Flathead Lake ( fla, člq̓etkʷ, label=
Salish, kut, yawuʔnik̓ ʔa·kuq̓nuk) is a large natural lake in northwest
Montana
Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columb ...
.
The lake is a remnant of the ancient, massive glacial dammed lake,
Lake Missoula of the era of the last
interglacial. Flathead Lake is a natural lake along the mainline of the
Flathead River. It was dammed in 1930 by
Kerr Dam
The Seli’š Ksanka Qlispe’ Dam previously known as the Kerr Dam is a concrete gravity-arch dam located at river mile 72 of the Flathead River (116 river kilometer). Built in 1938, it raises the level and increases the size of Flathead Lake nea ...
at its outlet on Polson Bay, slightly raising the lake level; the dam generates electricity.
[Kerr Dam](_blank)
PPL Montana The hydroelectric has been owned and operated by the
Confederated Salish and Kootenai Tribes since 2015. It is one of the cleanest lakes in the populated world for its size and type.
[Flathead Lake & Watershed Overview](_blank)
Flathead Lakers
Geography
Located in the northwest corner of the state of
Montana
Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columb ...
, south of
Kalispell, it is approximately long and wide, covering . It is a similar size as Minnesota's
Mille Lacs Lake, but smaller than
Red Lake. It is about half the area of
San Francisco Bay
San Francisco Bay is a large tidal estuary in the U.S. state of California, and gives its name to the San Francisco Bay Area. It is dominated by the big cities of San Francisco, San Jose, and Oakland.
San Francisco Bay drains water f ...
(main bay). It is larger in surface area than
Lake Tahoe, but it is much smaller in volume due to Tahoe's depth.
Flathead Lake has a maximum depth of ,
[About Flathead Head](_blank)
Flathead Lake Biological Station, The University of Montana and an average of . This makes Flathead Lake deeper than the average depths of the
Yellow Sea
The Yellow Sea is a marginal sea of the Western Pacific Ocean located between mainland China and the Korean Peninsula, and can be considered the northwestern part of the East China Sea. It is one of four seas named after common colour ter ...
or the
Persian Gulf
The Persian Gulf ( fa, خلیج فارس, translit=xalij-e fârs, lit=Gulf of Fars, ), sometimes called the ( ar, اَلْخَلِيْجُ ٱلْعَرَبِيُّ, Al-Khalīj al-ˁArabī), is a mediterranean sea in Western Asia. The bo ...
. Flathead Lake is in a scenic part of Montana, southwest of
Glacier National Park and is flanked by two scenic highways, which wind along its curving shoreline. On the west side is
U.S. Route 93
U.S. Route 93 (US 93) is a major north–south numbered highway in the western United States. The southern terminus is at US 60 in Wickenburg, Arizona. The northern terminus is at the Canadian border north of Eureka in Lincoln Cou ...
, and on the east, is
Route 35.
The lake is bordered on its eastern shore by the
Mission Mountains
The Mission Mountains or Mission Range are a range of the Rocky Mountains located in northwestern Montana in the United States. They lie chiefly in Lake County and Missoula County and are south and east of Flathead Lake and west of the Swan ...
and on the west by the
Salish Mountains. The Flathead valley was formed by the
glacial damming of the
Flathead River and sustains a remarkably mild
climate
Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorologi ...
for a region located this far north and inland; 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 conti ...
is almost to the west. The mild climate allows for
cherry orchard
An orchard is an intentional plantation of trees or shrubs that is maintained for food production. Orchards comprise fruit- or nut-producing trees which are generally grown for commercial production. Orchards are also sometimes a feature of ...
s on the east shore and
vineyard
A vineyard (; also ) is a plantation of grape-bearing vines, grown mainly for winemaking, but also raisins, table grapes and non-alcoholic grape juice. The science, practice and study of vineyard production is known as viticulture. Vineyard ...
s for
wine
Wine is an alcoholic drink typically made from Fermentation in winemaking, fermented grapes. Yeast in winemaking, Yeast consumes the sugar in the grapes and converts it to ethanol and carbon dioxide, releasing heat in the process. Different ...
production on the west shore. There are also
apple
An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple trees are cultivated worldwide and are the most widely grown species in the genus '' Malus''. The tree originated in Central Asia, where its wild ancest ...
