Water Resources Research Act Program

Details for Project ID 2018PA235B

Integrative Modeling to Quantify Systems-Level Benefits of Green and Grey Infrastructure Networks to Urban Water Quality

Institute: Pennsylvania
Year Established: 2018 Start Date: 2018-03-01 End Date: 2019-02-28
Total Federal Funds: $20,000 Total Non-Federal Funds: $68,444

Principal Investigators: Carla Ng

Abstract: The current state of US infrastructure presents both an enormous challenge and an enormous opportunity to guide the development of more livable and more resilient communities. There is a critical need to enhance the sustainability of all communities – shrinking and growing, rural and urban, coastal and inland – and future proof their performance in the face of changing population pressures, deteriorating infrastructure and risks associated with natural disasters such as extreme weather events. Urban environments in high-rainfall regions are particularly vulnerable to flood risks and the deterioration of water quality that results from non-point-source runoff and combined sewer overflows (CSO). Pennsylvania is expected to experience increasing rainfall frequency and intensity, further exacerbating existing issues with aging infrastructure. The city of Pittsburgh is highly vulnerable to flash flooding; Allegheny County reported the highest number of flash flood events in the region between 1986 and 2016. The city also produces more than three billion gallons of CSO annually, which affects local water quality through nutrient inputs and other contaminants. As existing infrastructure in many communities reaches the end of its design life or faces conditions that exceed design limits, there is an opportunity for replacement with more adaptive infrastructure that can bring substantial co-benefits such as habitat, biodiversity, food, etc. The use of green infrastructure (GI) to improve water management and enhance both livability and quality of local environments has been embraced as a more sustainable approach than the established practice of paving, piping and pumping. By incorporating urban planning and design into integrated water management, communities can reduce pressures from stormwater inputs on treatment facilities and natural water bodies, effectively decentralizing management, while reaping multiple direct and indirect benefits. However, our ability to undertake such an approach is currently held back by limitations on our ability to quantify the systems-level performance, as well as the direct and indirect benefits, of GI when embedded within a network of existing “gray” or built infrastructure (BI). The City of Pittsburgh, in partnership with the Pittsburgh Water and Sewer Authority (PWSA) is planning large-scale investment in GI over the next five years, as described in PWSA’s recent “Green First Approach and Process” and “Focusing on the Future” reports. The success of these plans will depend in part on an ability to reliably predict the performance and quantify the benefits of such infrastructure investment. The goal of the proposed project is to develop and test an integrative approach to modeling the performance of interlinked GI and BI networks, and quantifying their benefits at a systems level. These models can serve as tools to motivate GI investment, plan GI placement within existing BI to maximize flood control and water quality benefits, and identify opportunities to reap attractive ecosystem co-benefits such as habitat provision or pollinator support.