Better Representation of Urban Vegetation Alters Surface Water and Temperature Cycles

Speaker:  Aaron Alexander, PhD Candidate, Water Resources Engineering, UW, Madison

Urbanization substantially modifies surface water and energy cycles, due to widespread, low-permeability surfaces producing more runoff, trapping more heat, and lowering evapotranspiration. Cities are adapting to overcome these issues, which are all further amplified by climate change, by adopting nature-based solutions, which aim to reduce the hydrologic impacts of urbanization. However, current efforts to represent fine scale urban hydrology in city-to-regional scale climate models are too simplistic to capture the impacts of these management solutions, yet they must be resolved if we hope to understand potential holistic effects that nature-based solutions provide. We present a new version of a widely used land surface model capable of explicitly resolving fine scale lateral water transfers in urban areas. We also examine how these seemingly small hydrologic changes lead to large modifications of the surface water and energy cycles and how these influence near surface meteorology (e.g., temperature, humidity, etc.)  in Milwaukee, Wisconsin.