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<br />Guidelines and Specijicationsfor Flood Hazard Mapping Partners [April 2003] <br /> <br />When local jurisdictions have established their own vertical monument network, these <br />monuments also may be shown on the FIRM with the appropriate designations. Local <br />monuments shall be placed on the FIRM only if the community has requested that they be <br />included, and if the monuments meet the aforementioned inclusion criteria. Additional <br />information on qualifying criteria is provided below. <br /> <br />Temporary vertical control monuments-formerly referred to as Elevation Reference Marks <br />(ERMs) on FIRMs-that were established by FEMA SCs during the performance of a flood <br />hazard study shall not be shown on the FIRM unless they meet specific qualifying criteria as <br />indicated below, This standard applies to all FIRMs, regardless of whether they are being <br />created for the first time or being revised. ERMs that appear on FIRM panels being revised must <br />be removed and replaced with qualifying bench marks. <br /> <br />Descriptions of bench marks shall not appear on the FIRM. On the FIRM, map users will be <br />provided with a phone number and an Internet address that allows them to access the NSRS to <br />obtain the most up-to-date information on all vertical control monuments shown on the FIRM. <br /> <br />Qualifvinq Criteria for Inclusion of Existina Bench Marks <br /> <br />Bench marks cataloged by the NGS and included in the NSRS vary widely in stability <br />classification and level of precision relative to levels of confidence. The minimum criteria for <br />inclusion of an NSRS bench mark on the FIRM are that the monument be Second Order Vertical <br />and Stability Classification C, or better. <br /> <br />NGS stability definitions are as follows: <br /> <br />. Stability A Monuments are monuments of the most reliable nature and are expected to <br />hold position/elevation well (e.g., mounted in bedrock). <br /> <br />· Stability B Monuments are monuments that generally hold their position/elevation well <br />(e.g., concrete bridge abutment). <br /> <br />· Stability C Monuments are monuments that may be affected by surface ground <br />movements (e.g., concrete monument below frost line). <br /> <br />· Stability D Monuments are monuments of questionable or unknown stability (e.g., <br />concrete monument above frost line, or steel witness post). <br /> <br />For digital FIRMs, the locations of temporary monuments (Le., ERMs) shall be recorded in the <br />associated spatial database. For all FIRMs, the temporary monument elevation and description <br />information shall be recorded in the Technical Support Data Notebook (TSDN). Additional <br />information on TSDN requirements is provided in Appendix M of these Guidelines. <br /> <br />1-59 <br /> <br />Section 1.4 <br />