This page is a brief introduction into the reliability for the various types of water resources data served by the USGS on the "NWISWeb" Web pages, specifically groundwater, surface water, and water-quality data and information, and site location information.
More information is available at:
US Geological Survey Office of - Groundwater || Surface Water || Water-Quality
Please send us e-mail if you have more questions.
Groundwater Well Information and Data
All information in the groundwater database is provisional and subject to revision. The data have been collected and entered for a wide variety of projects and purposes over a long period of time and the resulting databases varies in quality and detail. The data represent a combination of measured (by USGS personnel) and reported information. Although many wells have accurate information (especially those field visited for use in recent projects), some problems are known to exist for older entries. Examples of known problems include, but are not limited to, inaccurate well locations, old information regarding the use of water from the well, and incorrect installation dates. Many of the wells in the database have not been field visited, but were entered into the database from well drillers' reports, using the general location information supplied by the drillers. Many other Federal, State, and local agencies use the same well-numbering system that is used in this database; consistency of assigned well numbers between agency databases should not be assumed. This database does not represent all wells in Washington State.
Realtime streamflow data available on the District Home Pages are PROVISIONAL data that have not been reviewed or edited. These data may be subject to significant change and are not citeable until reviewed and approved by the U.S. Geological Survey. Realtime streamflow data may be changed after review because the stage-discharge relationship may have been affected by:
algal and aquatic growth in the stream
malfunction of recording equipment
Information about water quality data is available at the following Web page:
Currently published water quality data is available through the end of the 1999 water year, September 30, 1999. Provisional current year water quality may be available later next year.
Information about the site location have been entered into the various computer databases over the decades using the latest maps and location information available at the time. Some locations are updated as the necessary, but some older, discontinued sites may not have had the site information checked or updated since the last update. Information such as latitute and longitude, county, and other data may not be accurate by today's standards or information. In the case of surface water sites, the site name is based on the name of the creek or river, or lake if appropriate, location information such as highways, bridges, etc., and the nearest Post Office or town. Many older sites have towns that are many miles from the site, or have towns that may have been incorporated into newer or larger towns or cities. If you have any questions about the information about any site(s), please use the links to ask.