Water Reclamation Facility to Conduct a Dye Tracer Mixing Zone Study of River Outfall

As part of its state-issued National Pollutant Discharge Elimination System Permit, the Liberty Lake Sewer and Water District (LLSWD) Water Reclamation Facility will be conducting a dye tracer mixing zone study of its outfall to the Spokane River, which is required by the Washington State Department of Ecology.

An environmentally safe red dye, Rhodamine WT, will be used for the dye tracer test. It will be added to the facility’s effluent water before it enters the river. The dye will allow water quality scientists to analyze how the effluent from the facility mixes into the river water.

The test is scheduled for Wednesday, August 26, 2026, from 9:00 a.m. until 3:00 p.m. Those conducting the test will use equipment to access and take measurements at different locations and depths of the river near the outfall. A drone will also be used to capture aerial views of the dye mixing.

The dye may be viewed from near the Centennial Trail approximately 1/2 mile west of North Harvard Road. It may also be visible for up to 1/4-mile further downstream for the duration of the testing timeframe.