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 (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

. 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 Civil ...

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 eac ...

counties, it is about south of

Florence Florence ( ; ) is the capital city of the Italy, Italian region of Tuscany. It is also the most populated city in Tuscany, with 362,353 inhabitants, and 989,460 in Metropolitan City of Florence, its metropolitan province as of 2025. Florence ...

and east of

U.S. Route 101 U.S. Route 101, or U.S. Highway 101 (US 101), is a major north–south highway that traverses the states of California, Oregon, and Washington on the West Coast of the United States. It is part of the United States Numbered Highway Syst ...

. 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 Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

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

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 g ...

. 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 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 a general term describing a process in which nutrients accumulate in a body of water, resulting in an increased growth of organisms that may deplete the oxygen in the water; ie. the process of too many plants growing on the s ...

nature, related to extensive populations of

Elodea ''Elodea'' is a genus of eight 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 v ...

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

, 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 fresh water or marine water systems. It is often recognized by the discoloration in the water from the algae's pigments. The term ''algae'' encompass ...

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 disposa ...

(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") and is often ...

and

steelhead Steelhead, or occasionally steelhead trout, is the Fish migration#Classification, anadromous form of the coastal rainbow trout or Columbia River redband trout (''O. m. gairdneri'', also called redband steelhead). Steelhead are native to cold-wa ...

. Anglers try for

bass Bass or Basses may refer to: Fish * Bass (fish), various saltwater and freshwater species Wood * Bass or basswood, the wood of the tilia americana tree Music * Bass (sound), describing low-frequency sound or one of several instruments in th ...

weighing up to , as well as

perch Perch is a common name for freshwater fish from the genus ''Perca'', which belongs to the family Percidae of the large order Perciformes. The name comes from , meaning the type species of this genus, the European perch (''P. fluviatilis'') ...

catfish Catfish (or catfishes; order (biology), order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Catfish are common name, named for their prominent barbel (anatomy), barbels, which resemble a cat's whiskers, though not ...

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 ''Pomoxi ...

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

, and

cutthroat trout The cutthroat trout (''Oncorhynchus clarkii'' clade) is a clade of four fish species of the Family (biology), family Salmonidae native to cold-water Tributary, tributaries of the Pacific Ocean, Rocky Mountains, and Great Basin in North America. ...

. 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