The effects of extreme precipitation and reservior construction on flood losses in China

China is severely impacted by extreme precipitation and flooding, with annual average direct economic losses from flooding exceeding $30 billion over the past few decades. To safeguard the population and assets, China has constructed numerous hydraulic infrastructure projects, with the total reservoir capacity doubling nationwide from 1991 to 2022. However, while many studies have explored the impact of extreme precipitation on flood losses, the specific effects of hydraulic infrastructure on these losses remain inadequately quantified. In this study, we employ statistical methods to analyze the influence of extreme precipitation and reservoir capacity on flood loss rates at the provincial level from 1991 to 2022. Our results show that both extreme precipitation and reservoir capacity significantly affect flood losses in most provinces (p < 0.05), with opposite directional effects. This study demonstrates that incorporating the effects of hydraulic infrastructure significantly improves the accuracy of flood loss assessments, underscoring the importance of including human activities in flood risk evaluations.