"... is a resource for environmental system developers and enterprise architects. It also provides environmental program managers and users of environmental information with automated services to enable better understanding of environmental terminology and data used by the Agency."
This site from the United States Geological Survey provides "access to water-resources data collected at approximately 1.5 million sites in all 50 States, the District of Columbia, and Puerto Rico." Data is divided into categories of surface water, ground water, and water quality.
"Data from status and trends provide important long-term trend information about specific changes and places and the overall status of wetlands in the United States. The historical data base that the Service has developed through Status and Trends, provides photographic evidence of land use and wetlands extent dating back to the 1950s. This provides an accurate record to assist in future restoration efforts. " U.S. Fish & Wildlife Service
"... maintains the world's largest climate data archive and provides climatological services and data to every sector of the United States economy and to users worldwide. Records in the archive range from paleoclimatic data to centuries-old journals to data less than an hour old. The Center's mission is to preserve these data and make them available to the public, business, industry, government, and researchers."
"... provide statistical information on fatalities, injuries and damages caused by weather related hazards. These statistics are compiled by the Office of Services and the National Climatic Data Center from information contained in Storm Data, a report comprising data from NWS forecast offices in the 50 states, Puerto Rico, Guam and the Virgin Islands."
"The GCMD holds more than 28,000 Earth science data set and service descriptions, which cover subject areas within the Earth and environmental sciences. ... The GCMD’s primary responsibility is to maintain a complete catalog of all NASA’s Earth science data sets and services. "