SR24 Industrial Area Infrastructure Improvements

Othello, Washington

HWA completed a geotechnical engineering study for the existing SR 24 Industrial Area Infrastructure Improvements project.

The objective of our investigation was to evaluate the subsurface conditions throughout the project area and to provide geotechnical and pavement engineering recommendations. The improvements will include construction of approximately 15,300 feet of new sanitary sewer system (8 inch diameter pipe), approximately 3,200 feet of 10-inch water mains to loop critical areas, and the paving of approximately 13,200 feet of distributor streets.

The project currently experiences considerable ground water problems due to nearby irrigation and variable subsurface conditions across the site. The subsurface conditions throughout the low-lying areas of the site consist predominantly of fine-grained, relatively impermeable soils, which contribute to ponding problems and pavement distress.

Our recommendations included French Drain systems throughout the low-lying project areas to collect and convey the ground water to appropriate off-site facilities. In addition, pavement recommendations were provided for heavy traffic areas. These pavement recommendations included geogrid-reinforced sections in order to reduce the total pavement thickness required.