Quantifying lake-Channel Connections on an Arctic River Delta
Arctic deltas host thousands of lakes that help to store water, sediments, and nutrients from rivers. This study developed a new method to identify channel-lake connections on a major Arctic river delta using satellite imagery to better understand the seasonal changes in surface water in these coastal landscapes.
Understanding connections between delta channels and lakes is essential to be able to quantify fluxes to the coast. This study developed a new method to identify channel-lake connections on a major Arctic river delta using satellite imagery. We estimated the potential storage of flood water in the connected lake network and provided new information about the frequency and duration of channel-lake connections that will help inform future modeling of water and sediment movement through Arctic river deltas.
River deltas are critically important landscapes and ecosystems that connect rivers and continents to the ocean. In the Arctic, these landscapes are covered by lakes that complicate our understanding of river-ocean transport for water, sediments, and nutrients. We developed a new satellite-based method to quantify lake-channel connections by identifying and comparing the turbidity of channels and lakes over time. Our results show that spatial patterns of connectivity on the delta change over the open water season as the river stage fluctuates. Some lakes exhibit constant connectivity (always connected or never connected) while many lakes exhibit time-varying connectivity, suggesting that identifying lake-channel connections only by mapping the channel network does not capture the functionality of the delta system. We also identified elevation thresholds for channel-lake connections across the delta that can be used in future models of water and suspended sediment transport through this system.