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At least 361 records · Page 20Linked to original sources

Flood-inundation maps for the South Platte River at Fort Morgan, Colorado, 2018

In 2017, the U.S. Geological Survey (USGS), in cooperation with the Colorado Water Conservation Board (CWCB), studied floods in the historic record to produce a library of flood-inundation maps for the South Platte River at Fort Morgan, Colorado. Digital flood-inundation maps for a 4.5-mile (7.2-kilometers) reach of the South Platte River at Fort Morgan from Morgan County Road 16 to Morgan County Road 20.5, were created. The flood-inundation maps depict estimates of the areal extent and depth of flooding corresponding to selected water levels (stages) at the U.S. Geological Survey streamgage on the South Platte River at Fort Morgan (streamgage number 06759500). Water-surface profiles were computed for the stream reach by means of a one-dimensional, step-backwater model. The September 15, 2013, and May 20, 2017, floods were used to calibrate the model, and the June 15, 2015, and May 29, 2017, floods were used to independently validate the model. Nine pressure transducers were deployed to record the stage at nine different locations along the reach and to document the floods of May 20 and 29, 2017, at the South Platte River at Fort Morgan streamgage. The hydraulic model was then used to compute 16 water-surface profiles for flood stages at 1-foot (ft; 0.3-meter [m]) intervals referenced to the streamgage datum and ranging from 12 ft (3.66 m) or below bankfull to 27 ft (8.23 m), which is 1 ft (0.3 m) greater than the highest recorded water level (25.73 ft [7.84 m] on September 15, 2013) at the South Platte River at Fort Morgan streamgage during its period of record; the 2013 flood exceeds the major flood stage of 21.5 ft (6.55 m) by more than 4 ft (1.2 m), as defined by the National Weather Service. The simulated water-surface profiles were then combined with a geographic information system digital elevation model (derived from light detection and ranging data having a 0.37-ft [0.11-m] vertical accuracy and 3.28-ft [1.00-m] horizontal resolution) to delineate the area flooded for stages ranging from 12 to 27 ft (3.66 to 8.23 m). These flood-inundation maps, in conjunction with the real-time stage data from the USGS streamgage on the South Platte River at Fort Morgan, are intended to help guide the general public in taking individual safety precautions and provide emergency management personnel with a tool to efficiently manage emergency flood operations and post flood recovery efforts.

Colorado↗

Relation of physical and chemical characteristics of streams to fish communities in the Red River of the North basin, Minnesota and North Dakota, 1993-95

Fish community composition was determined at 33 reaches (average length 150 meters) at 22 sites in the Red River of the North Basin during 1994. Sites were selected to represent a range of stream sizes and ecoregions within the basin. Physical and chemical characteristics (classified in data sets of instream habitat, terrestrial habitat, hydrology, and water quality) were determined for various sites for periods ranging from two to 48 years. Instream habitat measurements were made from 1993 through 1995 for 31 reaches at 19 sites. Terrestrial habitat measures of land use/land cover, soils, and riparian zones were determined from a geographical information system coverage for 23 reaches at 14 sites. The geographical information system coverage used data from aerial photographs taken from 1990 and 1991, National Wetlands Inventory data, soils maps from the Natural Resource Conservation Service, and data from the U.S. Department of Agriculture soils data base. Water chemistry data were collected from 14 sites in the basin from 1993 through 1994. Hydrologic variability was determined from U.S. Geological Survey gaging records. Correlation analysis, cluster analysis, and principal components analysis were used to determine representative variables which accounted for the most variation in each data set. The representative variables and the fish community data were analyzed with canonical correspondence analysis to determine the relative effect of each source of environmental influence on fish community composition. Instream habitat, terrestrial habitat, and hydrologic variability were analyzed together. Water chemistry data were analyzed separately due to a lack of corresponding sites. Within the instream habitat data set, measures of habitat volume (channel width and depth) and habitat diversity were most significant in explaining the variability of the fish communities. The amount of nonagricultural land and riparian zone integrity from the terrestrial habitat data set were also useful in explaining fish community composition. Variability of mean monthly discharge and the frequency of high and low discharge events during the three years prior to fish sampling were the most influential of the hydrologic variables.The first two axes of the canonical correspondence analysis accounted for 43.3 percent of the variation in the fish community and 52.5 percent of the variation in the environmental-species relation. Water-quality indicators such as the percent of fine material in suspended sediment, minimum dissolved oxygen concentrations, minimum concentrations of dissolved organic carbon, and the range of concentrations of major ions and nutrients were the variables that were most important in the canonical correspondence analysis of water-quality data with fish. No single environmental variable or data set appeared to be more important than another in explaining variation in the fish community. The environmental factors affecting the fish communities of the Red River of the North are interrelated. For the most part, instream environmental conditions (instream habitat, hydrology, and water chemistry) appear to be more important in explaining variability in fish community composition than factors related to the agricultural nature of the basin.

