When the smelt spawn in the Cowlitz River, the gulls go into a feeding frenzy that lasts for weeks. Kelso, Washington is known as the "Smelt Capital of the World".[7]
Dams
The Cowlitz River has three major hydroelectric dams, with several small-scale hydropower and sediment retention structures within the Cowlitz Basin.
The Cowlitz Falls Project is a 70 megawatthydroelectric dam built in the early 1990s and completed in 1994. The dam is 140 feet (43m) high and 700 feet (210m) wide. The Cowlitz Falls Project produces on average 260 GWh annually for Lewis County PUD. Its reservoir, Lake Scanewa, is located at the confluence of the Cowlitz and Cispus Rivers downstream of Randle.
Mossyrock Dam began generating power for Tacoma City Light in 1968. It rises 605 feet (184m) from bedrock and created the 23-mile (37km) long Riffe Lake (previously Davisson Reservoir). It is the highest dam in the Pacific Northwest.[8] The dam is named for the nearby city of Mossyrock, and the lake for the town of Riffe, which, along with Kosmos, was destroyed by the flooding of the Cowlitz River valley above the dam.
The Mayfield Dam is 850 feet (260m) long and 185 feet (56m) high. An 860-foot (260m) tunnel connects the reservoir to the powerhouse. The dam began producing electricity in 1963. Mayfield Lake offers many recreational opportunities: there are several county and state parks and the lake is below the Mossyrock Dam. The modulated inflow from the Mossyrock Dam allows Mayfield Lake to maintain a water level that rarely fluctuates more than a few feet. It is located several miles downstream of Mossyrock.
Packwood Lake was dammed in 1964 by the Washington Public Power Supply System (now called Energy Northwest). The dam holds back the lake (previously held back by an ancient landslide), redirecting streamflow to a 27 megawatt hydroelectric generator in the Cowlitz River valley floor 2,000 feet (600 m) below just outside the town of Packwood. When designing and building the dam, care was taken so as not to affect the abundant wildlife of the lake and surrounding area: the dam raised the water level by only a few feet.
The sediment retention structure on the North Fork of the Toutle River. The dam is approximately 22 miles (35km) upriver from the confluence of the Toutle and the Cowlitz.
A serious side effect of the Mount St. Helens1980 eruption has been the downstream movement of enormous amounts of sediment through the North Fork Toutle River. After the eruption, river-borne sediment increased over five thousand-fold, making the Toutle River one of the most sediment-laden rivers in the world.[citation needed] The Toutle River Sediment Retention Structure was constructed to trap this sediment before it was carried farther downstream, where it could clog the river channel, exacerbate floods along the lower Toutle and Cowlitz Rivers, and fill the Columbia River shipping channel, which still requires periodic dredging. An overflow channel has been added to divert lahars around the dam.
Bridges
The Box Canyon of the Cowlitz, viewed from a bridge in Mount Rainier National Park. The bottom of this panorama looks approximately 180 feet (55m) straight down.
Numerous road and rail bridges span the Cowlitz.
Just upstream from its mouth at the Columbia river, a railroad bridge connecting the Port of Longview to the BNSF rail line crosses the Cowlitz, with a road bridge for SR 432 (Tennant Way) beside.
Further upstream are the Allen St. and Cowlitz Way bridges, connecting West Kelso with the rest of Kelso. Just north of Kelso, a railroad bridge provides crossing for the Columbia & Cowlitz Railroad.
Connecting SR 411 to Interstate-5 is the Lexington bridge, a two-lane bridge between the large unincorporated community of Lexington to Exit 42 on the east side of the bank.
At Castle Rock, the A St. bridge provides access from downtown to the school and residential areas across the river. A few miles north, after the Toutle River split, the BNSF line crosses the river.
Where Highway 12 crosses Mayfield Lake, just west of Mossyrock, causeways were built out to the middle of the lake, where a short bridge section connects the two sides. A small bridge provides a crossing for SR 122 at the head of Mayfield Lake. Just east of Mossyrock, the Cowlitz River Bridge on Highway 12 was the largest concrete arch bridge in North America until 1971 at 550 feet (170m).
