In regions where permafrost (PF) is widespread, which make up the cryolithozone, the processes of runoff formation acquire exceptional specificity and complexity due to the presence of frozen soil. In the context of observed climate change leading to the degradation of the permafrost zone, understanding the mechanisms of river runoff formation in these regions becomes an important task. The article analyzes the characteristic features of the regime and the main factors determining the spatiotemporal variability of runoff. The water regime of the rivers in the permafrost zone is characterized by a pronounced spring flood, formed due to the melting of the snow cover on a practically impermeable frozen bed, relatively low summer–autumn floods, and a stable, but pronounced winter low-water season; the rivers are fed mainly by subpermafrost waters via through taliks. The nature and mechanisms of changes in the water regime are influenced by a number of climatic and landscape factors, as well as the continuous permafrost distribution in the basin. The main mechanisms of change include an increase in the thickness of the seasonally thawed layer (STL), expansion of taliks, and increased lateral groundwater flow.
The implementation of inter-basin water transfer (IBWT) projects effectively alleviates water supply-demand imbalances. Most such projects rely on natural river channels or canals for water conveyance. Prolonged high-water-level delivery can influence the interaction between surface water and groundwater (SW-GW) at the regional scale. This study focuses on the Liangji Canal project area of the South-to-North Water Transfer Project (SNWTP) Eastern Route, using the SWAT-MODFLOW coupling model to analyze and predict the SW-GW interactions under different water transfer scenarios. Three distinct water transfer scenarios were established to further predict and analyze the SW-GW interactions in the study area. The results show that the coupled model effectively simulates the dynamic changes of SW-GW in the region. Spatially, mutual recharge between SW-GW occurs in the Liangji Canal Hu-kou to Changgou section and the Denglou to Baligang section, while the Changgou to Denglou section experiences sustained river leakage recharging groundwater. Temporally, there is a strong interaction between SW-GW, with groundwater recharge to surface water primarily occurring in November and December.
Hydrological modeling plays a pivotal role in understanding, managing, and predicting water resources, particularly in a diverse and climate-sensitive country like India. This review critically examines the real-world applications of hydrological models across various Indian regions, emphasizing their relevance in flood forecasting, watershed management, irrigation planning, and climate change impact assessment. Models such as SWAT, HEC-HMS, MIKE SHE, and VIC have been widely employed in both rural and urban hydrological studies, each with specific strengths and limitations depending on the terrain, data availability, and climatic conditions. The review highlights key case studies from states like Maharashtra, Tamil Nadu, Kerala, and Uttarakhand, showcasing both successful implementations and challenges in calibration, validation, and integration with remote sensing and GIS technologies. Despite the advancements, significant gaps remain in model accuracy, stakeholder engagement, and the translation of model outputs into policy decisions. The paper concludes by recommending strategies for enhanced data integration, model customization, and interdisciplinary collaboration to improve the effectiveness of hydrological modeling in addressing India’s pressing water-related challenges.
This study analyzed the evolution characteristics of Poyang Lake water levels and explored methods for calculating suitable ecological water levels. It utilized daily water level data from the Hukou Station of Poyang Lake between 1988 and 2019, employing the Mann-Kendall test, cumulative anomaly method, RVA method, and intra-annual distribution method. Results indicate that Poyang Lake’s annual mean water level exhibits fluctuating changes. Although not statistically significant (Z = −1.38, |Z| < 1.96), 2004 was identified as a potential inflection point in water level variation. The study attempted to use the upper and lower ecological water level thresholds determined by the RVA method (mean fluctuation of 3.32 m) as the primary reference for maintaining lake ecological health, while employing the results calculated by the intra-annual distribution method (mean fluctuation of 6.68 m) as a secondary reference reflecting natural intra-annual variations. The overall degree of hydrological alteration was 31.69
This study investigates seasonal hydrogeochemical variations and anthropogenic influences on groundwater quality in Azamgarh district, India, analyzing 76 samples (38 post-monsoon 2021, 38 pre-monsoon 2022). Post-monsoon water quality shows significant deterioration, with 55 NO_3^ - and pH variations, while agricultural fertilizers influenced NO_3^ - and K+ concentrations. Groundwater depletion shows strong correlation with urban expansion (1991–2014), driven by 41.3
