Ross Dam
Encyclopedia
Ross Dam is a 540 feet (164.6 m)-high, 1300 feet (396.2 m)-long concrete thin-arch dam across the Skagit River
, forming Ross Lake
. The dam is in Washington State, while Ross Lake extends 23 miles (37 km) north into British Columbia
, Canada
. Both dam and reservoir are located in Ross Lake National Recreation Area
, bordered on both sides by North Cascades National Park
.
Built as part of the Skagit River Hydroelectric Project
by Seattle City Light
, the dam is part of a cascade of three dams through the Skagit Gorge that were built primarily to generate hydroelectricity
from the massive elevation drop of over 1000 feet (304.8 m) from the Canada-U.S. border to Newhalem
. The other two dams are Diablo Dam
, directly below Ross Dam, and Gorge Dam, further downstream. Ross Dam can generate up to 460 MW of electricity.
. However, by the time Ross Lake filled, 30 million more board feet remained in the basin.
coincided with an energy shortage in Seattle
, requiring that the dam be constructed quickly, but the dam did not generate any power until many years after the war ended. This third phase was finished in 1949, to 540 feet (164.6 m). This height would cause the reservoir at full pool to extend slightly past the Washington-British Columbia border. The reservoir, however, did not fill past the national border until 1954. As compensation for the flooded land, which totals about 500 acres (2 km²), Seattle City Light paid the Province of British Columbia $250,000, as well as an annual payment of $5,000. Two years prior to the reservoir reaching full pool, construction of the Ross Dam power plant began, and two turbines first went on line in 1956, generating 360 MW of power. Another two generators were added later, increasing the capacity to its current 460 MW.
. The stepped "concrete waffle" facing on the front of the dam was designed to accommodate this addition to the height. This would have flooded land into Canada approximately 3 miles (4.8 km) further, also extending up the Klesilkwa River
, a Skagit River tributary, and provided the opportunity to generate about 272 MW of extra power, bringing the generating capacity to 732 MW. It wasn't until the 1970's when the High Ross project was finally ended. Primarily due to the extensive work by Curley Chittenden - logger turned environmentalist. He worked tirelessly to rally opposition to this additional flooding of the Skagit River basin.
540 feet (164.6 m) high and about 1300 feet (396.2 m) long, stretching across one of the narrowest spots in the Skagit Gorge.
The North Cascades
mountains rise nearly 5000 feet (1,524 m) vertically from the floor of the canyon and surround it on both sides. Directly upstream of the dam, Ruby Creek flows into the reservoir, forming the Ruby Arm of Ross Lake. Directly downstream, Diablo Dam forms Diablo Lake, much smaller than Ross Lake. Other creeks that flow into Ross Lake include Little Beaver Creek and Big Beaver Creek from the west, and Lightning Creek from the east. North Cascades Highway, also known as Washington State Route 20, follows the Skagit River to where it turns away from the river at Ross Dam and follows Ruby Creek instead.
The power plant of Ross Dam is located just downstream of its base and produces 460 MW of power from four hydroelectric turbines. The dam has two over-the-crest spillways on its flanks, each with six individual spillway bays. The capacity of each individual spillway bay at full pool is rated at 6500 cuft/s, and with twelve bays, the maximum amount of water that can go through is 78000 cuft/s. It was found through modeling that with discharges of over 8330 cuft/s per spillway, the spillway channels would start to choke with water.
Skagit River
The Skagit River is a river in southwestern British Columbia in Canada and northwestern Washington in the United States, approximately 150 mi long...
, forming Ross Lake
Ross Lake
Ross Lake is a large reservoir in the North Cascade mountains of northern Washington state, USA, and southwestern British Columbia, Canada. The lake runs approximately north-south, is 23 miles long, up to 1.5 miles wide, and the full reservoir elevation is 1,604 feet above sea level .The U.S...
