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Cone Penetrometer Testing and Discrete‐Depth Ground Water SamplingL Techniques: A Cost‐Effective Method of Site Characterization in a Multiple‐Aquifer Setting
Author(s) -
Zemo Dawn A.,
Pierce Yvonne G.,
Gallinatti John D.
Publication year - 1994
Publication title -
groundwater monitoring and remediation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 47
eISSN - 1745-6592
pISSN - 1069-3629
DOI - 10.1111/j.1745-6592.1994.tb00495.x
Subject(s) - aquifer , penetrometer , sampling (signal processing) , geology , hydrology (agriculture) , groundwater , environmental science , water well , soil science , geotechnical engineering , soil water , engineering , filter (signal processing) , electrical engineering
Cone penetromcler testing (CPT). combined with discrete‐depth ground water sampling methods, can significantly reduce the time and expense required to characterize large sites that have multiple aquifers. Results from the screening site characterization can then be used to design and install a cost‐effective monitoring well network. At a site in northern California, it was necessary to characterize the stratigraphy and the distribution of volatile organic compounds (VC)Cs) to a depth of 80 feet within a ½‐mile‐by‐½‐mile residential and commercial area in a complex alluvial fan setting. To expedite characterization, a five‐week field screening program was implemented that consisted of a shallow ground water survey, CPT soundings and pore‐pressure measurements, and discrete‐depth ground water sampling. Based on continuous lithologic information provided by the CPT soundings, four predominantly coarse‐grained, water yielding stratigraphic packages were identified. Individual coarse‐grained units within each package are discontinuous, as they coalesce and pinch out in longitudinal and transverse directions. Seventy‐nine discrete‐depth ground water samples were collected using either shallow ground water survey techniques, the BAT Enviroprobe, or the QED HydroPunch I, depending on subsurface conditions. Using results from these efforts, a 20‐well monitoring network was designed and installed to monitor critical points within each stratigraphic package. Good correlation was found for hydraulic head and chemical results between discrete‐depth screening data and monitoring well data. Understanding the vertical VOC distribution and concentrations produced substantial time and cost savings by minimizing the number of permanent monitoring wells and reducing the number of costly conductor casings that had to be installed. Additionally, significant long‐term cost savings will result from reduced sampling costs, because fewer wells comprise the monitoring network. We estimate these savings to be 50 percent for site characterization costs, 65 percent for site characterization time, and 60 percent for long term monitoring costs.