Empirical Analyses of the Hydroclimatology of Flooding for Small Urban Watersheds

We examine the hydroclimatology of urban flooding through empirical analyses of rainfall and discharge in “small” (1 – 100 sq. km.) watersheds for a diverse collection of metropolitan areas in the US (Baltimore, Atlanta, Milwaukee, Charlotte, Chicago, Philadelphia, New York City and Kansas City). Analyses are based on USGS stream gaging observations and long-term (10+ years), high-resolution radar rainfall fields derived from volume scan WSR-88D radar observations using the Hydro-NEXRAD algorithms. The principal questions that we address are: 1) What are the dominant land-surface processes that control the spectrum of flood response in small urban watersheds and 2) How does urban modification of rainfall affect the hydroclimatology of small watersheds? In this paper, we synthesize urban flood hydroclimatology studies for the sample of urban watersheds listed above.