. The dam is in Washington State, while Ross Lake extends 23 miles (37 km) north into British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
. Both dam and reservoir are located in Ross Lake National Recreation Area
Ross Lake National Recreation Area
Ross Lake National Recreation Area is a US National Recreation Area located in north central Washington just south of the Canadian border. It is the most accessible part of the North Cascades National Park Service Complex which also includes North Cascades National Park and Lake Chelan National...
, bordered on both sides by North Cascades National Park
North Cascades National Park
North Cascades National Park is a U.S. National Park located in the state of Washington. The park is the largest of the three National Park Service units that comprise the North Cascades National Park Service Complex. Several national wilderness areas and British Columbia parkland adjoin the...
.
Built as part of the Skagit River Hydroelectric Project
Skagit River Hydroelectric Project
The Skagit River Hydroelectric Project is a series of dams with hydroelectric power-generating stations on the Skagit River in northern Washington State. The project is owned and operated by Seattle City Light to provide electric power for the City of Seattle and surrounding communities...
by Seattle City Light
Seattle City Light
Seattle City Light is the public utility providing electrical power to Seattle, Washington and parts of its metropolitan area, including all of Shoreline and Lake Forest Park and parts of unincorporated King County, Burien, Normandy Park, Seatac, Renton, and Tukwila...
, the dam is part of a cascade of three dams through the Skagit Gorge that were built primarily to generate hydroelectricity
Hydroelectricity
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...
from the massive elevation drop of over 1000 feet (304.8 m) from the Canada-U.S. border to Newhalem
Newhalem, Washington
Newhalem is a small, unincorporated community in northwestern Washington, USA, located in the western foothills of the North Cascades along the Skagit River. It is located within Whatcom County....
. The other two dams are Diablo Dam
Diablo Dam
Diablo Dam is one of three dams along the upper Skagit River in Whatcom County, Washington and part of the Skagit River Hydroelectric Project that supplies Seattle with a large proportion of its power needs. Work was begun in 1917 on a six-mile tunnel through Diablo Canyon and subsequent...
, directly below Ross Dam, and Gorge Dam, further downstream. Ross Dam can generate up to 460 MW of electricity.
Planning and early construction
Prior to construction of the dam the Skagit Gorge upstream of the dam was wild, free flowing, completely undeveloped area. The canyon had up to 340 million usable board feet of timber that had not yet been logged. With the creation of the Skagit River Hydroelectric Project in the 1910s, the first two dams, Gorge Dam and Diablo Dam, were constructed downstream of the Ross Dam site. In 1937, construction began on the dam, originally slated to be called Ruby Dam, on the first two of four planned construction phases. The name originates from the wife of Dam proponent James Ross, it is also the name of Ruby Creek, a Skagit River tributary that flows southwest to meet the Skagit just upstream of the dam site. By 1940, phases 1 and 2 of the dam were complete, and the dam stood 305 feet (93 m) above the river. While the reservoir filled, the Decco-Walton Logging Company was formed in 1945 with the awarding of a contract from Seattle City Light. Decco-Walton logged the Skagit Gorge as Ross Lake slowly rose, and floated logs up the river to British Columbia, where it was hauled to the Fraser RiverFraser River
The Fraser River is the longest river within British Columbia, Canada, rising at Fraser Pass near Mount Robson in the Rocky Mountains and flowing for , into the Strait of Georgia at the city of Vancouver. It is the tenth longest river in Canada...
. However, by the time Ross Lake filled, 30 million more board feet remained in the basin.
Third phase
In 1939, superintendent of the Skagit Hydroelectric Project James Delmage Ross died, so Ruby Dam was renamed Ross Dam in his memory. The year 1943 saw the beginning of the third phase of dam construction, which was completed to 475 feet (144.8 m) by the end of the year. Energy demands during World War IIWorld War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
coincided with an energy shortage in Seattle
Seattle, Washington
Seattle is the county seat of King County, Washington. With 608,660 residents as of the 2010 Census, Seattle is the largest city in the Northwestern United States. The Seattle metropolitan area of about 3.4 million inhabitants is the 15th largest metropolitan area in the country...
