JSEM Conference Submittal

Groundwater Remediation Goals
& Timelines Stuck in the
Basement?
Re-evaluate Facility Infrastructure
Impact on Groundwater Remediation
NDIA Symposium & Exhibition
June 2010

Joseph Lukas, CA. PG, Integrated Science Solutions, Inc.

Donald M. Chuck, NASA Ames Restoration Program Manager

Brian Reddig, CA. PG, Integrated Science Solutions, Inc.
Site Setting and
Contaminant History

NASA Ames Research Center and former Naval Air Station
Moffett Field (NASMF) (circa 1930‟s) located in the southern
portion of the San Francisco Bay Area, California

NASA acquired the former NASMF in 1994 as part of BRAC
closure process

NASA Ames lies down-gradient of EPA NPL sites

Primary groundwater contaminants are TCE and PCE

Secondary contaminants include cis-1,2-DCE, vinyl chloride, and
1,4-Dioxane

Other contaminants include petroleum fuels
Site Geology & Facility
Infrastructure
Distal end of fluvial system interacting with bay tidal influences
 Classic channel sand sequences in southern portion of plume
 Medial fluvial sand channel sequences in the core of site plume
 Majority of plume contaminants in upper 30 feet
1- to 2- story below-grade building infrastructure in plume core
 Engineered backfill surrounding below-grade infrastructure
 „E‟-backfill = high hydraulic conductivity “aquifer” material
Depositional System
Plume Definition

Groundwater monitored since the early 1980s

Three existing onsite groundwater pump and treat
systems (installed 1999-2001)

~200 wells used to define onsite TCE plume boundary

Semi-annual potentiometric maps

Annual TCE plume boundary and capture zones maps

Groundwater Model = Isotropic/Homogeneous Aquifer
Remedial System
Impacts

Effectiveness of remedial design reduced due to facility building and
underground utility infrastructure influence on contaminant flow

Extraction system not effectively capturing existing solvent plume as
designed

Extended timeframe for operation of remedial system = $$$

Relocation of extraction wells due to infrastructure impacts = $$$

Future action levels/MCLs may be decreased/lowered = $$$
Infrastructure
Evaluations

Target specific areas where facility infrastructure may potentially impact
contaminated aquifer flow pathways

Collect lithologic/geologic and groundwater data at target sites

Install temporary/permanent pieziometers at select locations

Complete adequate series of pump tests to determine actual
infrastructure influences on groundwater flow pathways.

Revise/modify existing remedial design to improve contaminant capture
Contact Information

Donald Chuck: [email protected];
650/604-0237

Joe Lukas: [email protected]; 650/604-2057

Brian Reddig, [email protected]; 650/604-1315