Flying J Travel Plaza

FLYING J TRAVEL PLAZA, FT. CHISWELL, PC#02-1010
Description of Role: Primary Environmental Consultant/Contractor
Project Team Leader(s): Christopher Swan, Jeffrey A. Fisher, Jr.
Project Cost: $151,175.00
Time Period of Project Work: August 2001 to Present
Client: Flying J, Inc.
Client Representative: Mr. Don Rognon
Regulatory Agency: Virginia Department of Environmental Quality (DEQ)
Regional Office(s): South West

Introduction"

Environmental Engineering, Inc. (EEI) is presenting this project as an example of EEI’s ability to provide consulting services to a private client in response to the purchase of a site with a history of petroleum releases and suspected groundwater contamination. The site is located in karst geology, presenting complex subsurface characteristics.

Scope of Work:

Pentacore Resources, Inc. discovered two apparent releases of gasoline and diesel fuel during a Phase II Environmental Site Assessment (ESA) performed in August of 2001. Subsequently, the Virginia Department of Environmental Quality (DEQ) was notified of a release in the vicinities of both the gasoline and diesel pump islands. In response to these releases, the DEQ requested that a Site Characterization Report (SCR) be presented that was to include data from permanent monitoring well placement and corresponding soil and groundwater sample results. EEI installed 11 monitoring wells using air rotary drilling due to the presence of near-surface bedrock, as discovered during the Phase II ESA. Five monitoring wells were installed near the gasoline islands, and six were installed near the diesel islands. It is important to note that several of the subject wells were placed to correspond to locations that contained elevated concentrations of petroleum contamination as found during the Phase II ESA,
Hydraulic parameters were calculated at each release location using standard slug testing methods on four monitoring wells. Slug test results revealed that the hydraulic conductivity near the diesel release was approximately an order of magnitude higher than conductivities near the gasoline release. Both residual- and dissolved-phase sample results confirmed the presence of two distinct releases of petroleum products; gasoline product near the gasoline pump islands and diesel near the truck fueling islands. A minor amount of separate-phase product was discovered in one monitoring at each release location. A receptor survey conducted during this SCR phase indicated that the only receptor potentially at risk was a small stream located north of the gasoline pump islands. This stream was located less than 500 feet from the nearest monitoring well. Contaminant fate and transport modeling predicted that the receptor stream would not be impacted at levels above In-Stream Quality Standards, assuming current on-site dissolved-phase concentrations and hydraulic conductivities. It was, however, noted that the nearby stream may become threatened by dissolved-phase petroleum migration via the site’s storm water discharge should contaminated groundwater enter the on-site storm water structures.
EEI’s conclusions in the SCR were that delineation of the dissolved-, residual-, and separate-phase petroleum plumes was incomplete, and therefore EEI recommended that a SCR Addendum be conducted to assess the amount of petroleum impact at the site and thus determine the most suitable remediation strategy. EEI also suggested that subsurface geotechnical testing would be useful in identifying preferential flow paths for siting additional monitoring wells within bedrock fractures at the site.
In response to the SCR, the DEQ requested an SCRA to further delineate the petroleum releases on-site. This SCRA included the following activities: 1) a soil-vapor survey that identified possible elevated zones of contamination; 2) fracture trace analysis and electromagnetic terrain conductivity surveys to identify bedrock fractures, and facilitate the accurate installation of additional monitoring wells in areas of perceived contamination and; 3) sampling of the monitoring wells and storm water structures. Seven new monitoring wells were advanced using air rotary at locations identified as either fractures or significant zones of impact. During the SCRA, separate-phase diesel product was found to have accumulated at a thickness of over six feet in one monitoring well. Due to elevated concentrations of dissolved-phase diesel contaminants, the fate and transport model was updated using naphthalene; however, the model still predicted no impact above In-Stream Quality Standards for a “Fresh C”–class Tier 2 stream.
Data conclusions of the SCRA suggested that further characterizations of the diesel release were warranted due to the amount of free product accumulation without an apparent source, as well as the historical release from the 300,000-gallon diesel AST, which may have been contributing to the recent diesel plume. Concurrent separate-phase remediation was also recommended to address accumulation in several on-site monitoring wells.
During the second SCRA phase (SCRA#2), EEI installed five additional monitoring wells to delineate the boundary of the diesel product plume. Data from this phase was used to identify that separate-phase did not appear to be migrating off-site, and that dissolved-phase monitoring was no longer pertinent due to the lack of dissolved-phase receptors. The use of a portable manual-recovery type device for one year was recommended to recover free product and maintain free product endpoints on-site in lieu of immediately developing and implementing a Corrective Action Plan (CAP). Data collected from three quarters of PSCR monitoring indicated that the manual recovery device is maintaining the free product thickness near the site remedial endpoint, and that a CAP may not be necessary at this site.

Staff and Resource Involvement:

Mr. Swan provided project oversight and client consultation assistance during EEI’s tenure with this project. Mr. Fisher was responsible for primary project management and report writing, which included drafting the SCRA#2 and quarterly PSCR monitoring reports. EEI field technicians collected field data and provided support for the operation of equipment and machinery. Equipment owned and operated by EEI that was used on this project included a hollow-stem auger rig. EEI staff conducted the soil-vapor, fracture trace analysis, and electromagnetic terrain conductivity surveys. Subcontractors provided labor and equipment for air-rotary drilling and monitoring well installation.