20230719 12133400 1.0 TRUE MS4 Outfall Drainage Areas MS4 (Municipal Separate Storm Sewer System) outfall drainage areas in the unincorporated areas of San Diego County. Mapped by Fred McCamic (LUEG-GIS) and Steve Di Donna (DPW Watershed Protection Program) using a mix of Esri Spatial Analyst and in-the-field observations and knowledge.