1975 810mw Lower Granite Lock and Dam on Snake River

(Satellite)

USACE-locations

USACE
The dam is about 3,200 feet long with an effective height of 100 feet. It includes a navigation lock with clear dimensions of 86 by 674 feet; and an eight-bay spillway that is 512 feet long, with eight 50-foot by 60.5-foot radial gates.
"The powerhouse has six 135,000-kilowatt units. Power generated during fiscal year 2017 was 2.77 billion kilowatt hours. The lake created by the dam extends upstream on the Snake River about 40 miles to Lewiston, Idaho, more than 460 river miles from the Pacific Ocean....The District constructed about 8 miles of levees around Lewiston to help protect lives and property from potentially destructive high-water conditions. Since construction, the levees have prevented more than $39.3 million in potential flood damages."
The installed pumping capacity for the levees is 450.4 cfs.
Maximum design capacity of the spillway is 850 kcfs.

I see the USACE must have concluded that using a lift gate for the downstream gate was a mistake. I've read that they were cheaper but have more maintenance issues. But what really intrigued me is the "submersible tainter" for the upstream gate. I wonder how that works.

USACE

Andy Michel posted five photos with the comment: "Work trip to Lower Granite today. Saw Brad, Neil and Lisa. Granite is a beautiful place with a lot of upgraded equipment. I love my job!"

1

2

3

4

5

cbr
The overload capacity is 932mw, and the hydraulic capacity is 130 kcfs.

WallaWallaUSACE posted
Photo of Lower Granite's navigation lock during construction.
The construction of Lower Granite Lock and Dam was the last step to create a river highway between the Pacific Ocean to the confluence of the Snake and Clearwater rivers, 465 miles inland.

This photo shows the tall miter gates.

D E W Adventures, Aug 2022

Some claims that require explanation: rail is cheaper than barges and wind+solar is cheaper than hydro. This page does have a nice Alamy photo showing a lot of water spilling. I now understand why the dams might be killing Orcas. But I still don't understand why the salmon can get past the Columbia River dams but can't get past the Snake River dams.

Is rail cheaper than barges because the tows have just four barges? On the Mississippi River they quote rail equivalence as well as truck equivalence.

WallaWallaUSACE posted
Lower Granite's navigation lock makes Lewiston, Idaho the farthest inland seaport on the entire west coast.
Barging goods up and down the Snake River used to be a dangerous and challenging mission. Now, the USACE lock system allows for the efficient and safe transport of goods to and from the ocean. A single lockage can accommodate one tow (a tug and 4 barges linked together) transporting the same volume of goods as nearly 540 semi-trucks, for a fraction of the fuel.
Fort Loudoun Lock shared
We don't hear or see much regarding the navigation locks out west on the Snake & Columbia river systems, but they serve an important function all the same! Here's some interesting information from our counterparts in Walla Walla District Corps of Engineers. Check out the gorgeous scenic view in the background! Wow! 

I saw a few photos of this spiral structure. My first thought was that it was a more gentle fish ladder than the one they have by the visitor center. But my second thought is that it is the "juvenile bypass system." [USACE-locations] This fish-tour confirms my second thought. As the most upstream dam on the Snake River, this dam has a lot of additional infrastructure to support the safe passage of juvenile fish.

D E W Adventures, Aug 2022

The released water near the power house is coming from a specially contoured spillway to create a "slide" for the juvenile fish. It is safer than the normal spillways, which is safer than the turbines. It's called the Removable Spillway Weir (RSW), but I don't understand what is removable. [fish-tour, Item 9] The apron of this spillway has 11 antenna & receiver pairs to detect the PIT tags of fish passing over the RSW. [Items 10 & 11]

3D Satellite

The term "surface passage weir" makes more sense to me than "removable spillway weir."

WallaWallaUSACE posted
"Spillway weirs and other surface passage structures allow fish to pass dams at depths where they naturally migrate. They are easier for fish to find, pass more fish per a given unit of flow, reduce migration delay, and minimize exposure to predation near dams. Surface spill generally provides the highest survival of all passage routes at dams; consistently at or near 100 percent. Surface passage structures currently exist at all Corps dams on the Lower Snake & Columbia rivers."

This satellite image caught all eight of the barges that haul captured juvenile fish to below the Bonneville dam near Portland, OR.

Satellite

The spray of water in this satellite image provides cool water for the adult salmon fish ladder exit.

Satellite

fish-tour, Item 7
"The adult fish exit the fish ladder here and continue their upriver journey. Modifications have been made to draw cooler water up from the bottom of the reservoir and sprayed into the fish ladder exit to cool the fish ladder and adjacent forebay area."
[That explains the three big pumps on the left side of this photo.]

WallaWallaUSACE posted
This turbine unit at Lower Granite weighs 400 tons and has 6 adjustable Kaplan blades.
 Hydropower is an incredibly efficient and clean form of power that can be summoned reliably on demand and once the water moves past the turbine it continues on down river, making more power at the next dam, and the next... and the next...
(photo from 2017)