GSDA:Soil Type

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Soil Type Data

EPA

http://wikis.aquaveo.com/xms/FTPImages/GSDA/GSDA_EPA.png Obtain the HUC number for your watershed Obtain land use and soil type data from the EPA HUC index

The EPA offers land use and soil type shapefiles.


NRCS - State Soil Geographic (STATSGO) Database

http://wikis.aquaveo.com/xms/FTPImages/GSDA/GSDA_NRCS.png Obtain STATSGO soil type data from the NRCS

The United States Department of Agriculture (USDA) supports the Natural Resources Conservation Service (NRCS). A website they have developed is the National Cartography and Geospatial Center (NCGC). Supplied on this website are numerous links and descriptions of geospatial datasets. Through these links it is possible to acquire soil type data maps from the two main soils databases; STATSGO, and SSURGO.


State Soil Geographic (STATSGO) Database

Details:
  • Database product files in three formats:
    1. USGS Digital Line Graphs (DLG-3)
    2. ArcInfo 7.0 Coverage
    3. GRASS 4.13 Vector
  • Coordinate systems are:
    1. Albers Conical Equal - Area: Continental U.S. and Alaska
    2. UTM Zone 4: Hawaii
    3. UTM Zone 19: Puerto Rico
  • Resolution at 1:250K scale, except Alaska (1:1M).
  • Complete coverage of U.S. and includes Puerto Rico.
  • Data files are downloadable in zip file compression.
  • Downloads are free (no cost).



NRCS - Soil Survey Geographic (SSURGO) Database

It is possible to obtain SSURGO data from the NRCS by two methods. The first is the Web Soil Survey. The other is through the Geospatial Data Gateway. Both are accessible on the NCGC website.


Web Soil Survey


<imagemap> Image:WSSMasthead4.png|none desc none default [1] </imagemap>
Obtain SSURGO soil type data from Web Soil Survey

Web Soil Survey is a data request site supported by the United Sates Department of Agriculture (USDA) through the Natural Resources Conservation Service (NRCS). From Web Soil Survey you can place orders requesting certain soil survey maps. It specifically caters to only soil data needs.

Details:
  • Database products available in three forms:
    1. Tabular
    2. Spatial
    3. Template Database
  • Spatial products downloads provided in the following format:
    1. ESRI Shapefile
  • Data are provided in the following coordinate system:
    1. Geographic WGS84
  • Typical scale resolution between 1:16K and 1:64K.
  • Soil downloads can be confined to a user defined area of interest
  • Files can be downloaded only one survey at a time.
  • Data files are acquired in zip file compression.
  • Downloads are free (no cost).



Geospatial Data Gateway


<imagemap> Image:GSDAImage042.png|none desc none default [2] </imagemap>
Obtain SSURGO soil type data from the Geospatial Data Gateway

The Geospatial Data Gateway is a site sponsored by the United States Department of Agriculture (USDA) through the Natural Resources Conservation Service (NRCS). Numerous databases are available by means of the Geospatial Data Gateway including; transportation, census, land use / land cover, soil type, ortho imagery, elevation, and topographic maps. Description below applies to SSURGO soil type data only.

Details:
  • Database product files in three formats:
    1. ESRI Shape File
    2. ESRI Coverage
    3. ESRI ASCII Export
  • Coordinate systems are available in a variety of projections:
    1. Geographic
    2. Universal Transverse Mercator (UTM)
    3. State Plane
  • Typical scale resolution between 1:16K and 1:64K.
  • Extensive coverage of U.S.
  • Data files are downloadable in zip file compression.
  • Downloads are free (no cost).



Soil Type Overview

For watersheds with multiple soil types and land uses, a composite CN (CCN) must be calculated to estimate the infiltration losses. The NRCS (part of the USDA) supplies tables so that a CCN can be determined from soil type, land use, moisture condition, and hydrologic condition. In hydrology, soil type can be classified in many ways. The USDA classifies them according to their infiltration rate and are referred to as either A, B, C, or D soils. Soil type A has a high infiltration rate whereas soil type D usually consists of clays that are nearly impermeable (low infiltration) and produce higher volumes of runoff.

NRCS STATSGO soil type for the state of Utah.
EPA soil type for an EPA watershed near Provo, Utah.


Soil Type Tips