Comite River Diversion Project

Client: U.S. Army Corps of Engineers, New Orleans District Hurricane Protection Office

The Challenge

Chester Engineers was contracted by the US Army Corps of Engineers, New Orleans District to perform preliminary geotechnical design on a portion of the Comite River Diversion project. The main element of the project is a 12-mile long channel located 15 miles north of Baton Rouge in East Baton Rouge Parish and running east-to-west connecting the Comite River and the Mississippi River. The Comite River Basin comprises approximately 348 square miles and includes portions of Wilkinson and Amite Counties in Mississippi, and East Feliciana and East Baton Rouge Parishes in Louisiana. The object of the diversion was to provide flood damage reduction for the residents in the lower part of the Comite River Basin. As the river diversion crosses between numerous existing highways, railroads, and utilities, permanent bridges needed to be incorporated into the design.

The Interdisciplinary Approach

Chester Engineers performed the geotechnical design for a portion of the diversion channel that crosses LA Highway 19, the Canadian National Railroad, and Old Baker Road in Zachary, LA; and geotechnical analysis for locating a new highway bridge, a railroad trestle, and alternatives for Old Baker Road (a new bridge or a tie-in to Highway 19). An investigation plan was prepared to test the geotechnical properties of the project area subsurface. Chester Engineers proposed a boring location plan consistent with the USACE, Louisiana Department of Transportation and Development (LDOTD), and the Canadian National Railroad design standards. Site exploration included 5-inch undisturbed tube samples, cone penetrometer tests, standard penetration tests, and piezometer installations. A laboratory testing program was prepared to analyze representative soil samples to determine soil properties. Laboratory testing included a variety of triaxial tests (UU, CKoU, and CU with pore pressure), compression, swell, consolidation, Atterberg limits, moisture content, and unit weights. Additionally, in-situ testing was conducted to determine specific soil strata permeability using the falling/rising head permeability test. Geotechnical aspects of this project included the development of design shear strengths through the different soil layers and pile capacity curves. This information was used in a preliminary design of the bridge structures and to study alternatives for the Old Baker Road alignment.

The Sustainable Result

A geotechnical report consisting of a design analysis and recommendations based on the performed work was generated for USACE. As the project moves forward, additional geotechnical design will be necessary including horizontal subgrade moduli, sheetpile tip elevations, settlement calculations, bearing capacities, channel slope stabilities, filter drains, underseepage, and dewatering requirements according to the stringent design criteria. This project is state, federally, and locally sponsored and provides flooding relief to the Baton Rouge Metropolitan Area.

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    Project Highlights:
  • Flood control project.
  • Geotechnical analysis for transportation (rail, highway) elements.
    Services Provided:
  • Development of Subsurface Sampling Plan.
  • Preliminary Geotechnical.
  • Field Observation of Drilling.
  • Laboratory Testing and Analysis.