Description http://water.usgs.gov/GIS/huc.html
Get the data http://water.usgs.gov/lookup/getspatial?huc250k
The 8-digit hydrologic cataloging units are the basic water resources subdivision of the United States
EPA Reach File 1 (RF1)
Description http://water.usgs.gov/GIS/metadata/usgswrd/erf1.html
Get the data http://water.usgs.gov/lookup/getspatial?erf1
Description http://www.epa.gov/OST/BASINS/
Get the data http://www.epa.gov/OST/BASINS/gisdata.html
Contains a large inventory of environmental data organized by 8-digit hydrologic cataloging units
Description http://nhd.usgs.gov
Get the data http://nhd.usgs.gov/data.html
NHD Applications Symposium, Dec 2000 http://www.crwr.utexas.edu/giswr/events/122000nhda/
The stream network and water bodies of the United States organized by 8-digit hydrologic cataloging units
National Inventory of Dams http://crunch.tec.army.mil/nid/webpages/nid.cfm
Seamless data distribution from EROS Data Center http://seamless.usgs.gov/
1 arc-second cells (1:24,000 scale) National Elevation Dataset http://edcnts12.cr.usgs.gov/ned/
Other USGS DEM data http://edc.usgs.gov/Webglis/glisbin/guide.pl/glis/hyper/guide/usgs_dem
Elevation Derivatives for National Applications (EDNA) http://edcnts12.cr.usgs.gov/ned-h/index.html
National Severe Storms Laboratory Basin Delineation project NSSL National Basin Delineation Project
US Coastline from National Geophysical Data Center
Coastline Extractor http://rimmer.ngdc.noaa.gov/coast/
Statsgo – State Soil Database (1:250,000 scale) http://www.ftw.nrcs.usda.gov/stat_data.html
Ssurgo – County Soil Database http://www.ftw.nrcs.usda.gov/ssur_data.html
Statsgo is available for the whole United States. Ssurgo is much more detailed but is available only in some counties. For an exercise on how to interpret Statsgo, see: http://www.ce.utexas.edu/prof/maidment/giswr98/statland/webfiles/viewstat.htm
USGS Land Use/Land Cover (LULC) http://nsdi.usgs.gov/products/lulc.html
National Wetlands Inventory Center http://www.nwi.fws.gov/
National Land Cover Dataset http://edcwww.cr.usgs.gov/programs/lccp/nationallandcover.html
Get the data http://edcwww.cr.usgs.gov/pub/edcuser/vogel/states/
National Atlas of the United States http://www.nationalatlas.gov/atlasftp.html
The LULC files have been the standard land use/land cover dataset of the US but are now being superseded by fresh mapping in the National Land Cover Dataset.
USDA Water and Climate Center (PRISM maps of mean precipitation) http://www.ftw.nrcs.usda.gov/prism/prism.html
National Climate Data Center http://www.ncdc.noaa.gov/
For an exercise using PRISM and land cover data to estimate nonpoint source pollution, see: http://www.ce.utexas.edu/prof/maidment/giswr98/nonpoint/webfiles/corpus.html
USGS National Water Information System http://water.usgs.gov/usa/nwis/
Real Time USGS Data on Water Watch http://water.usgs.gov/nwis/rt
ESRI Geography Network http://www.geographynetwork.com/
Digital Chart of the World http://www.maproom.psu.edu/dcw/
GTOPO30 - 30 arc-second cell (1:1,000,000 scale) global DEM http://edcdaac.usgs.gov/gtopo30/gtopo30.html
Hydro1K – hydrologic derivative datasets from GTOPO30 http://edcdaac.usgs.gov/gtopo30/hydro/index.html
EROS Data Center Gateway http://edcimswww.cr.usgs.gov/pub/imswelcome/
Global Water and Energy Experiment (GEWEX) http://www.gewex.org/
Texas
Data
Texas Natural Resource Information System http://www.tnris.state.tx.us/
TNRIS Vector Data http://www.tnris.state.tx.us/DigitalData/data_cat.htm
For more useful web links, see: http://www.ce.utexas.edu/prof/maidment/gishydro/docs/websites/othr_web.htm