Stream Monitoring Unit Station Numbering System

Station numbers consist of two digits, a letter, and three more digits (e.g., 04A100). The first two digits of each station number is the Water Resource Inventory Area (WRIA) number. This number can be used to identify which basin each station is in according to the table, below. The letters identify a stream within the basin. Letters were assigned in sequence as monitoring stations were established. (Typically, letters closer to 'A' indicate larger streams.) The final three digits roughly indicate distance upstream. Generally, a station ending in '050' would be very close to the mouth while '150' would indicate a station nearer the headwaters.

Basin	WRIAs	Basin	WRIAs
Cedar/Green	8-9	Nooksack/San Juan	1-2
Columbia Gorge	27-29	Okanogan	48-53
Eastern Olympics	13-14, 16-19	Puyallup/Nisqually	10-12
Esquatzel/Crab Creek	36, 42-43	Skagit/Stillaguamish	3-5
Horseheaven/Klickitat	30-31	Spokane	54-57
Island/Snohomish	6-7	Upper and Lower Snake	32-35
Kitsap	15	Upper Columbia/Pend Oreille	58-62
Lower Columbia	24-26	Upper Yakima	38-39
Lower Yakima	37	Wenatchee	40, 44-47
Mid Columbia	41	Western Olympics	20-23