4 A. "Lower Four Snake River Dams"

The Four Lower Snake River Dams were all constructed under the Flood Control Act of 1944 and 1945.

The southeastern area of Washington State is a desert, it receives about 8 to 10 inches of rainfall per year.   Before the dams were constructed there was very little habitation or development.

The Four Lower Snake River Dams have a peaking electrical power capacity of 3489 megawatts and provides approximately 1191 megawatts of firm electrical power 24/7. That's enough electricity to power the city of Portland of the city of Seattle and surrounding areas, or powering  both the states of Idaho and Montana together.  This generated electricity is clean carbon free renewable hydro-power and helps reduce our carbon footprint ( hydro-power being the lowest of most all renewable resources ) which reduces the effects of global warming.  They also have the ability to help firm up the power that other renewable resources provide as they are only available approximately one third of the time or less.  In contrast hydro-power is available 100 percent of the time 24/7.

Putting it in perspective.

Replacing the Peaking electrical power capacity of 3489 megawatts of the Four Lower Snake River dams would take 3 Nuclear, or 14 gas - fired, or 6 coal fired power plants.

Replacing the Firm electrical power of 1191 megawatts of the Four Lower Snake River Dams would take 2 Nuclear, or 6 gas - fired, or 3 coal - fired power plants.

These dams collectively provide flood control ( Portland Ore, flood of 1949) and irrigation, ( directly 37,000 acres in Washington and indirectly 450,000 acres in Idaho.) They also provide shipping of over 1 billion tons of goods annually.  43 states benefit from the Four Lower Snake River Dams, either through hydro-power or through barge shipping and we all benefit from the agricultural commodities that are produced.  The total commerce from the Snake River is second only to the Mississippi River.


The Snake River-Why the Dams are There ( Executive Productions, Youtube 15 Mins )

Value of Snake River Dams ( Northwest River Partners )

Benefits of the Four Lower Snake River Dams ( Bonneville Power Administration )

The Role of the Lower Four Snake River Dams in the Pacific Northwest ( Pacific Waterways Association )

Four Lower Snake River Dams ( Walla Walla Corps of Engineers )


The 4 Snake River Dams are located in Washington State, they are, dam 1 =  Ice Harbor Dam, Lock and Lake Sacajawea, dam 2 = Lower Monumental Dam, Lock and Lake Herbert G.West, dam 3 = Little Goose Dam, Lock and Lake Bryan, dam 4 = Lower Granite Dam, Lock and Lower Granite Lake.  These dams all have fish ladders, shipping locks and are some of the most fish friendly projects in the world.


Ice Harbor Dam

Ice Harbor Lock and Dam, Lake Sacajawea 

Pertinent Data

Detailed Hydro plant Information

AUTHORIZATION: The Ice Harbor Project was authorized by Section 2 of the River and Harbor Act of 1945 (Public Law 79-14, 79th Congress, 1st Session), and was approved March 2, 1945, in accordance with House Document 704, 75th Congress, 3d Session. Recreation was authorized in the River and Harbor Act of 1944 (Public Law 78-534), as amended. The lake behind Ice Harbor Dam has been designated "Lake Sacajawea."

PROJECT: The project consists of Ice Harbor Dam, powerhouse, navigation lock, two fish ladders, and facilities. The project provides navigation, hydroelectric generation, recreation, irrigation and flood control.

Ice Harbor Lock and Dam-Lake Sacajawea is Unit 1 of 4 included in the "Lower Snake River Project, Washington, and Idaho"

Lower Monumental Dam

Lower Monumental Lock and Dam, Lake Herbert G. West

Pertinent Data

Detailed Hydro plant Information

AUTHORIZATION: This project was authorized by the Flood Control Act of 1945 (Public Law 79-14), in accordance with House Document 704. Recreation was authorized in the Flood Control Act of 1944 (Public Law 78-534), as amended. Public Law 95-285, 95th Congress, approved May 25, 1978, designated the lake behind Lower Monumental Dam as "Lake Herbert G. West." 

PROJECT: The project includes Lower Monumental Dam, powerhouse, navigation lock, two fish ladders, and appurtenant facilities. The project provides navigation, hydroelectric generation, recreation, irrigation and flood control.

Lower Monumental Lock and Dam is Unit 2 of 4 from the "Lower Snake River Project, Washington, and Idaho."

Little Goose Dam

Little Goose Lock and Dam, Lake Bryan

Pertinent Data

Detailed Hydro plant Information

AUTHORIZATION: The project was authorized by Section 2 of the Flood Control Act of 1945 (Public Law 79-14), 79th Congress, 1st Session. It was approved on March 2, 1945, in accordance with House Document 704, 75th Congress, 3d Session. Recreation was authorized in the River and Harbor Act of 1944, as amended. Public Law 91-638, 91st Congress, 2d Session, approved December 31, 1970, designated the lake behind Little Goose Dam as "Lake Bryan" in honor of the late Doctor Enoch A. Bryan.

PROJECT: The project consists of Little Goose Dam, powerhouse, navigation lock, two fish ladders, and appurtenant facilities. The project provides navigation, hydroelectric generation, recreation, irrigation and flood control.

 Little Goose Lock and Dam is Unit 3 of 4 from the "Lower Snake River Project, Washington, and Idaho."

Lower Granite Dam

Lower Granite Lock and Dam, Lower Granite Lake

Pertinent Data

Detailed Hydro plant Information

AUTHORIZATION: The project was authorized by Section 2 of the Flood Control Act of 1945 (Public Law 79-14), 79th Congress, 1st Session. It was approved March 2, 1945, in accordance with House Document 704, 75th Congress, 3d Session. Recreation was authorized in the River and Harbor Act of 1944 (Public Law 78-534, as amended. 

PROJECT: This project consists of Lower Granite Dam, powerhouse, navigation lock, two fish ladders, and appurtenant facilities. The project provides navigation, hydroelectric generation, recreation, irrigation and flood control.

Lower Granite Lock and Dam is Unit 4 of 4 from the "Lower Snake River Project, Washington, and Idaho."

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