SPOKANE, Wash. (AP)— The benefits provided by four giant hydroelectric dams on the Snake River must be replaced before the dams can be breached to save endangered salmon runs, according to a final report issued by Washington Gov. Jay Inslee and Washington U.S. Sen. Patty Murray.

That is especially true regarding the reliable and carbon-free electricity the dams generate, the report concluded.

If the four Snake River dams were ultimately removed, it would be the largest such project in U.S. history. In 2012 the Elwha Dam on Washington state's Olympic Peninsula was removed to restore habita...