Publication Summary

The purpose of the Woodland Creek temperature study is to characterize mainstem and tributary surface water temperature regimes, channel morphology, hydrology, and streamside vegetation within the watershed. Woodland Creek is a small (29.7 mi2) watershed located in Thurston County, Washington, and is the largest tributary to the Henderson Inlet of Puget Sound.

The purpose of the Woodland Creek temperature study is to characterize mainstem and tributary surface water temperature regimes, channel morphology, hydrology, and streamside vegetation within the watershed. Woodland Creek is a small (29.7 mi2) watershed located in Thurston County, Washington, and is the largest tributary to the Henderson Inlet of Puget Sound.

Analysis of historical surface water temperature data in Woodland Creek show that violations of the Class AA criteria of 16°C occur only in the upper portions of the mainstem. Streamflow in this portion of the creek is derived from a series of shallow lakes which, during the summer months, frequently reach temperatures of 24°C. In addition, this same section of Woodland Creek can be characterized as influent or ‘losing′ (to the surrounding aquifer) and is frequently dry between the months of May and November. It is believed that these two conditions exert a major influence on surface water temperatures in the upper portions of Woodland Creek.

A predictive computer temperature model of the Woodland Creek stream system will be used to calculate the components of the heat budget and simulate surface water temperatures. Field data will be used to build model components and verify model output.

Results from this study will assist in determining whether surface water temperature exceedences in the upper portions of Woodland Creek are the result of natural or anthropogenic influences. A temperature TMDL will be initiated if surface water temperature violations in Woodland Creek are due to anthropogenic influences. The TMDL technical assessment will use effective shade as a surrogate measure of heat flux. Air and water temperature sites will be established at seven mainstem and three tributary locations for a period of five months (June-October). Periodic flow measurements, channel morphology, and streamside vegetation data will be collected at all ten sites.