An overall optimization and solution framework for urban historical and future DRIF under climate change

Abstract

Abstract The estimation and application of Intensity-Duration-Frequency (IDF) curves depend on the assumption of stationarity of the rainfall series, which is that the intensity and frequency of extreme hydrological events remain unchanged in the future. Climate change will have a significant impact on the collection and utilization of rainwater and its spatial characteristics. When the Gray-Green infrastructure is designed, if only historical precipitation is adopted to calculate the urban design rainstorm intensity formula (DRIF) and the total annual runoff control rate, it may be difficult to meet the demand of future precipitation changes on the city's ability to accommodate rainfall. Therefore, it is very important to study the impact of climate change on the IDF curve. This study proposes an overall optimization solution framework for historical and future DRIF. The impact of the extreme value on the IDF curve during the historical period is analyzed. The calculation method of the IDF curve in the future period is established. The changes of the rainstorm intensity in the historical and future period (SSP1-2.6,SSP2-4.5,SSP3-7.0,SSP5-8.5) were analyzed for the 15 durations and eight return periods in Beijing, China. The results of this study show that the nondominated sorting and local search (NSLS) has the best accuracy in fitting the statistical samples of precipitation for different durations. The best methods to judge and process the extreme value of the statistical sample are Z-score and average value of series greater than critical value (AVG). Under the four SSP scenarios, the estimated IDF value is larger than the observed value in the historical period. The results of the equivalent return period calculated using the DRIF show that the the four SSP scenarios are smaller than the historical period for the return period greater than five years. Taking 120 min of short-duration precipitation as an example, the 100-year equivalent return periods of the observation under the four SSP scenarios are 35-, 20-, 54-, and 17-years, respectively. The research can provide valuable reference for the design and planning of the drainage facility under climate change.