The Upper Tuolumne River Ecosystem Program: January 2009

Tuesday, January 27, 2009

Preliminary temperature modeling data assessment report available

An initial report assessing the quality and availability of data needed for water temperature modeling has been completed by SFPUC consultant Merritt Smith Consulting. The findings of the report will be used to build a water temperature model for the Upper Tuolumne River to evaluate the historical stream temperature regime and the effects of future environmental water release recommendations from Hetch Hetchy Project facilities.

Preliminary Analysis of Available Data for Modeling Temperature in the Hetch Hetchy Reach (PDF | 0.7MB)

Monday, January 26, 2009

Sediment supply and transport report available

SFPUC consultants McBain & Trush have produced a preliminary sediment transport report for the Upper Tuolumne River between O'Shaughnessy Dam and Early Intake. The report is a first step towards characterizing the sediment transport dynamics of the upper river and developing a model that can be "gamed" to help assess the effects of future environmental flow recommendations for O'Shaughnessy Dam on sediment dynamics in the river.

Preliminary Sediment Source and Sediment Transport Capacity Evaluation: O’Shaughnessy Dam to Poopenaut Valley (PDF | 1.1MB)

About the Program

The Tuolumne River is located on the west slope of the Sierra Nevada in central California. With headwaters in Yosemite National Park, the Tuolumne flows westward 150 miles to its confluence with the San Joaquin River in California's Central Valley.

The Upper Tuolumne River Ecosystem Program (UTREP) is a collaborative, long-term, science-based river management program led by the San Francisco Public Utilities Commission (SFPUC).

The UTREP monitors river ecosystem conditions and develops recommendations for river management downstream of Hetch Hetchy Project facilities to support broad river ecosystem values, while maintaining water supply reliability for 2.6 million San Francisco Bay Area customers and providing clean hydropower for San Francisco municipal facilities.

Scientific collaborators include Yosemite National Park, the US Fish and Wildlife Service, Stanislaus National Forest, consultants, researchers, and academics.

STATUS: UTREP efforts are currently focused on technical review and revision of the O'Shaughnessy Dam Instream Flow Management Plan and routine annual monitoring.