Executive Summary
As climate change accelerates, coastal regions face escalating flood risks driven by the combined effects of storm surge, river discharge, and extreme rainfall. These compound flooding events are increasing in both frequency and severity, particularly in areas affected by tropical cyclones. A groundbreaking study by Renato Amorim, Gabriele Villarini, Hanbeen Kim, Robert A. Jane, and Thomas Wahl introduces an advanced modeling approach that enhances the accuracy of flood prediction and infrastructure design. Focused on coastal Texas, their process-driven method equips engineers, planners, and resilience professionals with high-resolution data to improve climate adaptation and protect vulnerable communities.
Understanding the Growing Threat of Compound Flooding
Coastal flood risk is becoming more complex and less predictable. Rather than facing one hazard at a time, many regions now experience multiple overlapping threats—such as heavy rainfall and storm surge co-occurring. This phenomenon, known as compound flooding, can overwhelm drainage systems, erode coastlines, and cause billions in damage to infrastructure, homes, and businesses.
Climate change is amplifying this threat. Warmer oceans and rising sea levels intensify tropical cyclones, while heavier rainfall events stress coastal watersheds. The result is a greater likelihood that these hazards will coincide, producing catastrophic flooding that exceeds traditional design standards. Despite improved awareness, many flood management models still fail to capture the dynamic interaction between rainfall and storm surge across different regions and storm types.
A New Framework for Predictive Flood Modeling
To address this critical gap, the research team developed a process-driven modeling framework for a more accurate assessment of compound flood risk. Their study, “A Practitioner’s Approach to Process-Driven Modeling of Compound Rainfall and Storm Surge Extremes for Coastal Texas”, published in the Journal of Hydrologic Engineering, provides engineers with a step-by-step method to simulate and design for real-world flood events.
The study focuses on five coastal Texas watersheds and shows how tropical cyclone–driven storms exhibit a stronger correlation between rainfall and storm surge than non-cyclonic events. The framework also introduces techniques for reconstructing missing water-level data and quantifying the lag between peak rainfall and surge. This enables engineers to produce reliable, high-resolution design events for different annual exceedance probabilities (AEPs), a significant advancement for infrastructure resilience planning.
Building Climate-Resilient Coastal Infrastructure
The findings have significant implications for coastal engineering, floodplain management, and climate adaptation. By integrating this new compound-flood modeling approach, practitioners can design infrastructure that better withstands multi-hazard extremes and reduces both economic losses and downtime.
Incorporating process-driven modeling into coastal planning not only enhances risk forecasting but also supports compliance with emerging climate disclosure and resilience frameworks. Municipalities, utilities, and private developers can apply this methodology to strengthen capital investment strategies, inform zoning and permitting decisions, and protect critical infrastructure assets against future climate extremes.
Frequently Asked Questions (FAQs)
- What is compound flooding? Compound flooding occurs when multiple flood drivers, such as storm surge, heavy rainfall, and river discharge, overlap in time and space, amplifying flood impacts on coastal and urban areas.
- Why is compound flooding becoming more frequent? Climate change is intensifying rainfall, rising sea levels, and strengthening tropical cyclones, making the simultaneous occurrence of these hazards more likely and more destructive.
- What is process-driven flood modeling? Process-driven modeling uses physical and statistical relationships between hazards, such as rainfall and storm surge, to simulate realistic compound flood events and improve predictive accuracy.
- How does this research benefit infrastructure and planning? The framework enables engineers and planners to design infrastructure that can withstand multi-hazard flood events, enhancing climate resilience and reducing long-term economic losses.
- How can ClimaTwin support flood risk assessment and adaptation? ClimaTwin applies AI-powered Climate Business Intelligence to quantify physical and financial risks associated with climate extremes, enabling organizations to plan, invest, and adapt to future weather impacts.
(Source: Connelly, L. (2025, October 15). Accurately predicting the risk of compound flooding on coastal watersheds. Civil Engineering Source. American Society of Civil Engineers. www.asce.org/publications-and-news/civil-engineering-source/article/2025/10/15/accurately-predicting-the-risk-of-compound-flooding-on-coastal-watersheds.)
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