Heuristic for constructing minimum-well groundwater monitoring configurations at waste storage facilities.

A graphical heuristic was designed and evaluated for locating detection wells in aquifers beneath landfills. The heuristic identifies locations of a minimum number of wells on a compliance boundary to detect potential contaminant releases from a landfill. It maximizes gaps between wells while ensuring no potential releases pass between them. The solution progresses from one end of a compliance boundary to another. Heuristic solutions were compared with output from a second method, which equalizes cross-gradient distances between wells, given a specified number of wells in a monitoring network. The second approach is superior when increasing the number of wells for backup coverage or reducing them to save costs. Both approaches maintain high detection efficiency with increased seepage velocity or decreased source width relative to design values. To a lesser extent, they accommodate variations in flow direction relative to the design direction; in test cases, 20-degree variations reduced detection efficiency from 0 to 14%. Conjunctively, the approaches can identify effective candidate monitoring configurations at landfills.