South Fork Bull Run River

The South Fork Bull Run River is a tributary, about 6 miles (9.7 km) long, of the Bull Run River in the U.S. state of Oregon. Part of the system that provides drinking water to the city of Portland, it flows generally west through a protected part of the Mount Hood National Forest in Clackamas County. It joins the Bull Run River at Bull Run Reservoir 2, about 8 miles (13 km) from the larger stream's confluence with the Sandy River.

Source: Wikipedia https://en.wikipedia.org/wiki/South_Fork_Bull_Run_River