Government of Nepal

This study presents a hybrid metaheuristic framework integrating Non-dominated Sorting Genetic Algorithm III (NSGA-III) and Multi-objective Particle Swarm Optimization (MOPSO) to solve the Time–Cost–Environmental Sustainability Trade-off (TCEST) problem for sustainable construction planning in Nepal. The model simultaneously minimizes project completion time and cost while maximizing environmental performance, tailored to the Nepalese construction context. A detailed case study of a G + 1 residential building in the Kathmandu Valley—comprising 21 activities with multiple execution modes—validates the framework. The hybrid algorithm generates a well-distributed Pareto front, offering diverse trade-off solutions relevant to Nepal’s unique cost structures, resource availability, and environmental priorities, such as reducing reliance on imported materials and minimizing riverbed material extraction. Performance metrics confirm the framework’s superiority over standalone algorithms. The Weighted Sum Method is applied to identify the most suitable solution based on stakeholder priorities. Correlation and trade-off analysis further reveal key interdependencies among objectives. Validation results indicate high predictive accuracy (R² > 0.96) and Pareto front quality. Overall, the hybrid NSGA-III–MOPSO framework provides a robust, data-driven decision support system for Nepalese stakeholders to balance project timelines, budgets, and sustainability goals effectively.

The September 2024 floods along Nepal’s Banepa–Bardibas Road, commonly known as BP Highway, resulted in one of the most severe transport infrastructure failures in the Himalayan region to date. These floods, triggered by an extreme three-day rainfall event (including a 24-hour deluge exceeding 300 mm at multiple stations), heavily damaged the 26 km stretch between Bhakundebesi and Nepalthok. Using chainage-level field reconnaissance, rainfall analysis, and a review of emergency response and rehabilitation measures, this study provides the first integrated documentation of the hazard cascade, infrastructure failures, and institutional responses along the severely impacted road section. The results reveal distinct failure modes, including complete washouts, retaining wall and toe protection collapses, and debris-induced blockages, driven by interacting flood processes (riverbank erosion and sediment surges). Despite early national flood alerts, preparedness remained reactive, causing severe bottlenecks; recovery efforts relied heavily on emergency diversions and temporary gravel tracks. International comparisons show that, while global authorities now embed climate risk into design standards, Nepal’s roadway network remains anchored in obsolete design return periods. This study provides the first integrated, chainage-level documentation of the hazard cascade, infrastructure failure typologies, and institutional response along a severely impacted Himalayan river-corridor roadway, combining field reconnaissance, rainfall analysis, and international benchmarking within a single corridor-scale analytical framework. The findings demonstrate that compound hazard interactions, particularly the amplification of flood impacts by quarry-induced channel constriction and systemic gaps in risk-informed planning are the defining drivers of infrastructure vulnerability in this and comparable mountain road corridors across South Asia.

El Niño Southern Oscillation (ENSO), encompassing El Niño and La Niña, significantly influences river flooding patterns, which is prompting to investigate its relationship with floods in Nepal's transboundary Karnali River Basin (KRB). Focusing on extreme flood events during El Niño and La Niña years, this research aims to enhance the understanding of ENSO's impact on hydrological and hydrodynamic processes. Precipitation and discharge data spanning from 1964 to 2020 sourced from the Department of Hydrology and Meteorology (DHM), Government of Nepal, were analyzed. Hydrodynamic modeling, employing HEC-HMS and HEC-RAS, identified four significant El Niño events in 1983, 2000, 2014 (La Niña years), and 2015 (a strong El Niño year) at the basin. The study identified ENSO events and examined basin characteristics, precipitation depth, river discharge, and gauge height, utilizing daily data for model estimation of flood discharge and depth. Analysis of ENSO-related variability, including Sea Surface Temperature (SST), Southern Oscillation Index (SOI), and Multivariate ENSO Index (MEI), alongside pressure, temperature, and discharge data across the KRB, was conducted using a three-year running mean. The Soil Conservation Service (SCS) method was integrated within the HEC-HMS and HEC-RAS models to evaluate rainfall duration and flood response considering terrain, soil, and land use. Model simulations revealed river channel shifts, particularly along the right bank, during the 2015 ENSO event. Intensity–duration–frequency (IDF) and correlation/regression analyses further elucidated the impact of ENSO, with the lowest recorded precipitation and discharge observed during the 2015 El Niño event despite localized heavy rainfall. Comparative analysis of flood discharge, gauge height, inundation extents, depths, and velocities across ENSO years highlighted a significant relationship between observed and modeled discharge during the monsoon season. The positive correlation between basin mean precipitation and discharge during ENSO event indicating precipitation as a key driver of the basin's hydrology. These findings offer valuable insights for water resource management and development, aiding in the anticipation of future strong ENSO and El Niño events in the region.

