County of Sonoma Buried Waste Investigation
Healdsburg, CA

Buried waste materials were encountered in during the construction of an emergency vehicle access (EVA) roadway at the Healdsburg Landfill in an area which was outside of the permitted boundary. Several phases of investigation were completed at the site that included a geophysical survey and the installation of pothole excavations to identify the initial limits of the waste materials.

EBA performed a sampling event of surrounding domestic and irrigation water supply wells and evaluated off-site groundwater flow direction.

EBA oversaw the excavation of approximately 1,800 tons of buried waste materials and performed confirmation soil sampling. Based upon results of pothole excavations, EBA performed calculations to estimate the total volume of buried waste which remains in place and developed recommendations to define the areal and vertical limits of buried waste to inform future remedial action efforts. A Work Plan was prepared for the installation of groundwater monitoring wells downgradient of the waste disposal area.