The United States Bureau of Reclamation plans for a ten-dam, billion dollar Colorado River Storage Project began to arouse opposition in the early 1950s when it announced that one of the proposed dams would be at Echo Park, in the middle of Dinosaur National Monument.
After much debate, Congress settled on a compromise that eliminated Echo Park Dam and authorized the rest of the project.
Historians view the Echo Park Dam controversy as marking the start of an era that resulted in increased efforts to conserve wilderness areas.
Zahniser died of heart failure at age 58 on May 5, 1964, a few months before President Lyndon B. Johnson signed the Wilderness Act into law in September of that year.
Zahniser is buried in Tionesta's Riverside Cemetery; his rough-hewn marker, taken from the surrounding forest, faces his beloved Allegheny River.