Modeling the Impact of Climate Change on Stormwater Infrastructure: Application to the Elmhurst, IL

The main purpose of this dissertation is to assess and simulate the impact of climate change on stormwater infrastructure for the city of Elmhurst, Illinois. For this research, the Regional and Global Climate Model provided by NARCCAP and based on the HRM3-GFDL dataset are used to project future rainfall patterns. From the dataset, the 3-,6-,12-, and 24-hour rainfall data were extracted for the annual maximum rainfall depths. The annual maximum rainfall data were then used to determine new Intensity-Duration-Frequency (IDF) curves for different recurrence intervals using three different distributions: Log Pearson type III (LP(III)), Generalized Extreme Value (GEV), and Gumbel. Moreover, these new IDF curves were compared with current IDF curves available in the Illinois Bulletin 70 and NOAA Atlas 14. Hydrological modeling was then performed to evaluate the impact of climate change on the existing drainage system of Elmhurst with conceptual improvements in pipe sizes according to today’s rainfall standards (Illinois Bulletin 70). Specifically, the XPSWMM model was used to simulate peak flowrates and runoff volumes. The maximum flowrate was then used to estimate the required new size of the conveyance system. In the last part of this research, the performance of Green Infrastructure on stormwater management was evaluated using the HEC-HMS simulation platform. Overall, the results suggest that rainfall depth may to increase due to climate change and that current stormwater infrastructure capacity may need to be increased to be able to handle more severe rains. It also determined that Green Infrastructure performs better for relatively small rainfall depths (less than 3 inches) with relatively short duration (about 1-3 hours).