Assessment of rainwater resources in urban areas of reception basins of South-to-North Water Diversion Project under climate change.

The forecasting of future stormwater resources serves a pivotal role in gauging the potential effects of stormwater utilization on natural and societal systems. However, there has been limited research on the effect of climate change on future rainwater resources, particularly for large-scale water diversion projects. Based on global climate model data, future land use data and SCS-CN (soil conservation service curve number) model, this study proposed a calculation method of rainwater resources under different SSP scenarios in the future period, and carried out a case study on the cities in the receiving area of South-to-North Water Diversion Project (SNWDP). The results show that there will be an increase in the amount of rainfall in the future compared to 2020.The most significant increase in rainwater resources occurs in urban reception areas of the Eastern Route Project (ERP). However, according to future projections, the quantity of rainwater resources in the study area decreases from south to north. The spatial distribution of rainwater resources demonstrates a nearly normal distribution in the eastern and western routes and a bimodal distribution in the Central Route Project (CRP). In the context of global climate change, the increase in rainfall resources in the CRP may be beneficial for the establishment and implementation of the SNWDP. This study can provide a reference for analysing the uncertainty of rainwater resources in the future period under climate change. It can also provide guidance for the construction and develop scheduling schemes of the SNWDP, a world-class water diversion project.