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Petroleum Hydrocarbons and Organic Chemicals in Ground Water: Prevention, Detection, and Remediation® Conference |
Monday, November 3, 2008 : 2:45 p.m.
After the Fact. A Review of Poor Characterization Practices
At many sites, characterizations have been completed, and monitoring activities are utilizing wells that were installed during the early site investigations. A review of the boring logs from these sites indicates that at many sites monitoring wells were improperly installed to measure ground water and/or contaminant conditions in the subsurface. The most common problem encountered was that the subsurface geology was not apparently considered with respect to the monitoring well construction. As a result, the monitoring wells were improperly installed, which has limited the value of the well through the history of the site.
Common poor characterization practices can be categorized into several groups. These include (1) the installation of sump wells at LNAPL sites, (2) the penetration of aquitards, and (3) the installation of long screen intervals in zones of multiple water-bearing zones. The paper discusses the implications of these practices. Examples from sites document how these improper characterization practices have affected evaluating the hydrologic and transport conditions through time.
Jeffrey A. Johnson, Ph.D., PG, Acton-Mickelson Environmental Inc. Dr. Jeffrey A. Johnson has over 25 years of professional experience in natural resource assessment, site characterization, remedial operations, and technical analyses. He has worked on various projects throughout North America for major petroleum corporations, legal firms, manufacturing companies, and the U.S. Environmental Protection Agency. For the past 10 years, he has worked extensively in the characterization and remediation of LNAPL and DNAPL sites. He is a Senior Technical Consultant for Acton-Mickelson Environmental, Inc. Dr. Johnson holds a Ph.D. in Geology from the University of California, Berkeley, and is a Certified and Registered Professional Geologist and a Licensed Remediation Specialist.