Inundation controlling practice in urban area: Case study in residential area of Malang, Indonesia

Flood inundation processes in urban areas are primarily affected by artificial factors such as drainage facilities, local alterations of topography and land uses. The objective of this study is to examine the capability of hydrological model SI-MODAS to estimate runoff and investigating the utilization of storage well in controlling runoff in a residential area. The result of the estimated runoff from the hydrological model was compared with the existing capacity of the drainage channel to identify which channel experienced the problem of inundation. The location of inundation was used to determine the location and number of storage well. The results showed that SIMODAS model could be applied in runoff analyses with 8.09% of relative error compared with runoff depth from field measurement. The existing capacity of the channel could not accommodate runoff Q_10yr where the inundation discharge was approximately 0.24 m³·s^–1 (at outlet point 1) and 0.12 m³·s^–1 (at outlet point 2). The inundation problem was overcome by using a combination system between channel normalization (reduce 35% of total inundation discharge) and storage well system (reduce 65% of total inundation discharge). The storage well was designed at 20 locations (at outlet point 1) and 16 locations (at outlet point 2) which each well had a discharge of 0.0058 m³·s^–1. The storage well combined with channel normalization could be used as an alternative way to solve inundation problems in a residential area considering the constraint of land space limitation in the urban area.