Copper River, Copper River Delta

Copper River, Copper River Delta

by | Jul 12, 2021

The Copper River watershed drains about 24,000 square miles (62,000 sq km) in the Wrangell, Chugach, and Saint Elias mountains and the mainstem flows for about 290 miles (470 km) to the Gulf of Alaska where it creates a wide delta, about 195 miles west-northwest of Yakutat and 30 miles southeast of Cordova, Alaska. The Ahtna Athabascan name for the river is “Atna’tuu” meaning “river of the Ahtnas”. The Tlingit name for the river is “Eeḵhéeni” meaning “river of copper”. The current name of the river comes from the copper deposits that were mined in the early 20th century, primarily from the Chitina River the main tributary. Commercial extraction of the copper was enabled by the construction of the Copper River and Northwestern Railway, built between 1908 and 1911 by the Alaska Syndicate. The railway ran 196 miles (315 km) from the Port of Cordova, across the Copper River Delta, to the Kennecott Mines in the Wrangell Mountains. The mines were abandoned in 1938 but the railroad grade is still used as a roadbed and many of the bridges still exist, including the Million Dollar Bridge crossing the Copper River at Miles Glacier near the head of the delta.

A dominant ecological feature of the Gulf of Alaska’s northern coastline is the Copper River Delta. A strong westward-flowing nearshore current transports the suspended sediments from the Copper River which are deposited in a chain of treeless sandy barrier islands. These islands provide a crucial role in protecting the Copper River Delta wetlands which are the largest on the west coast of North America and are globally recognized as a flyway and stopover for millions of migratory birds. The delta has 700,000 acres (283,280 ha) of shallow ponds, lakes, marshes, and stream and river channels. As a result of the 1964 Alaska earthquake, uplifted marshes and outwash plains form a dendritic pattern of freshwater streams and tidal channels along the coast. The Copper River sediments, along with those of the Scott, Sheridan, and Bering rivers, have also created 123,520 acres (49,987 ha) of mudflats that extend for 65 miles (105 km) along the coast. These mudflats serve an important ecological function by supporting a rich benthic invertebrate community, including small clams, amphipods, polychaete worms, and chironomid larvae. Macoma clams comprise 90 percent of the biomass and constitute the primary food source for millions of migrating shorebirds. Each spring, an estimated 12 million shorebirds, the largest gathering in the western hemisphere, stop along the shores of the Copper River Delta on their way to more northern nesting grounds. Among these migrants are nearly the entire Pacific coast population of dunlins and western sandpipers, as well as least sandpipers, knots, and short and long-billed dowitchers. Millions of migratory waterbirds use the delta to feed and nest including ducks, geese, and swans. Aleutian and Arctic terns, mew gulls, and northern phalaropes are also common nesters, as are bald eagles that feed on spawned-out salmon.

The delta supports an important commercial salmon fishery that is vital to the Cordova economy. Major runs of sockeye, Chinook, and coho salmon rely on the shallow coastal waters surrounding the delta, first as smolt when they leave the freshwater streams and rivers for the sea, then again when they return as adults to seek out their natal streams to spawn. The Copper River is famous for early returning salmon runs of Chinook and sockeye that have a high fat content required for the long upstream swim and are prized by restaurants for their flavor. Over 2 million salmon each year arrive at the delta to begin the upstream spawning run. The river’s commercial salmon fishery is very brief, beginning in May for Chinook and sockeye salmon for periods lasting only a few days or hours at a time, however, the sport fishery is open all year long. A subsistence fishery allows the use of dipnets and fish wheels. A dip net is a bag-shaped net supported on all sides by a rigid frame attached to a long handle and used to manually scoop fish from the river. A fish wheel is a fixed, rotating device for catching fish, which is driven by river current or other means of power. The Copper River salmon fisheries are co-managed by the Alaska Department of Fish and Game and the Department of the Interior Federal Subsistence Board based largely on data from fish counts at Miles Lake, Baird Canyon, and Canyon Creek sonar stations. Read more here and here. Explore more of the Copper River Delta here:

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