Army Corps of Engineers Evaluates the Largest Remaining Flood Plain in Orange County
By Kim DiPasquale

The Westminster/East Garden Grove area is the largest remaining flood plain in Orange County. On November 5, 2018 the Chicago Division of the Army Corps presented a preliminary study of this area and potential solutions for flood protection against the next 100-year flood.

California has suffered from catastrophic flooding every 100-200 years with the last one being in 1861 when it rained for 43 days and dumped 60 inches of rain in Los Angeles alone. Incidentally, this flood was preceded by a 20-year drought. With this in mind and with concern over climate change and sea level rise, the Corps has been working on options for what they refer to as upstream and downstream modifications. Upstream options include building bypass channels, dams, and retention basins, and modifying the structure of existing channels. Because there is constriction of water flow under the Warner Bridge and because optimal function of the tidal gates is critical, possible downstream modifications include dredging the Outer Bay, rebuilding or removing the tidal gates, building a sea wall, and possibly raising Pacific Coast Highway. The downstream modification will be addressed first.

The Army Corps does recognize and appreciate the potential risk to marine life, adjacent fringe wetland habitat, and migratory birds. They emphasize that this is a preliminary study only and that a final report is expected in early 2020. They also indicated that this project will take decades to complete.