Ground-water Level Sites, September 2000 This is a subset of ground-water sites from the USGS, National Water Information System (NWIS) Ground-water Site Inventory (GWSI) database. Included .. U.S. Geological Surveyhttp://water.usgs.gov/pubs/of/2004/1030/htdocs/wl092k.htm- 18.9KB - USGS
GTOPO30 - Global Topographic Data GTOPO30 is a global digital elevation model (DEM) resulting from a collaborative effort led by the U.S. Geological Survey's EROS Data Center in Sioux Falls, S.D. . http://lpdaac.usgs.gov/gtopo30/gtopo30.asp- 10.8KB - USGS