INADVERTENTLY INFLUENCING DIRTY GROUND WATER TO FLOW BENEATH A STRUCTURE
 
By the earthDr!
 
Is it all that easy to re-direct ground-water flow, by pumping ground water from a well, so that only clean water flows beneath your basement preventing future exposures of potentially cancer causing vapors into your home from toxics such as benzene dissolved in the ground water from a nearby gasoline
spill originating at your local service station? There are a number of locations depicting possible recovery well locations in this first figure. Remember that a common purpose of ground-water pumpage is to influence clean ground-water to flow beneath a house so that future seeps of ground water are free of contamination; thereby, eliminating vapor generation in your home basement. Does it matter where a single recovery well is to be located? Can anyone of these potential recovery well locations be used to pump ground water so that we can re-direct contaminant-free ground water to flow beneath your home replacing the contaminated ground water now present there? The answer is no. Location..., Location..., Location! The location that the recovery well is to be placed is penultimate to the influencing clean ground water to flow beneath a structure in a timely manner.

In this second figure, the plume is split at the downgradient side of the house. What is the advantage to locating the recovery well so close to the upgradient (higher water table elevation) side of the house so that the plume is split on the downgradient (lower water table elevation) side of the house? In this situation the plume is split, but unfortunately the capture zone is located beneath the house. The capture zone is established to influence the transverse-lateral extent of contaminated ground water to flow within its boundaries and into the recovery well; and, to influence clean outer ground-water flowpaths to cause the plume to be split. In the scenario depicted by this figure, the capture zone is influencing contaminated ground water to flow beneath the house. Obviously, the recovery well is located too close to the upgradient side of the house. Unfortunately, I have all too often witnessed a recovery well being installed so that the stagnation point is located below the home to be remediated.
 
 
 
 
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