Why are temporary benchmarks included on some Flood Insurance Rate Maps (FIRMs) and not on others?
When completing detailed engineering studies, FEMA, or its mapping partners, establishes temporary benchmarks, also called elevation reference marks in the vicinity of the floodplain to aid in data collection. Upon publication of the studies, FEMA initially chose to include such information on the FIRMs and within the Flood Insurance Study report. However, FEMA and, in some instances, the community do not actively maintain these temporary benchmarks. Because it cannot be guaranteed that the benchmarks have remained undisturbed, FEMA elects not to include such benchmark information on subsequent FIRM revisions. If you have difficulty locating a specific benchmark, it is suggested that you contact the community for an inventory of active benchmarks or the National Geodetic Survey at 301-713-3242 for an inventory of federally maintained benchmarks.
