Chetco River - Watershed

Watershed

The Chetco River drains 352 square miles (912 km2) 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 5,098 feet (1,554 m) at the summit of Pearsoll Peak. Precipitation averages between 45 and 140 inches (1,143 and 3,556 mm) 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 93 acres (38 ha) have been identified in the watershed. Temperatures average between 32 and 82 °F (0 and 28 °C), although the Brookings effect (or Chetco effect; similar to a foehn wind) 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, 108 °F (42 °C), on July 8, 2008.

Earthquakes are common, and large-scale ones occur around every 300 years. The Cascadia earthquake of 1700—measuring over nine on the Richter 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 680 miles (1,100 km) long, slipped approximately 66 feet (20 m) 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 100 miles per hour (160 km/h). The Columbus Day Storm of 1962 brought devastating winds to nearly all of Oregon; nearby Port Orford recorded gusts exceeding 190 miles per hour (306 km/h). 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 500,000 acres (200,000 ha) of the Kalmiopsis Wilderness and surrounding regions.

As of the 2000 census, the city of Brookings had a population of 5,447, while nearby Harbor had 2,622. 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.