|- left||Farrell Creek, Bryan Creek|
|- right||Bronson Creek, Harvey Creek|
|Cities||Newberg, Oregon, Dundee, Oregon|
|Source||East side of the Oregon Coast Range|
|- location||Above Larsen Reservoir 6 mi (10 km) southeast of Gaston, Oregon|
|- elevation||560 ft (171 m)|
|- location||Newberg, Oregon|
|- elevation||59 ft (18 m)|
|Basin||170 sq mi (440 km2)|
Chehalem Creek is a stream in Yamhill County, Oregon with a 43,400-acre (176 km2) watershed. A tributary of the Willamette River, Its headwaters rise on the eastern slope of the Oregon Coast Range above Larsen Reservoir 6 mi (10 km) southeast of Gaston and discharge into the Willamette near Newberg. The word "Chehalem" is a corruption of the Atfalati Indian word "'Chahelim'", a name given in 1877 to one of the bands of Atfalati.
The indigenous Che-ahm-ill people of the "Yam Hills" area were a sub-group of the Kalapuyan culture. They occupied the valley at the time of Euro-American contact and for several decades afterward until their numbers dwindled and the few survivors were removed with other tribes to reservations, primarily the Grand Ronde Reservation in the Oregon Coast Range. By 1812 Pacific Fur Company traders entered the Willamette Valley under the leadership of Donald Mackenzie—this was the first documented contact between Kalapuyan and European people. Ewing Young, after leading pioneering fur brigades in California, came to Portland in 1834 and settled on the west bank of the Willamette River near the mouth of Chehalem Creek, opposite of Champoeg. Young's home is believed to be the first house built by European-Americans on that side of the river.
The first white explorers to the valley in the 1820s reported large prairies, oak savannas, and thick smoke from widespread burning by the Indians during the late summer. When Indian populations were decimated by European diseases, a Coast Douglas-fir (Pseudotsuga menziesii) forest matured over a last century and a half since there was no longer suppression of the natural forest by Indians. Indian-set fires were common since at least 1647 but ceased after 1848 according to tree ring analysis or dendrochronology. This changed in the twentieth century when the timber industry logged off the woods. Writing in 1902, J. E. Kirkwood explained that in the 50 years since the first considerable immigration into western Oregon, most of the original forest had been cleared in the lowlands.A 1947 Department of the Interior report, stated that the forests of Yamhill County were "seriously depleted" and the number of jobs in forestry and wood products was expected to drop due to "reduced lumber production resulting from exhaustion of local timber supplies."
In the 1980s stocking of hatchery coho salmon and rainbow trout discontinued after biologists began to question detrimental interactions between wild (native) and stocked species. In 1998 Winter steelhead (Oncorhyncus mykiss) in the upper Willamette watershed were listed as threatened under the Federal Endangered Species Act. The Chehalem Valley has several native anadromous species: winter steelhead, Pacific lamprey (Lampetra tridentata), and spring chinook salmon (Oncorhynchus tshawytscha). Because cutthroat trout (Oncorhynchus clarki clarki) are more widely distributed in the small streams of the Chehalem watershed than any other salmonid, the effects of habitat restoration programs can be more readily discerned by looking at the effects on trout, the latter an excellent indicator of water quality. The cutthroat are non-migratory.
When a beaver family built several dams on a tributary of Chehalem Creek upstream from the West Sheridan Street culvert, a large beaver pond formed and threatened the road bed. The city hired a professional trapper to rid the stream of beavers. However, the city reversed its order to kill the beavers when local citizens complained about the inhumane nature of using a trap likely to drown the beaver and also that wildlife had been resurgent since the beavers arrived. A third option might be to consider installation of a Flow device which utilizes pipe levelers and fencing to regulate the water level of beaver dams and keep culverts open.
- McArthur, Lewis A.; Lewis L. McArthur (2003) . Oregon Geographic Names (Seventh ed.). Portland, Oregon: Oregon Historical Society Press. ISBN 978-0-87595-278-9.
- "Chehalem Creek". Geographic Names Information System, U.S. Geological Survey.
- Chehalem Watershed Assessment (Report). Yamhill Basin Council. June 2001. http://www.co.yamhill.or.us/ybc/Assessments/cheassmnt.pdf. Retrieved May 6, 2010.
- Chehalem Creek Subwatershed Summary (Report). Yamhill Basin Council. http://www.co.yamhill.or.us/ybc/Monitoring/WQM0304/cheFnlRpt.pdf. Retrieved May 6, 2010.
- Hussey, John A. (1967). Champoeg: Place of Transition, A Disputed History. Oregon Historical Society.
- Gary Allen (Apr 27, 2010). "Beaver dams wreak havoc on drainage". Newberg Graphic. Retrieved May 4, 2010.
- Melica Johnson (Apr 29, 2010). "Controversy swirls over beaver dams". KATU News. Retrieved May 4, 2010.
- David Sale (May 12, 2010). "Beaver believers urge mitigation for local population". Newberg Graphic. Retrieved May 15, 2010.
- Michael Callahan (April 2003). "Beaver Management Study". Association of Massachusetts Wetland Scientists (AMWS) Newsletter: 12–15.