, requiring that the dam be constructed quickly, but the dam did not generate any power until many years after the war ended. This third phase was finished in 1949, to 540 feet (164.6 m). This height would cause the reservoir at full pool to extend slightly past the Washington-British Columbia border. The reservoir, however, did not fill past the national border until 1954. As compensation for the flooded land, which totals about 500 acres (2 km²), Seattle City Light paid the Province of British Columbia $250,000, as well as an annual payment of $5,000. Two years prior to the reservoir reaching full pool, construction of the Ross Dam power plant began, and two turbines first went on line in 1956, generating 360 MW of power. Another two generators were added later, increasing the capacity to its current 460 MW.
High Ross Dam
A controversy later arose over the planned fourth stage of the construction of Ross Dam. This argument over land became known as the High Ross Dam Controversy. The dam was built with the potential to be raised 125 feet (38.1 m) further, bringing the total height of the dam to 665 feet (202.7 m) and raising the reservoir to approximately 1725 feet (525.8 m) above sea levelSea level
Mean sea level is a measure of the average height of the ocean's surface ; used as a standard in reckoning land elevation...
. The stepped "concrete waffle" facing on the front of the dam was designed to accommodate this addition to the height. This would have flooded land into Canada approximately 3 miles (4.8 km) further, also extending up the Klesilkwa River
Klesilkwa River
The Klesilkwa River is a tributary of the Skagit River, flowing east to join that river to the west of Shawatum Mountain after arising near Klesilkwa Mountain, which is on the east flank of Chilliwack Lake.-References:...
, a Skagit River tributary, and provided the opportunity to generate about 272 MW of extra power, bringing the generating capacity to 732 MW. It wasn't until the 1970's when the High Ross project was finally ended. Primarily due to the extensive work by Curley Chittenden - logger turned environmentalist. He worked tirelessly to rally opposition to this additional flooding of the Skagit River basin.
Description
The Ross Dam is situated in the gorge of the Skagit River about midway along its 150 miles (241.4 km) length, and 23 miles (37 km) south of the Canada-U.S. border. It is a concrete thin-arch damArch dam
An arch dam is a type of dam that is curved and commonly built with concrete. The arch dam is a structure that is designed to curve upstream so that the force of the water against it, known as hydrostatic pressure, presses against the arch, compressing and strengthening the structure as it pushes...
540 feet (164.6 m) high and about 1300 feet (396.2 m) long, stretching across one of the narrowest spots in the Skagit Gorge.
The North Cascades
North Cascades
The North Cascades are a section of the Cascade Range of western North America. They span the border between the Canadian province of British Columbia and the U.S. state of Washington and are officially named in Canada as the Cascade Mountains...
mountains rise nearly 5000 feet (1,524 m) vertically from the floor of the canyon and surround it on both sides. Directly upstream of the dam, Ruby Creek flows into the reservoir, forming the Ruby Arm of Ross Lake. Directly downstream, Diablo Dam forms Diablo Lake, much smaller than Ross Lake. Other creeks that flow into Ross Lake include Little Beaver Creek and Big Beaver Creek from the west, and Lightning Creek from the east. North Cascades Highway, also known as Washington State Route 20, follows the Skagit River to where it turns away from the river at Ross Dam and follows Ruby Creek instead.
The power plant of Ross Dam is located just downstream of its base and produces 460 MW of power from four hydroelectric turbines. The dam has two over-the-crest spillways on its flanks, each with six individual spillway bays. The capacity of each individual spillway bay at full pool is rated at 6500 cuft/s, and with twelve bays, the maximum amount of water that can go through is 78000 cuft/s. It was found through modeling that with discharges of over 8330 cuft/s per spillway, the spillway channels would start to choke with water.