Appendix L - Federal Emergency Management Agency

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Appendix LL.8.3 Table: S_BFE [October 2011]The Base Flood Elevation (BFE) table is required for any digital data where BFE lines will be shown onthe corresponding FIRM, with the exception of areas where a profile exists. New for this revision, forareas where a profile exists, the water-surface elevation (BFE value) will be labeled on the cross sectionsas stored in the FIRM Database S_XS feature class. The use of BFE lines is now only required in specialcases. BFE lines must be placed in the S_BFE feature class for any area where cross section maximumvertical rise requirement is not met. As mentioned in the description for S_XS, if there is not at least onemapped cross section in S_XS for every 1-foot vertical rise in the 1-percent-annual-chance floodelevation, intervening BFE lines must be placed at whole-foot intervals. Other examples include; ariverine AE zone without a flood profile in the FIS report, areas studied with two-dimensional modeling,certain ponding areas, and backwater areas off to the side of streams with flood profiles. BFEs may beused for other exceptions at the discretion of the FEMA Project Officer. Any exceptions to theseguidelines should be documented in the metadata.The mapping partner must avoid overcrowding of the BFE and cross section lines. When a stream is toosteep to show BFEs and cross sections for every 1-foot vertical rise in the 1-percent-annual-chance floodelevation, the mapping partner must refer to Appendix C, Section 6.3 of these Guidelines for properspacing procedures or consult the FEMA Project Officer, as needed.There are cases when S_BFE may be required in the FIRM Database, even if it is not required by the datasubmittal requirements in Appendix M of these Guidelines. BFE line data can be added to the FIRMDatabase to meet the 1-foot vertical rise requirement. Table L-5 provides an overview of S_BFErequirements at different mapping stages.Table L-5. S_BFE RequirementsS tudy S cenariosS _B FER equired byAppendix M?S _B FER equired inFIR MDatabase?BFE L inesS hown onFIR M?Profiles available for all studied streams and 1-ft vertical riserequirement met for all cross sectionsProfiles available for all studied streams and 1-ft vertical riserequirement not met for all cross sectionsNo No NoNo Yes YesProfiles available for some studied streams Yes Yes YesStudy has two dimensional modeling Yes Yes YesStudy contains ponding areas or backwater areas Yes Yes YesStudy contains exceptions approved by FEMA Project Officer Yes yes YesThe S_BFE contains information about the BFEs within a flood risk project area. A spatial file withlocation information also corresponds with this data table. BFE lines indicate the whole-foot watersurfaceelevation of the 1-percent-annual-chance flood.The spatial elements representing BFE features are lines extending from Special Flood Hazard Area(SFHA) boundary to SFHA boundary. The ends of the BFE lines must be snapped precisely to the SFHAGuidelines and Standards forFlood Risk Analysis and Mapping Page L-38 Section L.8 Requirements for FIRM Databases
Appendix Lboundary. Each BFE is represented by a single line with no pseudo-nodes. Where BFE lines are shown,they must be consistent with procedures described in Volume 1 of these Guidelines.The S_BFE layer contains the following elements.DFIRM_ID R Study Identifier. For a single-jurisdiction flood risk project, the value iscomposed of the two-digit State FIPS code and the four-digit FEMA CIDcode (e.g., 480001). For a countywide flood risk project, the value iscomposed of the two-digit State FIPS code, the three-digit county FIPScode, and the letter “C” (e.g., 48107C). Within each FIRM Database, theDFIRM_ID value will be identical.VERSION_ID R Version Identifier. Identifies the product version and relates the feature tostandards according to how it was created.BFE_LN_ID R Primary key for table lookup. Assigned by table creator.ELEV R The rounded, whole-foot elevation of the 1-percent-annual-chance flood.This is the value of the BFE that is printed next to the BFE line on theFIRM.LEN_UNIT R BFE Units. This unit indicates the measurement system used for the BFEs.Normally this would be feet. Acceptable values for this field are listed in theD_Length_Units table.V_DATUM R Vertical Datum. The vertical datum indicates the reference surface fromwhich the flood elevations are measured. Normally this would be NorthAmerican Vertical Datum of 1988 for new studies. Acceptable values forthis field are listed in the D_V_Datum table.SOURCE_CIT R Source Citation. Abbreviation used in the metadata file when describing thesource information for the feature. The abbreviation must match a value inL_Source_Cit.Field R/A TypeTable: S_BFE [October 2011]Length/PrecisionScale(SHPOnly)Joined Spatial /Lookup Tables orDomainsDFIRM_ID R Text 6 N/AVERSION_ID R Text 11 N/ABFE_LN_ID R Text 25 N/AELEV R Double Default 2 N/ALEN_UNIT R Text 11 D_LENGTH_UNITSV_DATUM R Text 17 D_V_DATUMSOURCE_CIT R Text 11 L_SOURCE_CITGuidelines and Standards forFlood Risk Analysis and Mapping Page L-39 Section L.8 Requirements for FIRM Databases
Page 1 and 2:
Guidelines and Standards for FloodR
Page 3 and 4: Appendix LDate Affected Section(s)
Page 17 and 18: Appendix LTable of ContentsL.1. Flo
Page 19 and 20: Appendix LL.8.17 Table: S_Levee [Oc
Page 21 and 22: Appendix LAppendix LDigital Data an
Page 23: Appendix LFIRM Table NameTableTypeT
Page 26 and 27: Appendix LTable L-2. Mapping Partne
Page 28 and 29: Appendix LFIR M Table NameAcquireB
Page 30: Appendix LAppendix are identified i
Page 33 and 34: Appendix Lfiles for lookup tables.
