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Lewis River (Washington)
Encyclopedia
The Lewis River is a tributary of the Columbia River
, about 95 miles (152.9 km) long, in southwestern Washington in the United States
. It drains part of the Cascade Range
north of the Columbia River
. The drainage basin
of the Lewis River covers about 1046 square miles (2,709 km²). The river's mean annual discharge
is about 6125 cuft/s. Unlike nearby Lewis County
and Fort Lewis
the Lewis River was not named for Meriwether Lewis
, but rather for A. Lee Lewis, an early settler who homesteaded near the mouth of the river.
, approximately 75 miles (120.7 km) northeast of Portland, Oregon
. It flows generally southwest through Gifford Pinchot National Forest
, across central Skamania County, passing south of Mount St. Helens
. It forms the boundary between Cowlitz County
, to the north, and Clark County
, to the south. Towns along the river include Cougar
, Ariel
, and Woodland
. In its lower 10 miles (16.1 km), it turns sharply south, then west, and enters the Columbia from the east, opposite St. Helens, Oregon
, approximately 15 miles (24.1 km) north of Vancouver, Washington
. The mouth of the Lewis River is at Columbia river mile
(RM) 87 or river kilometer (RK) 140.
Near the confluence with the Columbia River the Lewis River is joined by the East Fork Lewis River. The main Lewis River, sometimes called the North Fork Lewis River, forms the boundary between Clark and Cowlitz counties, while the East Fork divides Clark County in half. The East Fork flows westward from headwaters on the western flanks of Lookout Mountain in Skamania County. Parks along the East Fork include Moulton Falls, Lucia Falls, Lewisville, and Paradise Point. A variant name of the East Fork is the South Fork Lewis River.
in its middle course by Swift Dam
, forming Swift Reservoir
; Yale Dam
, forming Yale Lake
; and Merwin Dam
, forming Lake Merwin
.
Columbia River
The Columbia River is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, Canada, flows northwest and then south into the U.S. state of Washington, then turns west to form most of the border between Washington and the state...
, about 95 miles (152.9 km) long, in southwestern Washington in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. It drains part of the Cascade Range
Cascade Range
The Cascade Range is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, and the notable volcanoes known as the High Cascades...
north of the Columbia River
Columbia River
The Columbia River is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, Canada, flows northwest and then south into the U.S. state of Washington, then turns west to form most of the border between Washington and the state...
. The drainage basin
Drainage basin
A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...
of the Lewis River covers about 1046 square miles (2,709 km²). The river's mean annual discharge
Discharge (hydrology)
In hydrology, discharge is the volume rate of water flow, including any suspended solids , dissolved chemical species and/or biologic material , which is transported through a given cross-sectional area...
is about 6125 cuft/s. Unlike nearby Lewis County
Lewis County, Washington
Lewis County is a county located in the U.S. state of Washington. As of 2010, the population was 75,455. The county seat is at Chehalis, and its largest city is Centralia....
and Fort Lewis
Fort Lewis
Joint Base Lewis-McChord is a United States military facility located south-southwest of Tacoma, Washington. The facility is under the jurisdiction of the United States Army Joint Base Garrison, Joint Base Lewis-McChord....
the Lewis River was not named for Meriwether Lewis
Meriwether Lewis
Meriwether Lewis was an American explorer, soldier, and public administrator, best known for his role as the leader of the Lewis and Clark Expedition also known as the Corps of Discovery, with William Clark...
, but rather for A. Lee Lewis, an early settler who homesteaded near the mouth of the river.
Course
The Lewis River rises in the Cascades in northeastern Skamania County, on the west flank of Mount AdamsMount Adams (Washington)
Mount Adams is a potentially activestratovolcano in the Cascade Range and the second-highest mountain in the U.S. state of Washington.Adams is a member of the Cascade Volcanic Arc, and is one of the arc's largest volcanoes,...
, approximately 75 miles (120.7 km) northeast of Portland, Oregon
Portland, Oregon
Portland is a city located in the Pacific Northwest, near the confluence of the Willamette and Columbia rivers in the U.S. state of Oregon. As of the 2010 Census, it had a population of 583,776, making it the 29th most populous city in the United States...
. It flows generally southwest through Gifford Pinchot National Forest
Gifford Pinchot National Forest
Gifford Pinchot National Forest is a U.S. National Forest located in southern Washington, USA. With an area of 1.37 million acres , it extends 116 km along the western slopes of Cascade Range from Mount Rainier National Park to the Columbia River. It includes the 110,000 acre Mount St....
