| Fir Creek | |
| Map: | Bull run river oregon watershed map.png |
| Map Size: | 300 |
| Pushpin Map: | USA Oregon |
| Pushpin Map Size: | 300 |
| Pushpin Map Caption: | Location of the mouth of Fir Creek in Oregon |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Subdivision Type2: | State |
| Subdivision Name2: | Oregon |
| Subdivision Type4: | County |
| Subdivision Name4: | Multnomah and Clackamas counties |
| Length: | 5miles[1] |
| Discharge1 Location: | 0.6miles from the mouth |
| Discharge1 Min: | 1.4cuft/s |
| Discharge1 Avg: | 34.5cuft/s |
| Discharge1 Max: | 1690cuft/s |
| Source1: | Mount Hood National Forest |
| Source1 Location: | Clackamas County, Oregon |
| Source1 Coordinates: | 45.46°N -121.9519°W[2] |
| Mouth: | Bull Run River |
| Mouth Location: | Multnomah County, Oregon |
| Mouth Coordinates: | 45.4906°N -122.0281°W |
| Mouth Elevation: | 1089feet |
| Basin Size: | 5.46sqmi |
Fir Creek is a tributary, about 5miles 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 northwest through a protected part of the Mount Hood National Forest in Clackamas and Multnomah counties. It joins the Bull Run River at the upper end of Bull Run Reservoir 1, about 14miles from the larger stream's confluence with the Sandy River.
The creek arises in the Mount Hood National Forest in northern Clackamas County near its border with Multnomah County. The stream flows north, crossing the border almost immediately and entering Multnomah County. Turning west, it receives an unnamed tributary from the right before turning gradually northwest. It passes under Forest Road 1211 and by a United States Geological Survey (USGS) stream gauge 0.6miles from the mouth. The creek joins the main stem Bull Run River near the upper end of Bull Run Reservoir 1, about 14miles from where the river joins the Sandy River.[1] [3]
Since 1975 the USGS has monitored the flow of Fir Creek at a stream gauge 0.6miles from the mouth. The average flow between then and 2009 was 34.5cuft/s. This is from a drainage area of about 6sqmi. The maximum flow recorded during this period was 1690cuft/s on November 25, 1999. The minimum was 1.4cuft/s on September 5 - 7, 2003.[4]
The Bull Run River watershed, which includes Fir Creek, drains 139mi2.[5] The basin, which is the main source of Portland's drinking water, is largely restricted to uses related to water collection, storage, treatment, and forest management. The Fir Creek basin of about 6mi2 amounts to about 4 percent of the total Bull Run River watershed,[4] which is managed by the Portland Water Bureau and the United States Forest Service.[6]