Do equations for groundwater flow refer to water density?

  • #1
Stephen Tashi
Science Advisor
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Summary:

Do the equations for groundwater flow contain terms representing the density of water in the soil?
As I understand Darcy's law, it computes the flux of water through an area. The same value of flux can be the realized by different combinations of a density of water in the soil and the velocity of that water. So. as far as I can see, Darcy's law is ambiguous about which combination of density and velocity occurs. Is that a correct interpretation? Are there other equations that deal with the density and velocity?
 

Answers and Replies

  • #2
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Darcy’s law refers to the superficial velocity of the water through the medium, driven by a pressure gradient.
 
  • #3
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Summary:: Do the equations for groundwater flow contain terms representing the density of water in the soil?

As I understand Darcy's law, it computes the flux of water through an area. The same value of flux can be the realized by different combinations of a density of water in the soil and the velocity of that water. So. as far as I can see, Darcy's law is ambiguous about which combination of density and velocity occurs. Is that a correct interpretation? Are there other equations that deal with the density and velocity?
While doing environmental testing, underground leaching of an old industrial landfill in the Seattle area (very hydrologically active glacial loess). The area is largely layers of sand (porous) and clay (impervious). The steep hillsides slide when earth movement liquifies sand layer. Density seems irrelevant as limiting low density is determined by layer "crush resistance" and pore availability. Some of the EPA toxics were delayed vs water so water flow not used but toxics mapping was similar.
 
  • #4
Baluncore
Science Advisor
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Wikipedia said:
This quantity K, often referred to as the Darcy flux or Darcy velocity, is not the velocity at which the fluid is traveling through the pores. The flow velocity (u) is related to the flux (q) by the porosity (φ) and takes the form u = q / φ;
https://en.wikipedia.org/wiki/Darcy's_law#Description
 

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