Abstract: This dataset is a table of information about impaired water quality on stream sections in the state of Washington. Each record, or event, in the 98WA303d event table describes a segment of stream and records related to this segment in the 98W3DATA contain a list the parameter(s) (ie. chemical, temperature, nutrients, etc.) for which this segment of the stream has been classified as water quality impaired under section 303(d) of the Clean Water Act. This event table was generated by applying the Washington DOE (Department of Encology) 1998 303(d) GIS coverage to the PNW Reach files 1:100,000 scale hydrography. These event tables may thus be "mapped" on the PNW Reach 1:100,000 scale hydrography using the LLID stream-based routing system. Contact Info: Regional StreamNet GIS Specialist (StreamNetGIS@psmfc.org) (http://www.streamnet.org) Purpose: Data is intended for use in a variety of applications that utilize the PNW Reach hydrography 1:100,000 scale LLID-based stream routing system. This water quality data may be compared on this system to other stream-based data including but not limited to, fish distribution and abundance data, land use data, land ownership data, stream habitat data, etc. Limitations_of_Data: Data was transferred from the Washington 1998 303(d) GIS coverage to the 1:100,000 scale hydrography and only on streams that are included in the PNW reach LLID-based routing system. Generally, this includes all named streams at the 1:100,000 scale. Smaller tributaries that are not included in this routing system are not shown in this coverage. This dataset thus SHOULD NOT be interpreted as a comprehensive list of 303(d) water quality impaired streams in Washington. Approximately 7.6% of the original 303(d) water quality impaired stream segments could not be transferred to LLID-based event tables because there is no LLID for these streams in the PNW Reach files. All of these stream segments that could not be transferred are referenced in the 98W3UNMP table and can be related to the impairment information in the 98W3DATA table. For a complete listing of Washington 303(d) water quality impaired streams, contact Washington Department of Ecology via their web site at http://www.ecy.wa.gov/programs/wq/303d/index.html. It is important to note that this data is under constant revision and may change without notice. See Washington Department of Ecology for updates. Entity_and_Attribute_Overview: There are 3 tables contained in this dataset: 98WA303D - Contains the LLID-based stream locations for each 303(d) event. 98W3UNMP - Contains a list of the stream segments that could not be mapped to LLID locations. 98W3DATA - Contains the parameters for which streams segments are impaired. Each stream segment is identified by the key field "IIP303DID". This field is the primary key for the 98WA303D and 98W3UNMP tables and relates them to the parameter information in the 98W3DATA table. Table: 98WA303D (303d event table) Attribute Type Definition IIP303D_ID Character Unique Washington Dept of Ecology key that identifies each 303(d) listed stream segment. HUC Character US Geological Survey 4th code hydrologic unit which identifies the subbasin where this stream segment. See ftp://ftp.streamnet.org/pub/streamnet/ASCII_Data/HUC.txt for a list of Northwest HUCs. LLID Character Unique stream identifier (Longitude/Latitude ID) which consists of the longitude (first 7 digits) and latitude (last 6 digits) of the mouth of the stream. See http://www.streamnet.org/pnwr/PNWNAR.html for more information about the PNW Reach hydrography and LLIDs. See ftp://ftp.streamnet.org/pub/streamnet/ASCII_Data/LLIDStream.zip for a complete list of stream names of LLIDs. BEGFT Binary Fl.point Beginning stream measurement of distribution event in feet ENDFT Binary Fl.point Ending stream measurement of distribution event in feet Table: 98W3UNMP (303d unmapped events) IIP303D_ID Character Unique Washington Dept of Ecology key that identifies each 303(d) listed stream segment. HUC Character US Geological Survey 4th code hydrologic unit which identifies the subbasin where this stream segment. See ftp://ftp.streamnet.org/pub/streamnet/ASCII_Data/HUC.txt for a list of Northwest HUCs. LENGTH Binary Fl.point Length of the stream segment in the source Washington DOE GIS coverage. Table: 98W3DATA (303d water quality parameter information) IIP303D_ID Character Washington Dept of Ecology key that identifies each 303(d) listed stream segment. PARAMETER Character Water quality impairment for which this stream segment is listed. Stream segments may have multiple impairments. MEDIUM Character Water, tissue, and/or sediment. ACTION_NEEDED Character Action Needed, TMDL, or other control based on listed parameter. LIST_96 Character Listed in 1996 (Yes/No) Procedures_Used: Linked 303D events from the Idaho coverage to the PNW River Reach 100K hydrography. This was accomplished by taking the source WA DOE 303(d) GIS coverage, reprojecting it to the PNW reach files projection parameters and then extracting the beginning and end points of each stream segment into a new point coverage. These points were then analyzed in comparison to the PNW Reach file routes with an AML that uses the Arc/Info AddRouteMeasure command and varying radius tolerances. The results were then analyzed in database software and route assignments were only accepted if the LLID matched the LLID in the WA DOE coverage or if the stream name could be postively matched. The results were then QA'd by creating a GIS coverage with the new LLID events and visually overlaying it with the source WA DOE coverage and also by comparing the total length of each derived LLID event with the length of the source event in the WA DOE coverage. Once the QA process was complete, the events were intersected with a huc polygon coverage to determine the huc information and the final event table and related data table were derived and converted to dbase files. Revisions: This is the first version of this coverage (compiled Winter 2001). No further revisions are planned. Reviews_Applied_to_Data: See QA process under 'Procedures Used'. Related_Spatial_and_Tabular_Data_Sets: - PNW River Reach Hydrography (spatial)-- This is the base hydrography used to map these events. This data set is available for download from http://www.streamnet.org/pnwr/pnwrhome.html References_Cited: Not Applicable Notes: Not Applicable Currentness_Reference: Data is current as of 1998. Maintenance_and_Update_Frequency: No additional maintenance or updates are planned. Access_Constraints: Not Applicable Data_Set_Credit: Data was compiled by the StreamNet project (http://www.streamnet.org) in cooperation with the Environmental Protection Agency (EPA), Region 10. Source 303(d) listings and GIS coverage were compiled by the Washington Department of Ecology. Completeness_Report: Complete data set. See "Limitations of Data" for limitations. Horizontal_Positional_Accuracy_Report: Not Applicable Vertical_Positional_Accuracy_Report: Not Applicable Cloud_Cover: Not Applicable