USGS stream gaging stations on the Cowlitz River
At the head of Riffe Lake, the 27 Road provides access to the forestland south of the Cowlitz from Morton and Glenoma to the north.
Between Randle and Packwood, Highway 12 crosses the Cowlitz at the Cora bridge.
At Packwood, Skate Creek Road spans the river, providing access to the Gifford Pinchot National Forest and Tatoosh Wilderness, as well as connecting the downtown and residential areas of Packwood.
Upstream from Packwood, the Cowlitz splits into the Muddy and Clear Forks, with several Forest Service and Park Service roads crossing each.
Other river structures
When the Cowlitz Salmon Hatchery began operation in 1968, it was the largest of its kind in the world. Currently, it produces nearly 13 million fish each year. Adjacent is the barrier dam, which diverts spawning and upriver migrating fish to a separating station where fish are sorted by species. Some of the fish are used by the hatchery while others are transported upstream to continue migration.
The Bonneville Power Administration, in cooperation with the Lewis County PUD, state and federal agencies and Tacoma Power, constructed a downstream anadromous fish collection facility as part of the Cowlitz Falls Project. The fish facility, along with the Cowlitz River Salmon Hatchery's diversion dam below Mayfield Lake, has permitted the reintroduction of salmon and steelhead in the upper Cowlitz River basin for the first time since the construction of the Mossyrock and Mayfield dams in the 1960s.
The Cowliz River's two hatcheries provide an exceptional sportfishing opportunity for recreational anglers in Washington and Oregon. The river consistently ranks as one of the states top ten steelhead and salmon producers.
The Columbia River is the largest river in the Pacific Northwest region of North America. The river forms in the Rocky Mountains of British Columbia, Canada. It 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 of Oregon before emptying into the Pacific Ocean. The river is 1,243 miles long, and its largest tributary is the Snake River. Its drainage basin is roughly the size of France and extends into seven states of the United States and one Canadian province. The fourth-largest river in the United States by volume, the Columbia has the greatest flow of any river entering the Pacific outside of Asia, and the 36th greatest discharge of any river in the world.
The Yakama are a Native American tribe with nearly 10,851 members, based primarily in eastern Washington state.
The Rogue River in southwestern Oregon in the United States flows about 215 miles (346 km) in a generally westward direction from the Cascade Range to the Pacific Ocean. Known for its salmon runs, whitewater rafting, and rugged scenery, it was one of the original eight rivers named in the Wild and Scenic Rivers Act of 1968. Beginning near Crater Lake, which occupies the caldera left by the explosive volcanic eruption and collapse of Mount Mazama, the river flows through the geologically young High Cascades and the older Western Cascades, another volcanic province. Further west, the river passes through multiple exotic terranes of the more ancient Klamath Mountains. In the Kalmiopsis Wilderness section of the Rogue basin are some of the world's best examples of rocks that form the Earth's mantle. Near the mouth of the river, the only dinosaur fragments ever discovered in Oregon were found in the Otter Point Formation, along the coast of Curry County.
The San Lorenzo River is a 29.3-mile-long (47.2 km) river in the U.S. state of California. The name San Lorenzo derives from the Spanish language for "Saint Lawrence" due to its reported sighting on that saint's feast day by Spanish explorers. Its headwaters originate in Castle Rock State Park in the Santa Cruz Mountains and flow south by southeast through the San Lorenzo Valley before passing through Santa Cruz and emptying into Monterey Bay and the Pacific Ocean.
The Grande Ronde River is a 210-mile (340 km) long tributary of the Snake River, flowing through northeast Oregon and southeast Washington in the United States. Its watershed is situated in the eastern Columbia Plateau, bounded by the Blue Mountains and Wallowa Mountains to the west of Hells Canyon. The river flows generally northeast from its forested headwaters west of La Grande, Oregon, through the agricultural Grande Ronde Valley in its middle course, and through rugged canyons cut from ancient basalt lava flows in its lower course. While it joins the Snake River upstream of Asotin, Washington, more than 90 percent of the river's watershed is in Oregon.
