Photo By Hannah Mitchell | Like its predecessors on the lower Snake River, Lower Granite was named after a local...... read more read more
It was early in the morning and a steam-powered paddleboat made its way up the lower Snake River, trimmed with colored flags. The date was June 19, 1975, and the mood was festive. The vessel was heading for Lower Granite Lock and Dam, whose pool had been raised just four months prior.
This steamboat, the “Portland,” had been traveling upriver for two days, stopping at Lower Monumental and Little Goose dams for their long-awaited dedication ceremonies. Once it arrived at Lower Granite, there would be another ceremony. Then it was onward to Lewiston, Idaho.
This steamboat would be the first seen in Lewiston since 1940.
Reaching navigable waters
The construction of Lower Granite Lock and Dam was the last step to create a river highway between the Pacific Ocean and the confluence of the Snake and Clearwater rivers, 465 miles inland.
Before this navigation channel was established, navigating the Snake and Columbia rivers depended on seasonal flows, which were higher in the spring and early summer and lower in the fall and winter. This could make river travel difficult and even dangerous. As early as 1876, Congress made appropriations to improve the Snake River and create a navigable channel. At first, improvements took the form of blasting obstructions, removing dangerous ledges, constructing dikes to close side channels and concentrate flows, and scraping sand and gravel bars.
However, it wasn’t enough. In 1916, the River and Harbor Act directed the examination of the lower Snake River for a series of locks and dams. In June of 1938, the work culminated with House Document 704, 75th Congress, 3rd Session. This report recommended, among other things, the construction of four dams on the lower Snake River.
The construction of these four dams was authorized by the River and Harbor Act of 1945.
Like its predecessors on the lower Snake River, Lower Granite was named after a local landmark, in this case, Granite Point. Granite Point, the original construction site for the dam, is a place of high-quality granite outcrops, which are relatively rare in a region dominated by basalt. Lower Granite was ultimately constructed just downriver, at one of the “lower” sites marked as suitable for construction.
Nose to the grindstone
Before construction could properly begin, there were a few items that needed addressed. Like Lower Monumental and Little Goose, building Lower Granite would require rerouting railroads and establishing access roads. There was also the matter of the Lewiston levees.
The communities of Lewiston and Clarkston both lie in flood plains at the confluence of the Snake and Clearwater rivers. The flood of 1948 resulted in severe damages in the area. In response, city officials in Lewiston sought to establish levees to prevent future flooding. Levees in Lewiston were already part of the Lower Granite construction plan, however, in 1950 the levees were authorized as a local flood protection project. They rejoined the Lower Granite project in 1959.
After the stage had been set, construction could commence. The first step was to build the coffer dam. This step was completed in 1967. The main construction contract for the dam was awarded May 13, 1970. After rock excavation, it was time to pour concrete, a process which took about two years, finishing in Spring of 1973. Between 1973 and 1974, the spillway gates were installed, along with the navigation lock equipment. The structure of the powerhouse was completed, and the first three units were installed.
Next came the earthen portion of the dam. This was completed in December 1974. The pool was raised in February 1975.
From there, bringing the powerhouse online went smoothly. The first three units came online in April, May and June of 1975 respectively. The last three units in the Lower Granite powerhouse would be installed before the end of the decade.
For those traveling downriver
Lower Granite is the first dam that juvenile salmon pass and the last dam for returning adults. Because of this, it plays an important role in fish passage.
Until Lower Granite was completed, USACE collected juvenile fish and transported them via tank trucks. In 1977, after the dam was completed, USACE began transporting juvenile fish via barge.
Today, there is a fleet of eight barges and five specially made transport trucks and trailers. These barges and trucks are loaded with juvenile salmon and steelhead at Lower Granite, Little Goose, and Lower Monumental dams. The fish are carried downriver to be released below Bonneville Dam on the Columbia River.
Approximately 6.4 million juvenile fish were transported downriver each year between 2013 and 2022. Transportation helps juveniles avoid potential predators and other hazards. Research has shown that transporting juvenile fish increases survival and can provide a higher rate of returning adults.
