ENVS 3060

• Groundwater (GW):

  • Is water stored in cracks in soil, sand and rock
  • Often below water table
  • Generally in saturated conditions
• GW Problems:

  • Misuses - waste, overuse
  • Contamination
  • Knowledge gap, user awareness
• Aquifer: underground water body
• Soil Water (SW):

  • Stored in soil pores (void space)
  • Above water table
• Wet Bulk Density

  $Pw =$$Mt / Vt$
• Dry Bulk Density


  $Pb =$$Ms / Vt$
• Particle Density


  $Pp =$$Ms / Vs$
• Gravimetric Water Content


  $θw =$$Mw / Ms$
• Volumetric Water Content


  $θw =$$Vw / Vt$
• $θv =$$θw Pb$
• Density of water = 1gcm^-3
• Porosity:

  • how porous the soil is
  • pores can be filled with liquid or air
• Void Ratio


  $e =$$Vair +$$Vwater / Vsolids$

  void ratio = empty space / solid space
• Water Filled Porosity


  $fw =$$Vw / Vt =$$θv$
• Air Filled Porosity


  $fa =$$Vair / Vtotal =$$f - θv$
• Total Porosity


  $f =$$Vf / Vt$
• Saturation Ratio


  $θs =$$θv / f$
• Porosity Factors

  • Packing
  • Grain shape
  • Grain size
  • Sorting
  • Grain orientation
• Macropore > Mesopore > Micropore
• Saturated: all water below water table (groundwater)
• Cohesion: attraction of water molecules to each other
• Adhesion: attraction of water molecules from solid surfaces
• Surface Tension: force of attraction between the water molecules on the surface

  Sphere drop of water is caused by pressure from air (balancing of pressure)
• Capillary Action: movement of water through soil pores due to adhesion, cohesion, and gravity
• Soil is just a bunch of capillaries (a capillary system)