The problem the researchers set out to solve is one that haunts hydraulic engineers across the developing world. Bridge scour, the removal of sediment from around foundations by flowing water, is the leading cause of bridge collapse worldwide, and its severity depends on river discharge, sediment load, and channel geometry. Yet most design codes still assume that the statistics of future floods will resemble those of the past, an assumption famously challenged in 2008 when hydrologists declared that stationarity is dead. In data-scarce tropical basins like the Rupnarayan, where gauge records are short and sparse, quantifying how climate change will alter the forces acting on critical infrastructure has remained poorly constrained. The team’s answer was to build a modelling pipeline that squeezes usable engineering numbers out of limited observations.

At the top of the pipeline sits a high-resolution global climate model, the Max Planck Institute Earth System Model version 1.2 Higher Resolution, known as MPI-ESM1-2-HR. Raw global model output is too coarse and too biased to drive a local river model, so the researchers downscaled and bias-corrected the projections before feeding them into the Soil and Water Assessment Tool, a widely used watershed model that simulates how rainfall becomes runoff and sediment. The calibration was strong: the coupled model achieved a Nash-Sutcliffe efficiency of 0.90 and a coefficient of determination of 0.86 for discharge, figures that indicate the simulated river flows track the observed record closely. That performance matters, because every downstream estimate of scour depends on the credibility of the flow and sediment series entering the hydraulic model.

To bracket the range of possible futures, the team ran three Shared Socioeconomic Pathways: the moderate SSP245, the intermediate SSP370, and the fossil-fuel-intensive SSP585. The observed record from 1960 to 2020 shows no significant trend in the basin’s hydrology, but the projections diverge sharply from that historical baseline. Under SSP585, mean annual temperature rises by 1.31 degrees Celsius and mean annual rainfall increases by 22.1 percent by 2100. Those shifts translate into altered river flow regimes and sediment delivery, which the researchers propagated through a two-dimensional Hydrologic Engineering Center River Analysis System model, HEC-RAS 2D, to compute water-surface elevations, energy gradients, and bed shear stress for floods with return periods ranging from 2 to 100 years.

The hydraulic results reveal a consistent intensification of the forces that move sediment. Across the three-scenario comparison, critical shear stress and the energy gradient at the Kolaghat Bridge increase by 11 to 18 percent, with the MPI-ESM1-2-HR-driven projections clustering around 15 percent. Bed shear stress is the fundamental quantity in sediment transport: it describes the drag exerted by moving water on the channel bed, and when it exceeds the critical threshold for the bed material, grains begin to move. A higher energy gradient means steeper, more energetic flow, and a higher critical shear stress at the site means the river is pushing harder against its bed precisely where the bridge foundations are anchored.

The most striking number in the study comes from applying the HEC-18 procedure, the standard method of the U.S. Federal Highway Administration for evaluating scour at bridges. Total pier scour at the Kolaghat Bridge, projected under the high-emissions pathway, grows from approximately 6.07 metres to approximately 10.93 metres, an increase of about 80 percent. Pier scour develops when flowing water accelerates around a pier, forming horseshoe vortices at the bed that excavate a hole around the foundation. The deeper that hole becomes, the less of the pile remains embedded in competent material, and the smaller the reserve of safety against collapse. According to the study, the projected scour would diminish the foundation safety margin below the code threshold, a finding that converts an abstract climate statistic into a concrete engineering liability.

Paradoxically, the same simulations point to a second, opposite hazard. The projected water-surface elevations show reduced high-frequency variability, which the researchers interpret as a signal of increased sedimentation, channel narrowing, and a rise in overall channel sinuosity from 1.08 to 1.67. A sinuosity increase of that magnitude describes a river meandering more sharply through its floodplain, reshaping its course over decades. Sedimentation and narrowing can raise flood levels for a given discharge, while the shifting thalweg, the deepest line of the channel, can direct erosive flow toward piers that were designed for a different channel alignment. The bridge, in other words, faces threats from both directions: stronger scour during floods and a progressively less stable channel around it.

