Comparative analysis of dredging and paddy field dams for flood mitigation under future changes in the Upper Citarum, Indonesia

Abstract

Flooding is a persistent challenge in the Upper Citarum River Basin (UCRB) in Indonesia. It is exacerbated by rapid urbanization, deforestation, and climate change. We evaluated the effectiveness of two flood mitigation measures, river dredging and paddy field dams (PFDs), under varying land-use and climate change scenarios. A coupled 1D-2D model and a rainfall-runoff model simulated flood conditions for various scenarios, integrating land-use projections for 2050 and future return period rainfall. The results show that river dredging reduces inundation areas and volumes by up to 54% for lower return period floods, whereas the combination of dredging and PFDs achieves a 24% reduction in far-future scenarios. However, both measures exhibited reduced effectiveness under extreme hydrological conditions.

River dredging involves high operational costs and long-term environmental risks. Although PFDs are a low-cost alternative, their effectiveness depends on land availability, outlet design, and community participation. These findings emphasize the potential role of river dredging and PFDs in future changes. This study also demonstrates the critical role of incorporating future changes into infrastructure planning to enhance resilience and operational efficiency.