AVAILABILITY OF GROUND-WATER DATA FOR CALIFORNIA, WATER YEAR
1996
U.S. Geological Survey Fact Sheet, FS 086-97
INTRODUCTIONThe Water Resources Division of the U.S.
Geological Survey, in cooperation with Federal, State, and local water
agencies, obtains a large amount of data pertaining to the ground-water
resources of California each water year. These data constitute a valuable
data base for developing an improved understanding of the water resources
of the State. Beginning with the 1985 water year and continuing through 1993,
these data were published in a report series entitled "Water Resources
Data for California, Volume 5. Ground-Water Data." Prior to the
introduction of this series, historical ground-water information was
published in U.S. Geological Survey Water-Supply Papers.
In 1994, the Volume 5 Ground-Water Data report was discontinued, but
data continue to be available in our data bases. This Fact Sheet serves
as an index to ground-water data for 1996. The 2-page report contains a
map of California showing the number of wells (by county) with available
water-level and water-quality data for the current water year (fig. 2)
and instructions for obtaining this and other ground-water information
contained in the data bases of the Water Resources Division, California
District.
HYDROLOGIC CONDITIONS
Because the geography and geology of California are so complex,
ground-water conditions are difficult to summarize. Ground-water levels
fluctuate in response to various stresses and changes in stress.
Recharge and discharge are affected by short- and long-term climatic
conditions and also by ground-water withdrawals and irrigation.
DATA COLLECTION
WATER-LEVEL MEASUREMENTS
Measurements of water levels are made in many types of wells under varying
conditions, but the methods and equipment are standardized to ensure that
these measurements are consistently accurate and reliable. All water levels
in the California data base are given in feet with reference to land-surface
datum.
WATER-QUALITY MEASUREMENTS
The quality of ground water ordinarily changes slowly; therefore, a
single annual sampling usually is sufficient. When the quality of
ground water is likely to change rapidly because of special
circumstances, more frequent sampling is done to identify the nature of
the change.
WELL-NUMBERING SYSTEM
Wells and springs in California are assigned numbers according to their
location in the rectangular system for the subdivision of public land.
For example, in the number 005S012E22P001M (fig.1), the first four
characters indicate the township (T. 5 S.), and the next four
characters indicate the range (R.12 E.); the digits following the range
indicate the section (sec. 22); the letter following the section
indicates the 40-acre sub-division of the section. Within each 40-acre
sub-division, the wells are numbered serially, as indicated by the last
three digits. The final letter indicates the baseline and meridian
designation as follows: H, Humboldt; M, Mount
Diablo; S, San Bernardino. This 15-digit number is called
the Local Number or State Well Number.
Information for an area may be requested using all or part of the Local
Number (township/range/section) or by defining a latitude/longitude
polygon.
Figure 1. Well-numbering system.
DATA AVAILABILITY
Data are available on paper, floppy disc, or magnetic tape, by ftp
transfer, or by internet e-mail in table or flatfile format. For more
information on how to obtain data, send e-mail or call:
pshiffer@usgs.gov for Northern
California data (916) 278-3100;
jahuff@usgs.gov for Southern California
data (619) 637-6823.
Figure 2. The number of wells, by county, for which data are available
for the 1996 water year.
NOTE: The number preceding the slash (/) indicates the number
of wells with water-level data; the number following the slash
indicates the number of wells with water-quality data.
(40 K)
For more information on ground water in California please write:
Julia A. Huff
U.S. Geological Survey, Water Resources Division
Data Management Unit
5735 Kearny Villa Rd., Suite O
San Diego, CA 92123
Water Resources of California
The URL for this page is
http://ca.water.usgs.gov/fs_gw/96/.
Contact:
webmaster@maildcascr.wr.usgs.gov
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