Vertical Barriers/Slurry Walls Bio-Polymer Trenches Permeable Reactive Barriers Soil Mixing Jet Grouting Wetlands Site Remediation Dam Grouting MGP Sites Levee/Dam Reinforcement & Repair

Vertical Barrier Installation

Marysville, CA: Soil-Bentonite Slurry Wall Feather River Setback Levee Slurry Wall


The Feather River Setback Levee is a multi-phase project intended to increase the flood capacity of the Feather River near Marysville, California. The project is sponsored by the State of California, with oversight by the US Army Corps of Engineers, and administered by local flood control authorities.

Geo-Con was hired to install 475,000 square feet of slurry wall on Phase IV of this project. The slurry wall serves as a seepage barrier under the newly constructed levee, and will decrease the risk of flooding to the nearby towns of Olivehurst, Linda, Marysville, and Yuba City.

The project consisted of the installation of soil-bentonite cutoff walls along the Feather River prior to the installation of the proposed setback levee. Geo-Con's portion of the work was divided into three separate stretches of future levee that totaled 8,000 linear feet. The depth of the trench varied from 54 to 71 feet deep, and was excavated using a Komatsu PC1250 and Geo-Con's custom made, long-reach stick and boom.

The project had strict requirements which called for extensive company experience in the slurry trench excavation and backfill method of installation, which Geo-Con was able to meet with its personnel of Project Managers, Site Superintendents, and long reach excavator operators. Each was required to have done a minimum of 5 slurry wall projects with a minimum average depth of 70 feet for a stretch of 1500 linear feet.

The specified required minimum permeability of the slurry wall was 5.0X10-7 cm/sec. The average permeability of Geo-Con's installed wall is 5.1X10-8 cm/sec, easily exceeding the project requirements.

In order to meet project specifications, slurry wall operations included the incorporation of sand and gravel into the slurry wall backfill in order to meet the gradation requirements, the incorporation of dry bentonite into the backfill using “side mixing”, and the desanding of the trench slurry to meet the 15% maximum sand content requirement.

The project was completed on schedule, with zero health and safety related incidents.


Corporate Headquarters: 1250 Fifth Avenue • New Kensington, PA 15068 • 724-335-7273

© 2014