Hydrological Connectivity in a Permafrost Tundra Landscape near Vorkuta, North-European Arctic Russia

Editorial for Special Issue: “Integrated Surface Water and Groundwater Analysis”

Comprehensive understanding of groundwater—surface water (GW–SW) interaction is essential for effective water resources management [...]

Responses of Urban Wetland to Climate Change and Human Activities in Beijing: A Case Study of Hanshiqiao Wetland

Hydrological connectivity is an essential indicator of wetland pattern and functional stability. The reduction of connectivity usually means the degradation of wetland ecological function, internal energy flow, and nutrient cycle disturbance. Taking Hanshiqiao wetland as a case, we used Morphological Spatial Pattern Analysis (MSPA) with the Connectivity Index (IIC, Integral Index of Connectivity; PC, Probability of Connectivity) to analyze the change in hydrological connectivity of Hanshiqiao Wetland from both spatial and temporal aspects. The results showed that the hydrological connectivity of Hanshiqiao Wetland significantly improved with the implementation of the wetland restoration project. According to the changes in MSPA function types, the spatial morphological evolution of Hanshiqiao Wetland can be divided into two stages: the recovery stage and the stable stage. In the restoration stage, the area of the core wetland gradually increased, and many croplands and islet wetlands were transformed into the core wetland. The area of the core wetland recovered from 33 hm2 in 2005 to 119 hm2 in 2020. However, during the stable period, the landscape pattern of Hanshiqiao Wetland did not change significantly, and the hydrological connectivity of the wetland was mainly affected by water resource supply. In general, during the restoration period of Hanshiqiao Wetland, the changes in core wetlands played a leading role in the hydrological connectivity of Hanshiqiao Wetland. In the stable period, the main factors affecting the hydrological connectivity of Hanshiqiao Wetland are upstream recharge water, land-use change, and climate change. However, with climate warming and population surge, upstream water supply gradually decreases, and Hanshiqiao Wetland faces an increasingly severe water resource crisis. Therefore, to maintain the hydrological connectivity of Hanshiqiao Wetland, it is necessary to increase the artificial ecological water supply. The combined MSPA model and grey relational analysis method can better reveal the evolution characteristics and driving mechanism of wetland hydrological connectivity, which can provide a methodological reference for other wetland-related research.

Late Summer Water Sources in Rivers and Lakes of the Upper Yana River Basin, Northern Eurasia, Inferred from Hydrological Tracer Data

Major ions, stable isotopes, and trace elements, including rare earth elements (REEs), are used as natural tracers in the qualitative assessment of potential water sources in lakes and rivers of the upper Yana River basin, between Verkhoyansk and Chersky Ranges, during the late summer period. Three distinct regions were sampled, and a dominant water source in each region was qualitatively inferred from water chemistry data. The REE distribution pattern was found to be highly regional and controlled by pH and carbonate contents. Mountain headwater stream at the Verkhoyansk Range north slope, the Dulgalakh River, shows an input from a mixture of shallow groundwater and icing meltwater, with a depleted isotopic signature (δ18O below –21‰), d-excess (dex = δ2H − 8·δ18O) above 18, enrichment in Mg and Sr, and depletion in heavy REEs. The Derbeke Depression lakes and streams are fed by rainfall having ultra-low total dissolved solids (TDS) content, below 25 mg/L, and a convex-up REE pattern. In a medium mountainous river at the Chersky Range flank, the Dogdo River, leaching through fissured Jurassic carbonates is a dominant runoff pathway. Riverine water is heavily depleted in light REEs, but enriched in Mo, Rb, Sb,W and U. In the Dulgalakh River water, high positive Sm and Gd anomalies were observed, attributed either to local geology (greenshists), historical mining legacy, or contemporary winter road operations.