,
pear
Pears are fruits produced and consumed around the world, growing on a tree and harvested in the Northern Hemisphere in late summer into October. The pear tree and shrub are a species of genus ''Pyrus'' , in the Family (biology), family Rosacea ...
and
plum
A plum is a fruit of some species in ''Prunus'' subg. ''Prunus'.'' Dried plums are called prunes.
History
Plums may have been one of the first fruits domesticated by humans. Three of the most abundantly cultivated species are not found ...
orchards around the lake as well as
vegetables,
hay,
honey
Honey is a sweet and viscous substance made by several bees, the best-known of which are honey bees. Honey is made and stored to nourish bee colonies. Bees produce honey by gathering and then refining the sugary secretions of plants (primar ...
,
nursery tree,
Christmas tree,
sod/turf, and
wheat
Wheat is a grass widely cultivated for its seed, a cereal grain that is a worldwide staple food. The many species of wheat together make up the genus ''Triticum'' ; the most widely grown is common wheat (''T. aestivum''). The archaeologi ...
production bordering or near the lake.
There are several islands in the lake.
Wild Horse Island
Wild Horse Island (Montana Salish: Čt'išeʔém, Kutenai: kwiⱡq̓anqmi), approximately in size, is the largest island on Flathead Lake, the largest freshwater lake in Montana. Protected as a state park since 1977, the island near Big Arm Ba ...
is the largest at .
Melita Island is a island on Flathead Lake, located about one-half mile off the west lakeshore. At its highest point Melita is above water level. The closest access is from Walstad Landing (one and a half miles), a state-maintained landing off Highway 93, approximately 15 minutes north of
Polson. The island is owned by the
Montana Council of the
Boy Scouts of America
The Boy Scouts of America (BSA, colloquially the Boy Scouts) is one of the largest scouting organizations and one of the largest youth organizations in the United States, with about 1.2 million youth participants. The BSA was founded in ...
, and is home to
Camp Melita Island, and is used and for other activities; there is a project for woodland rehabilitation run by the Montana Council. There is also a bald eagle reserve which is protected by the Native Americans. Boy Scouts began using the island in the 1940s.
History
Once known as "Salish Lake", this body of water was named for the
Salish Indians. Early European explorers, like
David Thompson, called them the Flathead Indians because of a misinterpretation of early
Native American sign language. A common misconception is that the name is derived from a practice of
head flattening
Artificial cranial deformation or modification, head flattening, or head binding is a form of body alteration in which the skull of a human being is deformed intentionally. It is done by distorting the normal growth of a child's skull by applyin ...
more common among tribes such as the
Chinook. There is no evidence to show that the
Salish ever had this custom. Since the late 19th century, the Salish were mostly removed to the
Flathead Indian Reservation
The Flathead Indian Reservation, located in western Montana on the Flathead River, is home to the Bitterroot Salish, Kootenai, and Pend d'Oreilles tribes – also known as the
Confederated Salish and Kootenai Tribes of the Flathead Nation. Th ...
, located at the southern end of the lake.
The
Seli’š Ksanka Qlispe’ Dam, built near
Polson, regulates the lake's water level, generates
hydroelectric power, and provides water for
irrigation
Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow crops, landscape plants, and lawns. Irrigation has been a key aspect of agriculture for over 5,000 years and has been devel ...
to support agriculture in the area. The lake has an irregularly shaped shoreline and a dozen small islands, the largest of which is a state park called
Wild Horse Island
Wild Horse Island (Montana Salish: Čt'išeʔém, Kutenai: kwiⱡq̓anqmi), approximately in size, is the largest island on Flathead Lake, the largest freshwater lake in Montana. Protected as a state park since 1977, the island near Big Arm Ba ...
. These islands cover .
The
Flathead River and the
Swan River (known also as the Bigfork River where it enters the lake) are the lake's major
tributaries
A tributary, or affluent, is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the main stem river drain the surrounding drain ...
