Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005] 

Summary of Changes for Appendix N, 
Data Capture Standards 


The Summary of Changes below details changes to Appendix N subsequent to the initial 
publication of the Draft Appendix N in April 2004. These changes represent new or updated 
guidance for Flood Hazard Mapping Partners. 

Date Affected 
Section(s)/Subsection(s) 
Description of Changes 
December 
2004 
All Required files and optional files are clearly 
identified. 
December 
2004 
All Applied naming conventions from Appendix L of 
these Guidelines, including the use of underscores, 
identification of Spatial data tables with S_ and 
Look-up tables with L_, and the use of _LID in field 
names that reference a domain table. 
December 
2004 
All Corrected cross references to tables and sections. 
December 
2004 
All Standardized all references to Wtr_Nm_ID. 
December 
2004 
N.1.1 Added text to clarify relationship to Appendix L of 
these Guidelines. 
December 
2004 
L_Submittal_Info Table Added row for SW_TF for statewide mapping. 
(Was Table N-1. [Dec. 2004] