This is an adaptation of a USACE map.

Grand Coulee Dam, although the largest and most productive on the Columbia, certainly could not work independently of all the other dams. For example, if the Canadian dams upstream fell Grand Coulee Dam would probably not be able to hold the water back. On the other hand, when there is too little water held in Roosevelt Lake, local residents depend on Chief Joseph Dam, the next downstream, to compensate for Grand Coulee's loss. This map details many of the dams in the Columbia River Basin, however, many are not shown. For example, the map excludes Boundary Dam, Cabinet Gorge Dam, Kerr Dam, Chandler Dam, Roza Dam, and Minidoka Dam. It also excludes Pelton, Round Butte, Big Cliff, Detroit, Foster, Green Peter, Cougar, Dexter, Lookout Point, and Hills Point dams on the Willamette River. Also, the Merwin, Yale, swift, Mayfield, Mossyrock, Gorge, Diablo, Ross, and Lost Creek dams are not mentioned. The dams marked by a red dot are the eleven major hydropower dams. Only Grand Coulee is run by the US Bureau of Reclamation.

Grand Coulee can be used as a point of comparison in scale. It is a concrete gravity dam with a drainage are aof 74,100 square miles. It hydraulic volume is 125,000,000 acre-feet. Its height is 550 feet with a crest length of 5,223 feet. The volume of concrete used is 11,975,520 cubic yards. The reservoir, Franklin D. Roosevelt Lake, has an elevation of 1290 feet and a storage of 9,562 acre-feet. It stands 596.6 miles from the ocean with an average waterflow of 109,500 cubic feet per second and an average power of 22,014 GWH. The hydroelectric potential generation is 10,309 but it runs at only 6,600 on its 33 generators.

Here is the Chief Joseph Dam, creating Rufus Woods Lake.

Chief Joseph is also a concrete gravity dam, built by the US Army Corps of Engineers, finished in 1955, 14 years after Grand Coulee. It stands 544.1 miles from the ocean blocking a reservoir of 518,000 acre-feet at an elevation of 946 feet above sea level. The reservoir is named after the ferocious journalist from the Wenatchee Daily World Rufus Woods. Rufus Woods Lake extends 51 miles north to the Grand Coulee Dam. The height of the dam is 236 feet above bedrock and has a crest length of 5,962 feet. Its drainage area is 75,400 square miles. Its average waterflow is just above Grand Coulee's at 109,800 cfs and has a average power of 11,887 GWH. It also runs under potential generation of 2,614 running only at 2,515 with its 27 generators.

Wells Dam is 515.1 miles from the ocean and was completed in 1967. It is run by the Douglas Country PUD. It has an average waterflow of 114,200 cfs and an average power of 4,520 GWH. It runs at total capacity, both potential and present generation being 774.3 on its 10 generators. On the eastern bank of Wells Dam is an exhibit of ancient Native American petroglyphs, as well as a waterwheel. Rocky Reach Dam stands 473 miles from the ocean and was completed for service in 1961. It is maintained by the Chelan County PUD. Rocky Reach has an average waterflow of 116,400 cfs and an average power of 6,579 Gwh. It also runs at full capacity with a potential and present generation of 1,213.2 with 11 generators.

Rocky Reach Dam.

Next downstream is Rock Island Dam, 453.4 miles from the ocean. Its date in service is 1933, the year Grand Coulee began construction. It is maintained by Chelan County PUD with an average waterflow of 120,000 cfs and an average power of 2.882 Gwh. It runs under its potential generation of 822.5 at 622.5 with 18 generators. Then Wanapum Dam is 415.8 miles from the ocean, maintained by the Grant County PUD. It was completed in 1963. It has an average waterflow of 120,000 cfs and average power of 5,659 Gwh. It runs under its potential generation of 1,330 at 985 with 10 generators. Priest Rapids Dam follows 397.1 miles from the ocean. It was completed for service in 1959 and is maintained by the Grant County PUD. It has an average waterflow of 120,200 cfs adn an average power of 5,484 Gwh. It runs under its potential generation of 1,262 at 910 with 10 generators. McNary Dam was completed in 1953 292 miles from the ocean. The Army Corps of Engineers maintains it. It has an average waterflow of 171,600 cfs and an average power of 7,600. It runs at less than half its capacity of hydropower with a potential generation of 2,130 and a present generation of 980 with 14 generators.

The Dalles Dam.

John Day dam is located 215.6 miles from the ocean. It was completed in 1968 and is maintained also by the US Army Corps of Engineers. It has an average waterflow of 174,000 cfs and an average power of 10,299 Gwh. Its 16 generators run at full capacity of 2,160. The Dalles Dam, on the site of a Native American religious fishing rapids, is 191.5 miles from the ocean. It was completed in 1968 and is maintained by the US Army Corps of Engineers. It has an average waterflow of 179,500 cfs and an average power of 8,212 Gwh. Its 22 generators run at full capacity of 1,807. Finally, the Bonneville Dam is the last major dam on the Columbia at 146.1 miles from the ocean. It was completed in 1938 and spurned Woody Guthrie's initial involvement in songwriting on the Columbia Basin Project. It is maintained by the Army Corps of Engineers and has an average waterflow of 184,900 cfs and an average power of 5,370 Gwh. Its 20 generators run at full capacity of 1,089.