With FEMA’s transition to the Digital Flood Insurance Rate Map system, numerous flood protection systems in the state of Pennsylvania needed to be evaluated for certification according to Title 44 Code of Federal Regulations 65.10. Schnabel provided geotechnical engineering services as part of a team awarded a four-year indefinite delivery contract to perform many of these evaluations.

The Pennsylvania Department of Environmental Protection (PADEP) funded the effort to evaluate flood protection systems comprised of earthen levees, concrete floodwalls, and various types of closure structures. The scope of our work followed a phased execution that included an initial Phase 1 file review and an assessment of available data to determine the likelihood that a levee would meet the requirements for certification.

In this phase, a field inspection was also performed according to USACE protocols, including evaluation of levee maintenance; the condition of concrete floodwalls; observations of encroachments, animal burrows, and vegetation; and evidence of erosion, settlement, seepage, piping, sloughs, or other forms of instability.

We performed geotechnical evaluations that were incorporated into final levee inspection reports. If the levee was considered likely to be certified, we developed and executed a detailed Certification Evaluation Scoping Study (Phase 2) based on the file review and levee inspection. This study included additional geotechnical field exploration, if necessary, and engineering analyses to determine the adequacy of the field protection system under the base flood event. If the analyses supported certification, the Phase 2 geotechnical results were incorporated into a Certification Determination Letter to FEMA. If deficiencies were identified, Flood Protection Design Improvements would be developed and evaluated by the sponsor and PADEP.