Hydrometeorologic impacts of urban expansion and the role of spatial arrangement (Invited)
Abstract
Global land cover/land use is changing notably due to expansion of urban areas, resulting in the conversion of natural landscapes to roads, industrial areas, and buildings. The associated reduction in infiltration and runoff lag time have long been the domain of the urban hydrologist, while this landscape transformation also leads to changes in land surface heterogeneities, resulting in alterations of land-atmosphere interactions and convective processes. The integrated impacts of both impervious area and precipitation changes to flood risk in urban environments have not been well-represented by existing predictive tools, which often focus at disparate scales. This presentation attempts an integrated assessment of the multi-scale interaction of urban landcover, hydrology and convective processes, in order to investigate how urbanization has altered the hydrometeorology of urban thunderstorm events, and the role of the spatial arrangement and scale of urban landcover on urban flood frequency. Studies suggest that in some cases, urban influence creates a convergence zone upstream of the urban area, resulting in precipitation increases both upstream and downstream of the urban influence. Total runoff increases consistently with urbanization by restricting infiltration on the land surface, but this is coupled with high uncertainty in the spatial pattern of precipitation change. For some watersheds, the convective influence can result in a significant increase in peak streamflow, relative to impervious influence alone. The spatial pattern of urban development can further affect the hydrologic regime by influencing the hydrologic connectivity of urban areas at the catchment scale, while at the river basin scale the travel time from urban centers to the watershed outlet controls flood magnitudes.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFMGC52A..05B
- Keywords:
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- 1834 HYDROLOGY Human impacts;
- 3322 ATMOSPHERIC PROCESSES Land/atmosphere interactions;
- 1655 GLOBAL CHANGE Water cycles;
- 1817 HYDROLOGY Extreme events