Flood Overflow Modeling for Analysis of Impact Loss and Flood Control Scenario Selection (Case Study: Karang Mumus River Samarinda City)

Various studies and plans for the flood control infrastructure have been carried out and some have been carried out in Samarinda City, but flooding still occurs every year. The flood overflow modeling was carried out using HEC-RAS 5.0.5 1D / 2D software. Analysis of impact losses due to floods is calculated based on criteria from BNPB. The flood discharge design of the Lower Karang Mumus sub-watershed at the time of the return of 2 years, 5 years, 10 years; 20 years; 25 years; 50 years; and 100 years was 185.5 m3/s; 213 m3/s; 231.2 m3/s; 248.6 m3/s; 254.1 m3/s; 271,1 m3/s; and 288 m3/s. The inundation area in the existing simulation at Q25 flood reaches 903.9 ha. The scenario of dredging the Benanga Dam in the simulation of the Q25 yr flood shows an inundation area of 856.6 ha; the construction of the Muang Dam shows an inundation area of 885.4 ha; and normalization of the Lower Karang Mumus River shows an inundation area of 873 ha. The normalization of Lower Karang Mumus River has the effect of reducing the number of houses most affected by floods, reaching 1680 units, compared to dredging the Benanga Dam as many as 340 units and the construction of the Muang Dam as many as 122 units