Odin was engaged by the California Department of Water Resources (DWR) to complete emergency repairs to the Victoria Island levee near Stockton. Damage to the levee from severe underseepage was discovered on October 21, 2024, where leakage was observed in the form of sand boils emerging from under the levee and onto the adjacent farmland. An emergency was declared by San Joaquin County officials, Reclamation District 2040 engineers provided temporary protective barriers, and DWR stepped in to oversee the emergency construction. The failure of this section of levee would have resulted in extensive damage to agricultural lands, disruptions along Highway 4, and potentially compromised regional drinking water sources for the wider area; therefore, the levee repair was designed and implemented under emergency response authority.

Following a site walk with DWR representatives, Odin’s engineers and construction experts held a constructability review and determined that an alternative project approach could offer multiple benefits. Using common and readily available 45-foot-long sheet piles, rather than the 40-foot-long sheet piles from the initial design, would expedite procurement, preparation (application of sheet pile interlock sealant), and delivery of the sheet piles to the site. The longer sheet piles were installed in a 3-foot-deep trench, eliminating the need to further degrade the already compromised levee. Trenching 3 feet into the levee and installing the longer sheet piles resulted in achieving the “tip depth” desired by DWR, a part of the expediated design. DWR design engineers issued a revised design to advance the procurement of sheet piles. This cooperative effort resulted in expediting the schedule, meeting DWR’s design intent, and providing improved overall levee strength via the longer sheet piles.

Odin proceeded to repair the landside of the levee in the 3-acre area. After mobilizing, developing staging areas, and delineating the site boundary, Odin constructed a level and stable aggregate base pad for the sheet pile driver to safely traverse during installation of the 300-foot-long sheet pile wall. The 45-foot-long sheet piles were installed on the levee toward its waterside. Proactive and cooperative engineering efforts between the sheet pile vendor, the pile driver subcontractor, and Odin resulted in the application of a self-leveling sealant on the sheet pile interlocks prior to their mobilization to the site. The pre-applied sealant resulted in an effective water seal immediately upon sheet pile installation. As part of the seepage berm construction, soil above and below the water line was excavated and soil that was unsuitable for reconstructing the levee was staged locally for beneficial reuse.

Upon completion of the sheet pile cutoff wall and a work pad on the landside toe of the levee, Odin constructed a seepage berm that consisted of several elements. A gravel toe drain was constructed to a specific profile using geotextile fabric and clean crushed rock to meet the DWR specification. Following toe drain construction, a sand core was placed and compacted and then sealed with an engineered earthen cap. The final profile was track-walked perpendicular to the slope with a dozer to mitigate erosion. The seepage berm fortified the levee, prevents future erosion and sediment deposits, and allows excess seepage pressure to bleed through and flow horizontally. For levee completion, an aggregate base roadway was constructed on top of the repaired levee.

Repair of the levee was completed in under 8 weeks during winter weather conditions with no safety incidents.

This emergency project illustrates the effectiveness of collaboration among the client, its design engineers, and a knowledgeable contractor. Odin’s constructability review identified methods to expedite the project while achieving a better outcome with design modifications. DWR’s team incorporated Odin’s constructability review concepts into the design working cooperatively with Odin’s sheet pile subcontractor and construction experts.

Previous projects that Odin completed for DWR set the stage for this successful collaborative effort. Odin and DWR were jointly honored for partnering by the International Partnering Institute (IPI) for work on DWR’s Eastside Bypass Levee Improvements near Merced, CA and by the American Society of Civil Engineers, Sacramento Section for the Loafer Point Stage 2 Boat Ramp project on Lake Oroville, which was named 2021 Outstanding Climate Change Project. DWR and Odin were able to cooperatively and rapidly execute this emergency project that provides future flood control benefits to the area.

The project team addressed challenges that included:

• Winter Weather.Following installation of the sheet piles, major storms resulted in overly wet subgrade conditions in the soft agricultural field adjacent to the levee. The project was safely paused while the site dried out since the sealed sheet pile wall had stopped the movement of water and sediment beneath the levee mitigating the immediate threat of failure.
• Sheet Pile Availability. Obtaining the specified sheet piles on an expedited schedule proved challenging. However, based on availability and further consideration of the benefit of longer sheets, Odin was able to quickly procure sheet piles and have the DWR specified  sealant applied to the sheets in a controlled environment at the vendor’s facility. This step allowed immediate installation upon arrival at the Victoria Island project site.
• Sand Boils.The ongoing underseepage resulted in sand boils on the landside of the levee. This seepage continued through construction of the sheet pile wall, resulting in safety concerns. Sheet pile installation sequence and timing was considered to minimize equipment time on potential suspect areas of the levee and installation was expedited and completed during a night shift to complete the installation, which conclusively stopped the boil almost instantly.