Multifunctional Blue-Green Infrastructure and Low Impact Development for Climate Change Adaptation

<p>Blue-Green Infrastructure (BGI) and Low Impact Development (LID) have been identified as promising approaches to help cities mitigate urbanization and adapt to climate change. Among BGI/LID systems, green roofs and permeable pavements are popular ground-based and rooftop applications. As the understanding of the performance of these two established applications has increased, efforts have been made to develop other technologies to maximize the multiple benefits of adapting to climate change. Through a series of three studies conducted by field monitoring, this dissertation investigates the hydrologic and thermal performance of blue and blue-green roofs, including farmed roofs as rooftop systems and permeable interlocking concrete pavers (PICP) and a dome concrete forming system (DCFS) as ground-based systems. The results revealed that the blue-green roof achieved the highest stormwater retention (63%) with the highly organic substrate, whereas the lowest retention was observed on blue roofs with larger orifices (32%). Blue-green roofs significantly improved detention and peak delay compared to green roofs. On the farmed blue-green roof, mean values for retention ranged from 85—88%, peak attenuation ranged from 82—85%, and peak delay ranged from 7.7 to 8 hours. Blue-green and green roofs with highly organic substrates had the highest near-surface air cooling (2.9 °C) compared to the green roof with FLL substrate (1.6 °C). On the rooftop farm and compared to a control roof, the mean air temperature difference above okra, tobacco and beet was 2.5 °C, whereas, above squash, potato and milkweed, it was 1.4 °C. Compared to conventional concrete pavement, the PICP and DCFS achieved an average runoff volume reduction of 33% and 85% and an average peak flow reduction of 43% and 89%, respectively. Surface and near-surface air temperatures were the highest on the DCFS due to the insulating effect of its void-based structure, with a warming effect of 2.3 °C on the surface and 0.7 °C on near-surface air. Altogether, the selection and design of these novel technologies would require a consideration of their trade-offs and a holistic approach considering environmental, social and economic aspects. Future research is therefore needed to determine the optimal design of each technology.</p>