role of monitoring wells in modern landfill designs

Modem technology has led to a new generation of landfill liner systems that are
highly efficient at intercepting and removing leachate. Many of the modem liner systems
are so effective that little or no leakage occurs through the liner systems. What leakage
may occur is so minimal that, although it can be theoretically predicted, it cannot be
measured, i.e., the resulting groundwater concentrations are well beneath minimum
detection levels of available monitoring well technology. In addition to being highly
effective, some modem liner systems are constructed with two liners separated by a
drainage medium which detects and removes any leakage through the top liner.
These significant improvements in liner system technology have led many landfill
designers, operators, and regulators to question the necessity for current monitoring well
practices. Currently, landfills are required to have a large number of monitoring wells,
and the associated large installation, sampling, and testing costs are inevitably reflected
in higher tipping fees or higher taxes. In either case, the costs are borne by the public.
If the number and frequency of sampling of monitoring wells could be reduced,
significant cost savings could be realized, and the money saved could perhaps be better
spent elsewhere.
This thesis reports the results of research conducted at eleven landfills constructed
with modem landfill liner systems to determine the actual and probable efficacy of the
role o: monitoring wells, and conducts a cost-saving analysis to evaluate whether funds
would have been better spent elsewhere.