SPOKANE, Wash. (AP) — The U.S. government says four huge dams on the Snake River in Washington state will not be removed to help endangered salmon migrate to the ocean.

Friday’s announcement thwarts the desires of environmental groups that fought for two decades to breach the structures.

The Final Environmental Impact Statement was issued by the Army Corps of Engineers, Bureau of Reclamation and the BPA, and sought to balance the needs of salmon and other interests.

The plan calls for spilling more water over the dams at strategic times to help fish migrate faster to and from the ocean.