Page 35 and 36: Appendix LWhen possible, tables req
Page 37 and 38: Appendix L• Area spatial features
Page 39 and 40: Appendix LTopologyFilename(*_TOPOLO
Page 41 and 42: Appendix LIn the FIRM Database, flo
Page 43 and 44: Appendix Lfield length indicates th
Page 45 and 46: Appendix LL.4.8 Deliverables [Octob
Page 47 and 48: Appendix LL.5. Database Table Struc
Page 49 and 50: Appendix LL.7. Metadata Example for
Page 51 and 52: Appendix LFAN_VEL_MX A Alluvial Fan
Page 53: Appendix LTable: S_Base_Index [Octo
Page 57 and 58: Appendix LTable: S_CBRS [October 20
Page 59 and 60: Appendix LTIME_UNIT A Recording Int
Page 61 and 62: Appendix LL.8.6 Table: S_Cst_Tsct_L
Page 63 and 64: Appendix LCON_PD A Controlling Wave
Page 65 and 66: Appendix LTable: S_Cst_Tsct_Ln [Oct
Page 67 and 68: Appendix LL.8.7 Table: S_Datum_Conv
Page 69 and 70: Appendix LL.8.8 Table: S_FIRM_Pan [
Page 71 and 72: Appendix LL.8.9 Table: S_Fld_Haz_Ar
Page 73 and 74: Appendix LTable: S_Fld_Haz_Ar [Octo
Page 75 and 76: Appendix LL.8.11 Table: S_Gage [Oct
Page 77 and 78: Appendix LL.8.12 Table: S_Gen_Struc
Page 79 and 80: Appendix LL.8.13 Table: S_HWM [Octo
Page 81 and 82: Appendix LL.8.14 Table: S_Hydro_Rea
Page 83 and 84: Appendix LL.8.16 Table: S_Label_Pt
Page 85 and 86: Appendix LL.8.17 Table: S_Levee [Oc
Page 87 and 88: Appendix LTable: S_Levee [October 2
Page 89 and 90: Appendix LL.8.19 Table: S_LOMR [Oct
Page 91 and 92: Appendix LL.8.20 Table: S_Nodes [Oc
Page 93 and 94: Appendix LL.8.21 Table: S_PFD_Ln [O
Page 95 and 96: Appendix LTable: S_PLSS_Ar [October
Page 97 and 98: Appendix LST_FIPS R State FIPS. Thi
Page 99 and 100: Appendix LL.8.24 Table: S_Profil_Ba
Page 101 and 102: Appendix LFLD_PROB3 A Description o
Page 103 and 104: Appendix LL.8.26 Table: S_Stn_Start
Page 105 and 106:
Appendix LL.8.27 Table: S_Subbasins
Page 107 and 108:
Appendix LL.8.28 Table: S_Submittal
Page 109 and 110:
Appendix LField R/A TypeTable: S_Su
Page 111 and 112:
Appendix LTable: S_Trnsport_Ln [Oct
Page 113 and 114:
Appendix LField R/A TypeTable: S_Ts
Page 115 and 116:
Appendix LTable: S_Wtr_Ar [October
Page 117 and 118:
Appendix LTable: S_Wtr_Ln [October
Page 119 and 120:
Appendix LXS_LTR A Cross Section Le
Page 121 and 122:
Appendix LL.8.34 Table: S_Zone_AR [
Page 123 and 124:
Appendix LH_DATUM R Horizontal Datu
Page 125 and 126:
Appendix LField R/A TypeTable: Stud
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Appendix LIN_ID_DAT R Initial Ident
Page 129 and 130:
Appendix LL.8.37 Table: L_Comm_Revi
Page 131 and 132:
Appendix LSTRM_PRM A Storm Paramete
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Appendix LTable: L_Cst_Model [Octob
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Appendix LField R/A TypeTable: L_Cs
Page 137 and 138:
Appendix LL.8.41 Table: L_ManningsN
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Appendix LL.8.43 Table: L_MT2_LOMR
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Appendix LL.8.44 Table: L_Mtg_POC [
Page 143 and 144:
Appendix LL.8.45 Table: L_Pan_Revis
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Appendix LL.8.46 Table: L_Pol_FHBM
Page 147 and 148:
Appendix LL.8.48 Table: L_Profil_La
Page 149 and 150:
Appendix LL.8.49 Table: L_Source_Ci
Page 151 and 152:
Appendix LL.8.50 Table: L_Summary_D
Page 153 and 154:
Appendix LL.8.51 Table: L_Summary_E
Page 155 and 156:
Appendix LL.8.52 Table: L_XS_Elev [
Page 157 and 158:
Appendix LWSEL_FLDWY A Base Flood W
Page 159 and 160:
Appendix LField R/A TypeTable: L_XS
Page 161 and 162:
Appendix LV_DATUM R Vertical Datum.
Page 163:
Appendix LL.10. Domain Tables [Octo
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Appendix L - Federal Emergency Management Agency

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