Mapping hydrologically sensitive areas on the Boreal Plain: a multitemporal analysis of ERS synthetic aperture radar data

Characterizing the spatial and temporal dynamics of hydrologically sensitive areas (HSAs) is vital to the effective management of the boreal forest. HSAs are defined as saturated or inundated areas that, if disturbed, might result in a significant change in the movement of water, nutrients and biota within landscapes. This study presents a remote sensing technique that uses archived European Remote Sensing Satellite (ERS)-1 and ERS-2 synthetic aperture radar (SAR) images to monitor HSAs in the Willow River watershed (1030km2) on the western Boreal Plain of Canada. ERS images were used to generate a probability of HSA occurrence map for a 10-year period (1991-2000). This map revealed the complexity of HSAs on the western Boreal Plain, where some areas remained consistently dry or wet whereas others were dynamic, transitioning from dry to wet and vice versa. A probability map of HSA occurrence provides spatial and temporal information previously unavailable for this region that may expand our understanding of the hydrological behaviour of drainage basins and serve as a planning tool for land management decisions.