UST Investigations and Characterization Reports, UST-R Site 1, UST-R Site 4, UST-R Site 5, UST-R Site 6, and IR Site 28, Naval Air Station (NAS) Fallon, NV.

This task order includes planning documents and field work for the characterization of five USTs. Upon completion of the fieldwork, Site Characterization Reports were prepared for all five sites.

The purpose of this project was to characterize potential petroleum releases at five former Underground Storage Tank (UST) or petroleum release sites at Naval Air Station (NAS) Fallon, NV and advance the sites towards regulatory closure. UST-R Site 1 was a Military Gas Station that formerly contained a 10,000-gallon gasoline tank and a 3,000-gallon diesel tank. Free product was observed in the excavation at the time of removal of both UTSs and a monitoring well was installed to periodically remove free product. UST-R Site 4 was the site of a removed 750-gallon fuel oil tank with limited site characterization data. UST-R Site 5 was previously the site of a 60,000-gallon aboveground storage tank (AST), which contained fuel oil. During AST removal activities, it was discovered that fuel was released to the environment. UST-R Site 6 was the site of a fuel oil distribution system that supplied fuel oil to buildings in the southeast quadrant of NAS Fallon with limited site characterization data. Installation Restoration (IR) Site 28, with limited site characterization data, was the reported location of petroleum release likely attributable to an auxiliary fuel tank that fell from an aircraft. All five sites were investigated using direct push drill rig outfitted with an Ultra Violet Optical Screening Tool laser induced fluorescence field screening probe to place the location of soil and groundwater samples more accurately at each individual site. At the conclusion of the investigations, UST-R Site 6 and IR Site 28 were granted no further action (NFA) status from the State of Nevada under the low threat petroleum guidance. The remaining sites have Corrective Action Plans prepared under a separate contract to advance them towards NFA status. In addition, a flowing artesian monitoring well that was flooding a taxiway was destroyed in accordance with State of Nevada guidance.