----------------------------------------------------------------------

qwtable.txt - Water quality data

(Note some records are duplicated if a well is included in
two SITETYPEs, for example, some NAWQA aquifer study wells 
("Mas") are also Public supply ("Pws") wells and are included
twice in this table.

Column     Data Type   Description
--------   ----------  ------------
STAID      text        USGS 15-character station identifier
SITETYPE   text        Dom, domestic well; 
                       Mas, well included in NAWQA aquifer study; 
                       Pws, Public-supply well
DATATYPE   text        AWWARF, sampled as part of AWWARF study;
                       NAWQA, sampled by USGS NAWQA program;
                       RETRO, sampled by USGS or other agencies
                             prior to the NAWQA program
SAMPDATE   text        date of sample, in the form YYYYMMDD
PCODE      text        USGS Parameter code (see qwparam.txt)
REMRK      text        USGS Remark code: 
                       "<" not detected at value CVALUE
                       "E" detected, concentration estimated to be CVALUE
                       "-" detected at concentration CVALUE
CVALUE     number      concentration (micrograms per liter)


----------------------------------------------------------------------

qwparam.txt - Water quality parameters (constituents) 

Column     Data Type   Description
--------   ----------  ------------
PCODE      text        USGS Parameter code
CAS        text        CAS-ID
NAME       text        IUPAC Name
GROUP      text        VOC Group (groups used in report)
HBSLVAL    text        Health-based screening level, "-" if not available
MCLVAL     text        EPA Drinking water reporting limit,
                       "-" if not available
                       
----------------------------------------------------------------------

qwsites.dat - Information about wells included in the study

STAID
SITETYPE  text
LATDD     number        Geographic location, latitude *
LONDD     number        Geographic location, longitude *
LUTYPE    text          Type of NAWQA study for which well was sampled:
                        MAS, major aquifer study;
                        URBAN, urban land-use study;
                        AG, agricultural land-use study;
                        -, not studied as part of NAWQA
NAWQAYR   number        Year of NAWQA study: 1991, 1994, 1997, 
                        or 0  (not sampled as part of NAWQA)
STUDY     text          Aquifer study code
DOMESTIC  number        0, not a domestic well; 1, domestic well
AQUIFERS  number        0, well not sampled in NAWQA or RETRO aquifer study;
                        1, well sampled in NAWQA or RETRO aquifer study
PUBLIC    number        0, Well is not a public-supply well;
                        1, Well is a public-supply well


* Locations are referenced to the North American Datum of 1983.
  Location of public-supply wells have been rounded to the
  nearest 0.1 degree for this public release.