Minnesota, North Dakota, South Dakota↗

Overview of the land analysis system (LAS)

The Land Analysis System (LAS) is a fully integrated digital analysis system designed to support remote sensing, image processing, and geographic information systems research. LAS is being developed through a cooperative effort between the National Aeronautics and Space Administration Goddard Space Flight Center and the U. S. Geological Survey Earth Resources Observation Systems (EROS) Data Center. LAS has over 275 analysis modules capable to performing input and output, radiometric correction, geometric registration, signal processing, logical operations, data transformation, classification, spatial analysis, nominal filtering, conversion between raster and vector data types, and display manipulation of image and ancillary data. LAS is currently implant using the Transportable Applications Executive (TAE). While TAE was designed primarily to be transportable, it still provides the necessary components for a standard user interface, terminal handling, input and output services, display management, and intersystem communications. With TAE the analyst uses the same interface to the processing modules regardless of the host computer or operating system. LAS was originally implemented at EROS on a Digital Equipment Corporation computer system under the Virtual Memorial System operating system with DeAnza displays and is presently being converted to run on a Gould Power Node and Sun workstation under the Berkeley System Distribution UNIX operating system.

Conference Paper↗

Development of a seamless multisource topographic/bathymetric elevation model of Tampa Bay

Many applications of geospatial data in coastal environments require knowledge of the nearshore topography and bathymetry. However, because existing topographic and bathymetric data have been collected independently for different purposes, it has been difficult to use them together at the land/water interface owing to differences in format, projection, resolution, accuracy, and datums. As a first step toward solving the problems of integrating diverse coastal datasets, the U.S. Geological Survey (USGS) and the National Oceanic and Atmospheric Administration (NOAA) are collaborating on a joint demonstration project to merge their data for the Tampa Bay region of Florida. The best available topographic and bathymetric data were extracted from the USGS National Elevation Dataset and the NOAA hydrographic survey database, respectively. Before being merged, the topographic and bathymetric datasets were processed with standard geographic information system tools to place them in a common horizontal reference frame. Also, a key part of the preprocessing was transformation to a common vertical reference through the use of VDatum, a new tool created by NOAA's National Geodetic Survey for vertical datum conversions. The final merged product is a seamless topographic/bathymetric model covering the Tampa Bay region at a grid spacing of 1 arc-second. Topographic LIDAR data were processed and merged with the bathymetry to demonstrate the incorporation of recent third party data sources for several test areas. A primary application of a merged topographic/bathymetric elevation model is for user-defined shoreline delineation, in which the user decides on the tidal condition (for example, low or high water) to be superimposed on the elevation data to determine the spatial position of the water line. Such a use of merged topographic/bathymetric data could lead to the development of a shoreline zone, which could reduce redundant mapping efforts by federal, state, and local agencies by allowing them to customize their portrayals of the shoreline using a standard baseline elevation dataset.

Marine Technology Society Journal↗

Streamflow of 2006 -- Water Year Summary

The maps and graphs appearing in this summary describe streamflow conditions for water-year 2006 (October 1, 2005 to September 30, 2006) in the context of the 77-year period 1930-2006, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey's (USGS) National Streamflow Information Program. The period 1930-2006 was used because prior to 1930, the number of streamgages was too small to provide representative data for computing statistics for most regions of the country. In the summary, reference is made to the term 'runoff,' which is the depth to which a river basin, State, or other geographic area would be covered with water if all the streamflow within the area during a single year was uniformly distributed upon it. Runoff quantifies the magnitude of water flowing through the Nation's rivers and streams in measurement units that can be compared from one area to another. The runoff value for a geographic area is computed as the median runoff value for all streamgages in that geographic area. For example, the runoff value for a state is the median for all streamgages in that state, and the median for the Nation is the median value for all streamgages in the Nation. Each of the maps and graphs below can be expanded to a larger view by clicking on the image. In all the graphics, a rank of 1 indicates the highest flow of all years analyzed.

