U.S. Geological Survey's (USGS) National Water Information System (NWIS) Data
The U.S. Geological Survey's (USGS) National Water Information System (NWIS) is a comprehensive and distributed application that supports the acquisition,
processing, and long-term storage of water data.
Water Data for the Nation serves as the publicly available portal to a geographically seamless
set of much of the water data maintained within NWIS.
The USGS collects and analyzes chemical, physical, and biological properties of water, sediment and tissue samples from across the Nation.
The Water Data for the Nation discrete sample data base is a compilation of over 4.4 million historical water quality analyses in the USGS district data bases through September 2005.
The data includes both active and inactive data. The inactive data is from sites that are no longer collecting data but the earlier data is retained for analysis. The active data is from sites that still provide data either regularly or irregularly.
Zoommi and the USGS Water Quality Data
As Zoommi's focus is to provide access to current data, we have only linked to approximately 2000 active items of USGS hydrological and water quailty data.
Zoommi has a programmatic access to all the active sites with instantaneous and daily data, thanks to the USGS website support staff.
This data can be combined with any of the other data in the Zoommi database.
The USGS data is not stored in the Zoommi database, but is requested as is required by a user. Please note that some queries will take longer depending on the volume of data to be retrieved.
The USGS data includes both the current condition data as well as the daily data, for trend analysis through its portal.
Zoommi is designed to provide quick and simple trend analysis of a subset of variables, not to provide scientific analysis of approved data.
USGS Water-Quality Data
For any detailed scientific analysis, please use the USGS query pages shown below.
Current (instantaneous) Condition Data
Current Conditions for the Nation -- Water Quality provides comprehensive access to the full range of data, both active and inactive.
Current conditions at selected sites based on the most recent data from on-site automated recording equipment.
Measurements are commonly recorded at a fixed interval of 15- to 60-minutes and transmitted to the USGS every hour. Values may include "Approved" (quality-assured data that may be published) and/or more recent "Provisional" data (of unverified accuracy and subject to revision).
Most current data are provisional.
The USGS NWIS Site Selector provides a query page for further analysis.
Summary of all data for each day for the period of record and may represent the daily mean, median, maximum, minimum, and/or other derived value.
Values may include "Approved" (quality-assured data that may be published) and/or more recent "Provisional" data (of unverified accuracy and subject to revision).
Statistical data is not currently included in the Zoommi database.
Statistics are computed from approved daily mean data at each site. These links provide summaries of approved historical daily values for daily, monthly, and annual (water year or calendar year) time periods.