“Untangling the hydrologic effects of urbanization”
Urban development consists of many processes and results in a variety of hydrologic alterations. I will present work 
quantifying the effects of urbanization on groundwater-surface water interactions using intensive data analysis, 
field data collection, and mathematical modeling. In the Baltimore region, we quantified the water balance for 65 
area watersheds including estimation of spatially-distributed anthropogenic fluxes (water supply pipe leakage, lawn 
irrigation, and infiltration and inflow (I&I) of groundwater and stormwater into wastewater pipes) as well as 
natural fluxes of precipitation, streamflow, and evapotranspiration.  Building on knowledge of the altered urban 
water balance, an integrated hydrologic model of the Baltimore metropolitan was developed to quantify the effects of 
urban development on water availability. A three-dimensional integrated hydrologic model was implemented and a 
methodology to incorporate urban and hydrogeologic input datasets was developed. Using the model, the effects of 
reduced vegetative cover, impervious surface cover, I&I, and other anthropogenic discharge and recharge fluxes were 
isolated. Our latest work quantifies the changes to the stream base flow regime and episodic groundwater recharge 
resulting from green infrastructure during and after suburban development in Clarksburg, Maryland.