Disclosed herein are exemplified methods and systems for evaluating a contaminant plume so as to generate presentations of temporal and spatial changes in the contaminant plume that facilitates readily identifiable interpretations of subtle, though significant, changes in concentrations or mass of the plume overtime. Exemplified presentations of the changes in the contaminant plume can facilitate more accurate assessment of plume behavior as well as the beneficial identification (in a more readily and systematic manner) of actionable events at the plume, including identification of new contaminant sourcing, identification of effective or ineffective applied remediation (e.g., monitor progress of Monitored Natural Attenuation (MNA)), and identification of changing site location, among others.