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Final Well Installation Report
Section 1 - Overview
Between November 2001 and October 2003, 17 new groundwater monitoring wells (MWs) were installed, and eight existing wells were upgraded at Camp Stanley Storage Activity (CSSA). The wells will aid in the horizontal and vertical delineation of solvent contamination in the Middle Trinity Aquifer. This report describes the field methods, results, conclusions, and recommendations associated with the well installation activities.
The MW installations and modifications were authorized under Air Force Center for Environmental Excellence (AFCEE) Contract F41624-00-D-8024, Task Order 0042 (TO42). This work was conducted by Parsons under the technical supervision of AFCEE, and has been overseen by the U.S. Environmental Protection Agency (EPA) Region VI Resource Conservation and Recovery Act (RCRA) Enforcement Section since October 1993.
This report summarizes work associated with new MW installations under TO42. Limited interpretation of data collected during installation of the wells, including that based on discrete-interval sampling, is presented in this report. Further interpretation of the CSSA well data collected under TO42 and previously completed Contract F11623-94-D-0024, Delivery Order RL83 (RL83) and Contract F1624-94-D08136, Delivery Order 0023 (DO23) work, integrated with data collected from other wells at CSSA and regional information, will be presented in an update to the Hydrogeologic Conceptual Site Model (HCSM) Report.
Additional wells are being planned and the quarterly groundwater monitoring program continues. A chronology of work conducted in association with the groundwater investigation is provided in Volume 1-1 of the CSSA Environmental Encyclopedia. A detailed review of the investigation�s regulatory basis and previous MW well installations is contained in the Well Installation Report, RL83, August 2003. Decontamination and investigation-derived media management procedures, which have not changed for TO42, are also explained therein.
1.3 - Objectives and Scope of Investigation
The goals of this portion of the environmental investigation are to provide additional data for determining the extent of groundwater contamination at CSSA and gain a better understanding of the hydrologic properties of the Middle Trinity Aquifer (herein referred to as the Aquifer). The TO42 well installation efforts included the following specific objectives:
Install five conventional and three multi-port MWs in the Lower Glen Rose (LGR), two conventional wells in the Bexar Shale (BS), four conventional wells in the Cow Creek (CC), and one multi-port well with monitoring access to all three members of the Aquifer.
Complete four well clusters, two with wells completed in each of the three units of the Aquifer, and two clusters each having a well completed in the LGR and CC.
Conduct downhole geophysical surveys at each drilling location, and hydrophysical surveys at four selected locations.
Collect discrete groundwater samples from selected hydrologic zones based on log data. Analyze for the predetermined short list of volatile organic compounds (VOCs).
Develop MWs.
Survey well locations.
Install a low-flow pump in 13 MWs.
Install transducers in 12 MWs.
Manage investigation-derived media and construction debris.
Prepare a well installation report.
This report is organized into five sections. Section 1 presents an overview of the report, including the project purpose, objectives, and scope of the well installation work accomplished under TO42. Section 2 contains the methodology used for the well installations. This includes discussion of the coring and drilling of well boreholes, MW construction, surface completions, MW development, geophysical and hydrophysical logging (HpL), discrete interval sampling, and well surveying. A field narrative of relevant events in chronological order is presented in Section 3. Section 4 describes findings of the ongoing groundwater investigation. Finally, Section 5 contains report conclusions and recommendations. Supporting data and electronic data compact discs (CDs) are included in the appendices.