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Port of Houston Authority Wetland Mitigation Plan also remove organic materials from the footprint of the levees to improve their foundations and increase levee integrity. Other than necessary brush control and other preparatory measures, areas not selected for excavation or levee placement will not be disturbed. Water will overflow from the systems through a spillway structure in the north marsh and discharge to the Harris County drainage canal through an existing drainage point. The spillways will be designed to handle the maximum discharge that would be expected from a 100-year precipitation event. Appropriate erosion control measures (e.g., contouring, vegetation planting, and riprap) will be implemented downstream of the spillways. After earthwork is complete, but before planting is initiated, a topographic "as -built' survey will be conducted by a licensed surveyor. The survey will be conducted to determine if, planting surface elevations, levee elevations, and spillway elevations are within the thresholds set forth in this document. If the results of the survey show that the structures are at appropriate elevations, PHA will initiate planting. If the survey indicates that expected elevations have not been achieved, as defined, corrective actions will be taken to bring the Site to required elevations. A second survey will be conducted in areas affected by the corrective actions to ensure that the Site meets required elevations. If required elevations are not achieved, additional corrective actions and surveys will be required. The "as -built' survey drawing(s) will be submitted to the USACE along with the Post -Construction Report (5%o c-t 4 l ) following completion of planting. Prior to planting, all planting surfaces will be fertilized based on soils analysis results, and formulated for root and rhizome production (high phosphorus). The area will be flooded to the point where the soil is saturated prior to planting. The constructed wetland area will be planted with a variety of emergent wetland species to augment the existing site diversity 31 ). A reference wetland near the mitigation site was identified on the Armand Bayou Nature Center property across Red Bluff Road from the mitigation site The reference wetland has been recently restored by the Nature Benchmark Ecological Services, Inc. June 2002