Recorded presentation7A.3
Hydrologic response to urbanization in the Milwaukee River basin, WI
Guoxiang Yang, Purdue University, West Lafayette, IN; and L. C. Bowling, K. A. Cherkauer, and B. C. Pijanowski
The Milwaukee River Basin is one of the most urbanized basins along Lake Michigan. Urban land cover has greatly different hydrological response characteristics from natural land cover and can potentially influence watershed hydrology, such as increased flood frequency and magnitude, increased flow variability, and redistribution of streamflow from base flow to storm flow. The northern part of the Milwaukee River basin is mostly rural, while the southern is the most densely developed area in Wisconsin, containing 90% of the basin's population. Based on projected land use scenarios using the Land Transformation Model (LTM), urban expansion in the next several decades is predicted to occur where agriculture (and forest) is now -- which is along the middle and northern part of the basin. This study first analyzes how the hydrologic regime will change in the upper tributaries of the basin with increasing impervious cover and forest regrowth under future land cover scenarios. The impact of urbanization in the six primary tributaries on the hydrologic regime of the main stem is then investigated by analyzing the simulated magnitude and timing of peak flow with statistical methods. The Variable Infiltration Capacity (VIC) urban land surface model, is used together with projected LTM land cover scenarios to simulate the hydrologic responses for future urban, forest and agriculture for the period of 2005-2035. In addition, to better explain the effect of urbanization process on peak flow changes in the main stem, landscape spatial metrics, such as Edge density (ED), contagion (CONTAG), largest patch index (LPI), number of patches (NP) and mean nearest neighbor (MNN) distance of the urban areas are also employed in order to link spatial patterns of future land cover scenarios to shifts in hydrologic regimes in the study area.
Session 7A, Hydrological Impacts of Land Use Change
Wednesday, 14 January 2009, 1:30 PM-2:30 PM, Room 127B
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