Analysis of flooding and nature-based solutions in the improvement of urban drainage system

Abstract

Abstract This paper studies the drainage system performance of a conventional system with concrete channels and a retention pond. Also, the analysis of runoff reduction by implementing a nature-based solutions (NBSs) technique of rainwater harvesting and recharge well. The case study site is located in an industrial area in West Karawang City, West Java. The analysis was carried out by simulating the flood event using rainfall data from the site for a 10-year return period. The flood simulation was performed using the Storm Water Management Model (SWMM). The model consists of the analysis of flooding events in the drainage system and retention pond and the analysis of flooding prevention scenarios. The result reveals that the cause of the flooding is an extreme rainfall event which leads to the large accumulation of water at one junction point. Moreover, although the capacity of the retention pond is sufficient, the discharge rate is way larger than the infiltration rate, so the overflow occurred and resulted in flooding. The scenario of widening the drainage channel and installing a pump in the retention pond provides a good solution scenario to prevent flooding. The implementation of rainwater harvesting and recharge well could reduce the surface runoff volume of 21%. Further study should be conducted to analyze the combination of conventional and NBSs drainage system performance under the highest daily rainfall of the series.