Climate warming-induced glacier recession has resulted in the development and rapid expansion of glacial lakes in the Himalayan region. The increased melting has enhanced the susceptibility for Glacial Lake Outburst Floods (GLOFs) in the region. The catastrophic failure of potentially dangerous glacial lakes could be detrimental to human life and infrastructure in the adjacent low-lying areas. This study attempts to assess the GLOF hazard of Gangabal lake, located in the Upper Jhelum basin of Kashmir Himalaya, using the combined approaches of remote sensing, GIS, and dam break modeling. The parameters, such as area change, ice thickness, mass balance, and surface velocity of the Harmukh glacier, which feeds Gangabal lake, were also assessed using multitemporal satellite data, GlabTop-2, and the Cosi–Corr model. In the worst-case scenario, 100% volume (73 × 10⁶ m³) of water was considered to be released from the lake with a breach formation time (bf) of 40 min, breach width (bw) of 60 m, and producing peak discharge of 16,601.03 m³/s. Our results reveal that the lake area has increased from 1.42 km² in 1972 to 1.46 km² in 1981, 1.58 km² in 1992, 1.61 km² in 2001, 1.64 km² in 2010, and 1.66 km² in 2020. The lake area experienced 17 ± 2% growth from 1972 to 2020 at an annual rate of 0.005 km². The feeding glacier (Harmukh) contrarily indicated a significant area loss of 0.7 ± 0.03 km² from 1990 (3.36 km²) to 2020 (2.9 km²). The glacier has a maximum, minimum, and average depth of 85, 7.3, and 23.46 m, respectively. In contrast, the average velocity was estimated to be 3.2 m/yr with a maximum of 7 m/yr. The results obtained from DEM differencing show an average ice thickness loss of 11.04 ± 4.8 m for Harmukh glacier at the rate of 0.92 ± 0.40 m/yr between 2000 and 2012. Assessment of GLOF propagation in the worst-case scenario (scenario-1) revealed that the maximum flood depth varies between 3.87 and 68 m, the maximum flow velocity between 4 and 75 m/s, and the maximum water surface elevation varies between 1548 and 3536 m. The resultant flood wave in the worst-case scenario will reach the nearest location (Naranaag temple) within 90 min after breach initiation with a maximum discharge of 12,896.52 m³ s⁻¹ and maximum flood depth and velocity of 10.54 m and 10.05 m/s, respectively. After evaluation of GLOF impacts on surrounding areas, the area under each inundated landuse class was estimated through the LULC map generated for both scenarios 1 and 2. In scenario 1, the total potentially inundated area was estimated as 5.3 km², which is somewhat larger than 3.46 km² in scenario 2. We suggest a location-specific comprehensive investigation of Gangbal lake and Harmukh glacier by applying the advanced hazard and risk assessment models/methods for better predicting a probable future GLOF event.

Wetlands are among the most vital ecosystems on Earth, offering numerous ecosystem services such as habitats for biodiversity, water purification, carbon sequestration, and flood mitigation. The Bakhira Wetland, located in eastern Uttar Pradesh, India, is a designated Ramsar Site and was selected for this study to assess hydro ecologic and landscape changes. Agricultural expansion in the region has led to significant loss of natural vegetation, increased landscape fragmentation, and severe threats to wetland communities and biodiversity. These changes have adversely impacted the hydrological richness that sustains water resources. In recent years, the Bakhira Wetland has also faced challenges such as invasive species encroachment, water quality deterioration, and habitat fragmentation, primarily driven by continuous agricultural development. These issues have further affected migratory bird species, falling the ecological balance of the region. This study used remote sensing data to analyze land use and land cover changes, water extent shrinkage, siltation, aquatic vegetation dynamics, urbanization, and wetland landscape fragmentation. Results revealed a significant decline in water extent during both pre-monsoon and post-monsoon periods, largely due to excessive aquatic plant growth and substantial water withdrawals. The extent of agricultural land in the Bakhira catchment expanded from 62.44 km² in 2000 to 114.93 km² in 2022, while built-up areas grew from 5.77 km² to 8.40 km² over the same period. The study emphasized substantial habitat fragmentation and reduced ecological connectivity, particularly during the dry season, due to intensified human activities. Landscape diversity and fragmentation indices indicated an increase in the number of patches and patch density, reflecting a more fragmented habitat. However, metrics such as the Number of Patches (NP) and the Large Patch Index (LPI) showed a decline, signifying smaller, less cohesive, and more isolated patches. This fragmentation disrupts ecological flows and hinders species movement, raising concerns about long-term biodiversity conservation in the wetland. To address these challenges, sustainable practices in catchment areas are essential. This includes adopting strategies for improved cropland management, water conservation, and wetland rehabilitation. The findings from this study provide valuable insights into the hydrological functioning of wetlands and can guide future efforts in wetland resource protection, sustainable utilization, and the development of infrastructure for rational surface water use. Additionally, restoring degraded agricultural lands is crucial for maintaining ecological balance and ensuring the long-term sustainability of the Bakhira Wetland.