Water use indicators of evapotranspiration, water use efficiency, and gross ecosystem productivity were derived using eddy covariance (EC) measurements of surface-atmosphere exchanges of water, carbon, and energy. They were examined with the goal of identifying potential indicators for assessment and certification of reclaimed landscapes in the Athabasca Oil Sands Region (AOSR). The research outcomes suggest that these indicators provide meaningful assessments of reclaimed AOSR upland and wetland landscapes, thus improving our understanding of ecosystem function, reclamation practices, and certification guidelines. An initial study using a 12-year EC data record for a single reclaimed upland forest dominated by aspen suggested that following approximately 10 years of post-construction variability, the water use characteristics of the site were within the range of variability of natural upland forests in the region. The second study of this thesis expanded the scope of the research to include seven additional EC data records with four AOSR reclaimed sites and four western boreal reference sites. By ~ 20 years of age, the post-disturbance sites' water use indicators were within the range of natural variability. The initial post-disturbance water use variability was related to disturbance type, vegetation cover, moisture, and temperature. The final study examined annual growing season EC-derived water use indicators for 21 upland reference and reclaimed sites, which provided > 100 site years for assessing the potential of these data sets to contribute to assessment and certification in additional ways beyond what can be provided by other ecosystem assessment techniques such as biometrics (including soil and vegetation surveys) and remote sensing. The integrated assessments of ecosystem functioning derived from EC measurements of water and carbon fluxes may be used to situate reclaimed landscapes in relation to the range of variability and along development trajectories for upland boreal sites.