Thirty Years of Valley Oak and Blue Oak Woodland Restoration at the Los Vaqueros Reservoir Watershed and Conservation Lands: A Review and Recommendations

Matt Wacker, H. T. Harvey & Associates

Charles McClain, H. T. Harvey & Associates

The Los Vaqueros Reservoir (Reservoir), owned by the Contra Costa Water District (District), is a 1,900-acre water supply reservoir constructed in 1997 and expanded in 2013. In addition to the Reservoir itself, the District owns the surrounding 18,535-acre Los Vaqueros Watershed (watershed), which spans Contra Costa and Alameda counties and is protected and managed by the District to maintain water quality in the Reservoir. The District also owns over 5,000 acres of additional conservation lands within San Joaquin, Alameda, and Contra Costa Counties. The watershed and conservation lands support extensive areas of oak woodland and savanna that have been protected and are being restored, enhanced, and managed by the District.

Since the 1990s, the District has planted more than 5,600 valley oaks (Quercus lobata) and 1,500 blue oaks (Quercus douglasii) on nearly 500 acres within the watershed, managed oak woodlands through a targeted livestock grazing program, and monitored the effectiveness of oak restoration, management, and enhancement efforts. We review this long-term monitoring dataset, identify the factors that have contributed to success or challenges of the District’s oak restoration efforts, and, based on our review, provide management recommendations for restoring and enhancing oak woodland and savanna in Central California.