| INTRODUCTION
The U.S. Geological Survey (USGS) investigates the occurrence,
quantity, quality, distribution, and movement of the surface and underground
waters that constitute the Nation's water resources. The USGS is the principal
Federal water-data agency that collects and disseminates the data being used by
State and local governments, public and private utilities, and other Federal
agencies to develop and manage our water resources. Data are collected by USGS
personnel in all 50 States, plus Puerto Rico and Guam. These hydrologic data are
used not only for determining the adequacy of water supplies, but also for
implementing flood-warning systems; designing dams, bridges, and flood control
projects; allocating irrigation water; locating sources of pollution, planning
for energy development; and predicting the potential effects of radioactive
waste disposal on water supplies.
DESCRIPTION OF THE NWIS
As part of the Survey's program of disseminating water data to the
public, the Water Resources Division (WRD) maintains a distributed network of
computers and fileservers for the storage and retrieval of water data collected
through its activities at approximately 1.4 million sites. This system is called
the National Water Information System (NWIS).
The NWIS is a distributed water database in which data can be processed over
a network of workstations and fileservers at Survey offices throughout the
United States. The system is composed of four subsystems: the Ground-Water
Site-Inventory System, the Water-Quality System, the Automated Data-Processing
System, and the Water-Use Data System.
Many types of data are stored in the NWIS' distributed, local data bases,
including:
- Site information
- Time-series (flow, stage, precipitation, chemical) .
- Peak flow
- Ground water
- Water quality
- Water use
Ground-Water Site-Inventory
System
The Ground-Water Site-Inventory (GWSI) System contains and provides
access to inventory information about sites at stream reaches, wells, test
holes, springs, tunnels, drains, lakes, reservoirs, ponds, excavations, and
water-use facilities. The system also provides for entering new sites within the
local database.
Approximately 300 components make up the descriptive elements of the GWSI.
These components are stored in one general data file called the Site File, which
contains site information common to all subsystems of the NWIS, and eight GWSI
data files that contain ground-water-related information. The eight GWSI data
files contain well-construction, ground-water level, ground-water well or spring
discharge, geohydrologic characteristics, observation-well report header,
aquifer hydraulic, State ground-water use, and miscellaneous data.
The GWSI retrieval program can be used for retrieving information from the
Site File and the associated GWSI files to generate two types of general data
tables, four types of water-level tables, or a file suitable for input to other
programs.
Through the system menu, the GWSI System maintains the local databases and
performs other administrative tasks, including data dictionary modifications and
site identification changes, and provides programs for entering field data into
files used to update the local database.
Water-Quality System
The Water-Quality (WQ) System contains results of more than 3.5
million analyses of water samples that describe the chemical, physical,
biological, and radiochemical characteristics of both surface and ground waters.
Types of chemical data include filtered and/or unfiltered concentrations of
major ions, trace elements, nutrients, pesticides, base-neutral organics, acid
organics, and volatile organic compounds. Physical characteristics data include
pH, specific conductance, water and air temperature, dissolved oxygen,
barometric pressure, and percent dissolved oxygen saturation.
Water samples data are analyzed at laboratories equipped to perform chemical
analyses ranging from determinations of simple inorganic compounds, such as
chlorides, to complex organic compounds, such as pesticides. As each analysis is
completed, the results are verified by laboratory personnel and transmitted to
the originator of the data by use of a computer, and then stored in their
water-quality database.
Sediment data in the Water-Quality System include suspended-sediment
concentrations in water, sediment-size distributions, and chemical
concentrations of suspended sediments and bottom sediments. Biological data in
the system include population densities and diversity indexes of periphyton,
phytoplankton, and benthic invertebrates.
The system can produce three types of tables of water-quality data and one
table of biological population data. Types of summary tables include frequency
percentiles; analytical detection limits; sample summary; and alert limits.
Several standard output formats, such as flatfile and the 1- and *- format, are
available for input to applications. The system's graphic outputs include: X-Y
plots, regression plots, boxplots, time-series plots, Stiff diagrams, and Piper
diagrams.
Automated Data-Processing
System
The Automated Data Processing System (ADAPS) contains more than
850,000 station years of time-series data that describe stream-water levels,
streamflow (discharge), reservoir water levels, surface-water quality,
ground-water levels, and rainfall. ADAPS consists of a collection of computer
programs and databases.
The water data stored in ADAPS results from the processing of data collected
by automated recorders and by observations and manual measurements at field
installations around the Nation. The data from these sites are transported by
field personnel or are relayed through telephones or satellites to offices where
USGS personnel, using ADAPS procedures, process the data.
The data relayed through the Geostationary Operational Environmental
Satellite (GOES) system are processed automatically in near-real time, and in
many cases are available within minutes at the local USGS Web pages.
Water-Use Data System
The Water-Use Data System (WUDS) stores summary data on water use
throughout the Nation and includes two database systems: the Site-Specific
Water-Use Data System (SWUDS), and the Aggregate Water-Use Data System (AWUDS).
SWUDS stores measurements and estimates of water use by individual users. AWUDS
stores aggregated estimates of water use by county, hydrologic unit, and
aquifer. The WUDS is used to enter and update existing water-use data. and to
provide retrievals and displays of data that are stored in a local database. |
