A subsurface monitoring system and method is provided that includes a sensor array and a monitoring system in communication with the array. The sensor array may include several sensors, such as subsurface temperature sensors, water-level sensors, and oxidation reduction potential sensors may be disposed in a vertical and/or horizontal fence through the subsurface of the monitored site. The sensor array may measure, collect, and analyze the subsurface conditions and provide the measurements to a monitoring system. The monitoring system may provide access the measurements via a user interface for analysis of the measurements. In addition, the monitoring system may process the measurements to generate one or more graphs of information for better understanding of the conditions of the subsurface of the monitored site.