Assessing Surface Water Dynamics of Wetlands in Reclaimed Mining Areas in the Athabasca Oil Sands Region, Alberta, Canada, with Time-Varying Sentinel-1 SAR and Sentinel-2 Multi-Spectral Imagery

Abstract

Highlights: What are the main findings? Satellite-based imaging estimates of wetland surface water extent derived from Sentinel-1 and Sentinel-2 multispectral data closely matched estimates derived from high-resolution UAV data ((Formula presented.), open-water model; (Formula presented.), open-water + emergent vegetation model). Surface water dynamics were broadly similar between recently formed wetlands in reclaimed and reference landscapes, with larger wetlands exhibiting greater variability in water extent. What are the implications of the main findings? Sentinel-1/2 imagery provides a reliable method for monitoring wetland surface water and intra-annual hydrodynamics. Deeper and larger wetlands are more vulnerable to fluctuations in water availability. Wetlands provide critical ecological and socio-economic benefits, covering approximately 45% of the Athabasca Oil Sands Region in Alberta, Canada. However, open-pit oil sand mining has led to widespread wetland loss. While reclamation efforts are ongoing, the development of effective wetland monitoring methods remain essential. This paper presents a novel approach to tracking wetland dynamics in reclaimed and reference landscapes using Sentinel-1 SAR and Sentinel-2 multispectral imagery. We assess surface water extent and emergent vegetation, validating our satellite-based measurements against high-resolution UAV-derived wetland area data ((Formula presented.)). Our results reveal minor differences in intra-annual variability in wetland area between wetlands in reclaimed versus those in reference landscapes. Wetlands exhibit a positive log-linear relationship between maximum depth and variability in open-water area, a pattern that was consistent between landscape types. Intra- and interannual variability in spatial extent were both positively associated with wetland area. This paper introduces the first ground-truthed automated wetland monitoring approach for the region. These findings document the similarities in range of variation between wetlands developing in reclaimed and reference landscapes and provide a simple tool to support long-term monitoring to document the persistence of wetlands forming in reclaimed landscapes.