In 2001, a prototype structure was constructed and installed at Lower Granite to let fish bypass within the surface layer of water. This engineering marvel, called a Removable Spillway Weir (RSW), won an engineering award in 2003, the same award granted to NASA for the space shuttle the year before. Since then, spillway weirs have been installed at the other dams on the lower Snake and Columbia rivers.
Passive Integrated Transponders, or PIT tags, are an important part of fish research. These tags, embedded in the bodies of juvenile salmon, enable researchers to track the progress of individual juvenile fish migrating through the dams downstream, and to track them as adults returning to spawning grounds.
In January of 2020, USACE finished construction of a PIT tag monitoring array in Lower Granite dam’s Spillbay 1. This array of antennas and receivers allows researchers to detect PIT tagged fish passing over the removable spillway weir. This allows researchers to track the juvenile fish that don’t pass Lower Granite via the juvenile bypass system.
This is the largest system ever installed in the entire Columbia and Snake River system with the capability to detect fish going over a spillway and the only one of this magnitude in the world. The information from the monitoring array provides fisheries managers with critical information on the timing of PIT tagged fish passing Lower Granite dam.
For those traveling upriver
In the summers, when adult salmon and steelhead are traveling upstream, Dworshak Dam releases cool reservoir water to maintain optimal water temperatures for their migration. When this water reaches Lower Granite, it is pumped to the surface via an intake chimney to cool the fish ladder and adjacent forebay area.
As fish climb the fish ladder, some are diverted to Lower Granite’s adult fish facility. Multiple state, federal, and tribal agencies use this unique opportunity to track the migration timing and smolt to adult return rates of salmon and steelhead at Lower Granite Dam.
The Lower Granite adult fish facility is used for multiple research projects that collect the data required to make decisions on Snake River salmon recovery programs and operations through the river system. And while most fish are released to continue their migration to spawning areas, some are collected and brought to hatcheries for broodstock.
Going the extra mile
Before the dams, river travel was unpredictable and dangerous. The completion of Lower Granite Lock and Dam completed a reliable and navigable channel of water that stretched from the Pacific Ocean to Lewiston, Idaho. This channel allows commerce to be shipped up and down river via barge, a method of transportation far more efficient and cost effective than either truck or train.
In fiscal year 2021, nearly 1.5 million tons of cargo passed through the Lower Granite navigation lock. Most of the cargo consisted of grains, petroleum products, fertilizer, and wood products.
The final stop
The dedication celebration for the completion of the navigation channel needed to include ceremonies for Lower Monumental, Little Goose and Lower Granite dams. The occasion merited an appropriate amount of fanfare and, as plans were made, a four-day agenda took shape.
On June 17, 1975, the steam-powered sternwheeler “Portland” traveled to Lower Monumental Lock and Dam. The next day, two dedication ceremonies took place: one for Lower Monumental in the morning and one for Little Goose in the afternoon. The dedication remarks were given from the deck of the ship.
On June 19, the “Portland” reached Lower Granite. Cecil Andrus, the governor of Idaho, gave the dedication remarks from the deck to an audience of about 800 people.
But this wasn’t the end of the tour. After the ceremony, the “Portland” continued upriver until it reached Lewiston, Idaho. On June 20, a celebration was held at the Lewiston Roundup grounds. Senator Warren G. Magnuson of Washington and Senator Frank Church of Idaho gave speeches to an audience of 1,500.
This final stop marked the historic accomplishment of establishing the furthest inland seaport on the west coast. It is a channel made up of some of the highest lift locks in the world, with an average lift of nearly 100 feet.
This navigation channel had been a central part of the Walla Walla District’s history since its establishment in 1948. Today, navigation remains a central mission for the district. On November 1, 2023, the Walla Walla District celebrates its 75th anniversary of serving the Snake River Basin and the Nation. It will continue to serve for years to come.
| Date Taken: | 08.25.2023 |
| Date Posted: | 12.01.2023 15:42 |
| Story ID: | 458925 |
| Location: | WASHINGTON, US |
| Web Views: | 114 |
| Downloads: | 0 |
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