Posted on November 4, 2026
Federal, state and local partners marked the completion of construction on Tenmile Slough Reach 30 Left Bank (TS30L) on Oct. 30, 2026, celebrating the first completed flood protection levee reach of the Lower San Joaquin River Project, a major flood-risk management effort serving north and central Stockton.
The ribbon-cutting ceremony reconized the completion of approximately 1.1 miles of levee improvements along Tenmile Slough. The work addresses critical seepage and stability deficiencies and also represents an important step toward reducing flood risk for communities in the Stockton area.
“Smart engineering has to be matched with smart project execution,” says Col. Robert M. McTighe, U.S. Army Corps of Engineers (USACE) Sacramento District commander.
The TS30L reach was identified as one of the most at-risk portions of the existing Stockton area levee system. Although it is a dryland levee, meaning water is not normally present against it, its deficiencies presented flood risk management challenges.
Construction began in 2025 and included installation of a soil-bentonite seepage cutoff wall, levee reshaping, rock slope protection and construction of a maintenance access road. The improvements are designed to strengthen the levee and improve its resistance to seepage and waterside erosion.
Construction and completion of TS30L required coordination among the U.S. Army Corps of Engineers, Central Valley Flood Protection Board, California Department of Water Resources (DWR), San Joaquin Area Flood Control Agency (SJAFCA), Reclamation Districts 2119 and 2074, along with local farmers and landowners.
“The completion of this project reflects years of planning, coordination and a shared commitment to protecting our community,” said Michael Blower, chairperson of the San Joaquin Area Flood Control Agency Board of Directors.
“We are grateful for the dedication of our federal, state and local partners, whose collaboration made this milestone possible. Projects of this magnitude simply cannot happen without strong partnerships, and we look forward to continuing that collaboration as we advance the remaining improvements needed to reduce flood risk throughout Stockton.”
While TS30L marks a significant milestone, additional phases of the Lower San Joaquin River Project remain. Authorized by the America’s Water Infrastructure Act of 2018, the project includes approximately 24 miles of levee improvements and closure structures at Fourteenmile Slough and Smith Canal to reduce the flood risk for north and central Stockton.
“Over the past decade, significant investments across the Central Valley Flood System have driven down flood risk for our communities. This newest completed levee segment demonstrates how those investments are paying off,” said Laura Hollender, DWR deputy director of flood management and dam safety.
The levee system provides flood risk management benefits for more than 71,000 acres of mixed-use land, 264,000 residents and approximately $21 billion in property and critical infrastructure.
The Smith Canal Closure Structure was completed by SJAFCA in 2024. TS30L is the first completed levee reach of the broader project.
About the U.S. Army Corps of Engineers, Sacramento District
The U.S. Army Corps of Engineers Sacramento District delivers engineering solutions to the nation’s toughest challenges, including flood-risk management, navigation, environmental restoration and other water resources infrastructure. Through collaboration with federal, state, local and Tribal partners, the district works to support public safety and resilient communities. To learn more about USACE Sacramento, visit: https://www.spk.usace.army.mil/
