Warm Season Thunderstorm Systems and the Flood Hydrology of the Baltimore Metropolitan Region
James A. Smith, Princeton University
Flood response in the Baltimore metropolitan region is examined using high-resolution radar rainfall estimates, "unit values" discharge observations and land surface data sets. Analyses focus on organized convective systems during the warm season. These events become an increasingly important element of regional flood hydrology with urbanization. Model analyses are used to characterize flood response in terms of land use and cover, structure of the natural and storm water drainage system, and space-time variability of rainfall. Drainage basins range in area from 2 to 25 sq. km. and reflect diverse land cover properties and development histories. Particular attention is given to White Marsh Run, Baisman Run, upper Gwynns Falls, Dead Run, Moores Run and Minebank Run. Flood analyses utilize observations from storms on 16 July 2000, 13 May 2000, 26 August 1999 and 15 July 2000. It is shown that storm structure, motion and magnitudes of rainfall rates play a major role in urban flood response, even at the 2 to 25 sq. km. scale of the basins under study.