The North Fork Toutle River is a tributary of the Toutle River in southwestern Washington in the United States. The river has its headwaters near Spirit Lake, on the north side of Mount St. Helens, and flows 39 miles (63 km) to the Toutle River, about 17 miles (27 km) upstream of its confluence with the Cowlitz River. The largest tributary is the Green River, which joins near the unincorporated town of Toutle.
The Capilano River flows from north to south through the Coast Mountains on Vancouver's North Shore between West Vancouver and North Vancouver and empties into Burrard Inlet, opposite Stanley Park. The river is one of three primary sources of drinking water for residents of Greater Vancouver, and flows through the Capilano watershed. The Cleveland Dam, built in 1954, impounds a reservoir for this purpose. The entire area of the reservoir and watershed area upstream of the dam is closed to the public to ensure the quality of the drinking water. Prior to construction of the Cleveland Dam, the Capilano River deposited large amounts of sediment into Burrard Inlet. A dredge was needed to remove this sediment build-up in order to keep Burrard Inlet open for ship traffic.
Lake Mayfield is a reservoir located near Mossyrock, Washington, in Lewis County. It was created by Mayfield Dam on the Cowlitz River, one of the dams in the Columbia River watershed.
The Toutle River is a 17.2-mile (27.7 km) tributary of the Cowlitz River in the U.S. state of Washington. It rises in two forks merging near Toutle below Mount St. Helens and joins the Cowlitz near Castle Rock, 20 miles (32 km) upstream of the larger river's confluence with the Columbia River.
The Cispus River is about 54 miles (87 km) long and flows into the Cowlitz River at Lake Scanewa in the Cascade Range of Washington. Its tributaries drain most of south-central and southeastern Lewis County, extreme northeast Skamania County, and some of western Yakima County.
The Baker River is an approximately 30-mile (48 km), southward-flowing tributary of the Skagit River in northwestern Washington in the United States. It drains an area of the high North Cascades in the watershed of Puget Sound north of Seattle, and east of Mount Baker. With a watershed of approximately 270 square miles (700 km2) in a complex of deep valleys partially inside North Cascades National Park, it is the last major tributary of the Skagit before the larger river reaches its mouth on Skagit Bay. The river flows through Concrete, Washington, near its mouth and has two hydroelectric dams owned by Puget Sound Energy.
The Sediment Retention Structure is an earthen dam, 1,888 feet (575 m) long and 184 feet (56 m) high, on the North Fork Toutle River in the U.S. state of Washington. Completed by the United States Army Corps of Engineers in 1989, it is meant to prevent sediment from the 1980 eruption of Mount St. Helens from increasing flood risks along the Toutle and Cowlitz rivers.
Kosmos was an unincorporated community in Lewis County, Washington, southwest of Glenoma and is now considered a flooded town. Kosmos is named from a Greek term meaning "the world or universe as an embodiment of order and harmony".
The Elwha Ecosystem Restoration Project is a 21st-century project of the U.S. National Park Service to remove two dams on the Elwha River on the Olympic Peninsula in Washington state, and restore the river to a natural state. It is the largest dam removal project in history and the second largest ecosystem restoration project in the history of the National Park Service, after the Restoration of the Everglades. The controversial project, costing about $351.4 million, has been contested and periodically blocked for decades. It has been supported by a major collaboration among the Lower Elwha Klallam Tribe, and federal and state agencies.
Mossyrock Dam is a concrete arch-gravity dam on the Cowlitz River near Mossyrock in Lewis County, Washington, United States. The reservoir created by the dam is called Riffe Lake. The primary purpose of the dam is hydroelectric production while flood control is a secondary function. The dam is the tallest in Washington state and its hydroelectric power station supplies 40% of Tacoma Power's electricity.
Riffe Lake is a long reservoir on the Cowlitz River in the U.S. state of Washington. The 23.5 mi (38 km) lake was created by the construction of Mossyrock Dam, the tallest dam in the state, in 1968 by Tacoma City Light.
Coldwater Lake is a barrier lake on the border of Cowlitz County and Skamania County, Washington in the United States. The lake was created during the 1980 eruption of Mount St. Helens, which blocked its natural outlet, Coldwater Creek, with volcanic debris. It is one of several lakes in the area that were created or otherwise enlarged by the eruption.
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