The process of shearing loose, saturated sand raises the pore water pressure. When the extra pore water pressure reaches the effective overburden stress, the soil liquefies or behaves like a fluid, deforming without gaining shear strength. The dynamic response of sand was simulated in this study utilizing finite element method (FEM) analysis and a critical state compatible constitutive model calibrated for Ottawa sand. The liquefaction susceptibility and settling behavior of structures built on such soil were examined using OpenSees. The impact of ground characteristics (thickness of top and bottom non-liquefiable layers) and structural parameters (foundation width, structure height, and bearing pressure) on the liquefaction induced settlement of shallow foundations was examined numerically and parametrically. The findings showed that the acceleration time history of ground motion controls the rate of settlement, with peak acceleration times resulting in the greatest amount of settlement. It was discovered that shear induced displacement was crucial to structural settlement, indicating that empirical techniques created for free field settings might not be accurate. The results also showed that, in contrast to popular belief, liquefaction induced settlement is not always lessened by wider foundations. Higher contact pressure was also shown to promote settlement, possibly as a result of ratcheting effects brought on by shear. The thickness of the non-liquefiable crust was found to have a greater effect on settlement than the thickness of the non-liquefiable base among the ground parameters examined.

Potato late blight, caused by Phytophthora infestans , remains a major constraint to potato production and is predominantly managed through repeated fungicide applications. Biological control offers a potential complementary strategy, but its field performance under natural epidemic conditions remains inconsistent. This study evaluated the comparative efficacy of Pseudomonas fluorescens , Trichoderma viride , and their consortium for suppressing potato late blight and maintaining tuber yield under natural disease pressure. A field experiment was conducted in 2026 at Mude, Sindhupalchok, Nepal (2500 m above sea level), using cv. Desiree in a randomized complete block design with four treatments and five replications. Disease severity was assessed at weekly intervals using the CIP 1–9 late blight scale and converted to percentage severity, while epidemic development was quantified using the area under the disease progress curve (AUDPC). Total tuber yield was recorded at harvest. Disease severity increased progressively across all treatments. T. viride produced the lowest overall estimated mean disease severity (37.0%), which was significantly lower than that of P. fluorescens (42.9%; P = 0.0349). It also recorded the lowest AUDPC (762.65), corresponding to a 7.41% reduction relative to the untreated control, although treatment effects on AUDPC were not significant ( P = 0.372). The consortium resulted in a 2.70% numerical reduction in AUDPC, whereas P. fluorescens increased AUDPC by 7.75% relative to the control. Tuber yield was not significantly affected by treatment ( P = 0.286), although P. fluorescens produced the highest numerical yield (8.51 kg plot⁻¹). Overall, T. viride demonstrated greater disease-suppressive potential than P. fluorescens and the consortium under the conditions tested, but the magnitude and consistency of suppression were insufficient to establish reliable field-level control. These findings indicate that T. viride may have value as a component of integrated late-blight management, warranting further evaluation of locally adapted strains, preventive application schedules, and integration with reduced-fungicide programs under multi-location and multi-season conditions.