Fact Sheet↗

Streamflow of 2007--Water year summary

The maps and graphs appearing in this summary describe streamflow conditions for water-year 2007 (October 1, 2006 to September 30, 2007) in the context of the 78-year period 1930-2007, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey's (USGS) National Streamflow Information Program. The period 1930-2007 was used because prior to 1930, the number of streamgages was too small to provide representative data for computing statistics for most regions of the country. In the summary, reference is made to the term "runoff," which is the depth to which a river basin, State, or other geographic area would be covered with water if all the streamflow within the area during a single year was uniformly distributed upon it. Runoff quantifies the magnitude of water flowing through the Nation's rivers and streams in measurement units that can be compared from one area to another. The runoff value for a geographic area is computed as the median runoff value for all streamgages in that geographic area. For example, the runoff value for a State is the median for all streamgages in that State, and the median for the Nation is the median value for all streamgages in the Nation. Each of the maps and graphs below can be expanded to a larger view by clicking on the image. In all the graphics, a rank of 1 indicates the highest flow of all years analyzed.

Fact Sheet↗

Streamflow of 2008--Water year summary

The maps and graphs appearing in this summary describe streamflow conditions for water-year 2008 (October 1, 2007 to September 30, 2008) in the context of the 79-year period 1930-2008, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey's (USGS) National Streamflow Information Program. The period 1930-2008 was used because prior to 1930, the number of streamgages was too small to provide representative data for computing statistics for most regions of the country. In the summary, reference is made to the term "runoff," which is the depth to which a river basin, State, or other geographic area would be covered with water if all the streamflow within the area during a single year was uniformly distributed upon it. Runoff quantifies the magnitude of water flowing through the Nation's rivers and streams in measurement units that can be compared from one area to another. The runoff value for a geographic area is computed as the median runoff value for all streamgages in that geographic area. For example, the runoff value for a State is the median for all streamgages in that State, and the median for the Nation is the median value for all streamgages in the Nation. Each of the maps and graphs below can be expanded to a larger view by clicking on the image. In all the graphics, a rank of 1 indicates the highest flow of all years analyzed.

Fact Sheet↗

Multi-regional synthesis of temporal trends in biotic assemblages in streams and rivers of the continental United States

Biotic assemblages in aquatic ecosystems are excellent integrators and indicators of changing environmental conditions within a watershed. Therefore, temporal changes in abiotic environmental variables often can be inferred from temporal changes in biotic assemblages. Algae, macroinvertebrate, and fish assemblage data were collected from 91 sampling sites in 4 geographic regions (northeastern/north-central, southeastern, south-central, and western), collectively encompassing the continental United States, from 1993 to 2009 as part of the U.S. Geological Survey National Water-Quality Assessment Program. This report uses a multivariate approach to synthesize temporal trends in biotic assemblages and correlations with relevant abiotic parameters as a function of biotic assemblage, geographic region, and land use. Of the three groups of biota, algal assemblages had temporal trends at the greatest percentage of sites. Of the regions, a greater percentage of sites in the northeastern/north-central and western regions had temporal trends in biotic assemblages. In terms of land use, a greater percentage of watersheds draining agricultural, urban, and undeveloped areas had significant temporal changes in biota, as compared to watersheds with mixed use. Correlations between biotic assemblages and abiotic variables indicate that, in general, macroinvertebrate assemblages correlated with water quality and fish assemblages correlated with physical habitat. Taken together, results indicate that there are regional differences in how individual biotic assemblages (algae, macroinvertebrates, and fish) respond to different abiotic drivers of change.

Continental United States↗

Relations between introduced fish and environmental conditions at large geographic scales

Data collected from 20 major river basins between 1993 and 1995 as part of the US Geological Survey's (USGS) National Water-Quality Assessment (NAWQA) Program were analyzed to assess patterns in introduced and native fish species richness and abundance relative to watershed characteristics and stream physicochemistry. Sites (N = 157) were divided into three regions-northeast, southeast, and west- to account for major longitudinal differences in precipitation/runoff and latitudinal limits of glaciation that affect zoogeographic patterns in fish communities. Common carp (Cyprinus carpio) and largemouth bass (Micropterus salmoides) were the most frequently collected introduced fish species across all river basins combined. Based on the percentage of introduced fish species, the fish communities most altered by the presence of introduced fish occurred in the western and northeastern parts of the US. Native fish species richness was not an indicator of introduced fish species richness for any of the three regions. However, in the west, introduced fish species richness was an indicator of total fish species richness and the abundance of introduced fish was negatively related to native fish species richness. Some relations between introduced fish species and environmental conditions were common between regions. Increased introduced fish species richness was related to increased population density in the northeast and southeast; increased total nitrogen in the northeast and west; and increased total phosphorous and water temperature in the southeast and west. These results suggest that introduced fish species tend to be associated with disturbance at large geographic scales, though specific relations may vary regionally. ?? 2003 Elsevier Science Ltd. All rights reserved.

