Permafrost Degradation and Its Hydrogeological Impacts

• Published in: Water
• Main Authors: Jin, Huijun, Huang, Yadong, Bense, Victor F., Ma, Qiang, Marchenko, Sergey S., Shepelev, Viktor V., Hu, Yiru, Liang, Sihai, Spektor, Valetin V., Jin, Xiaoying, Li, Xinyu, Li, Xiaoying
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2022
• Subjects: Degrading permafrost; Groundwater flow systems; Hydraulic connectivity; Hydrogeological impact; Sub-permafrost water; Supra-permafrost water; Ice; permafrost; Thermokarst
• Online Access: https://research.wur.nl/en/publications/permafrost-degradation-and-its-hydrogeological-impacts; https://doi.org/10.3390/w14030372

Under a warming climate, permafrost degradation has resulted in profound hydrogeological consequences. Here, we mainly review 240 recent relevant papers. Permafrost degradation has boosted groundwater storage and discharge to surface runoffs through improving hydraulic connectivity and reactivation of groundwater flow systems, resulting in reduced summer peaks, delayed autumn flow peaks, flattened annual hydrographs, and deepening and elongating flow paths. As a result of permafrost degradation, lowlands underlain by more continuous, colder, and thicker permafrost are getting wetter and uplands and mountain slopes, drier. However, additional contribution of melting ground ice to groundwater and stream-flows seems limited in most permafrost basins. As a result of permafrost degradation, the permafrost table and supra-permafrost water table are lowering; subaerial supra-permafrost taliks are forming; taliks are connecting and expanding; thermokarst activities are intensifying. These processes may profoundly impact on ecosystem structures and functions, terrestrial processes, surface and subsurface coupled flow systems, engineered infrastructures, and socioeconomic development. During the last 20 years, substantial and rapid progress has been made in many aspects in cryo-hydrogeology. However, these studies are still inadequate in desired spatiotemporal resolutions, multi-source data assimilation and integration, as well as cryo-hydrogeological modeling, particularly over rugged terrains in ice-rich, warm (>−1 °C) permafrost zones. Future research should be prioritized to the following aspects. First, we should better understand the concordant changes in processes, mechanisms, and trends for terrestrial processes, hydrometeorology, geocryology, hydrogeology, and ecohydrology in warm and thin permafrost regions. Second, we should aim towards revealing the physical and chemical mechanisms for the coupled processes of heat transfer and moisture migration in the vadose zone and expanding supra-permafrost taliks, ...