Temporal Downscaling of IDF Curves Applied to Future Performance of Local Stormwater Measures

Abstract

Low-impact development (LID) structures are combined with traditional measures to manage stormwater and cope with increased runoff rates originating from heavy urbanization and climate change. As the use of LIDs for climate adaptation increases, practitioners need more knowledge on LID performance in future climates for successful planning and implementation. In this study, temporal downscaling of regional climate projections for three cities in Norway is performed, using the concept of scale invariance to downscale the distribution of extreme precipitation from daily to sub-daily timescales. From this, local-scale intensity-duration-frequency (IDF) curves for future precipitation were obtained. Using climate projections of daily temporal resolution as input to water balance models and the obtained IDF relationships as input to event-based models allowed for assessing the retention capacity, peak flow reduction potential and pollution control of three different types of LIDs: green roofs, bioretention cells, and detention basins. The downscaling resulted in large local variations in presumed increase of both precipitation amount and intensity, contradicting current design recommendations in Norway. Countrywide, a decrease in the overall LID performance was found, although some positive effects of temperature rises were detected. The study illustrated the importance of evapotranspiration- and infiltration-based processes in future stormwater management and how coupling of LID structures in series can significantly reduce required detention volumes.

Detention-based green roofs for stormwater management under extreme precipitation due to climate change

“…Secondly, these DDF curves were multiplied by a climate factor of 1.4 to estimate expected rainfall in the period between 2071 and 2100, including a worst-case scenario with Representative Concentration Pathway (RCP) 8.5 for shortterm events. The use of this factor was also suggested in other studies (Kristvik et al 2018;Kristvik et al 2019).…”

Exploring the Optimal Cost-Benefit Solution for a Low Impact Development Layout by Zoning, as Well as Considering the Inundation Duration and Inundation Depth

“…These disasters cause enormous social and economic losses, and they severely threaten the safety and property of residents [4][5][6]. Frequent and serious urban rainstorms require the extensive adoption of low-impact development (LID) to supplement the traditional drainage infrastructures [7,8]. LID is a storm water management strategy based on distributed management and localized practices for controlling the runoff and pollution caused by storms in order to enhance the capacity for absorption, storage, and purification, and the recovery of the urban resilience system [9].…”

Temporal downscaling of precipitation time-series projections to forecast green roofs future detention performance

“…In order to conclude on the applicability of downscaled time-series to predict the future performance of green infrastructure, the methods were compared to the current recommended practice in Norway: the use of the variational method (Alfieri et al, 2008) with the use of a climate factors (CF) (Kristvik et al, 2019;Trondheim Kommune, 2015). The results presented, for the city of Trondheim and 2, 5 and 10-year return period rainfall and runoff events, include: i) peaks runoff of runoff events based on an observed precipitation time-series, ii) the peak runoff or rainfall events based on variational method with and without climate factor and, iii) an hybrid approach based on downscaling 10 5 rainfall events with a daily depth based on to the return period curves with and without climate factors (Figure 8).…”