What makes the study methodologically significant is that it accomplishes this assessment in a basin with almost no dedicated monitoring infrastructure. The authors combined openly available bias-corrected CMIP6 climate projections, published by Mishra and colleagues on Zenodo, with satellite-derived terrain data and standard public modelling tools, creating a replicable template for other data-scarce rivers. The three-scenario, three-model comparison also gives engineers a sense of uncertainty: the 11 to 18 percent spread in shear stress intensification reflects how different scenario pathways and model configurations propagate through the chain. Similar physics-based approaches have been applied to regional bridge scour risk in the United States and to national scour assessments in Sweden, but applications to tropical, monsoon-dominated, peri-urban basins in South Asia have been rare, despite the region’s dense inventory of aging river crossings.

The practical implications extend well beyond a single bridge. The authors argue that their results make a clear case for climate-adjusted hydraulic design loads, meaning that new structures and retrofits should be sized not on historical flood statistics but on projected future flows and shear stresses. They also recommend regular bathymetric monitoring, repeated surveys of the riverbed depth around foundations, so that scour can be tracked as it develops rather than discovered after the fact, together with planned dredging to manage sediment accumulation. For the Kolaghat Bridge, which carries traffic across a working river in a densely populated corridor of West Bengal, such monitoring could mean the difference between a scheduled intervention and an emergency.

More broadly, the study is a reminder that climate change does not only arrive as floods and droughts; it arrives as altered physics in the beds of rivers, working silently on the foundations of the built world. A warming atmosphere loads more moisture into monsoon systems, reshaping discharge regimes and sediment budgets in ways that standard design manuals, written for a stationary climate, never anticipated. As extreme rainfall intensifies across South Asia, the modelling chain demonstrated here, from downscaled Earth system projections through watershed simulation to two-dimensional hydraulics and scour analysis, offers a way for engineers in data-poor regions to see that hidden stress coming, and to reinforce their infrastructure before the river quietly undermines it.

Subject of Research: Climate change impacts on bridge pier scour and river channel morphology in the data-scarce Rupnarayan basin, India

Article Title: Climate-induced hydraulic stress and geomorphological changes: an assessment of vulnerability of critical river infrastructure in the data-scarce basin, India

Article References: Ghosh, A., Kundu, M., & Padhi, E. (2026). Climate-induced hydraulic stress and geomorphological changes: an assessment of vulnerability of critical river infrastructure in the data-scarce basin, India. Environmental Monitoring and Assessment, 198(11), Article 1175. https://doi.org/10.1007/s10661-026-16013-6

Image Credits: AI Generated

DOI: 10.1007/s10661-026-16013-6

Keywords: bridge scour, climate change, HEC-RAS, SWAT, CMIP6, Rupnarayan River, bed shear stress, hydraulic modelling, infrastructure vulnerability, SSP585, India, geomorphology

Across the United States, severe weather events have been shown to precipitate large-scale power outages, leading to significant socioeconomic repercussions. These outages can have dire implications, particularly in times when power is essential for the operation of medical equipment, heating, air conditioning, and other critical services. The ongoing climate crisis serves to exacerbate these challenges, as it increases both the severity and frequency of severe weather events, necessitating a better understanding of the patterns and distributions of power outages to inform community preparedness and resource management.

In this meticulous research effort, the authors, led by Vivian Do, a PhD candidate specializing in environmental health sciences, utilized comprehensive data sets spanning from 2018 to 2020. This extensive investigation focused on over 1,600 counties nationwide, evaluating the correlation between severe weather events—such as rain, snow, extreme heat, intense cold, cyclones, and wildfires—and significant power outages that lasted eight hours or longer. The findings underscored that approximately three-quarters of the analyzed counties experienced major power outages coinciding with severe weather occurrences during the observed three-year span. Alarmingly, over half of these counties dealt with outages associated with multiple simultaneous weather events, illustrating a complex and interlinked system of vulnerability.

