Chetco River
The Chetco River is a stream located in the southwestern portion of the U.S. state of Oregon. It drains approximately of Curry County. Flowing through a rugged and isolated coastal region, it descends rapidly from about to sea level at the Pacific Ocean. Except for the lowermost, the river is located entirely within the Rogue River – Siskiyou National Forest. The river rises in the Kalmiopsis Wilderness, northwest of Chetco Peak at the junction of the Oregon Coast Range and the Klamath Mountains. It flows generally north, west, and then southwest, before emptying into the ocean between Brookings and Harbor, approximately north of the California state line. The Chetco River's watershed remains largely undeveloped, protected by the Rogue River – Siskiyou National Forest and the Kalmiopsis Wilderness. The upper of the river have been designated Wild and Scenic since 1988.
Native Americans have lived in the Chetco River's watershed for the last one to three thousand years. Several explorers, including Sir Francis Drake, George Vancouver, and Jedediah Smith, visited the region between the 16th and 19th centuries, and found the Chetco people inhabiting the area. Non-indigenous settlers arrived soon after gold and other precious metals were discovered in the 1840s and 1850s. The town of Brookings was founded in the early 20th century, and incorporated in 1951. Fourteen thousand residents of Brookings and Harbor rely on the Chetco for drinking water.
Supporting a large population of salmon and trout, the Chetco's water is of very high quality. The watershed is home to many other species, including several that are endemic to the Siskiyou Mountains area. The northernmost grove of Redwoods—the tallest trees on Earth—grow in the southern region of the Chetco's drainage basin. In total, the river is home to over 200 species of animals, and 97 percent of the watershed is forested.
Course
The Chetco River begins about east of Chetco Peak, approximately above sea level. It flows north, gathering small tributaries such as the Little Chetco River and Babyfoot Creek. The river turns west near the Pearsoll Peak, the highest point in the watershed. It receives Box Canyon Creek on the left bank, Tincup Creek on the right bank, and Boulder Creek on the left. It then flows south, gathering the South Fork Chetco River. A few miles farther south, the river passes through a Redwood grove. It flows between Bosley Butte to the north and Mount Emily to the south; the latter is the impact site of one of only four bombs known to have been dropped in the continental United States by an enemy aircraft. This occurred during the Lookout Air Raids of 1942.Turning southwest, the river flows through Alfred A. Loeb State Park and collects the North Fork Chetco River on the right at river mile 5. The Chetco becomes an estuary about from its mouth. It passes through the communities of Brookings to the north and Harbor to the south, and discharges into the Pacific Ocean.
Discharge
The United States Geological Survey monitors the flow of the Chetco River at a stream gauge at RM 10.7, which is northeast of Brookings. It opened in 1969, and continues to operate. The average flow was from a drainage area of, about 77 percent of the Chetco's total drainage basin. The maximum recorded flow was on December 22, 1964, during the Pacific Northwest flood of 1964. The minimum flow was on October 14, 1987.Watershed
The Chetco River drains of the southern Oregon Coast. About 78 percent is owned by the United States Forest Service, and another 5 percent is owned by the Bureau of Land Management. Sixteen percent is privately owned, while the remaining one percent is managed by the cities of Brookings and Harbor, Curry County, and the state of Oregon. Approximately 97 percent of the land is used for forestry, 2 percent for agriculture and rural areas, and 1 percent is urban. Gravel and minerals are mined from the lower and upper regions of the watershed, respectively.The region is mostly mountainous, characterized by steep river valleys. Elevations in the Chetco River watershed range from sea level to at the summit of Pearsoll Peak. Precipitation averages between per year, with October through June being the wettest months. Seventy percent of surface runoff is collected from rain, and 30 percent from rain on snow. Twenty-five separate wetlands totaling have been identified in the watershed. Temperatures average between, although the Brookings effect often brings localized hot weather to the Brookings area. The increase in temperature is caused by the geography of the region; cool air funnels down the Chetco River valley from the Siskiyou and Coast ranges, gradually heating up before eventually reaching Brookings as a warm wind. The mountains also shield the area from cool marine layers. Partially as a result of this phenomenon, Brookings recorded its highest temperature ever,, on July 8, 2008.
Earthquakes are common, and large-scale ones occur around every 300 years. The Cascadia earthquake of 1700—estimated at 8.7–9.2 on the moment magnitude scale—caused a tsunami to sweep across California, Oregon, Washington, and British Columbia, reaching Japan the next day. It was produced when the entire Cascadia subduction zone, about long, slipped approximately in a megathrust event. Another major earthquake occurred in 1873 near present-day Brookings. With a magnitude of 7.3, the quake was felt from Seattle to San Francisco. Wind is also a factor in the region; storms can sometimes reach over. The Columbus Day Storm of 1962 brought devastating winds to nearly all of Oregon; nearby Port Orford recorded gusts exceeding. The storm killed 38 people across the state and caused over $200 million worth of damage. The watershed often experiences wildfires, some of them major. The Biscuit Fire of 2002 burned over of the Kalmiopsis Wilderness and surrounding regions.
