The design, shown in figure 102, assumes that the proposed airfield levee will be constructed north of the existing STP3 ponds, but that the ponds would not be protected by it. The design recommends that all existing interior pond levees be removed. In addition, it is recommended that the pond basins be lowered an estimated 1m to an elevation of 11m, within 0.2m of the high water table. This elevation would place newly planted trees and shrubs within 2m of the mean water table elevation of 10m. This is a requisite for long-term plant survival. An irregular base grade is proposed to create a variety of micro-habitats to support a diversity of plant species. Leaf litter and debris from adjacent riparian plant communities would be spread over the graded base to re-introduce mycorrhizal fungi, which are important in stimulating the growth of new plantings on restored sites. The regraded and prepared basin would be revegetated using species, spacing, and densities appropriate as least Bell's vireo habitat. The outer levees would be removed three to five years later, after the planting established. This sequence of levee removal would protect the new plantings through establishment and ultimately allow the river to flood freely into the former pond basins.
Once established, the specified plant species are pre-adapted to survive the flood and potential burial by silt and sand. This design will allow the plant community and ponds to become a functional part of the Santa Margarita River floodplain.