Ecological Indicators↗

Land-cover change in the central irregular plains, 1973-2000

Spearheaded by the Geographic Analysis and Monitoring Program of the U.S. Geological Survey (USGS) in collaboration with the U.S. Environmental Protection Agency (EPA) and the National Aeronautics and Space Administration (NASA), the Land Cover Trends is a research project focused on understanding the rates, trends, causes, and consequences of contemporary United States land-use and land-cover change. Using the EPA Level III ecoregions as the geographic framework, scientists process geospatial data collected between 1973 and 2000 to characterize ecosystem responses to land-use changes. The 27-year study period was divided into five temporal periods: 1973-1980, 1980-1986, 1986-1992, 1992-2000 and 1973-2000. General land-cover classes for these periods were interpreted from Landsat Multispectral Scanner, Thematic Mapper, and Enhanced Thematic Mapper Plus imagery to categorize land-cover change and evaluate using a modified Anderson Land Use Land Cover Classification System for image interpretation. The rates of land-cover change are estimated using a stratified, random sampling of 10-kilometer (km) by 10-km blocks allocated within each ecoregion. For each sample block, satellite images are used to interpret land-cover change. Additionally, historical aerial photographs from similar timeframes and other ancillary data such as census statistics and published literature are used. The sample block data are then incorporated into statistical analyses to generate an overall change matrix for the ecoregion. These change statistics are applicable for different levels of scale, including total change for the individual sample blocks and change estimates for the entire ecoregion. The results illustrate that there is no single profile of land-cover change but instead point to geographic variability that results from land uses within ecoregions continuously adapting to various factors including environmental, technological, and socioeconomic.

Open-File Report↗

Recent developments in the U. S. Geological Survey's Landsat image mapping program

At the 1984 ASPRS-ACSM Convention in Washington, D. C. a paper on 'The Emerging U. S. Geological Survey Image Mapping Program' was presented that discussed recent satellite image mapping advancements and published products. Since then Landsat image mapping has become an integral part of the National Mapping Program. The Survey currently produces about 20 Landsat multispectral scanner (MSS) and Thematic Mapper (TM) image map products annually at 1:250,000 and 1:100,000 scales, respectively. These Landsat image maps provide users with a regional or synoptic view of an area. The resultant geographical presentation of the terrain and cultural features will help planners and managers make better decisions regarding the use of our national resources.

Conference Paper↗

Commemorative naming in the United States

Naming is a basic human tendency; it allows us to perceive the distinct identities of people and places and conveys those characteristics that make them unique. The name of a geographic feature can describe spectacular physical attributes (such as the Grand Canyon or Half Dome in Yosemite National Park), indicate cultural or historical significance (such as Washington Crossing on the Delaware River), or commemorate a worthy individual (such as the Hudson River, named for Henry Hudson, the explorer). Names have many different origins, and regardless of the type of name, they give us a greater familiarity with our surroundings and a sense of belonging to our environment. Naming rivers, mountains, and valleys after individuals was one way settlers marked the land; it signified their lives on these lands were important and, in addition to being a point of reference, usually satisfied the need for stability and enhanced the general concept of sense of place. Even today, naming geographic features after individuals helps us to recognize their special achievements and contributions to the physical or cultural landscape. However, what may be most significant about the present commemorative naming decisions is their permanence. It is important for us to realize that the commemorative names assigned today may last for centuries.

Fact Sheet↗

Commemorative Naming in the United States

Naming is a basic human tendency; it allows us to perceive the distinct identities of people and places and conveys those characteristics that make them unique. The name of a geographic feature can describe spectacular physical attributes (such as the Grand Canyon or Half Dome in Yosemite National Park), indicate cultural or historical significance (such as Washington Crossing on the Delaware River), or commemorate a worthy individual (such as the Hudson River, named for Henry Hudson, the explorer). Names have many different origins, and regardless of the type of name, they give us a greater familiarity with our surroundings and a sense of belonging to our environment. Naming rivers, mountains, and valleys after individuals was one way settlers marked the land; it signified their lives on these lands were important and, in addition to being a point of reference, usually satisfied the need for stability and enhanced the general concept of sense of place. Even today, naming geographic features after individuals helps us to recognize their special achievements and contributions to the physical or cultural landscape. However, what may be most significant about the present commemorative naming decisions is their permanence. It is important for us to realize that the commemorative names assigned today may last for centuries.

