Exploring the impact of landscape changes on runoff under climate change and urban development: Implications for landscape ecological engineering in the Yangmei River Basin

Abstract

The increase in impervious surfaces caused by urbanization and the frequency of precipitation events resulting from climate change significantly impact the hydrological and geomorphological processes of urban watersheds. Landscape changes caused by urban development may affect surface/groundwater generation and circulation processes. In-depth research on the relationship between landscape changes and runoff is a precondition of urban watershed restoration and stormwater management. Taking the Yangmei River Basin as the study area, the storm water management model (SWMM), landscape index, correlation analysis, and the random forest importance measure were integrated to simulate the runoff process under urban development and climate change scenarios and analyze the direction and contribution of landscape composition and configuration to runoff changes. Results indicated that the runoff change rate relative to the reference period under the RCP 4.5 and RCP 8.5 scenarios gradually decreased as the return period increased. Landscape composition and configuration were significantly correlated with runoff change. Specifically, woodland could reduce runoff, while farmland and water bodies positively impacted runoff changes. The higher fragmented landscape pattern was likely to have altered the runoff, while landscape patterns of a larger size, higher concentrations, and a declining richness typically reduced runoff. The random forest importance evaluation demonstrated the significant contributions of Patch Density, Shannon's Diversity Index, and Large Path Index to runoff. By exploring the potential relationship between landscape changes and runoff, urban planners can better understand the runoff process and find feasible ecological landscape optimization schemes, thus strengthening the sustainable management of water resources and enhancing the resilience of cities to climate change.