The research highlighted that power outages were most frequently linked to severe precipitation and extreme heat, revealing significant regional disparities in the distribution of these outages. For instance, counties in the Northeast U.S. were more prone to precipitation-related outages, whereas heat-related outages were predominantly observed in the Southeast. Additionally, the researchers noted a growing trend of co-occurring outages and wildfires along the West Coast, marking a worrying development that raises important questions about the management of electrical grids in wildfire-prone areas.

Despite the insightful findings presented by Do and her colleagues, it is important to acknowledge the limitations in the data. In particular, reliable data was not uniformly available for all counties, creating gaps in information that left regions such as the Southwest and Mountain West less represented in the study. In light of these limitations, the authors advocate for further research that can provide additional data, as well as realistic simulations of severe weather combinations across diverse geographies, to enhance the capability of municipalities to construct effective mitigation and response strategies.

The implications of this research extend beyond merely identifying problem areas; they delve into the broader societal importance of understanding the interdependencies between infrastructure and environmental factors. In an era when the electrical grid is becoming increasingly antiquated, and as severe weather continues to pose escalating threats, strategies that preemptively address the intersection of severe weather challenges and power failures are crucial. The careful mapping of outage patterns, as highlighted in this study, is fundamental for designing robust systems geared toward minimizing public health risks and economic losses.

Vivian Do emphasized the practical importance of recognizing these patterns, stating: “Power outages frequently co-occur with severe weather events like heavy precipitation, tropical cyclones, or multiple severe weather events simultaneously.” Understanding when and where these phenomena will likely converge is vital for developing strategic responses that can effectively reduce adverse societal consequences. This becomes even more urgent as communities adapt to the realities of a changing climate.

Furthermore, as climate models predict increasingly dramatic shifts in weather patterns, researchers and policymakers must work in tandem to preemptively address the vulnerabilities associated with energy dependence. These insights could be incorporated into future revisions of national response frameworks, ensuring that contingencies are established to protect critical infrastructure in times of weather-related crises. This can also enhance public awareness and preparedness initiatives, ensuring that communities are equipped to handle power loss and its cascading effects.

The study received financial backing from several prominent institutions, including the National Institute for Environmental Health Sciences and the National Institute on Aging, underscoring the broad interest in understanding the health impacts of environmental hazards. Importantly, the funding bodies had no direct influence over the study’s design, data collection, or the conclusions drawn, thereby ensuring the integrity of the research process.

As climate change continues to reshape the landscape, studies such as this one serve as crucial tools for informing public health policies, energy conservation measures, and community resilience planning. The convergence of severe weather events and power outages is not merely an infrastructure issue; it encapsulates broader societal challenges, including equity in public health and the necessity for robust disaster preparedness systems.

As communities across the U.S. grapple with these evolving threats, the findings of this research underscore the imperative of a collective response to strengthen resilience against the dual challenges posed by climate change and electrical grid vulnerabilities. This holistic approach will be essential for safeguarding public health, ensuring equitable access to vital services, and reinforcing the electric grid against the increased strains brought on by an unpredictable climate.

In conclusion, understanding the shifting relationship between severe weather and power outages is not only a scholarly endeavor but a fundamental necessity for fostering community health and safety in an era where extreme weather becomes the norm rather than the exception. The integration of science-informed strategies into community planning will be essential for minimizing disruption and safeguarding the well-being of populations at risk.

Subject of Research: Relationship between severe weather events and power outages.
Article Title: Spatiotemporal patterns of individual and multiple simultaneous severe weather events co-occurring with power outages in the United States.
News Publication Date: 22-Jan-2025.
Web References: PLOS Climate
References: Not provided.
Image Credits: Not provided.

Keywords: Climate data, Environmental health, Electrical power generation, Weather.