Potential Impacts of Future Extreme Precipitation Changes on Flood Engineering Design Across the Contiguous United States. Issue 4 (5th April 2022)

• Record Type: Journal Article
• Authors: Coelho, Gustavo de A.; Ferreira, Celso M.; Johnston, Jeremy; Kinter, James L.; Dollan, Ishrat J.; Maggioni, Viviana
• Is Part Of: Water resources research. Volume 58:Issue 4(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-04-05
• Subjects: intensity‐duration‐frequency -- CESM2 -- large ensemble -- global climate model -- climate change -- flood resilience; Hydrology -- Periodicals; 333.91
• DOI: 10.1029/2021WR031432
• Languages: English
• ISSNs: 0043-1397

Abstract

Abstract: The intensification of extreme precipitation in a warming climate is expected to increase flood risk. In order to support flood resilience efforts, it is important to anticipate and quantify potential changes in design standards under future climate conditions. This study assessed how extreme precipitation is expected to change over the 21st century in relation to current National Oceanic and Atmospheric Administration (NOAA) Atlas 14 design standards over the contiguous United States (CONUS). We used the Community Earth System Model Version 2 large ensemble (CESM2‐LE) simulations from the Coupled Model Intercomparison Project Phase 6 and incorporated future changes into flood engineering design standard with a spatially distributed quantile delta mapping method. Relative changes in extreme daily precipitation were computed for multiple average recurrence intervals (ARIs) up to 100‐year and different planning horizons (2020, 2040, 2060, 2080, and 2100). The results indicated an intensification of extreme precipitation by approximately 10%–40% in northern regions and 20%–80% in southern regions by 2100. The current 100‐year ARI with 24‐hr duration from NOAA Atlas 14 is projected to become the 50‐year ARI in the Northern Great Plains, less than the 25‐year ARI in Southwest areas, and approximately the 25‐year ARI in the other regions by 2100. While a nationwide consensus is still needed, this work presents a possible methodology for incorporating climate uncertainty in engineering design. A comparison across major metropolitan areas also illustrates regional variability in projected changes relative to NOAA Atlas 14, suggesting a need for varied local‐scale responses. Plain Language Summary: Extreme precipitation events, which are the major cause of urban and flash floods, are expected to become more intense and frequent due to a warming climate. Anticipating and quantifying changes in extreme precipitation is key to evaluate the level of protection provided by current infrastructure and adapt for the future. We assessed the changes in extreme precipitation using the most recent climate projections for the 21st century as well as the potential impacts on the current engineering design standards across the contiguous United States. We found that heavy precipitation is projected to become more frequent and that current design standards are projected to become obsolete in parts of the Midwest and Northeast regions, and in most of the southern United States by 2100. Results from this work indicate that different actions will be required to increase the flood resilience of our communities at both regional and local scales. Key Points: Recent extreme precipitation projections for the 21st century are incorporated in flood engineering design standards at continental scale The current 100‐year return period precipitation in 24 hr is projected to approach the 25‐year return period in most of the country by 2100 Current intensity‐duration‐frequency curves for most of the United States are expected to become obsolete by 2080