Discrete Water-Quality Data in NWISWeb In Reply Refer To: Mail Stop 412 September 15, 2000 Office of Water Quality Technical Memorandum 2000.10 Subject: Discrete Water-Quality Data in NWISWeb The NWISWeb software has been tested internally by the Water Resources Division (WRD) over the last few months and will be made available to the public on September 18, 2000. All discrete water-quality data through September 30, 1999 will be available, with some limitations. These limitations and a few points on future plans for water-quality data in NWISWeb are described below, particularly to help those who may have to answer questions from the public about the data. Listed at the end of this memorandum are two specific steps (and one optional step) Districts should perform to improve the data available on NWISWeb. The water-quality data were retrieved by each District in May 2000 and provided to NWIS. Some data were excluded from the Web-accessible data set for a variety of reasons. 1. District Processing Status: All data with a code of 'R' (ready to transmit) or 'T' (transmitted) were initially retrieved. Samples coded as 'Z' (local only) were excluded from the retrieval. 2. Analysis Status: All samples with a code of '9' (proprietary) for the Analysis Status were removed from the NWISWeb database. Although it is suspected that these samples were coded erroneously as proprietary data, all such sample data were excluded (to err on the side of caution). Refer to John Brigg's July 6, 2000 email for information regarding the number of samples in your District coded "proprietary," and steps to take review these samples. 3. Unapproved method data: Data analyzed by unapproved methods at the National Water Quality Laboratory (NWQL), and other U.S. Geological Survey labs were screened from the NWISWeb database. The specific parameter code and method code combinations that were screened are listed at the following web location: http://ok.water.usgs.gov/nawqa/phoenix/www/nonweb_pcodes.html 4. Water Year (WY) 2000 data: These data are not included in this release for several reasons. First, much of these data are preliminary. WRD policy (WRD 95.19) for release of preliminary water-quality data on the web that may exceed regulatory standards and for required quality control are not in place. Also, the capability to update discrete water-quality data is not included in this release of NWISWeb. Current plans are to retrieve and reload the water-quality data in the spring of 2001. Plans are being made to develop appropriate policies and to put a timely data reload process in place for water-quality data, so that our current water-year data can be included in the future. 5. Site Flag: Districts have the capability to set a flag in the sitefile to prevent the display of all data from that site on the Web. The sitefile in NWISWeb is reloaded frequently, and changes to this site flag will determine whether or not any data, including water-quality data, can be viewed. The water-quality data provided to NWISWeb were retrieved without rounding. NWQL data stored in NWIS since April 1997 have been stored as 'raw' or unrounded values, and the exact nature of those raw values has varied with analytical method. NWISWeb currently displays the unrounded data. During the last three years, the data may indicate much more precision than is 'real.' The spring 2001 retrieval and reload using NWIS 4_1 will provide rounded values to NWISWeb. Most of the selection options in this first release of NWISWeb are site-based criteria. The only chemistry-based data selection option is a parameter group. There are suggestions for retrieving the data in the help sections of NWISWeb. Additional selection criteria more tailored to discrete water-quality data will be included in the next release. A data refresh is planned for October 2000. The refresh is required for two reasons. First, if the site flag was turned off at the time of the original load of water-quality data, no data will be loaded for that site. The refresh provides an opportunity to add that data. Second, some Districts would like to provide a fresh retrieval of their data. Districts will need to decide whether to make a new retrieval or stay with the data already retrieved in May. Those sites that have cleaned up their data since May 2000 should do a new retrieval. All sites will be asked to retrieve their data again in the Spring of 2001. At that time, WY 2000 data will be added to NWISWeb. This implementation of the discrete water-quality system of NWISWeb is a first step. There are many improvements to be made and new capabilities to be added to this system. An NWISWeb User Group will work with the NWISWeb development team, the Water Quality User Group (a.k.a. the Phoenix Group), and representatives from the water quality user community to define the requirements and prioritize their implementation. Mark Brigham (Minnesota District, Phoenix member), and Mark Nilles (Office of Water Quality, Atmospheric Deposition Program Coordinator) are the specific water-quality representatives on the NWISWeb User Group. District ACTIONS for NWISWeb water-quality data: 1. Check site flag status before the NWISWeb refresh in October 2000. 2. Check the validity of any samples with an analysis status code of "9" (proprietary) and make corrections so these samples will be included in the data retrieved this fall (optional) or next spring. 3. Optional: Make a new retrieval of your District water-quality data for the October 2000 refresh. Janice R. Ward /s/ Acting Chief, Office of Water Quality This memorandum does not supercede any other OWQ Technical Memorandum. Distribution: All WRD Employees (See attached file: techmemo0010.doc) ************************************************** Janice Ward Acting Chief, Office of Water Quality US Geological Survey Reston, VA 703-648-6871 jward@usgs.go