**2. Methods**

The methodology used in this study consists of five parts. First, monitoring nodes for cooperative operation of drainage facilities are selected. Second, we perform CR operation based on monitoring node levels and review the resulting flood volume. The aim of CR operation is rapid urban area drainage and increased drainage effectiveness. Third, we perform DR operation based on monitoring node levels and review the resulting flood volume. The aim of DR operation is to obtain additional capacity in DR and improve detention effectiveness. Fourth, we review the operation of CR and DR based on monitoring node levels and compare the resulting flood volume with that of current drainage facility operations. The objective of cooperative operation between CR and DR combines the rapid drainage effectiveness of CR and the detention effectiveness of DR. Fifth, we use the resilience index to quantify how well each operation method mitigates the magnitude of failure (i.e., flooding) of the drainage system.
