Challenge. Prevent crude oil from discharging into a creek adjacent to a residential area

Solution. INTERA provided remedial design and construction oversight during implementation of a remedial action at a site along the Texas Gulf Coast to prevent a plume of crude oil from reaching nearby Chiltipin Creek. Our efforts included aquifer characterization, development of a groundwater flow and contaminant transport model to perform design simulations, remedial design, preparation of plans and specifications, and oversight during implementation of the remedial action. To address the crude oil contamination, we: designed a passive interceptor/collection trench; developed an engineer’s cost estimate for the project; provided plans and specifications for the trench installation; prepared the Invitation for Bids and assisted during the bidding process; supported the pre-construction phase; and provided construction oversight during installation of the interceptor trench. To address issues with cut stability, the trench was constructed using a bio-polymer slurry to provide support to the trench walls. A high-density polyethylene (HDPE) liner was used as a barrier on the down-gradient edge of the trench. The trench was partially filled with gravel to collect the crude oil. The upper portion of the trench was capped with low-permeability clay to minimize the potential for oil entering overlying permeable strata. Construction was completed under the Engineer’s estimate, and the trench is functioning as designed.