Tryon Creek Watershed

The Tryon Creek Watershed in southwest Portland covers over 4,000 acres. About 3,000 acres are in the Portland city limits. Tryon Creek flows southeast for about 7 miles from its headwaters near Multnomah Village to its confluence with the Willamette River in Lake Oswego.

Single-family residential housing is the predominant land use. Parks and open space make up about 21% of the watershed. The Tryon Creek State Natural Area contributes a large portion of this undeveloped area and provides good habitat and recreation opportunities.

There are steep slopes throughout the watershed with predominant sandy loam soils. Major transportation corridors contribute to the large impervious surface area and fragment stream connectivity. The abundant forested areas consist of native plants as well as invasive vegetation. 

The Tryon Creek Watershed provides important habitat to fish, birds, and other wildlife.

The watershed is divided into three subwatersheds.

Tryon Creek Mainstem

The Tryon Creek subwatershed is 3,083 acres. The mainstem of Tryon Creek is about 7 miles long from its headwaters near Multnomah Village (just north of Interstate 5 and Highway 99) to its confluence with the Willamette River in Lake Oswego at the Highway 43 crossing.

Arnold Creek

The Arnold Creek subwatershed is about 775 acres. Arnold Creek joins Tryon Creek at the Boones Ferry Road crossing.

Falling Creek

The Falling Creek subwatershed is about 283 acres. Falling Creek joins Tryon Creek at SW 26th Avenue and Taylors Ferry Road. Other smaller tributaries flow into Tryon Creek both within and outside Portland's city limits.

For More Information

Contact Tryon Creek Watershed Manager Amin Wahab at 503-823-7895.