| Title |
Analysis of Optimal Simplification of Storm Sewer Networks and Surface Grid Resolution for Flood Prediction in Urban River Basins |
| Authors |
심상보(Sim, Sang Bo);김형준(Kim, Hyung-jun) |
| DOI |
https://doi.org/10.12652/Ksce.2025.45.6.0731 |
| Keywords |
홍수예보; 이중배수; 우수관망; 격자해상도; 최적 간소화 Flood forecasting; Dual drainage; Sewer network; Grid resolution; Optimal simplification |
| Abstract |
This study quantifies the operational balance between accuracy and speed for the HC-SURF dual-drainage model. For Seoul's Sillim basin, we configured 16 scenarios combining 2D grid resolutions (2-100 m2) and 1D sewer network simplifications (Base-1 ha). Using the 2022 flood event, accuracy was evaluated via Critical Success Index (CSI), Probability of Detection (POD), and False Alarm Ratio(FAR) against inundation traces. Operational speed was assessed by normalizing the 6-hour wall-clock time. Results showed that 1D network detail overwhelmingly dominated accuracy. The ‘Base’ network achieved the highest CSI (0.51), while simplified networks
saw a sharp CSI drop (0.31-0.37), attributed to the loss of 1D-2D flow exchange points (manholes). High-resolution 2D grids (e.g.,2 m2) improved POD but failed to increase CSI, offset by a rise in FAR due to surface runoff spreading and scale mismatch. The optimal balance, determined by the harmonic mean, was found in the 100 m2-Base and 10 m2-Base scenarios, which met the 10-minute speed target with high CSI. We conclude that preserving 1D-2D interaction points is the paramount prerequisite, with 2D grid resolution(10-100 m2) being a secondary optimization choice. |