Effects of urbanization on the ephemeral lake flood risks under subtropical humid monsoon climate

Abstract

Study region

Poyang Lake region, China.

Study focus

This study focuses on addressing severe summer monsoon floods in the Poyang Lake region under subtropical monsoon climate conditions. Employing the Seasonal Water Yield analysis within the Integrated Valuation of Ecosystem Services and Tradeoffs framework to investigate and assess the impacts of subtropical monsoon climate and urban dynamics on regional flood risk. By combining simulation results with analysis of regional urban distribution, the study aims to identify sensitive changes in flood hazard characteristics. Ultimately, the research seeks to enhance regional flood resilience to address climate change and urban development challenges.

New hydrological insights for the region

Upon analyzing the model simulation results, we discovered that the subtropical humid monsoon climate contributes significantly, accounting for 35.98 % of surface runoff variability during the ephemeral lake region's flood season. Rapid urbanization amplifies the negative impact of land use change on surface runoff (with a contribution rate of 26.00 %). In urban agglomeration areas, surface runoff increased by 30 mm, and the area with surface runoff production of 60–90 mm increased by 120.33 km². Implementing proactive ecological management measures around lakes and riverbanks has mitigated flood risks across 22 administrative regions, reducing high-risk flood areas by 92.15 km². Restoration of lake flood storage capacity has significantly bolstered resilience against flood disasters.