Web Soil Survey

Web Soil Survey
Name	Web Soil Survey
Developer	United States Department of Agriculture Natural Resources Conservation Service
Released	2006
Platform	Web browser
Type	Soil survey portal

Web Soil Survey is an online soil information system created to provide public access to digital soil survey data, interpretive products, and mapping tools for land-use planning and resource management. It serves users ranging from private landowners and farmers to planners at the U.S. Forest Service, Bureau of Land Management, and municipal agencies. The service integrates spatial data, interpretive tables, and customizable reports to support decisions by practitioners in agriculture, conservation, and environmental compliance.

Overview

Web Soil Survey is administered by the Natural Resources Conservation Service (NRCS) within the United States Department of Agriculture (USDA). The platform delivers the official NRCS soil survey geographic database (SSURGO) and the Soil Survey Geographic Database as digital map units and attribute tables. It enables users to define an area of interest (AOI), retrieve soil map unit descriptions, and generate interpretive outputs such as suitability rankings, hydrologic interpretations, and engineering constraints. Partner organizations like the Soil Science Society of America and state land grant universitys frequently use its outputs in research and extension activities.

Data and Tools

The system provides access to primary data layers including map unit polygons, component soil series, taxonomic classifications, and property tables derived from SSURGO and the National Resources Inventory. Tools include an interactive map viewer, AOI drawing utilities, soil data explorer, and report generation modules that export printable PDFs and tables for analyses used by the Environmental Protection Agency, Army Corps of Engineers, and local planning commissions. The database links to standardized soil taxonomy maintained by the International Union of Soil Sciences conventions and cross-references the NRCS Soil Survey Handbook. GIS interoperability is supported through OGC-compliant services, enabling integration with software used by the United States Geological Survey and academic GIS labs at Iowa State University and University of California, Davis.

Applications and Uses

Practitioners apply the platform for agricultural management, erosion control, irrigation planning, septic system site evaluation, and wetland delineation used by the Fish and Wildlife Service and state departments of natural resources. Landscape architects and civil engineers consult its engineering interpretations for foundation, slope stability, and compaction guidance in projects overseen by municipal building departments and transportation agencies such as the Federal Highway Administration. Conservation planners use derived interpretations for nutrient management plans submitted to the Natural Resources Conservation Service programs and for compliance with statutes administered by the Environmental Protection Agency and state environmental protection agencies. Extension educators at land grant universitys and nonprofit organizations like The Nature Conservancy employ reports for outreach and landowner decision-support.

Methodology and Data Sources

Soil mapping and attribute compilation follow protocols established by NRCS field survey procedures, including pedon descriptions, transect observations, and laboratory analyses consistent with standards from the Soil Science Society of America. Primary sources include SSURGO, the State Soil Geographic database (STATSGO), and field soil survey archives held by regional NRCS offices. Laboratory data such as particle size distribution, organic carbon, and bulk density derive from USDA laboratory methods and interlaboratory standards used in collaborations with institutions like North Carolina State University and University of Minnesota. Spatial integration employs geodetic references conforming to the North American Datum of 1983 and cartographic conventions compatible with datasets produced by the United States Geological Survey.

Limitations and Accuracy

Users are cautioned that map unit delineations represent surveyed map unit polygons that may contain multiple soil components and that SSURGO data vary in resolution and recency by county and state. Accuracy depends on original survey scale, field verification, and updates maintained by NRCS staff; consequently, fine-scale site assessments often require supplemental field investigation or laboratory testing as performed by private soil testing laboratories or university extension services. Interpretive outputs are general-purpose and may not satisfy regulatory thresholds set by agencies such as the Environmental Protection Agency or Army Corps of Engineers for specific permitting decisions. Metadata and accuracy statements included with each dataset document lineage, survey date, and confidence measures aligned with federal spatial data standards.

History and Development

Development began as an NRCS initiative to modernize access to digital soil survey products and was publicly released in 2006 after pilot efforts with regional NRCS offices. Enhancements over time integrated SSURGO, STATSGO, web mapping services, and interoperability protocols influenced by standards from the Open Geospatial Consortium. Collaborations with academic partners at Cornell University, University of Illinois Urbana–Champaign, and state NRCS offices expanded interpretive modules and outreach. Ongoing development responds to technological changes in web GIS, contributions from regional soil scientists, and user feedback from municipalities, conservation districts, and national agencies such as the Natural Resources Conservation Service and United States Department of Agriculture.

Category:Soil science