Las Posas Estates Drain and N. Ramona Place Drain are located along Ramona Place between Las Posas Estates Detention Basin and Ramona Detention Basin in the county unincorporated area and the city of Camarillo. FEMA mapped these drains as an Approximate Zone A Special Flood Hazard Area (SFHA) on the Flood Insurance Rate Map (FIRM) in the 1980’s. The Las Posas Estates Detention Basin and Ramona Detention Basin were both constructed by the Soil Conservation Service (SCS) in the early 1960’s. The two detention basins were later rebuilt by the Watershed Protection (WP) in 1992 to meet the WP’s standards. However, the SFHA designation has not changed. Currently, thirteen (13) residential structures are affected by the SFHA designation. With updated hydrologic and topographic data and the latest hydraulic modeling techniques, the Ventura County Public Works Agency- Watershed Protection working with Kasraie Consulting, has completed a detailed floodplain analysis to better assess the flood hazards in the area. The analysis report was used to support a Letter of Map Revision (LOMR) from FEMA. The LOMR application was filed on 5/21/2021. Depending on the complexity, a LOMR process normally takes about 3 to 6 months.
Based on the detailed floodplain analysis, much of the watershed is regulated by the two detention basins. However, stormwater runoff from un-regulated drainage areas downstream of the two basins will create ponded flood water in low lying areas during a 100-year flood (base flood) event. The ponded flood water will not pose flooding threats to residential structures which are built on higher elevations. Figure 1 below shows the proposed 100-year (high risk) and 500-year (moderate risk) floodplains.
Interested persons may contact the Public Works Agency at: (805) 258-2423, or call Kasraie Consulting for additional information at (805) 340-4744 during normal business hours.