The U.S Geological Survey Water Resources Division home page is a gateway to a variety of water-resource information, at
water.usgs.gov/

For information and graphics relating to aquifers and ground water, see
capp.water.usgs.gov/aquiferBasics/index.html

and for specific groundwater-related information
water.usgs.gov/ogw/

The USGS has a National Water-Use Information Program offering information to the public; its home page is at
water.usgs.gov/public/watuse/wufactsheet.html

Two notable water-related fact sheets are: "Saltwater intrusion in Los Angeles Area coastal aquifers— the marine connection". (USGS Fact Sheet 030-02, 2002)
geopubs.wr.usgs.gov/fact-sheet/fs030-02/

and "Climatic fluctuations, drought, and flow in the Colorado River Basin" (USGS Fact Sheet 2004-3062, 2004)
pubs.usgs.gov/fs/2004/3062/

Water-supply and water-quality impacts of the Iraq-Kuwait war are explored in text and satellite images at
edcwww.cr.usgs.gov/earthshots/slow/Iraq/Iraq

More on Lake Chad is found at the same "Earthshots" site
edcwww.cr.usgs.gov/earthshots/slow/Lake_Chad/ Lake_Chad

as is information on karst in Florida
edcwww.cr.usgs.gov/earthshots/slow/Orlando/Orlando

and on the rapid expansion of irrigation in Saudi Arabia
edcwww.cr.usgs.gov/earthshots/slow/Riyadh/Riyadh

A great deal of resource-related data, including information on water resources, is available via WRI's "EarthTrends" page; click on "Water Resources and Freshwater Ecosystems"
earthtrends.wri.org/

The Climate Prediction Center of the National Centers for Environmental Prediction engages in short-term climate predictions, which involves considering historic climate trends. Historic precipitation data, U.S. and foreign, can be accessed via links at
www.cpc.ncep.noaa.gov/

The United Nations Commission on Sustainable Development has a website with water-related information at
www.un.org/esa/sustdev/sdissues/water/water.htm