Outstanding Flood Management Project

The C-Complex Flood Basin is a flood control basin with 170-AF of storage volume that provides flood attenuation and flow mitigation for the approximately 1300-acre area of the Rancho Mission Viejo (RMV) Rienda community development. This large-scale earthen basin facility includes a 144-inch RCP, an approximately 72-inch inlet, and a 12’x8’ RCB outlet pipe, which convey the peak design flow of approximately 3,000 cfs and 1,300 cfs in and out of the basin, respectively. The basin provides detention for storm events in excess of the high-confidence 100-year storm. The basin is one of five basins that will ultimately be developed to provide flood control for the development tributary to San Juan Creek.