I don?t know if many of you were around when the El Toro MCAS (Marine Corps Air Station) was still active. It hosted an annual air show that over a hundred thousand spectators attended the event. There were several fatal aircraft fatalities.
Contamination was limited to the south and south west of the site. MCAS sited the maintenance facilities at the lowest elevation of the entire 4 square mile plot of land. The strategy was to avoid run off since it was at the lowest point. Aircrafts took off toward the north easterly direction over the current Baker Ranch. The air lift was better against Saddleback mountains. It was much safer to fly against the Santa Ana wind direction.
The aircrafts were parked at the south west run way tarmac closest to Old Town Irvine. This was the ideal location for aircraft maintenance. The chemical and solvents used were the one contributed to the PLUME pulled by gravity toward the lower elevation of Irvine which is Woodbridge lake. Chemicals deposited on the concrete aprons just outside of the maintenance building were hosed off by water or washed off by rain. The most contaminated area is soil near the edge of the concrete tarmac slab and not under the concrete slab itself. Because the soil under the slab was too dense and compacted, capillary action pulled the toxic fluid away to the looser soil.
This should explain why the best view lots along Baker Ranch were all blank walls of the R&D buildings. It was zoned industrial for years until recently rezoned for residential.
The southern edge were the operational hub of the MCAS. This part of the site was ideal for truck and train delivery when access roads to the north were not built until much later in late 80?s. A sharp shooter training facility was there also. Sand Canyon was then just a dirt path. This location is the subject area of contaminants. No residential is being planned there based on the plans from City of Irvine. The city still owns this portion of the Great Park.
We need to understand topography of the former MCAS. It is approximately 2mi x 2 mi. The entire site averages 2 percent grade. The high point is near the jail and low point is near Old Town Irvine. 2 miles x 5280? x the square root of 2 =14,936?. At 2% there is a grade difference of almost 300?. Contaminants did not travel up hill. Aircraft mist contributed to pollution and so did John Wayne flight path over Newport Beach.
Formerly the MCAS residential villages were located across the street north of Irvine Blvd and at the North West quadrant which now are the current locations of PP and BP. Horse corral, cafeteria, admin, equestrian and health care facilities were located between Irvine Blvd and Trabuco next to the toll road.