Little Falls: (
HAER;
Satellite)
Little Falls Dam
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schnabel
"The Spillway Dam is a 59-foot[18m]-high, 597-foot[182m]-long cyclopean concrete gravity overflow spillway dam. Its 37-foot[11.3m]-high and 73-foot[22.3m]-long concrete gated spillway section has two 20-foot[9m]-wide by 24-foot[7.3m]-high Tainter [Parker] gates." |
The powerhouse takes advantage of a rock outcrop so that it is further downstream from the Spillway Dam. Thus it is at the foot of a rapids and has more head.
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BigBendRailroadHistory, Credit: Clayton photo collection held by the Reardan Memorial Library
"Washington Water Power Co (now Avista) built Little Falls Dam between 1907 and 1910. Every part of the dam was shipped to Reardan and then carted by wagon to Little Falls. This includes the cement, turbines, penstocks, generators, transformers, and wiring. The dam had four turbines which each weighed 750 tons. These were the largest in the world at the time."
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"It boasted having the largest turbines in the world, matching the size of the Niagara Falls turbines." [
odessarecord]
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HAER WASH,33-WELPI.V,1--8
8. VIEW OF SOUTHEAST ELEVATION OF LITTLE FALLS TIE LINE TOWER NO. 185. LOOKING NORTHWEST. - Little Falls Tie Line Towers, Near Little Dam Falls on Spokane River, Wellpinit, Stevens County, WA |
"Significance: The Little Falls Tie Line Towers are significant as components of
one of the trans-Mississippian West's earliest steel tower
transmission lines. This system distributed electrical power from
The Washington Water Power Company's Little Falls Dam (a
National Register of Historic Places property, 12/15/88) to the
Spokane vicinity of eastern Washington, beginning in the early
twentieth century. Its construction pioneered the use of steel
towers for electrical transmission by utilizing modular units
adapted from existing technologies of the U.S. windmill industry.
In terms of engineering, the towers are unique as examples of the
evolution in long distance transmission lines from wooden poles to
metal structures, which facilitated regional hydroelectric
development and resulted in wide-scale distribution of electrical
power at affordable rates to urban Spokane and its outlying rural
geographical region." [
HAER_data]
These towers are a significant advance over the towers used in the Chicagoland area in 1907, including the voltage.
Long Lake Dam
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HAER WASH,33-FORD.V,4--1
1. Contextual view of four operating houses, control gates, penstock and power plant, looking east of the spillway dam - Long Lake Hydroelectric Plant, Spanning Spokane River, Ford, Stevens County, WA |
"Significance: The Long Lake hydroelectric facility is significant as one of the earliest and,
for many years, largest hydroelectric generating facilities in The Washington
Water Power Company's electrical power generating network. It is the
largest hydroelectric facility on the Spokane River. Its construction played
a vital role in facilitating the urban, industrial, and agricultural development
of eastern Washington and northern Idaho. The Long Lake Dam possesses
engineering significance as a reflection of advanced hydroelectric technology
of the early twentieth century. It is architecturally important for the
imposing Romanesque Revival style of its power house. The Long Lake
Hydroelectric Plant and its setting have remained largely unaltered since
original construction of the facility in 1915. The historic property was
nominated to the National Register of Historic Places in 1988. Constituent
elements include the spillway dam, control dam (intake), cut-off (arch dam),
and the four brick operating houses situated on top of the spillway dam." [
HAER_data]
lll
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“Spokane -- Washington Water Power Company (#04),” Spokane Public Library, accessed April 2, 2026, https://lange.spokanelibrary.org/items/show/2005.
"WWP's Long Lake Dam is still an impressive structure more than 75 years after its construction. The project which would have spillways 170 feet [52m] high- the highest in the world at the time- and the largest turbines then in operation, was a mammoth undertaking. To ship the 100,000 tons of materials required, a railroad spur was run 19 miles from the Great Northern Railroad main line at Springfield to the river, where a bridge - with a 172-foot span- was constructed to cross the river to the construction site." |
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RenewableEnergyWorld
"More than 100 years ago, the 88 MW Long Lake hydro plant was completed on the Spokane River in Washington State, U.S. The plant, owned by Avista, was built to serve rural communities and provide power for mining operations. The dam stands 213 feet [65m] high and is located where the river makes a horseshoe bend and passes through a canyon with tall granite walls. When it was built, it was the world’s highest spillway dam with the largest turbines then in use. Because of its historic significance, the property was nominated to the National Register of Historic Places in 1988."
"Beginning in 2016, Avista, working with the Department of Ecology, Spokane Tribe, and many other stakeholders, began examining ways of improving river conditions at the dam for the benefit of the fish living downstream. Water testing below the dam showed elevated levels of dissolved gases in the river during times the dam spills a lot of water. Supersaturation of dissolved gas can cause bubble trauma in fish, resulting in injury or mortality. Production of total dissolved gas is a complex process but is affected by the amount of air entrained in the spillway and during plunging of spillway flows. "Avista installed deflectors on the lower face of Long Lake Dam to make the water skim instead of plunge at the dam’s base, and at the same time the depth of the dam’s plunge pool was reduced and rock at a nearby outcropping removed so it would not obstruct the flow of the river. Together, these changes are lowering dissolved gas levels in the water and keep the fish healthy. "In January 2022, Avista contracted work to rehabilitate and modernize the four generator units at Long Lake, as they were installed in the late 1970s and have a 40-year design life. The project scope includes the complete renewal and supply of the stators, poles, fans and spider/rim designs. The main objective of the refurbishment is to maintain the overall plant equipment reliability for decades to come. When the refurbishment is complete, the facility will have an installed capacity exceeding 100 MW. The first modernized unit is scheduled to go into operation at the end of 2024 and the last one in 2029." |
Note the concrete pump at the toe of the dam.
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mcmillen
"McMillen’s team designed and built a solution to reduce excess total dissolved gases (TDG) during overflow spill events at Long Lake Dam. The result is a reduction in fish mortality and ongoing environmental benefits to sensitive riparian and aquatic habitats in the Spokane River." |
In 2016, the $11m project "installed deflectors on the lower face of the dam to make the water skim instead of plunge at the dam’s base. They also reduced the depth of the dam’s plunge pool and removed rock at a nearby outcropping so it would not obstruct the flow of the river. Together, these changes should lower dissolved gas levels in the water and keep the fish healthy and happy." [
myavista]
