Verdantas (formerly TIG Environmental) assisted the PRP group with pre-remedial design studies for a contaminated intertidal channel in a highly urbanized area with San Francisco Bay, in which the EPA proposed a time-critical removal action for removal of more than 20,000 cubic yards of contaminated sediment.

Working with a engineers and scientists from multiple specialist firms, we helped our client achieve agreement with EPA to apply a risk-based multi-technology remedial approach. We are now conducting pre-remedial design studies that include specialized evaluations of sedimentation rates, depth of the biologically active zone, bulk sediment and pore water chemistry, erosion and particle transport, and geotechnical parameters. Overall, the studies will support the design for dredging, capping, and monitored natural recovery of the contaminated sediments.

EPA’s original proposal focused solely on removal of contaminated sediments, which would have been costly. Verdantas was able to utilize our expertise at sediment cleanup sites to demonstrate the effectiveness of a risk-based approach. This alternative approach resulted in significant reduction in removal volume and overall project cost.