Fact Sheet↗

Using land-cover data to understand effects of agricultural and urban development on regional water quality

The Land-Cover Trends project is a collaborative effort between the Geographic Analysis and Monitoring Program of the U.S. Geological Survey (USGS), the U.S. Environmental Protection Agency (EPA) and the National Aeronautics and Space Administration (NASA) to understand the rates, trends, causes, and consequences of contemporary land-use and land-cover change in the United States. The data produced from this research can lead to an enriched understanding of the drivers of future landuse change, effects on environmental systems, and any associated feedbacks. USGS scientists are using the EPA Level III ecoregions as the geographic framework to process geospatial data collected between 1973 and 2000 to characterize ecosystem responses to land-use changes. General land-cover classes for these periods were interpreted from Landsat Multispectral Scanner, Thematic Mapper, and Enhanced Thematic Mapper Plus imagery to categorize and evaluate land-cover change using a modified Anderson Land-Use/Land-Cover Classification System for image interpretation.

General Information Product↗

The U.S. Geological Survey Land Remote Sensing Program

In 2002, the U. S. Geological Survey (USGS) launched a program to enhance the acquisition, preservation, and use of remotely sensed data for USGS science programs, as well as for those of cooperators and customers. Remotely sensed data are fundamental tools for studying the Earth's land surface, including coastal and near-shore environments. For many decades, the USGS has been a leader in providing remotely sensed data to the national and international communities. Acting on its historical topographic mapping mission, the USGS has archived and distributed aerial photographs of the United States for more than half a century. Since 1972, the USGS has acquired, processed, archived, and distributed Landsat and other satellite and airborne remotely sensed data products to users worldwide. Today, the USGS operates and manages the Landsats 5 and 7 missions and cooperates with the National Aeronautics and Space Administration (NASA) to define and implement future satellite missions that will continue and expand the collection of moderate-resolution remotely sensed data. In addition to being a provider of remotely sensed data, the USGS is a user of these data and related remote sensing technology. These data are used in natural resource evaluations for energy and minerals, coastal environmental surveys, assessments of natural hazards (earthquakes, volcanoes, and landslides), biological surveys and investigations, water resources status and trends analyses and studies, and geographic and cartographic applications, such as wildfire detection and tracking and as a source of information for The National Map. The program furthers these distinct but related roles by leading the USGS activities in providing remotely sensed data while advancing applications of such data for USGS programs and a wider user community.

