than 1,000 records are expected for the future version 4. Together, these advances offer a pathway to explore how the strengths of fire data and fire modeling could address the weaknesses in the overall understanding of human-climate–fire linkages. A community of researchers studying fire in the Earth system with individual expertise that included paleoecology, paleoclimatology, modern ecology, archaeology, climate, and Earth system modeling, statistics, geography, biogeochemistry, and atmospheric science met at an intensive workshop in Massachusetts to explore new research directions and initiate new collaborations. Research themes, which emerged from the workshop participants via preworkshop surveys, focused on addressing the following questions: What are the climatic, ecological, and human drivers of fire regimes, both past and future? What is the role of humans in shaping historical fire regimes? How does fire ecology affect land cover changes, biodiversity, carbon storage, and human land uses? What are the historical fire trends and their impacts across biomes? Are their impacts local and/or regional? Are the fire trends in the last two decades unprecedented from a historical perspective? The workshop 1 aimed to develop testable hypotheses about fire, climate, vegetation, and human interactions by leveraging the confluence of proxy, observational, and model data related to decadal- to millennial-scale fire activity on our planet. New research directions focused on broad interdisciplinary approaches to highlight how knowledge about past fire activity could provide a more complete understanding of the predictive capacity of fire models and inform fire policy in the face of our changing climate.

Bulletin of the American Meteorological Society↗

USGS1981

Assessment of impacts of proposed coal-resource and related economic development on water resources, Yampa River basin, Colorado and Wyoming: A summary

Expanded mining and use of coal resources in the Rocky Mountain region of the western United States will have substantial impacts on water resources, environmental amenities, and social and economic conditions. The U.S. Geological Survey has completed a 3-year assessment of the Yampa River basin, Colorado and Wyoming, where increased coal-resource development has begun to affect the environment and quality of life. Economic projections of the overall effects of coal-resource development were used to estimate water use and the types and amounts of waste residuals that need to be assimilated into the environment. Based in part upon these projections, several physical-based models and other semiquantitative assessment methods were used to determine possible effects upon the basin's water resources. Depending on the magnitude of mining and use of coal resources in the basin, an estimated 0.7 to 2.7 million tons (0.6 to 2.4 million metric tons) of waste residuals may be discharged annually into the environment by coal-resource development and associated economic activities. If the assumed development of coal resources in the basin occurs, annual consumptive use of water, which was approximately 142,000 acre-feet (175 million cubic meters) during 1975, may almost double by 1990. In a related analysis of alternative cooling systems for coal-conversion facilities, four to five times as much water may be used consumptively in a wet-tower, cooling-pond recycling system as in once-through cooling. An equivalent amount of coal transported by slurry pipeline would require about one-third the water used consumptively by once-through cooling for in-basin conversion. Current conditions and a variety of possible changes in the water resources of the basin resulting from coal-resource development were assessed. Basin population may increase by as much as threefold between 1975 and 1990. Volumes of wastes requiring treatment will increase accordingly. Potential problems associated with ammonia-nitrogen concentrations in the Yampa River downstream from Steamboat Springs were evaluated using a waste-load assimilative-capacity model. Changes in sediment loads carried by streams due to increased coal mining and construction of roads and buildings may be apparent only locally; projected increases in sediment loads relative to historic loads from the basin are estimated to be 2 to 7 percent. Solid-waste residuals generated by coal-conversion processes and disposed of into old mine pits may cause widely dispersed ground-water contamination, based on simulation-modeling results. Projected increases in year-round water use will probably result in the construction of several proposed reservoirs. Current seasonal patterns of streamflow and of dissolvedsolids concentrations in streamflow will be altered appreciably by these reservoirs. Decreases in time-weighted mean-annual dissolved-solids concentrations of as much as 34 percent are anticipated, based upon model simulations of several configurations of proposed reservoirs. Detailed statistical analyses of water-quality conditions in the Yampa River basin were made. Regionalized maximum waterquality concentrations were estimated for possible comparison with future conditions. Using Landsat imagery and aerial photographs, potential remote-sensing applications were evaluated to monitor land-use changes and to assess both snow cover and turbidity levels in streams. The technical information provided by the several studies of the Yampa River basin assessment should be useful to regional planners and resource managers in evaluating the possible impacts of development on the basin's water resources.

Colorado, Wyoming↗

USGS2012

Geospatial datasets for watershed delineation and characterization used in the Hawaii StreamStats web application

The U.S. Geological Survey Hawaii StreamStats application uses an integrated suite of raster and vector geospatial datasets to delineate and characterize watersheds. The geospatial datasets used to delineate and characterize watersheds on the StreamStats website, and the methods used to develop the datasets are described in this report. The datasets for Hawaii were derived primarily from 10 meter resolution National Elevation Dataset (NED) elevation models, and the National Hydrography Dataset (NHD), using a set of procedures designed to enforce the drainage pattern from the NHD into the NED, resulting in an integrated suite of elevation-derived datasets. Additional sources of data used for computing basin characteristics include precipitation, land cover, soil permeability, and elevation-derivative datasets. The report also includes links for metadata and downloads of the geospatial datasets.

Hawai'i↗