Pluvial flood risk and opportunities for resilience

Abstract

The risk presented by pluvial flooding has emerged as a critical issue in urban water management. Pluvial flooding occurs when precipitation intensity exceeds the capacity of natural and engineered drainage systems, and it is expected to increase in frequency, severity and impact through the 21st century due to the combined effects of climate change and urbanization. Although there have been recent advances in approaches to assess the risk presented pluvial flooding and to enhance the resilience of cities to its impacts, they have not been broadly implemented and there are many opportunities for additional research. We provide case studies of pluvial flooding in six cities in the continental United States, which serve as examples of the current vulnerability of cities that have not developed comprehensive pluvial flood management plans and the challenges in conducting pluvial flood research in light of existing data gaps. We also identify key research challenges that should be prioritized by the interdisciplinary water research community to better support urban resilience practice. This article is categorized under: Engineering Water > Sustainable Engineering of Water Science of Water > Water Quality Engineering Water > Planning Water

Exploring the application of topographic indices in urban areas as indicators of pluvial flooding locations

“…Both are eastern cities located close to major waterways. Urban centers in these cities have a history of problems with pluvial flooding given the high imperviousness within the urban core (Rosenzweig et al, 2018). Climate in NYC is continental, with average Whereas study watershed SI2 is drained by MS4s to constructed wetlands, SI1 is drained by a combination of combined sewer system and MS4s.…”

“…Additionally, topographic indices may be good indicators of flooding, regardless of engineered drainage type, in more extreme storm events that would exceed the design capacity of the storm sewer system, which often is for a 2-to 5-year return period (Rosenzweig et al, 2018). Though more work is needed to refine an approach for combining TIs and community-based flooding reports, our promising findings demonstrate the potential of these data sources to improve our understanding of the timing and location of nuisance flooding.…”

“…This type of flooding is of concern given the cumulative effects of high potential for exposure in urban areas alongside observed increases in the high intensity, short-duration precipitation events that drive pluvial flooding (Westra et al, 2014). Floods may also occur when engineered drainage is insufficient, when rainfall exceeds the design storm or when storm sewers back up due to overfilling or due to the presence of clogs (e.g., leaves) that block water movement from the streets to the sewers (Rosenzweig et al, 2018). Floods may also occur when engineered drainage is insufficient, when rainfall exceeds the design storm or when storm sewers back up due to overfilling or due to the presence of clogs (e.g., leaves) that block water movement from the streets to the sewers (Rosenzweig et al, 2018).…”

“…Nuisance flooding leads to direct (e.g., from flowing water) and indirect damages (e.g., disrupting traffic and other activities, production losses, and administrative costs) as well as social consequences (which can be more difficult to measure, e.g., negative impacts on social well-being, economic development, and quality of life; König, Saegrov, & Schilling, 2002). Though often associated with coastal areas, nuisance floods are also prone to occur in inland urban areas where pluvial flooding is driven by excess precipitation in combination with inadequate drainage (Rosenzweig et al, 2018). This type of flooding is of concern given the cumulative effects of high potential for exposure in urban areas alongside observed increases in the high intensity, short-duration precipitation events that drive pluvial flooding (Westra et al, 2014).…”

“…Pluvial flooding in urban systems often occurs due to the high imperviousness of urban surfaces preventing natural drainage, instead of routing water via street networks and sewer infrastructure, leading to runoff collecting in localized depressions. Floods may also occur when engineered drainage is insufficient, when rainfall exceeds the design storm or when storm sewers back up due to overfilling or due to the presence of clogs (e.g., leaves) that block water movement from the streets to the sewers (Rosenzweig et al, 2018).…”