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Establishing Design Storm Values from Climate Models in Coastal Regions: Challenges and Opportunities
Yang, J., M. Liang, Y. Zhao, AND J. Neal. Establishing Design Storm Values from Climate Models in Coastal Regions: Challenges and Opportunities. In Proceedings, World Environmental and Water Resources Congress 2017, Sacramento, CA, May 21 - 25, 2017. American Society of Civil Engineers (ASCE), Reston, VA, (2017). https://doi.org/10.1061/9780784480618.040
Coastal storm events currently lead to large and frequent changes in precipitation and wind speed, and they are expected to increase in frequency as our climate changes. This variability of wind and rain can impact the design and sustainability of water infrastructure and associated assets. The purpose of this research was to assess whether past rain and wind data could determine how to design water infrastructure in the future. However, it was determined that past data will not accurately forecast future events because there has been an increase in precipitation in recent years. This research determined there is a need for a newer procedure to design water infrastructure assets based on anticipated impacts from future storms. Cities, states, planners, engineers and others who are considering designing water infrastructure can consider this research in their planning.
Dynamic interactions of atmospheric and hydrological processes result in large spatiotemporal changes of precipitation and wind speed in coastal storm events under both current and future climates. This variability can impact the design and sustainability of water infrastructure and other environmental assets. We have examined the nature of this challenge and explored the feasibilities of determining future design basis along the U.S. eastern coastal sites. Long-duration historical precipitation datasets, along with wind records, at 14 local USHCN stations are analyzed. Design storm values are determined using sliding time window of the 30-yr and 50-yr duration. The results are compared to the Atlas-14 precipitation design curves and with the design storms derived from the downscaled CMIP5 daily precipitation datasets (1950-2000). We show that Atlas-14 design charts, mostly based on pre-1990 data, sufficiently describe the design storms of the past, but do not describe the high-intensity precipitation of recent years. The 132 CMIP5 climate models and their ensembles also under-estimate the design storms. Similar bias is found in design wind speeds from AOGCM outputs. Based on these results, a post-bias correction procedure is proposed for developing design storm values from CMIP5 and AOGCM projections.
Establishing Design Storm Values from Climate Models in Coastal Regions: Challenges and Opportunities Exit