Federal officials suppressed a lengthy environmental document that details how one of California’s unique salmon runs would be imperiled by Trump administration plans to deliver more water to Central Valley farms. The July 1 assessment, obtained by The Times, outlines how proposed changes in government water operations would harm several species protected by the Endangered Species Act, including perilously low populations of winter-run salmon, as well as steelhead trout and killer whales, which feed on salmon. But the 1,123-page document was never released.