Challenge

In 2011, hydrocarbon contamination was discovered in groundwater and soil at the site of the Former Y Shamrock Station, which had operated from the 1950s through 1981 in Clovis, New Mexico. The New Mexico Environment Department (NMED) Petroleum Storage Tank Bureau (PSTB) considers the site a high priority site due to the threat to the municipal drinking water supply, obtained from regional groundwater from the Ogallala Aquifer. An investigation that included sampling of ten monitoring wells identified a large plume of hydrocarbon contaminated groundwater. The challenge of the project site was further complicated by the location; near the busy intersection of major thoroughfares and an area that includes residential neighborhoods and multiple businesses.

Solutions

In 2018, GLA was awarded a State Lead remediation services contract. We initiated an extensive investigation to define the lateral and vertical extent of the contamination. This investigation involved installation of 13 monitor/groundwater extraction wells and subsequent groundwater sampling. To delineate soil contamination in the vadose zone, we used sonic drilling methods for accurate lithologic characterization and discrete soil samples. These methods helped characterize the Former Y Station as the primary point of release. We also performed aquifer testing to characterize key aquifer parameters and plan for remediation. Our Soil Testing Laboratory performed hydraulic conductivity to confirm results of the aquifer testing.

GLA oversaw design and construction of a permanent remediation system that utilizes dual phase extraction technology. Soil vapor is extracted from multiple screen intervals and routed to a 1,000-standard cubic feet per minute (scfm) thermal oxidizer for treatment prior to discharging to atmosphere. Extracted groundwater (20 gallons per minute from up to 9 wells) is treated with diffused aeration technology and discharged to the City of Clovis sanitary sewer, which conveys water through a direct potable reuse system.

Activities at this site have required coordination with multiple stakeholders: from neighborhood residents to small businesses to big box retail stores. GLA has worked with individual property owners, multiple lawyers, and several corporate real estate directors. Wells were installed in residential streets and City right-of-way, in large parking lots, and, in one case, seven feet from the front door of a small business. We also worked closely with the City of Clovis to facilitate multiple public meetings to disseminate information about the contamination and cleanup and to coordinate water rights transfer during the remedial action.

Results

GLA has been operating the remediation system in Clovis since November 2023 and has removed more than 15,000 gallons of gasoline from the drinking water aquifer. We have served the NMED and developed positive working relationships with the City of Clovis administration and local businesses. GLA worked with all the affected property owners to minimize impacts, while maximizing benefit to the community by remediating the direct threat to the municipal water supply in Clovis.