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Thursday, January 30, 2014

Update from Tri Dam and possible drought effects on Lake Tulloch

Tri-Dam’s Board of Directors, members of the South San Joaquin Irrigation District and Oakdale Irrigation Districts are keenly monitoring drought forecasts, area conditions, and their potential impact on agency facilities.  Tri-Dam is also in direct contact with all agencies who operate facilities along the water system, both up and downstream from Tulloch.

At Tulloch, Tri-Dam’s use of the water is primarily for the generation of power at the dam near South Shore and downstream irrigation needs.  Water flows in to Tulloch Reservoir directly from New Melones Reservoir.  Tri-Dam and the United States Bureau of Reclamation (USBR) are signatory to a 1988 operating agreement coordinating the operation of New Melones and Tulloch Reservoirs and the subsequent balancing of power generation, reservoir levels, flood management, water supply demand for Stockton East Water District, Oakdale Irrigation District, South San Joaquin Irrigation District, Calaveras County Water District, and riverine habitat downstream of Goodwin reservoir. 
 
 The USBR has the direct responsibility for coordinating all of these operational needs. The maximum operating level of the reservoir at Tulloch is 510.0’. The operating agreement with the USBR allows a typical operating range between 509.5 and 506.5 on a daily basis during the summer months. The USBR generally does a very good job of managing all of these considerations and keeping changes to the levels of Tulloch small on a daily basis.  Tri-Dam staff is in communication with the USBR on at least a daily basis and typically more often during summer months because of the complexities involved in the operation.  During the winter months, the operational agreement calls for Tulloch to be drawn down in accordance with a schedule provided by the USBR primarily for the purposes of flood protection storage.

At present, we have not received any updates from the USBR about operational changes at Tulloch for the coming season.

S. Larson