Lookout Below

As part of a collaborative study of the Tuolumne River downstream of O’Shaughnessy Dam, the National Park Service and
San Francisco Public Utilities Commission are conducting an experimental “pulse flow” release of water to simulate a
typical pre-dam spring runoff condition. The Tuolumne River downstream of the dam is presently running at about 3,400
cubic feet per second, but is expected to rise to about 6,000 cubic feet per second by Tuesday, May 19. This high flow will
continue through May 20, then slowly reduce to about 2,500 cubic feet per second by Friday, May 22. Visitors to areas
downstream of O’Shaughnessy Dam (for example, Poopenaut Valley) should expect high and variable flows during that
time period.