This study addresses time-related capture zones relevant to the activity of extraction wells with different pumping rates. Particle tracking approaches show the effects of well configuration, pumping rate and interaction between individual capture zones on the variation of second spatial moments as well as the form of capture zones. Total probability that initial particle distributions associated with time-related capture zones are extracted by the well within a given time is identified Extraction well comprising the outer capture zone displays a substantial increase of total probability due to the particle pass through a boundary between the inner and outer capture zones.
Pump-and-tread is probably the oldest and most reliable of all technologies available for groundwater remediation and groundwater quality management. Although the method has been criticized recently for being incapable of cleaning up a contaminated aquifer completely, there is no doubt that this method alone can remove a large portion of the contaminants from the aquifer and prevent the contamination from further spreading (Bedient et al., 1999). Capture zones delineate the area around a pumping well from which groundwater is captured a specified time period. They play an important role in the protection of groundwater supply wells, which are used in the definition of source protection zones. The accurate and precise assessment of a capture zone is therefore of great importance, not only from an environmental point of view, but also in terms of public health (Shan, 1999; Riva et al., 2006). Bear and Jacobs (1965) derived the general equation of isochrones for flow toward a fully penetrating, steady state well in an infinite, homogeneous and isotropic confined aquifer. Shan (1999) derived the analytical solution related to capture zones for two arbitrarily located wells that pump water from a confined aquifer at an equal flow rate based on the theorem of potential and the principle of superposition.
