Additional system background

Introduction

As part of the U.S. Geological Survey's (USGS) program for disseminating water data within USGS, to USGS cooperators, and to the general public, the USGS maintains a distributed network of servers for the acquisition, processing, review, and long-term storage of water data. This water data is collected at over 1.5 million sites around the country and at some border and territorial sites. This distributed network of computers is called the National Water Information System (NWIS). Many types of data are stored in NWIS, including comprehensive information for site characteristics, well-construction details, time-series data for gage height, streamflow, groundwater level, precipitation, physical and chemical properties of water and water use data. Additionally, peak flows, chemical analyses for discrete samples of water, sediment, and biological media are accessible within NWIS.

Water Data for the Nation is the USGS public web interface to much of the data stored and managed within NWIS. It is not, however, configured to present all NWIS data and users may need to contact local Water Science Centers to obtain some information. For example, well construction details, many miscellaneous measurements, and peak flows less than annual maximums are not available from the Water Data for the Nation site. The goal of the Water Data for the Nation site is to provide USGS, USGS cooperators, and users from the general public with a geographically seamless and easy-to-use interface to most of the USGS water data maintained in NWIS. Data provided by this site are updated from NWIS on a regularly scheduled basis, and current condition data are generally updated upon receipt at local Water Science Centers. Several output options are provided including: graphs of current conditions, water levels, and water quality; tabular output in HTML and ASCII tab-delimited files; and summary lists for selected sites that can be used as a basis for reselection to acquire refined details.

The USGS Water Data for the Nation site provides a framework to obtain data on the basis of category, such as surface water, groundwater, or water quality, and by geographic area. Further refinement is possible by choosing specific site-selection criteria and by defining the output desired. NWIS data originates from all 50 states, plus border and territorial sites, and include data from as early as 1899 to present. Of the over 1.5 million sites with NWIS data, the vast majority are for wells; however, there are thousands of sites with streamflow data, many sites with atmospheric data such as precipitation, and about 10,900 of the sites provide current condition data. In addition, there are over 90 million water-quality results from about 5 million water samples collected at hundreds of thousands of sites.

Fact Sheet

National Water Information System Web U.S. Geological Survey, Fact Sheet FS-128-02, November 2002