In Reply Refer To:
Mail Stop 412
June 26, 2007
Office of Water Quality Technical Memorandum 2007.04
Subject: Controlling Flow of Water-Quality Data to NWISWeb
Major changes are forthcoming to the National Water Information System (NWIS) processes for compilation and display of water-quality data on the NWISWeb system (http://waterdata.usgs.gov/nwis/nwis). This memorandum provides detailed guidance to the U.S. Geological Survey (USGS) Water Science Centers (WSCs) on options for controlling the release of water-quality data based on the policies described in Office of Water Quality Technical Memorandum 2007.03. This memorandum supercedes Office of Water Quality Technical Memorandum 2000.10.
The flow of water-quality data into an aggregated national database and subsequent NWISWeb display are controlled by WSC personnel by controlling the aggregation frequency and the attributes of the stored data. The aggregated national database will be used internally for national program needs and NWIS redesign investigations. A subset of the aggregated national database will be used to serve data to internet users via NWISWeb.
Controlling the attributes of stored data:
There are NWIS attributes at the site, sample, and result levels that each provides restrictions on the release of data. The exclusion effects are cumulative. For example, restricting data for a site restricts all the sample and result data for that site, regardless of the sample- and result-level attributes. Similarly, restricting a sample restricts all the stored results associated with that sample.
Site-web flag: This field contains the status and availability of a site record for display on NWISWeb. All sites will be aggregated nationally, but only records flagged with a ‘Y’ (which indicates that the record has been checked and is ready for web display) are displayed on NWISWeb. The site-web flag can be set by NWIS database administrators (DBAs) using programs described in the NWIS GWSI User's Manual.
District processing status code: In NWIS version 4.6 and earlier, the sample-level district processing status code (DSTAT) is one of two sample-level codes that can be used to control the release of samples and associated results. Samples with DSTAT code = Z [Complete, but do not transmit (Local-use data for internal use)] will not be displayed on NWISWeb. The DSTAT code has been eliminated in NWIS version 4.7, and specific elements of the code have been incorporated within a modified analysis status code domain as discussed below.
Analysis status code: The sample-level analysis status code (ASTAT) can also be used to control the flow of samples and associated results to NWISWeb. In NWIS version 4.6 and earlier, the ASTAT code was used to identify the workflow progression of data entry, review, approval, and distribution. The ASTAT codes are listed in table 7 of Appendix A of the QWDATA User's Manual.
In NWIS 4.7, the ASTAT domain will be revised and contain the following elements:
U - Unrestricted
I - Internal-use only
P - Proprietary
Proprietary data consist of information obtained by the USGS for which the Bureau’s rights of ownership are restricted in a manner that limits our ability to freely distribute the data (http://wwwnwis.er.usgs.gov/SECURITY/Privacy/Proprietary.data.Policy.html). Internal-use data, which include quality-control (QC) data, are generally not available to the public. Unrestricted data are available to the public, and the distribution of these data is not restricted in any way. Samples coded with an ASTAT of ‘P’ will not be aggregated nationally. Samples coded with an ASTAT of ‘I’ will be aggregated nationally, but not displayed on NWISWeb. Samples coded with an ASTAT of ‘U’ will be aggregated nationally and displayed on NWISWeb.
|Restriction Level||Data attribute||Values that allow the data flow to:|
|National aggregation||Display on NWISWeb|
|Site||Site-web flag||Not restricted||Yes|
|Sample||Analysis status code||U or I||Only U|
|Result||Data-quality indicator code||Not P, O, or X||Among A, S, or R|
|Null-value qualifier code||Not restricted||Not displayed|
|Parameter-public flag||Not restricted||Yes|
|Parameter code in 71995-71998 and result value = 4941||Not restricted||Not displayed|
|Parameter code = 72005 and result value in 44, 46, 69, or 70||Not restricted||Not displayed|
Controlling the aggregation frequency (future enhancement):
Walton H. Low /s/ for Timothy L. Miller
Chief, Office of Water Quality
This memorandum supersedes Office of Water Quality Technical Memorandum 2000.10.
Distribution: All WRD Employees