Fundamentals of Groundwater Contamination

Definition of Terms and Principles of Groundwater Flow in the subsurface:

• Water Cycle; importance of groundwater; water scarcity
• Water occurrence in the subsurface: saturated and unsaturated (vadose) zones: definitions and water movement
  • circulation media: porous, fractured, karstic environments and significance to water flow
  • aquifers, aquitards, aquicludes and aquifuges
  • unconfined, confined, leaky-confined aquifers; perched groundwater
• Definition of aquifer hydraulic parameters: permeability, hydraulic conductivity, transmissivity, storage terms, porosities, hydraulic gradients
• Groundwater flow regime:
  • regional to local flow systems, driving forces; active versus ‘fossil’ groundwater
  • Surface Water – Groundwater Interaction: rivers, springs, wetlands, seepage paces
  • Water Budgets and recharge estimate
• Water well design concepts and capture zone concepts (drawdown, radius of influence, steady state versus transient behavior).
• Summary and discussion

Quantifying groundwater flows

• Measuring groundwater elevations: definition of water heads, pressure head and elevation heads, basic design of monitoring wells/piezometers
• Flow Direction: Potentiometric maps and flow nets; effects of anisotropy and heterogeneities on flow patterns
• Effects of pumping on flow field and typical hydrological impacts: reduction of river base flows, flows to wetlands, well interference
• Groundwater behavior in near shore environments: tidal oscillations, saltwater intrusion, density driven flow
• Groundwater flow quantification: Darcy’s Law, 3-D groundwater flow equation, typical simplifications used in groundwater hydrology and pumping test analysis
• Example calculations of groundwater flows and seepage velocity
• Summary and discussion

Water Quality and Monitoring

• Natural groundwater quality:
  • major ions and graphical representation methods (Stiff, Piper, Schoeller and other hydrochemistry graphs)
• Typical natural contaminants:
  • Arsenic, Iron/manganese, dissolved radioactive elements, salinity, saltwater intrusion
• - Industrial contamination:
  • sources, typical compounds, contamination plumes and typical remediation techniques, importance of prevention versus remediation
  • Fate and transport of contaminants in groundwater
  • Common remediation techniques
• Groundwater Monitoring:
  • groundwater monitoring network objectives and design principles for flow and contamination assessment problems
  • monitoring wells design and materials; single versus multi-level wells: why and when
  • pressure transducers and remote transmission systems, data correction for barometric changes
• Summary and discussion

Aquifer Tests and Simulating Groundwater Flow using Models

• Determining Aquifer Parameters: Pumping Tests and Slug Tests
  • Aquifer and pumping tests procedure and common interpretation techniques (Theis, Hantush, Neumann, etc). Basic principles of well hydraulics. Head losses and well interference.
  • Slug Tests: quickly determining Hydraulic Conductivities
  • Exercise: example of aquifer test interpretation using AquiferTest.
  • Discussion: groundwater resource evaluation and sustainable yield
• Practical exercise: using models to understand and illustrate groundwater flow:
• Introduction: types of models, input parameters, use, advantages and disadvantages
• laboratory exercise to allow students to understand the impacts of pumping a well on the groundwater flow field, and using models to simulate common remediation systems.
• Summary and discussion