. The lake is inhabited by the native
bull trout and
cutthroat trout, as well as the non-native
lake trout,
yellow perch
The yellow perch (''Perca flavescens''), commonly referred to as perch, striped perch, American perch, American river perch or preacher is a freshwater perciform fish native to much of North America. The yellow perch was described in 1814 by Sam ...
, and
lake whitefish. Local residents have reported sighting other aquatic fauna in the lake as well, such as
sturgeon
Sturgeon is the common name for the 27 species of fish belonging to the family Acipenseridae. The earliest sturgeon fossils date to the Late Cretaceous, and are descended from other, earlier acipenseriform fish, which date back to the Early ...
and the
Flathead Lake Monster.
The non-native
opossum shrimp
Mysida is an order of small, shrimp-like crustaceans in the malacostracan superorder Peracarida. Their common name opossum shrimps stems from the presence of a brood pouch or "marsupium" in females. The fact that the larvae are reared in this ...
, (''Mysis diluviana''), were introduced by Montana Department of Fish, Wildlife and Parks in the Flathead drainage basin to encourage production of larger kokanee salmon; they migrated into Flathead Lake and have altered the ecosystem.
Fishermen had introduced lake trout 80 years prior but remained at low densities until the non-native Mysis became established. The bottom-dwelling mysids eliminated a recruitment bottleneck for lake trout by providing a deep water source of food where little was available previously. Lake trout subsequently flourished on mysids; this voracious piscivore now dominates the lake fishery. The formerly abundant
kokanee were extirpated, and native bull and westslope cutthroat trout are imperiled. Predation by Mysis has shifted
zooplankton
Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...
and
phytoplankton
Phytoplankton () are the autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater ecosystems. The name comes from the Greek words (), meaning 'plant', and (), meaning 'wanderer' or 'drifter'.
...
community size structure. Bayesian change point analysis of primary productivity (27-y time series) showed a significant step increase of 55 mg C m−2 d−1 (i.e., 21% rise) concurrent with the mysid invasion, but little trend before or after despite increasing nutrient loading. Mysis facilitated predation by lake trout and indirectly caused the collapse of kokanee, redirecting energy flow through the ecosystem that would otherwise have been available to other top predators (bald eagles).
Geology
Flathead Lake lies at the southern end of a geological feature called the
Rocky Mountain Trench. The
trench, which formed with the
Rocky Mountains
The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico ...
, extends north into the southern
Yukon
Yukon (; ; formerly called Yukon Territory and also referred to as the Yukon) is the smallest and westernmost of Canada's three territories. It also is the second-least populated province or territory in Canada, with a population of 43,964 as ...
as a straight, steep
valley
A valley is an elongated low area often running between hills or mountains, which will typically contain a river or stream running from one end to the other. Most valleys are formed by erosion of the land surface by rivers or streams ove ...
, which also holds the headwaters of the
Columbia River. During the last
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 gre ...
this trench was filled by an enormous
glacier
A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such a ...
. As the glacier moved southward it carved out the trench. The Polson Moraine, near present-day
Polson, Montana, marks the southernmost extent of the glacier during the last ice age and thus is the site of the glacier's
terminal moraine.
The large size of the Polson Moraine indicates that the glacier stalled here for many years before retreating. As the climate warmed, a portion of the glacier in the Mission Valley receded more slowly than the main body, which kept the lake basin from being filled with sediment. Eventually this ice also melted, forming a lake behind the moraine. Once the water reached the top of this
moraine dam, it began to cut a channel through it. Most
moraine dammed lakes drain quickly because water cuts entirely through the moraine. However, Flathead Lake remains because a
bedrock hill buried underneath the Polson Moraine prevented the moraine from being completely cut through so the meltwater never completely drained.
At one time, probably when the valley was partially filled by a
glacier
A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such a ...
, the level of Flathead Lake was about higher and drained through the valley west of
Elmo, Montana
Elmo ( Salish: sqʷʔeʔ, Kutenai: k̓upawi¢q̓nuk) is a census-designated place (CDP) in Lake County, Montana, United States. The population was 180 at the 2010 census, up from 143 in 2000.
