Remediation Technology Summit

Chet Clarke
Chet Clarke

Senior Hydrogeologist
Shell Global Solutions (US), Inc

Shell (2013 -present). Senior Hydrogeologist, responsible for providing technical assurance to US and Canada downstream soil and groundwater assessment & remediation projects, and is the global function leader for SGW advocacy for the SGW team. AMEC Earth & Environment (2006 to 2013). Principal Hydrogeologist and manager for the Austin environmental staff responsible for business development, and a portfolio of SGW assessment & remediation and uranium mine permitting projects. Texas Commission on Environmental Quality Remediation Division (1988-2006). Developed Texas RBCA regulations and associated guidance, RBCA training, first line and second line manager roles, and managed portfolio SGW assessment & remediation projects.


LNAPL Risk Management - A 30 Year Lookback

Federal requirements enacted approximately 30 years ago to recover LNAPL to the “maximum extent practicable” were adopted before subsurface LNAPL behavior was well understood. The lag in science contributed to in-well LNAPL thickness becoming a metric for recoverability and migration potential, and consequently a belief that LNAPL recovery could effectively reduce LNAPL saturations, dissolved-phase constituent concentrations, and overall plume longevity. LNAPL research completed over the last 30 years, some supported empirically with big-data studies, has enhanced understanding of LNAPL behavior with findings counter to early misperceptions. Those findings have been shared with decision makers through many outreach efforts and presented in easy-to-read technical documents and are slowly leading to effective LNAPL management programs in the US. This presentation will review landmark scientific developments in LNAPL understanding and how big data studies underpin those understandings, highlight subsequent regulatory program developments, and discuss practical challenges of programs not supported by sound science.

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