As of the 2010 census, the city of Brookings had a population of 6,336, while nearby Harbor had 2,391. In total, over 14,000 residents of the Brookings–Harbor area depend on the Chetco River for drinking water. Nearby watersheds include the Winchuck and Smith rivers to the south, the Pistol River to the north, and the Illinois River, a tributary of the Rogue River, to the north and east.
Flora and fauna
The Chetco River watershed is covered primarily by temperate coniferous forest, which includes species such as Douglas fir, western hemlock, white fir, Port Orford cedar, California incense cedar, and Sitka spruce. Jeffrey pine, knobcone pine, and golden chinquapin have also been identified. Hardwoods including tanoak, bigleaf maple, red alder, and Pacific madrone are common. Manzanita, hazelnut, vine maple, western skunk cabbage, and multiple species of berries and grasses make up the understory. Kalmiopsis, a flowering evergreen shrub and the namesake of the Kalmiopsis Wilderness, only grows in the Siskiyou Mountains. Several noxious weeds have also been identified, including gorse, Scotch broom, blackberries, and thistles.The most prevalent species of the extreme southern portion of the watershed is the coastal redwood, one of the tallest types of trees on Earth. The world's northernmost redwood grove is located near the south bank of the Chetco at RM 15, about north of the California border. Trees here are around 300 to 800 years old, in diameter, and some exceed tall. The redwoods were heavily logged in the early 20th century. Prior to logging, the massive trees created their own microclimate by capturing moisture from fog, and also by the immense amount of shade they produced. The redwoods region is less mountainous than the rest of the watershed, and meandering streams are much more common.
Over 200 species of animals inhabit the river and its tributaries. Birds such as loons, grebes, ducks, kingfishers, and bald eagles are known to live around streams and other regions of the watershed. Auks, gulls, and terns have been spotted around the river's mouth, and black-legged kittiwakes nest in the area during the winter. The wildlife in the Kalmiopsis region of the Chetco watershed is more diverse than that of any other region in Oregon. Mammals such as American black bears, black-tailed deer, bobcats, ring-tailed cats, and gray foxes are common inhabitants of this region. The rare Siskiyou chipmunk is endemic to the Klamath Mountains. Steelhead and chinook and coho salmon are the most common anadromous fish that inhabit the Chetco River. Steelhead are abundant and have been spotted in most major and minor streams. Chinook salmon usually travel as far as Boulder Creek, about halfway between the Chetco's headwaters and its mouth. Coho also generally stay in this area, but some have been found in the Granite and Carter Creek area, about above Boulder Creek. Coastal cutthroat trout can be found all around the watershed; some migrate to the ocean, while others live in the river and its tributaries year round. Pacific lamprey, three-spined stickleback, and various sculpins have also been observed.
Geology
The Chetco River flows through the ancient Klamath Mountain terrane, which is between 400 and 100 million years old, the oldest rocks in Oregon. The Klamath microcontinent was originally located beneath the ocean near southern California before separating hundreds of millions of years ago. Plate tectonics pushed the microcontinent north, and bits of granite, sea floor sediment, subduction zones, and coral reefs gradually accreted into small islands. Between 212 and 170 million years ago, a massive volcanic arc erupted on the Klamath microcontinent, binding the islands together in a single block. The Klamath microcontinent went through a period of intense tectonic activity known as the Siskiyou orogeny roughly 170 to 165 million years ago. The process was strong enough to force sedimentary rocks deep into the Earth's crust, melting them into large plutons of granite, which rose slowly to the surface. Shortly after, a large portion of sea floor was thrust over the older Klamath terranes; much of it is still visible atop Vulcan and Chetco peaks. This region is known as the Josephine Ophiolite, and contains a rare type of rock called peridotite, originating from the Earth's mantle.The mountainous terrain of the Chetco River watershed was created approximately 130 million years ago when the microcontinent collided with the much larger North American continent. The process uplifted the complex and exotic terranes of the microcontinent to form the Klamath Mountains. Many glaciers carved U-shaped valleys and cirques during the last ice age, and several alpine lakes still exist today.
Today, sandstone, shale, granite, and serpentine are the primary rock types in the Chetco region. Various forms of loam comprise its soil. Erosion levels are high due to a combination of high precipitation, steep slopes, and landslides, which can result in earthflows.