Gov. Gavin Newsom’s administration unveiled a $2.6 billion environmental peace treaty on the Central Valley’s overtaxed rivers Tuesday. The deal calls for farms and cities to surrender billions of gallons of water while contributing funds to help restore troubled fish habitats.

Newsom’s top aides called the 34-page memorandum of understanding a compromise measure that will leave more water in the rivers — but not as much as many environmentalists believe is needed to prop up ailing populations of salmon, steelhead and other fish. And some key water users, such as the city of San Francisco, haven’t yet signed onto the plan.