1990 Map of Hetch Hetchy Reservoir

About this map

The Tuolumne River dominates this high-country landscape, transformed by the massive Hetch Hetchy Reservoir which fills the valley floor within Yosemite National Park. This 1990 provisional map documents the rugged interior of the Yosemite Wilderness, where the Grand Canyon of the Tuolumne River cuts a deep path through granite formations. The survey detail highlights an intricate network of Pack Trails that provided the only access to remote landmarks like Le Conte Point and Smith Peak. To the south, the terrain descends toward the Middle Tuolumne River, passing smaller water bodies such as Harden Lake and Smith Meadow. The map illustrates the 20th-century management of this vital watershed, including infrastructure like the Sewage Disposal Pond tucked near the riverbanks below the reservoir's elevation.