Siltcoos Lake (silt’-koos), at , is the largest lake on the

Oregon Coast The Oregon Coast is a coastal region of the U.S. state of Oregon. It is bordered by the Pacific Ocean to its west and the Oregon Coast Range to the east, and stretches approximately from the California state border in the south to the Columbia ...

of the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. Fed by runoff from a basin of about in

Douglas Douglas may refer to: People * Douglas (given name) * Douglas (surname) Animals * Douglas (parrot), macaw that starred as the parrot ''Rosalinda'' in Pippi Longstocking *Douglas the camel, a camel in the Confederate Army in the American Civi ...

and

Lane In road transport, a lane is part of a roadway that is designated to be used by a single line of vehicles to control and guide drivers and reduce traffic conflicts. Most public roads (highways) have at least two lanes, one for traffic in each ...

counties, it is about south of

Florence Florence ( ; it, Firenze ) is a city in Central Italy and the capital city of the Tuscany region. It is the most populated city in Tuscany, with 383,083 inhabitants in 2016, and over 1,520,000 in its metropolitan area.Bilancio demografico an ...

and east of

U.S. Route 101 U.S. Route 101, or U.S. Highway 101 (US 101), is a north–south United States Numbered Highway that runs through the states of California, Oregon, and Washington, on the West Coast of the United States. It is also known as (The Royal Roa ...

. Its name comes from a Lower Umpqua ( Siuslaw) placename, a variant of which is ''Tsiltcoos''. The lake, with a mean elevation of above sea level, empties into the Siltcoos River, which meanders generally west for about to its mouth on the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

River mile A river mile is a measure of distance in miles along a river from its mouth. River mile numbers begin at zero and increase further upstream. The corresponding metric unit using kilometers is the river kilometer. They are analogous to vehicle roa ...

s between the ocean and the lake are marked on the map. A dam about a half-mile downriver regulates the lake's outflow.

Geology and biology

Siltcoos Lake is a submerged remnant of a Siltcoos River delta that existed before the most recent

ice age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gree ...

. The lake formed after melting glaciers caused a rise in sea level that drowned the lower reaches of Oregon's coastal rivers. Sediments from the sluggish rivers formed sand dunes, behind which the ancestral mouths of rivers like the Siltcoos became lakes. Nearby

Woahink Lake Woahink Lake (hō' hingk) extends further below sea level than any other lake dammed by sand dunes along the coast of the U.S. state of Oregon. The lake fills a depression in the Siltcoos River watershed about from the Pacific Ocean south of Flor ...

and Tahkenitch Lake are similar remnants. Fed mainly by four small freshwater tributaries—Woahink, Fiddle, Maple, and Lane creeks—the lake is very shallow. About 80 percent of it is less than deep, and 32 percent of it consists of shoal areas. The shallowness contributes to the lake's

eutrophic Eutrophication is the process by which an entire body of water, or parts of it, becomes progressively enriched with minerals and nutrients, particularly nitrogen and phosphorus. It has also been defined as "nutrient-induced increase in phytoplank ...

nature, related to extensive populations of

Elodea ''Elodea'' is a genus of 6 species of aquatic plants often called the waterweeds described as a genus in 1803. Classified in the frog’s-bit family ( Hydrocharitaceae), ''Elodea'' is native to the Americas and is also widely used as aquarium ve ...

Myriophyllum ''Myriophyllum'' (water milfoil) is a genus of about 69 species of freshwater aquatic plants, with a cosmopolitan distribution. The center of diversity for ''Myriophyllum'' is Australia with 43 recognized species (37 endemic). These submersed ...

, and other aquatic plants. A wide variety of warm-water fish thrive in the lake, where nutrients are plentiful, but these nutrients have also led historically to troublesome

algal bloom An algal bloom or algae bloom is a rapid increase or accumulation in the population of algae in freshwater or marine water systems. It is often recognized by the discoloration in the water from the algae's pigments. The term ''algae'' encompas ...

s. Some of the residents of Dunes City and nearby areas depend on the lake for drinking water. For 52 days in the fall of 2007, state and local authorities advised against domestic use of the lake water because of a dense bloom of Anabaena planktonica, a blue-green algal species that can produce toxins. The

Oregon Department of Environmental Quality The Oregon Department of Environmental Quality (DEQ) is the chief regulatory agency of the government of the U.S. state of Oregon responsible for protecting and enhancing the state's natural resources and managing sanitary and toxic waste disposal ...

(DEQ) has placed the lake on its list of impaired water bodies because of its problems with algae.

Recreation

Siltcoos Lake is a popular destination for fishing and is home to many warm-water species as well as transient seagoing fish such as

Coho salmon The coho salmon (''Oncorhynchus kisutch;'' Karuk: achvuun) is a species of anadromous fish in the salmon family (biology), family and one of the five Pacific salmon species. Coho salmon are also known as silver salmon or "silvers". The scientif ...

and

steelhead Steelhead, or occasionally steelhead trout, is the common name of the anadromous form of the coastal rainbow trout or redband trout (O. m. gairdneri). Steelhead are native to cold-water tributaries of the Pacific basin in Northeast Asia and ...

. Anglers try for bass weighing up to , as well as

perch Perch is a common name for fish of the genus ''Perca'', freshwater gamefish belonging to the family Percidae. The perch, of which three species occur in different geographical areas, lend their name to a large order of vertebrates: the Percif ...

catfish Catfish (or catfishes; order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the three largest species alive, ...

crappie Crappies () are two species of North American freshwater fish of the genus ''Pomoxis'' in the family Centrarchidae (sunfishes). Both species of crappies are popular game fish among recreational anglers. Etymology The genus name ''Pomoxis'' ...

bluegill The bluegill (''Lepomis macrochirus''), sometimes referred to as "bream", "brim", "sunny", or "copper nose" as is common in Texas, is a species of North American freshwater fish, native to and commonly found in streams, rivers, lakes, ponds and ...

, and

cutthroat trout The cutthroat trout is a fish species of the family Salmonidae native to cold-water tributaries of the Pacific Ocean, Rocky Mountains, and Great Basin in North America. As a member of the genus '' Oncorhynchus'', it is one of the Pacific tro ...

. The state record coho salmon was caught on this lake. The state record coastal cutthroat trout was caught here in 1984 by Kay Schmidt, 6 lbs 4 oz. Camping is available at several spots within a few miles of the lake. These include the iconic Darlings Marina and RV resort, located on North Beach of Siltcoos lake, ADA fishing resort located on Fiddle creek, Tyee Campground along the Siltcoos River; Waxmyrtle and Lagoon campgrounds, accessible from

south of the lake, and Driftwood II Campground, west of Lagoon Campground. Siltcoos Lake Seaplane Base is located at the lake. Base headquarters are in Westlake.

References

External links

* {{authority control Lakes of Oregon Lakes of Douglas County, Oregon Lakes of Lane County, Oregon

Geology and biology

Recreation

See also

References

External links