Reclamation District No. 17 (RD-17) consists of approximately 19 miles of continuous levee on the San Joaquin River, spanning the cities of Stockton, Lathrop, and Manteca. The levees protect residential, commercial, and industrial agricultural facilities. Due to the historic performance, of some portions of the levee, and our analytical findings, several seepages and stability improvements such as cutoff walls, seepage berms, and relief wells were deemed necessary to obtain a 200-year ULDC level of protection.
ENGEO performed a geotechnical exploration and levee evaluation in accordance with the 200-year level of flood protection Urban Levee Design Criteria (ULDC) for the RD-17 levees. Establishing the extent of levee improvements required to meet ULDC criteria, a necessary prerequisite to allow the cities of Stockton, Lathrop, and Manteca, as well as the County of San Joaquin, to seek State and Federal funding assistance to improve the RD-17 levees. These cities and counties would experience significant financial shortfalls without the funding assistance necessary to improve the levee systems’ flood protection abilities.
ENGEO’s analyses involved approximately 200 subsurface exploration points on private and public land, developing and performing an extensive laboratory testing program, and conducting engineering analyses of 73 cross-sections. The analyses, and resulting levee improvements, have been performed in a phased approach starting with a focus on maintaining a 100-year level of flood protection for RD-17 and expanding to achieve a 200-year level of flood protection. ENGEO worked alongside RD-17, the Cities of Lathrop and Manteca, the California Department of Water Resources, and the San Joaquin Area Flood Control Agency to perform various portions of the levee analysis and improvements.