Remote sensing of hydrologic recharge in the Peace-Athabasca Delta, Canada

Northern wetlands like Canada's Peace-Athabasca Delta (PAD) have global environmental significance, yet fundamental processes of hydrologic recharge critical to their functionality remain poorly understood. We use in situ water level and MODIS satellite data to examine how main-stem river level fluctuations drive inundation across the delta. Temporal covariance between the two datasets allows inference of hydrologic connectivity processes, not just inundation extent. A strong contrast is found between hydrologic connectivity properties in a high-water (2007) vs. low-water year (2006). Results suggest that existing theoretical models of floodplain recharge fail to capture observed patterns of inundation in the PAD. Instead, we find a dichotomy between the distributary channel network, which responds to summer high-water events, and floodplain lakes and wetlands, which do not. The latter occurs even where hydrologic connections do exist between the two. Results have strong management implications for the impact of proposed up-river water diversion on PAD hydrology.