Impacts of climate change and land cover factor on runoff in the Coastal Chinese Mainland region

Abstract

The increasingly frequent storms pose a significant threat to the sustainable development of coastal regions, particularly in densely populated and economically vibrant areas. Comprehending the intricate mechanisms and dynamics underlying runoff generation is curial, especially in the context of climate change and anthropogenic interference. This study aims to investigate the runoff production and its variation in the Coastal Chinese Mainland (CCM) by analyzing hydro-meteorological and land-use data from 1982 to 2020. Based on hydro-meteorological and land-use data from 1982 to 2020, this study investigates the runoff production and its variation in the Coastal Chinese Mainland (CCM), to reveal the temporal and spatial trends of runoff yielding and its driving factors, and to clarify the sensitivity of runoff in coastal cities to the integrated and individual parameters of climate change and anthropogenic interference, including precipitation (P), potential evapotranspiration (E0), and land cover factor (n). The results show that: (1) runoff has generally increased over the period, particularly in regions such as the Yangtze River Delta, Shandong, and Guangxi, while it has decreased in Beijing and eastern Guangdong; (2) in the northern CCM with larger aridity index, the land cover factor plays a dominant role in runoff production, while in the wetter southern CCM, precipitation is more influential, and potential evapotranspiration mainly hinders runoff generation all over CCM; (3) urban expansion tends to negatively impact n, while the loss of forests and shrinkage of croplands tend to enhance the value range of n. Other land use types have minimal impact. To ensure the achievement of sustainable development goals in the CCM, it is imperative to introduce a more comprehensive and theoretical framework that encompasses the natural, technical, and social dimensions of human-water systems into traditional flood regulation and water resource management. This framework should promote interdisciplinary collaboration and a watershed perspective, bridging administrative and watershed boundaries, to effectively address the complex challenges posed by climate change and anthropogenic activities on runoff and water resources in coastal regions.