River & Stream Water Quality Monitoring

Station attribute descriptions

Washington State Department of Ecology

"Long-term" stations are monitored monthly every year. We currently have 62 long-term stations; most have been monitored for more than 20 years. "Basin" stations are monitored monthly for a single year. Often, basin stations are revisited every 5 years.

Latitude and longitude
Reported in decimal degrees. The datum is NAD 83 HARN.

LLID and Route Measure
The LLID is the "longitude/latitude identifier" number. It is a 13-character longitude/latitude-derived unique watercourse route identifier The identifier is based on position of the downstream point (mouth) of the watercourse. The identifier code is composed by concatenating the decimal degree values (to four places of precision) of the coordinates (minus the decimal points). The route measure is the distance in miles upstream from the point of longitude/latitude designated by the LLID. Since LLIDs have no width, measurements begin at approximately mid-channel of the stream being discharged into, hence this distance is not the same as river mile, which begins at the mouth of the stream.

Ben. Use
The Stream class (AA, A, or B) was superceded by the November 2006 water quality standards, which specify the individual beneficial uses each stream is expected to support. This field shows the designated Aquatic Life use (current uses include Char, Core, Salmonid Spawning, and Salmonid Rearing), the Aquatic Recreation use (extraordinary contact, primary contact, and secondary contact), and whether supplemental spawning temperature criteria apply (an interior code where 0=no supplemental criteria and >0 refers to different seasonal windows). (Note that a few waterbodies have exceptions to the standard criteria for the designated uses shown here.)


Upstream watershed area. Watershed area is often related to expected water quality. All else being equal, a stream draining a larger watershed may be expected to have greater discharge and carry greater loads and concentrations of dissolved and suspended materials.

Ecoregions are geographical areas with similar land-surface form, potential natural vegetation, land use, and soil classifications.


Counties are governmental subdivisions to Washington state.

Water Resource Inventory Area. Washington has been divided into 62 major watersheds and sub-watersheds. These divisions are often used at the state level to organize watershed-monitoring and -management activities.

The person listed here is generally the person responsible for monitoring at this station. Station-specific questions should be referred to this person.

Map detail
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The sampler's assessment of the stream bottom material at the sampling location (e.g., cobble, sand, mud).

The sampler's assessment of the flow regime at the station (e.g., tidal influence, stagnant, good flow).

Type of discharge gauging anticipated (e.g., continuous, staff, routed, tape-down)

The sampler's assessment of how well mixed the stream is at the sample site (and therefore how representative a single grab sample would be of cross-sectional conditions).

Elevation of the water surface above mean sea level.

The sampler's assessment of land uses in the vicinity of the station.

A Water Body IDentification number: An identifier generated by Ecology which designates stream reaches. Reaches boundaries were chosen such that water quality should be similar throughout the reach. This number may be useful when searching for Ecology technical reports.

Ecology Region
The Department of Ecology has four regional offices that serve Washington State. The Olympia office serves the Southwest region, Bellevue the Northwest, Yakima the Central, and Spokane the Eastern).

River mile
The distance of the station in miles measured up from the stream's mouth.

Location type
'Bank' samples are generally only collected where bridges are unsafe or unavailable and where the water appears to be well mixed with in reach of the bank. 'Bridge' samples are generally collected from in or near the thalweg (the area of strongest flow). 'Other' may refer to a footbridge, floatplane, culvert, wading, etc