An overview of flood risk components: The Land subsidence case of Pekalongan City

Abstract

Pekalongan City is located on the northern coast of Java Island, where climate crises, floods, and tidal waves pose significant threats exacerbated by rising sea levels and land subsidence. This study aims to mitigate of flood future losses and emphasizes its potential as input for Indonesian regulators to enhance current flood hazard classifications. This study conducts a comprehensive flood risk analysis, emphasizing a detailed review of flood hazard classification quantitatively with flood hazard mapping. The results showed flood hazard mapping, comparing NDMA, MPW, and proposed classifications, indicates a tendency for MPW to overestimate hazards, particularly categorizing depths of 0.5 m and above as “High”. The flood depth according to MPW with land subsidence produces a flood inundation area of 14,145 Ha. This shows that land subsidence recorded in risk mapping can increase the overall hazard level. This study proposed flood depth and velocity classification, balancing NDMA’s underestimation and MPW’s overestimation, offering a more comprehensive approach.