The 1844 Km² Tualatin River basin feeds into the Willamette River near Portland, Oregon. The Tualatin River Watershed Council has created an interactive map of the basin with more information regarding its natural history and land use.

For our current study, we selected three sub-basins (Fanno Creek, Rock Creek, and Chicken Creek) because they represent a gradient of development history with ongoing monitoring of flow and steam temperature.