Tuolumne River Management Plan

The Modesto and Turlock Irrigation Districts have developed a comprehensive management plan for the Tuolumne River.


The plan describes the Districts’ proposed operations, improvements and resource protection measures under a new Federal Energy Regulatory Commission (FERC) license for the Don Pedro Project.


With historic water rights dating back to the late 1880s, MID and TID have confidently developed a plan based on the best-available science, which includes balanced solutions that benefit all: the Tuolumne River, the Don Pedro Project, various stakeholder agencies and, most importantly, MID and TID customers and their communities.

Plan Goals

Maintain water supply reliability for Tuolumne River agricultural and municipal users, and promote the long-term prosperity of the communities served.

Identify measures to protect and expand the fall-run Chinook salmon and O. mykiss populations.

Support recreational opportunities and riparian resources on the lower Tuolumne River.

Protect cultural, terrestrial and recreational resources at the Don Pedro and La Grange projects.


Improvements to existing river habitat will increase fish spawning habitat quality, capacity and productivity. Proposed measures include a gravel augmentation program, experimental gravel cleaning, increased habitat complexity through site-specific enhancements and water hyacinth removal on the lower river.

8,000 T O N S 7 5,0 0 0 TONS

The first 10-year phase of habitat management could contribute approximately 75,000 tons of coarse sediment—compared to an 8,000 ton loss sustained over 8 years between 2005 and 2012.


It’s a known fact that non-native predation is a leading stressor in the decline of juvenile salmon in the Central Valley. To reduce the detrimental effects that non-native predators have on Chinook salmon and O. mykiss populations, proposed measures include a predation-reducing permanent counting and barrier weir to prohibit the upstream movement of striped bass and other bass species.

90% of juvenile salmon are eaten by predatory fish before they reach the San Joaquin River.

Environmental Flows

Science shows significant improvements can be made to salmon and O. mykiss populations by modifying the timing of river flow requirements. To manage the environmental flow, proposed releases from Don Pedro Reservoir at La Grange Diversion Dam are designed to improve habitat conditions for targeted species’ various life stages.

Diverting water for irrigation purposes at the infiltration galleries allows additional water to flow from La Grange to benefit Tuolumne River cold-water fisheries, notably O. mykiss, while at the same time protecting the Districts’ water supplies. This new diversion option for irrigation ensures a balanced and sustainable use of the resources the Districts are entrusted with.


With the goal of protecting, improving and maintaining a Tuolumne River fall-run Chinook salmon population, the Districts propose building a hatchery—in conjunction with and to be operated by California Department of Fish and Wildlife—below La Grange Diversion Dam.

This restoration hatchery would support the protection and expansion of a Tuolumne River fall-run Chinook population and ultimately reduce the overall percentage of strays in the Tuolumne River.

This plan is a necessary component to promote the long-term prosperity of the communities it serves and is the key to providing water security and reliability to the Modesto and Turlock regions for the next 50 years.

For further information or to learn more about recreational improvements, cultural resource protection, Don Pedro Reservoir resource protection, and program costs, visit www.donpedro-relicensing.com