It is expected that the US population living in urban areas will increase from 83% of the total population in 2020 to over 89% by 2050. Urbanization, with the accompanying alterations to the physical environment, has a significant impact on various of the processes that control streamflow. The effects of urbanization on storm runoff have been found to be very consistent across geographic regions, leading to higher runoff efficiency. However, the effects of urbanization on baseflow can vary widely in magnitude and direction across urban areas. Previous studies have analyzed changes in streamflow driven by urban development in the Denver Metro Area and have found considerable effects on the magnitude and duration of stormflow and baseflow. We aim to build on this work by developing predictive models for changes in streamflow considering different watershed characteristics. For this, 21 gauged watersheds with different extents of urbanization located in the Denver Metro Area will be analyzed. The studied watersheds range in size from 0.7 km2 to 90 km2, and in imperviousness from 0.8% to 47%. So far, the analysis suggests that the lower values of imperviousness have a linear relationship with the median discharge, but other watershed characteristics should be explored for a better fit in the higher end of imperviousness. These predictive models will help us determine the factors that most affect the change in streamflow from an undeveloped watershed to a traditionally developed watershed. The results of this project will help decision makers in the urban planning process by providing a tool to explore the potential effects of different future urban development scenarios on streamflow.
