 Colby was a pioneer in the Sierra Club's outing program, and led his High Trips to the Yosemite area from 1901 to 1929; he also led the 1928 High Trip to the Canadian Rockies, and at the end of that trip was given a heartfelt fireside tribute by his fellow hikers, who included 26-year-old photographer Ansel Adams.Colby joined Sierra Club founder John Muir in lobbying the U.S. Federal authorities to protect the Yosemite Valley, by the creation of the Yosemite National Park.In 1905, when the city of San Francisco lobbied Congress to allow it to dam the Hetch Hetchy Valley to provide the growing city with water, Muir and Colby were leaders of the campaign to prevent the damming of the Tuolumne River and the flooding of the valley.