Using Simplicity to Address Contaminant Problems Under Conditions of Uncertainty
Instructor: Dr. Donald I. Siegel

Webinar recording from May 10, 2021

Course Description:

Academic hydrogeologists, unconstrained by time, spend careers doing experiments, field studies, and mathematical exploration to discover new science and engineering and achieve a level of certainty they hope will be “beyond reasonable doubt.” In contrast, practicing hydrogeologists and engineers usually have to adhere to legal standards of proof, being “scientifically more likely than not.” Very detailed information on the subsurface usually is obtained at contaminant sources to be able to remove the most contaminant mass during remediation efforts. But farther away, the scientific certainty of fate, transport, and attenuation unaffected by engineering seldom achieves precision and accuracy better than factors to even an order of magnitude because of unknown subsurface heterogeneities, vertical flow, and aquifer properties.

Professionals attending this course will gain a better appreciation of the degree to which unknown heterogeneities influence engineering and regulatory decisions, and then be introduced to a comparatively simple hydraulic and then a geochemical technique to evaluate contaminant fate and transport and achieve essentially the same level of certainty as do more complicated methods such as complex numerical modeling using default parameters by necessity.

Course Agenda:

• Hour 1: Introduction:
  Why uncertainty proves to be much greater than inferred from local hydraulic testing because of subsurface heterogeneities that control Darcy’s Law. Why do field studies provide limited information and what do geochemical tracer tests show with respect to where groundwater flow paths actually go?
  
  
• Hour 2: Setting the Challenge:
  The major causes of subsurface uncertainty - scale dependency, refraction of flow lines, and nested flow systems.
  
  

• Hour 3: Two examples of Using Simplicity in Analysis within Probable Error Bars of Uncertainty
  a. Hydraulics: How long does it take for airborn PFAS to move from the soil zone to the water table?
  b. Remediation of BTEX: An Unappreciated Effectiveness of Ternary diagrams.
  
  
• Hour 4: Case Studies: Practicing What You Learned
  Q&A Summary and Conclusions.