Assessing Performance of an Aging Green Roof in Pittsburgh, PA
Date:
Abstract: Green infrastructure is increasingly recognized as a potential solution for climate adaptation and flood management in urban areas. Research evaluating and reviewing the performance of green infrastructure, and particularly of green roofs, has highlighted the uniqueness of each installation, and the need for site specific data to draw accurate conclusions for planning and implementation. In this research, we aim to use water balance equations to assess performance of a green roof in Pittsburgh, PA, under the effects of age and climate change, and therefore inform future decision making for green roofs in particular, and green infrastructure in general. We develop a Python model to simulate performance of the Hamerschlag Hall Green Roof on Carnegie Mellon University’s campus. The model uses measurements of precipitation and other atmospheric variables measured on the green roof to estimate evapotranspiration during the periods between storms and to estimate infiltration during storms, and then applies a water balance to estimate runoff. The model is calibrated and validated using data collected for storms observed on the green roof in 2019-2020. Previous research has evaluated performance of the green roof for select storms in 2009-2011. By forcing the calibrated model with time series of precipitation and atmospheric variables representing the storms that were observed in 2009-2011, we will be able to compare observed and modeled performance, attributing differences in performance to the age of the green roof.