The Flood Control District’s system of more than 1,600 reference marks plays an important role in the permitting of development and administration of the National Flood Insurance Program in Harris County. The system aids 35 communities in Harris County with their administration of floodplain ordinances.
Each reference mark – whether in the form of an engraved disk, rod or other type of permanent monument—is referenced to an established vertical elevation datum. Usually affixed to bridges or other stable structures, they provide a necessary reference point in determining the location of a structure in a floodplain within Harris County.
The Harris County Floodplain Reference Marks interactive mapping tool provides information from the Flood Control District’s countywide network of reference marks. This on-line tool allows users to search by watershed, street address and other parameters to access information about specific numbered benchmarks. For each benchmark, the tool includes a description of its site location, plus a photograph and sketch of the site to help in locating the marker within the site. PDFs of the information may be easily downloaded and printed for field use.