Fact Sheet↗

The National Park Service stratotype inventory

Introduction An Inventory of Stratigraphic Origins within the National Park Service The geologic history of Earth is recorded in layers or bodies of rock that are classified in a hierarchical order with several different categories of geologic units, including: supergroup, group, formation, member, bed, supersuite, suite, or complex. Geologists analyze and classify rock types based on properties that include lithology, texture, thickness, sedimentary structures, fossils, geographic or geospatial distribution, and age. In instances where new geologic units are proposed, a stratotype is assigned to a designated section, locality, or area of well-exposed rock that displays diagnostic characteristics for identification and correlation. Stratotypes are also namesakes, in that formally recognized rock units are named for the places where they were first described, measured, and mapped. Thus, a vast majority of the stratigraphic nomenclature alludes to geographic or geologic features. Some particularly recognizable examples (and their stratotype assignments) include the Paleoproterozoic Vishnu Schist (Vishnu Canyon in Grand Canyon National Park, Arizona), the Early Cambrian Harpers Formation (Harpers Ferry National Historical Park, West Virginia), and the Late Cretaceous Whitney Granodiorite (Mount Whitney in Sequoia and Kings Canyon National Parks, California). Beginning in 2020, the National Park Service (NPS) began a systematic effort to document the occurrence of stratotypes exposed within, partially within, and near NPS administrative boundaries. The NPS stratotype inventory project represents an important component of a geologic resource inventory, as these designations are vital to our national geologic heritage (herein referred to as “geoheritage”) and possess significant scientific, historic, educational, cultural, and aesthetic values. The geoheritage significance of stratotypes is analogous to libraries and museums, in that they are geologic landmarks of Earth history and record the prodigious forces and evolving life forms that define our understanding of the planet. These designated exposures preserve knowledge, represent comparative geologic references where previous observations can be re-examined or reinterpreted, and can serve as valuable educational tools for future geoscientists (Brocx and others, 2019). The NPS stratotype inventory includes the following: Documentation of designated stratotype exposures to confirm their geospatial occurrence within, partially within, and near NPS administrative boundaries, compiled from published reports and maps; Compilation and visualization of the precise geographic locations of the stratotype exposures; and Recommendations that address potential land and resource management issues associated with NPS stratotypes. By achieving these goals, this project helps to raise awareness of stratotypes as a geologic resource by educating NPS staff and the public so that they may better understand, recognize, and protect these important park resources. The focused approach adopted for conducting the stratotype inventories throughout the NPS has centered on the 32 Inventory and Monitoring (I&M) networks established by the NPS during the late 1990s (for more information on each network, see https://www.nps.gov/im/networks.htm). The I&M networks represent groups or clusters of park units that are based on shared geography and natural resource characteristics. The Greater Yellowstone I&M Network, encompassing Bighorn Canyon National Recreation Area, Grand Teton National Park, John D. Rockefeller Jr. Memorial Parkway, and Yellowstone National Park, was used as the pilot network for initiating this stratotype inventory and was first published in November 2020 (Henderson and others, 2020). The 32d and final report on the Northeast Temperate I&M Network was published in October 2022 (Henderson and others, 2022). Currently, the NPS stratotype inventory project has identified more than 700 stratotypes within NPS administrative boundaries.

Professional Paper↗

Progress and lessons learned from water-quality monitoring networks

Stream-quality monitoring networks in the United States were initiated and expanded after passage of successive federal water-pollution control laws from 1948 to 1972. The first networks addressed information gaps on the extent and severity of stream pollution and served as early warning systems for spills. From 1965 to 1972, monitoring networks expanded to evaluate compliance with stream standards, track emerging issues, and assess water-quality status and trends. After 1972, concerns arose regarding the ability of monitoring networks to determine if water quality was getting better or worse and why. As a result, monitoring networks adopted a hydrologic systems approach targeted to key water-quality issues, accounted for human and natural factors affecting water quality, innovated new statistical methods, and introduced geographic information systems and models that predict water quality at unmeasured locations. Despite improvements, national-scale monitoring networks have declined over time. Only about 1%, or 217, of more than 36,000 US Geological Survey monitoring sites sampled from 1975 to 2014 have been operated throughout the four decades since passage of the 1972 Clean Water Act. Efforts to sustain monitoring networks are important because these networks have collected information crucial to the description of water-quality trends over time and are providing information against which to evaluate future trends.

Chemistry and Water↗

POLARIS: A 30-meter probabilistic soil series map of the contiguous United States

A new complete map of soil series probabilities has been produced for the contiguous United States at a 30 m spatial resolution. This innovative database, named POLARIS, is constructed using available high-resolution geospatial environmental data and a state-of-the-art machine learning algorithm (DSMART-HPC) to remap the Soil Survey Geographic (SSURGO) database. This 9 billion grid cell database is possible using available high performance computing resources. POLARIS provides a spatially continuous, internally consistent, quantitative prediction of soil series. It offers potential solutions to the primary weaknesses in SSURGO: 1) unmapped areas are gap-filled using survey data from the surrounding regions, 2) the artificial discontinuities at political boundaries are removed, and 3) the use of high resolution environmental covariate data leads to a spatial disaggregation of the coarse polygons. The geospatial environmental covariates that have the largest role in assembling POLARIS over the contiguous United States (CONUS) are fine-scale (30 m) elevation data and coarse-scale (~ 2 km) estimates of the geographic distribution of uranium, thorium, and potassium. A preliminary validation of POLARIS using the NRCS National Soil Information System (NASIS) database shows variable performance over CONUS. In general, the best performance is obtained at grid cells where DSMART-HPC is most able to reduce the chance of misclassification. The important role of environmental covariates in limiting prediction uncertainty suggests including additional covariates is pivotal to improving POLARIS' accuracy. This database has the potential to improve the modeling of biogeochemical, water, and energy cycles in environmental models; enhance availability of data for precision agriculture; and assist hydrologic monitoring and forecasting to ensure food and water security.

Geoderma↗