2024-08-19 カリフォルニア大学校アーバイン校(UCI)
＜関連情報＞
- https://news.uci.edu/2024/08/19/uc-irvine-team-says-urban-street-networks-building-density-shape-severity-of-floods/
- https://www.nature.com/articles/s41467-024-50347-4
都市形態が洪水に与える影響 How urban form impacts flooding
Sarah K. Balaian,Brett F. Sanders & Mohammad Javad Abdolhosseini Qomi
Nature Communications Published:19 August 2024
DOI:https://doi.org/10.1038/s41467-024-50347-4
Abstract
Urbanization and climate change are contributing to severe flooding globally, damaging infrastructure, disrupting economies, and undermining human well-being. Approaches to make cities more resilient to floods are emerging, notably with the design of flood-resilient structures, but relatively little is known about the role of urban form and its complexity in the concentration of flooding. We leverage statistical mechanics to reduce the complexity of urban flooding and develop a mean-flow theory that relates flood hazards to urban form characterized by the ground slope, urban porosity, and the Mermin order parameter which measures symmetry in building arrangements. The mean-flow theory presents a dimensionless flood depth that scales linearly with the urban porosity and the order parameter, with different scaling for disordered square- and hexagon-like forms. A universal scaling is obtained by introducing an effective mean chord length representative of the unobstructed downslope travel distance for flood water, yielding an analytical model for neighborhood-scale flood hazards globally. The proposed mean-flow theory is applied to probe city-to-city variations in flood hazards, and shows promising results linking recorded flood losses to urban form and observed rainfall extremes.