The townsite was platted in 1917. Elmo had a dock ...
, which is at the end of Big Arm Bay, bottom center in the aerial photo above. Water carved out a wide, flat-bottomed pass with a deeper, narrow channel at the south edge of the pass. The deeper channel and traces of the dry riverbed are still visible from Route 28.
Fish
Flathead Lake is home to a number of native and non-native fishes, and is managed cooperatively by both Montana Fish, Wildlife and Parks and the Confederated Salish and Kootenai Tribes. The lake is home to the semi-annual "Mack Days" Lake Trout fishing contest, which aims to reduce the non-native "Mackinaw trout" or
lake trout (''Salvelinus namaycush'') populations, as well as educate people about the Flathead Lake Fisheries Management Plan. Like the majority of other nonnative species, they became established in the lake from the late 1800s-early 1900s. The introduction of lake trout has placed increased pressure on the ecologically similar threatened native
bull trout (''Salvelinus confluentus'').
Since the inception of this event in 2002, over 402,000 lake trout have been harvested.
Another recent introduced non-native fish is the Dodd Fish, another name for
yellow perch
The yellow perch (''Perca flavescens''), commonly referred to as perch, striped perch, American perch, American river perch or preacher is a freshwater perciform fish native to much of North America. The yellow perch was described in 1814 by Sam ...
(''Perca flavescens'').
*Native
#
Cutthroat Trout
#Northern Pikeminnow
#
Bull Trout
#Mountain Whitefish
#Westslope Cutthroat Trout
*Nonnative
#
Brown Trout
The brown trout (''Salmo trutta'') is a European species of salmonid fish that has been widely introduced into suitable environments globally. It includes purely freshwater populations, referred to as the riverine ecotype, ''Salmo trutta'' morp ...
#
Lake Trout
#
Golden Trout
#Yellowstone Cutthroat Trout
#
Brook Trout
The brook trout (''Salvelinus fontinalis'') is a species of freshwater fish in the char genus ''Salvelinus'' of the salmon family Salmonidae. It is native to Eastern North America in the United States and Canada, but has been introduced elsewhere ...
#
Rainbow Trout
The rainbow trout (''Oncorhynchus mykiss'') is a species of trout native to cold-water tributaries of the Pacific Ocean in Asia and North America. The steelhead (sometimes called "steelhead trout") is an anadromous (sea-run) form of the coast ...
#
Kokanee Salmon
#
Northern Pike
The northern pike (''Esox lucius'') is a species of carnivorous fish of the genus ''Esox'' (the pikes). They are typical of brackish water, brackish and fresh waters of the Northern Hemisphere (''i.e.'' holarctic in distribution). They are kno ...
#
Yellow Perch
The yellow perch (''Perca flavescens''), commonly referred to as perch, striped perch, American perch, American river perch or preacher is a freshwater perciform fish native to much of North America. The yellow perch was described in 1814 by Sam ...
#
Largemouth Bass
The largemouth bass (''Micropterus salmoides'') is a carnivorous freshwater gamefish in the Centrarchidae ( sunfish) family, a species of black bass native to the eastern and central United States, southeastern Canada and northern Mexico, ...
#
Smallmouth Bass
#Sturgeon (sp)
In addition to these commonly-pursued game fish, the lake is also home to other native species that currently are not actively managed by government fish and wildlife agencies, including the
longnose sucker (''Catostomus catostomus''),
redside shiner
The redside shiner (''Richardsonius balteatus'') is a species of cyprinid fish found in the western 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 pr ...
(''Richardsonius balteatus''), and
slimy sculpin (''Cottus cognatus'').
Panorama
Notes
References
* Alt, David. "The Making of Flathead Lake" in ''Profiles of Montana Geology: A layman's guide to the Treasure State''. Butte, MT: Montana Bureau of Mines and Geology, 1984.
External links
Flathead Basin Commission
{{authority control
Bodies of water of Lake County, Montana
Geology of Montana
Lakes of Flathead County, Montana
Lakes of Montana
Lakes of the Rocky Mountains