Groundwater Remediation in Karst Terranes: State of the Practice
Monday, May 5, 2014: 3:40 p.m.
Platte River Room (Westin Denver Downtown)
David S. Lipson, Ph.D., PG
,
ARCADIS U.S. Inc., Lakewood, CO
Keith A. White
,
Arcadis BBL, Syracuse, NY
Groundwater remediation at sites located in karst terranes can be extremely challenging, impracticable, or even impossible within reasonable timeframes due to the presence of conduits that are difficult to locate, very high and even turbulent groundwater flow velocities, extreme geologic heterogeneity, dual-porosity and dual-permeability regimes, and sediment transport. Successful groundwater remediation can be further impeded when contaminants are transported deep within karstic geologic formations because the cost of investigating, remediating, and monitoring deep groundwater flow paths can be very high.
The fact that successful groundwater remediation in karst is at best very challenging within reasonable timeframes is highlighted by the fact that few peer-reviewed papers have been published on the topic, and little to no attention has been given to this topic at professional conferences. Nonetheless, the problem of groundwater contamination in karst terranes is both persistent and widespread because approximately 20% of the earth’s land surface is underlain by karst, and the presence of karstic features has not prevented the siting of chemical storage or hazardous waste disposal facilities within these terranes.
To better understand the state of the practice regarding groundwater remediation in karst and provide insights regarding future prospects, we retrieved records of decision (RODs) from USEPA’s superfund database for 71 sites in karst terranes. We reviewed the RODs and extracted information regarding site conceptual models and the evaluation, selection, and implementation of groundwater remedies. Lastly, we looked for trends in types of remedial strategies employed. Key results are that 53% of Superfund sites in karst had no active groundwater remedy, 37% of sites utilized pump and treat, and 21% of sites utilized some form of in-situ remediation technology. Only one Superfund site in karst had a technical impracticability waiver. Furthermore, performance-monitoring data generated at many Superfund karst sites may be inadequate for their intended purpose.
David S. Lipson, Ph.D., PG, ARCADIS U.S. Inc., Lakewood, CO
David Lipson has more than 22 years of experience as a contaminant hydrogeologist with particular emphasis on chemical transport, subsurface remediation, and fractured bedrock hydrogeology. He provides technical support on a wide range of groundwater contamination and remediation projects. Lipson is well-versed at using mathematical models, engineering controls, and risk-based corrective action approaches at sites regulated under CERCLA, RCRA, and state-led regulatory programs. He earned a doctorate degree in Geological Engineering at Colorado School of Mines, a master’s degree in Hydrogeology at Syracuse University, and a bachelor’s degree in Geology at the State University of New York.
Keith A. White, Arcadis BBL, Syracuse, NY
Keith White is a Senior Geologist at Arcadis BBL with 19 years of experience as a hydrogeologist. He has designed and managed various hazardous waste investigations, provided oversight and critical review of site characterizations on behalf of the USEPA, served as the technical lead for multiple karst sites, and serves as a corporate resource for characterizing and remediating DNAPLs. White holds a B.S. in Geology from the State University of New York and has performed his master’s coursework at Syracuse University. He is a Licensed Professional Geologist in several states, and is certified as a professional geologist by the AIPG.
