Understanding changes in river flow – where does the water come from?

Scientific questions:

  • How much is thawing permafrost contributing to river flow?
  • How does ice jam impact people living along the rivers, and the hydrograph of river discharge?
  • What leads to formation of critical situation for permafrost in central Yakutia?

Contribution of permafrost thaw to changing discharges of Arctic rivers remains unresolved fundamental issue in permafrost hydrology. Although it was recognized that frozen ground with low ice content does not significantly contribute to river streamflow (Walwoord and Kurylyk, 2016), impact of permafrost with high ground ice content is still unclear. Such icy permafrost is widely spread in the Arctic and Subarctic regions in Yakutia and prone to degradation due to ground ice melt in changing climate. It could lead to thermokarst activation, ground subsidence and following negative socio-economic consequences as well as to shifting of the river dominant water sources and hydrograph structure.

Understanding of where water comes from to Arctic rivers in different seasons of the year is important for development and verification of the operational forecasting system. The model for river discharge separation into river-ice water, snow-melt water, rain water, and permafrost (ground-ice)-melt water will be set up and tested against available and obtained in the field data on stable isotope compositions.

Video showing Lena River ice drift in 2018, by Vasiliy Ogonerov.