, across central Skamania County, passing south of Mount St. Helens
Mount St. Helens
Mount St. Helens is an active stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United States. It is south of Seattle, Washington and northeast of Portland, Oregon. Mount St. Helens takes its English name from the British diplomat Lord St Helens, a...
. It forms the boundary between Cowlitz County
Cowlitz County, Washington
Cowlitz County is a county located in the U.S. state of Washington. As of the 2010 census its population was 102,410. It forms the Longview, Washington, Metropolitan Statistical Area which encompasses all of Cowlitz County. The county seat is at Kelso, and its largest city is Longview...
, to the north, and Clark County
Clark County, Washington
Clark County is a county located in the southwestern part of the U.S. state of Washington, across the Columbia River from Portland, Oregon.Clark County was the first county of Washington, named after William Clark of the Lewis and Clark Expedition...
, to the south. Towns along the river include Cougar
Cougar, Washington
Cougar is a former town, and now unincorporated community, in Cowlitz County, Washington, United States. The population was 122 at the 1990 census; it was not measured in 2000....
, Ariel
Ariel, Washington
Ariel is an unincorporated place in Cowlitz County, Washington....
, and Woodland
Woodland, Washington
Woodland is a city in Clark and Cowlitz counties in the U.S. state of Washington. Most residents live within Cowlitz County, in which the majority of the city lies. It is part of the 'Longview, Washington Metropolitan Statistical Area'...
. In its lower 10 miles (16.1 km), it turns sharply south, then west, and enters the Columbia from the east, opposite St. Helens, Oregon
St. Helens, Oregon
St. Helens is the county seat of Columbia County, Oregon. It was founded by Captain H. M. Knighton, a native of New England, in 1845 as "Plymouth". The name was changed to St. Helens in the latter part of 1850 for its view of Mount St. Helens some away in Washington. The population was 10,019 at...
, approximately 15 miles (24.1 km) north of Vancouver, Washington
Vancouver, Washington
Vancouver is a city on the north bank of the Columbia River in the U.S. state of Washington. Incorporated in 1857, it is the fourth largest city in the state with a 2010 census population of 161,791 as of April 1, 2010...
. The mouth of the Lewis River is at Columbia river mile
River mile
In the United States, 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...
(RM) 87 or river kilometer (RK) 140.
Near the confluence with the Columbia River the Lewis River is joined by the East Fork Lewis River. The main Lewis River, sometimes called the North Fork Lewis River, forms the boundary between Clark and Cowlitz counties, while the East Fork divides Clark County in half. The East Fork flows westward from headwaters on the western flanks of Lookout Mountain in Skamania County. Parks along the East Fork include Moulton Falls, Lucia Falls, Lewisville, and Paradise Point. A variant name of the East Fork is the South Fork Lewis River.
River modifications
It is impounded for hydroelectricityHydroelectricity
Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy...
in its middle course by Swift Dam
Swift Dam
Swift Dam or Swift No. 1 is an earth-type hydroelectric dam on the Lewis River, in the U.S. state of Washington. It is located in Skamania County. Its reservoir is called Swift Reservoir.-References:...
, forming Swift Reservoir
Swift Reservoir
Swift Reservoir is a reservoir on the Lewis River in the U.S. state of Washington. It is located in Skamania County. It was created in 1958 with the construction of Swift Dam....
; Yale Dam
Yale Dam
Yale Dam is a 323-foot high earth-type hydroelectric dam on the Lewis River, in the U.S. state of Washington, owned by PacifiCorp. It is located on the border between Cowlitz County and Clark County. Its reservoir is called Yale Lake. The dam's power plant generates 134 megawatts.-References:...
, forming Yale Lake
Yale Lake
Yale Lake is a 3,780 acre reservoir on the Lewis River in the U.S. state of Washington. It lies on the border between Clark County and Cowlitz County. It was created in 1953 with the construction of Yale Dam....
; and Merwin Dam
Merwin Dam
Merwin Dam is a concrete arch gravity-type hydroelectric dam on the Lewis River, in the U.S. state of Washington. It is located on the border between Cowlitz County and Clark County. Its reservoir is called Lake Merwin....
, forming Lake Merwin
Lake Merwin
Lake Merwin is a reservoir on the Lewis River in the U.S. state of Washington. It lies on the border between Clark County and Cowlitz County. It was created in 1931 with the construction of Merwin Dam....
.