README file for Access Database of Geochemical data at Geothermal Sites in Nevada
(Lisa Shevenell, Larry Garside, Mark Coolbaugh)
README file for NWIS (National Water Information System)
This README file describes a set of six excel files containing a water quality database downloaded from the USGS NWIS web site by at: http://water.usgs.gov/nv/nwis/qw. The data were downloaded on
The resulting Excel files that were created are:
major_elem.xls (major elements)
minor_trace.xls (minor and trace elements)
phys_prop.xls (physical properties; includes temperature)
radio_chem.xls (radioactive elements)
header.xls (basic sample site location and information)
information.xls (more detailed sample and site information, such as laboratory code)
Selection criteria used to download the data from the web site were:
(1) Lat-Long: A 0.3-degree buffer was used around the state of
(2) Site Attributes: Data from groundwaters and springs were selected, but other types of data, such as lakes and rivers, were excluded.
(3) Parameter groupings selected include: "Information", "Major Inorganics", "Minor and Trace Inorganics", "Physical Property", and "Radiochemicals." In addition, a summary file "Header" of site information was generated (which contains latitude and longitude, among other variables). Each excel file corresponds to one of these groupings. Other parameter groupings are available from the web site and were not included here.
Coordinate, Temperature, and Lab data were merged into individual chemical tables. Coordinate information contained in the "header" file were joined into the other data files permitting their conversion into event themes in ArcView. The latitudes and longitudes refer to NAD27. A few NAD83 values were converted to NAD27. Information identifying the laboratory and collection agency, initially contained in the "information" file, was also joined into the other data files. And temperature data contained in the "phys_prop" file were joined into the "major_elem", "minor_trace", and the "radio_chem" files. Codes in the database were replaced with text for the following fields: geohydrologic unit of the aquifer, sampled medium, purpose of the visit, sampler type, sample purpose, sample treatment, and sampling method.
Each excel spreadsheet contains from two to three individual sheets. The first sheet contains the data in table format. The second sheet contains a brief description of each data field (column). More detailed information and an explanation of codes can be found at the USGS NWIS web site "http://water.usgs.gov/nv/nwis/help". A third sheet contains a key of alphanumeric codes found in data entries in the first sheet. The third sheet also contains a listing of the sample sites found in the main data table of sheet 1.
CAUTIONS:
1) Many of the sites have multiple analyses, represented by multiple rows of data, in the spreadsheets.
2) A check for errors in the original USGS database has not been made.
These files, which were incorporated into the Access database, can be found under USGS-NWIS. Note, any fields which were populated in <0.5% of the samples were not retained in the database.
Composition of the Access Database:
The NWIS files were joined into a single database into Access, as were other data sets, most of which did not require as much manipulation as the NWIS data. Separate tables were constructed in Access for major element, trace elements, isotopes and gases. In order to retain all data values as numeric (rather than having them be automatically converted to text by Access), any < or other text were separated into a separate field from the numeric value in the database. Hence, all data exported from Access to Excel will have two columns for all chemical data that had any values preceded by a less than sign: one for the value, one for the sign (e.g., B, and B_alpha for the non numeric portion of the entry). Descriptions of the fields contained in the database are located in FieldDescrip-fnl.xls.
Additional data that were included in the Access database were obtained from the following sources:
Brannock, W.W., Philip, F.F., Gianella, V.P., & White, D.E., 1948. Preliminary Geochemical Results at
Cohen, P., and Loeltz, O., 1964. Evaluation of Hydrogeology and Hydrogeochemistry of
Garside, L., 1994.
GEOTHERM
Goff, F., Bergfeld, D., Janik, C., Counce, D., and Murrell, M., 2002. Geochemical data on waters, gases, scales, and rocks from Dixie Valley Region,
Goranson, C., 2000. Digital data entered from hard copy supplied to Washoe County Department of Public Works files for samples collected at Steamboat Hot Springs from 1984 through 1997. (digitally provided) (Goranson.xls)
Goranson, C., van de Kamp, P., and DeLong, T. (No Date). Geothermal Injection and Monitoring Program History at the Caithness Power, Inc. Flash Steam Power Plant Steamboat Springs, Nevada, 103 pp.
Mariner, R. Data from the 1970s through 1990s (data hand entered from hundreds of paper data sheets provided by Robert Mariner (USGS, Menlo Park, CA); data entry funded by Robert Mariner in 2001-2002). (Mariner.xls)
Mariner, R.H., and Janik, C.J., 1995. Geochemical data and conceptual model for the Steamboat Hills geothermal system,
Nehring, N.L., Geochemistry of
Stamates, M, 2001, Evaluation of injection effects on the Dixie Valley, Nevada, geothermal reservoir system through the use of geochemical data. University of
Trexler, D.T., B.A. Koeing, T. Flynn, J.L. Bruce, G. Ghusn, Jr., 1981. Low-To-Moderate Temperature Geothermal Resource Assessment for
Washoe County Department of Public Works files and personal communication with Mr. Michael Widmer. Digital data entered from hard copy supplied to Washoe County Department of Public Works files for samples collected at Steamboat Hot Springs from 1998 through 2001.
White, D.E., 1968. Hydrology, Activity, and Heat Flow of the Steamboat Springs Thermal System,
Yeamans, F., 1988. Unpublished Data: Bureau of Laboratories and Research,
Individual samples quite likely occur in more than one database. Each existing digital database was included in its entirety, hence, there may be duplicate sample analyses for a particular site on a particular day in the combined Access database.
A spring area name was assigned to each sample that was located within a known spring area (e.g., see groupings depicted in the map at http://www.nbmg.unr.edu/geothermal/gthome.htm). The constructed database locations were imported into ArcView, as were the locations of all known springs associated with an area name. Any spring in the constructed database that was located within 2 km of the spring in the master spring file (http://www.nbmg.unr.edu/geothermal/Mapfiles/Master/Master.xls) was assigned that area name. Some areas, most notably from NWIS data, are outside of any known geothermal areas because that database specifically includes cold waters sampled by the USGS for purposes other than for geothermal assessments. No area names were assigned to those sites. Note, no locations (latitude, longitude) in the combined Access database were checked, but all in the master file were checked for accuracy. For accurate locations, users should consult the master.xls file.
Note, most data sources and databases did not specify how or if the samples were filtered. It is assumed that, unless otherwise noted, the reported analyses were the result of filtering through 0.45 µm filter papers. Analyses are reported in mg/L for the major and trace element chemistry, tritium units (T.U.) for tritium, and per mil relative to SMOW for d18O and dD, and per mil relative to PDB for d13C. Note, the trace element analyses for the entries from the NWIS database are reported in µg/L. Details of the NWIS database can be found in the individual files obtained from their website: major_elem.xls, minor_trace.xls, phys_prop.xls, radio_chem.xls, header.xls, information.xls. Detailed descriptions of each of the fields can be found on the second tab of each of these spreadsheets.
New data are continuously being collected, some of which can be found in 2002 data. These new data will be incorporated into the master Access database as time permits.