Коос Бұхтасы: Орегонның ірі эстуарийі

Estuary in Oregon, United States
the body of water
Coos Bay is an estuary where the Coos River enters the Pacific Ocean, the estuary is approximately 12 miles long and up to two miles wide. It is the largest estuary completely within Oregon state lines. The Coos Bay watershed covers an area of about 600 square miles and is located in northern Coos County, Oregon, in the United States. The Coos River, which begins in the Oregon Coast Range, enters the bay from the east. From Coos River, the bay forms a sharp loop northward before arching back to the south and out to the Pacific Ocean. Haynes Inlet enters the top of this loop. South Slough branches off from the bay directly before its entrance into the Pacific Ocean. The bay was formed when sea levels rose over 20,000 years ago at the end of the Last Glacial Maximum, flooding the mouth of the Coos River. North Bend, located at the apex of the peninsula, is home to the Southwest Oregon Regional Airport. The estuary has been altered over 150 years of modern anthropogenic use. Dredging, deepening, river diversion and spoil disposal has led to physical, biological, and chemical changes to the system over time.

The bedrock of the greater Coos Bay region was formed from the Mesozoic through the Pliocene eras out of volcanic rock, sedimentary rock, and igneous rock intrusions. The area's geologic history is highlighted by tectonic interaction between oceanic and continental plates. The center of Coos Bay, where the towns of North Bend and Coos Bay sit, was formed during the late Pliocene or early Pleistocene. These formed much more recently as sand was deposited along the coast after eroding from other areas. By studying the transition from peaty to muddy intertidal sediment and the associated microfossils in the estuary, researchers were able to determine 10 instances of sudden rises in sea level as a potential proxy for earthquakes, including two dating 1,700 and 2,300 years ago when sea level rose by at least half a meter. This same study also found evidence of a large earthquake 300 years ago along the great plate boundary. and is heavily influenced by the Pacific Ocean and precipitation from the Coast Range. Regional weather consists of a cool, wet season in the winter (October through April) with an average annual rainfall of 56 inches, and a mild, dry season in the summer (May through September) with an average rainfall of less than 4 inches. Air temperatures range from 40° to 75 °F. Winter storms lead to accumulation of winter precipitation and which is a significant input of fresh water and sediments. For an estuary, this involves the tributaries and their flow rates, bottom topography, water discharge and the drainage basin, and sedimentation and deposition.

Jordan Cove, located across the inlet from the airport, was the proposed site of a liquefied natural gas (LNG) terminal by Jordan Cove Energy Project. The terminal would have exported liquefied natural gas from an underground pipeline that would have met with existing pipelines near Malin. The terminal and pipeline projects were cancelled in 2021. Oregon Governor Kulongoski expressed various environmental concerns.