Oak Creek is named for the Oregon white oak savanna and woodlands that once flourished in this watershed and to a lesser extent still does.
During the Kalpuyan era prior to 1850, the uplands were burned annually creating an oak savanna. The lowlands were primarily dry prairie or wetlands controlled by beaver dams and ponds. The upland forests of Oak Creek that are common today, did not exist prior to 1850. The deeply incised Oak Creek of the lowlands looked nothing like it does now, prior to 1850.
Oak Creek is one of the least developed watersheds in Corvallis and it is the largest watershed, even though most of it is outside of the municipal boundaries.
Oak Creek Statistics
- 8,199 Acres – Covers about 4% of the Marys River watershed.
- 15 miles long – Measured from its highest and furthest perennial flow at McCulloch Peak down to its outfall into the Marys River plus the length of its main tributaries.
- Highest point – McCulloch Peak at 2,155 above sea level.
- Lowest point – 210 feet above sea level at its confluence with the Marys River across from Avery Park.
- Main tributaries – Over 125 tributaries feed Oak Creek from the highlands—the principal tributaries are the West Branch, East Branch, Alder, Skunk, Mulkey, Russian and Lamprey Creeks.
- Flow rates – 5 cfs in summer, 5 cfs in winter, over 200 cfs at flood stage.
- Ownership – 40% OSU, 55% private, 5% City or County.
- Paved or built impervious surfaces – 5,5% of watershed is covered with pavement or buildings & 11% of the watershed is considered urban.
- Forest cover – 36% is covered with forest.
- Over 25 creek bridges – Is crossed by a road or pedestrian bridge about every half mile.
- Pollution status – State studies have found the creek has excessively high temperature and bacterial counts, culminating in 303(d) violations of the federal Clean Water Act.
- Mills – Six known mills were built in the Oak Creek watershed in the 1800’s—three lumber mills and three carding mills.
- Dams – There is one true dam remaining in Oak Creek. It is located to the southeast of the intersection of 53rd & Harrison Blvd. It is a pop-up dam owned and operated under State permit by OSU to provide irrigation water to the OSU Dairy Farm during the dry months. Ironically, OSU has the permit to withdraw more water per day than Oak Creek normally flows in the summer. Fortunately, OSU has never used its full permitted use and allowed Oak Creek to run dry. The dam is lowered during the wet season to allow unobstructed creek flow.
- Fish barriers – The last significant fish barrier is located in McDonald Forest just upstream from the Oak Creek Drive entrance to the forest. It is a concrete structure that was built decades ago for testing purposes. It is not used for that purpose but it still restricts fish passage. Other fish passages on Oak Creek have been removed in the past 15 years at great expense. An irrigation dam downstream of 35th Street was removed on OSU property. A raised culvert was re-engineered by ODOT for fish passage underneath Philomath Blvd east of Brooklane.
- Fish in Oak Creek – Despite all of the human abuses, small numbers of native fish continue to survive in this harsh environment, though in non-sustainably low populations. These species include Cutthroat Trout, Pacific Lamprey, mountain whitefish, rainbow trout, large-scale sucker, mountain sucker, speckled dace, redside shiners, reticulate sculpin and torrent sculpin. Up until 1980, three-spined stickelback were found in Oak Creek. During Willamette and Marys Rivers flooding, Chinook Salmon find refuge in the lower Oak Creek floodplain.
- Beaver – Beaver and beaver dams have been found in recent years in the lowland corridors of Oak Creek, including on OSU Campus…Beaver Nation!
- Northern boundary – McCulloch Peak east to Dimple Hill, south to Skyline West neighborhood and then east towards the west and south sides of Witham Oaks Hill.
- Western boundary – The western watershed boundary is Bald Hill (west and north sides to Mulkey Ridge, then north to McCulloch Peak).
- Southern boundary – A barely discernible ridge borders the North Branch Dunawi Creek watershed listing from northwest to southwest.
- Eastern boundary – The eastern headwaters at Chip Ross Park form a distinct border traversing from northwest to southeast. In the lowlands starting at Walnut Blvd, Witham Hill Oaks provides the eastern boundary, still traversing from northwest to southeast. In the lowlands starting at Harrison Blvd, a barely discernible ridge line continues to traverse from northwest to southeast through OSU Campus toward the Marys River.
Water Action Team Activities in Oak Creek
- Partnered with OSU Engineering School to conduct studies and design mitigation strategies to improve water quality and reduce the impact of the unnatural rapid response stormwater system draining into Oak Creek from campus.
- Provided consultation to OSU students to research and build rainwater harvesting systems on-campus, to reduce the impacts of stormwater runoff and to reuse for later irrigation.
- Produced a 3D model of the Oak Creek watershed as an educational tool.
- Led two bike tours of Oak Creek, as well as two hiking tours to the highest source of Oak Creek on McCulloch Mountain.
- Published an article in Wild in the Willamette to familiarize readers about the wonders of Oak Creek.
- Discovered and researched the Lost Creeks of Oak Creek.
- Partnered with OSU, Marys River Watershed Council, Marys Peak Group of the Sierra Club, Columbia River Inter-Tribal Watershed Council and Freshwater Illustrated to have a previously named 3-mile Oak Creek tributary named as Lamprey Creek—the first creek in the United States named after this most ancient species of fish (450 million-years-old) and one which spawns in Oak Creek.