Nuisance Flooding Risk on the Rise in Coastal Urban Areas

A groundbreaking study by UVA researchers reveals new insights into the growing risk of nuisance flooding in urban coastal communities, with a focus on Norfolk, Virginia. The increasing frequency and impact of these floods are driven by a combination of urbanization and rising sea levels.

Urban areas around the world are facing greater flood risks due to a combination of urbanization and changing climate conditions. As cities become more dense, impervious surfaces such as roads and buildings prevent rainwater from soaking into the ground, leading to increased runoff and overwhelmed stormwater systems. These systems, originally designed to handle predictable rainfall patterns, are struggling to keep up with the increasing intensity and frequency of storms caused by climate change.

Coastal cities like Norfolk, Virginia are particularly vulnerable to rising sea levels, land subsidence, and compound flooding, which occurs when both high tides and heavy rainfall combine to exacerbate flooding. This type of flooding, known as “nuisance flooding,” may not always cause major property damage or immediate safety risks, but its increasing frequency disrupts daily life, causes minor infrastructure damage, and strains drainage systems.

Climate Fellow Sergio Barbosa published a paper conducted with colleagues stating that nuisance flooding in Norfolk has increased by 325% since 1960.

A new study recently published by UVA Environmental Institute Climate Fellow Sergio Barbosa and co-authors demonstrates that nuisance flooding in Norfolk has increased by 325% since 1960 and is projected to grow even further in the coming decades. The research, published in the Journal of Hydrology, was conducted by Jiwoo Jeong, Sergio A. Barbosa, and Jonathan L. Goodall.

By 2050, the paper states, Norfolk could experience up to 125 days of nuisance flooding annually, up from about 10–15 days in 2020. The study also suggests that by 2100, storm surges could exceed 1.6 meters on a weekly or even daily basis, significantly amplifying flood risks.

“While previous studies have primarily focused on extreme flooding events, this research emphasizes the growing importance of understanding and preparing for more frequent, lower-magnitude nuisance floods,” Barbosa explained. “These floods can strain infrastructure, disrupt daily routines, and lead to gradual property damage as they occur more regularly over time.”

The study takes a novel approach by incorporating rainfall and compound flooding events, which are often overlooked in current flood models. Researchers used an advanced 2D overland and 1D pipe hydrodynamic model to simulate and analyze how tides, rainfall, and sea level rise interact to create nuisance flooding. This model, which was developed specifically for urban coastal areas like Norfolk, allows for a more realistic representation of how urban drainage systems will be impacted by rising seas and more intense rainfall.

Through the study, Barbosa and his team provide a methodology for assessing and quantifying nuisance flooding risks, which can be applied to other coastal cities worldwide. The study outlines different scenarios and the effects of future climate change on both types of flooding. These scenarios help to identify vulnerable areas and estimate the depth and extent of future flood risks.

“Our findings underscore the urgent need for better flood management strategies in coastal urban areas,” Barbosa added. “By understanding the interactions between stormwater systems, sea levels, and rainfall, cities can prepare for the increasing threat of nuisance flooding and implement creative countermeasures to protect both people and infrastructure.”