http://h2o.usgs.gov/public/nawdex/nawdex.html
The National Water Data Exchange (NAWDEX) is a group of water-oriented organizations working together to improve the access to water data and water information. Its publications include--Definitions of Database Files and Fields of the Personal Computer-Based Water Data Sources Directory, a Directory of Assistance Centers of the National Water Data Exchange, and a Directory of Member Organizations of the National Water Data Exchange. Membership in NAWDEX is voluntary and is open to any water-oriented organization that wishes to take an active role. Membership includes organizations from the federal, state, interstate, local governmental, academic, and private sectors of the water-data community.