This data was then formatted into a relational data model by the StreamNet project and was georeferenced to the StreamNet lakes/reservoirs GIS coverage. This resulting coverage is a polygon coverage of the lakes and reservoirs where the sites exist and a point coverage of the specific point locations of sites. Each sample site has corresponding water quality sampling data in the WQ_LakeData table which is included in the data set. Approximately 65% of the lake sites in the original PSMFC lakes water quality data compilation were georeferenced to create these GIS coverages. The remaining 35% were not included because they could not be linked to a lake or reservoir with confidence. References are documented with the RefID field for each data record in the WQLake_Data table. Each RefID relates to the source reference of the data which is kept in hardcopy at the StreamNet library.
For questions about the dataset, use the following contacts:
Any questions concerning the original PSMFC data compilation can be directed to
Erik Hanson Pacific States Marine Fisheries Commission 45 SE 82nd Drive Suite 100 Gladstone, OR 97027 (503) 650-5400 erik_hanson@psmfc.org
Any questions about the georeferencing of this data or this GIS data file can be addressed to:
Travis Butcher Pacific States Marine Fisheries Commission StreamNet Project 45 SE 82nd Drive Suite 100 Gladstone, OR 97027 (503) 650-5400 travis_butcher@psmfc.org
Any background information, reports, or data can be found at:
StreamNet Library Columbia River Inter-Tribal Fish Commission Ste. 190, 729 NE Oregon St. Portland, OR. 97232-2107 (503) 731-1304 www.streamnet.org/library.html
Dataset structure:
This database contains a number of related tables, both spatial and tabular:
WQ_Lakes (spatial) - The polygons of the lakes that were sampled. Relates to the WQ_LakePoints (spatial) and WQ_LakeSites (tabular) data sets on the WaterBodyID field (one to many relationship). Each lake or reservoir has a unique StreamNet waterbodyID.
WQ_LakePoints (spatial) : Contains a point for each lake water quality sampling site. This may be helpful for determining the excact location of a sample site, particularly on large lakes where there were multiple sampling locations. Please note that some lake sites are not included in this points coverage. Lake sites are only included in this GIS data set when we could establish a very high level level of confidence (ie. greater than 99.5%) that this is the correct lake that the sampling took place on based on the information from the source PSMFC data set. Lake sites where we could not determine the correct lake with this high level of confidence were not included. Many of the latitude/longitude coordinates for the point locations of the site on the lake from the source PSMFC data set were found to be unreliable, mostly at the Idaho sites. Point locations of the lake sampling sites are only included in the GIS point coverage and longitude/latitude coordinates are only included in the table when the following criterion were met:
* The latitude/longitude point fell within the banks of the lake where the sampling is documented to take place.
* Both the latitude and the longitude information for the coordinate was detailed to at least 3 decimal degrees. This allows for a margin of error of no greater than approximately 300 feet in site location. Most sites are resolved to 4 degrees which limits the margin of error to approximately 30 feet.
WQ_LakeSite (tabular) - Contains information about each sampling site. Relates to the WQ_Lakes (spatial) data set on the WaterbodyID attribute (many to 1 relationship), and relates to the WQ_LakePoints (spatial) (one to one relationship) and WQ_LakeData (one to many relationship) on the LakeSite attribute.
WQ_LakeData (tabular) - Contains actual water quality measurements (one record per measurement).
WQ_Parameters - Describes the water quality parameters that were sampled for. Relates to the WQ_LakeData table on the ParamID attribute (one to many relationship)
WQ_Flag (tabular) - Describes flags which were given to some of the data samples. Relates to the WQ_LakeData table on the Flag attribute (one to many relationship).
WQ_Reference (tabular) Contains information about the source documents for these water quality records. Relates to the WQ_LakeData table on the RefID attribute (one to many relationship)
** NOTE: Tabular data is included with this data set both as single MS Access 97 database and as individual text files to serve the needs of various users. Additional attribute information for this tabular data is contained in the WQ_tabularformat.doc which is also included.