A Safety Factor Approach to Designing Urban Infrastructure for Dynamic Conditions. Issue 12 (24th November 2021)

• Record Type: Journal Article
• Authors: Sharma, Sanjib; Lee, Ben Seiyon; Nicholas, Robert E.; Keller, Klaus
• Is Part Of: Earth's future. Volume 9:Issue 12(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-11-24
• Subjects: extreme precipitation -- flood risk -- infrastructure design -- climate change -- decision making -- deep uncertainty; Environmental sciences -- Periodicals; Environmental sciences; Periodicals; 550
• DOI: 10.1029/2021EF002118
• Languages: English
• ISSNs: 2328-4277

Abstract

Abstract: Current approaches to design flood‐sensitive infrastructure typically assume a stationary rainfall distribution and neglect many uncertainties. These assumptions are inconsistent with observations that suggest intensifying extreme precipitation events and the uncertainties surrounding projections of the coupled natural‐human systems. Here we demonstrate a safety factor approach to designing urban infrastructure in a changing climate. Our results show that assuming climate stationarity and neglecting deep uncertainties can drastically underestimate flood risks and lead to poor infrastructure design choices. We find that climate uncertainty dominates the socioeconomic and engineering uncertainties that impact the hydraulic reliability in stormwater drainage systems. We quantify the upfront costs needed to achieve higher hydraulic reliability and robustness against the deep uncertainties surrounding projections of rainfall, surface runoff characteristics, and infrastructure lifetime. Depending on the location, we find that adding safety factors of 1.4–1.7 to the standard stormwater pipe design guidance produces robust performance to the considered deep uncertainties. The insights gained from this study highlights the need for updating traditional engineering design strategies to improve infrastructure reliability under socioeconomic and environmental changes. Key Points: We demonstrate a safety factor approach to design flood‐sensitive infrastructure under changing climate and socioeconomic conditions We quantify the deep uncertainty surrounding extreme rainfall projections, surface imperviousness, and infrastructure lifetime to inform a stormwater system design We find that adding safety factors between 1.4 to 1.7 to the standard design guidance can achieve the 1/100‐year hydraulic reliability for all considered cases, but at sizable additional costs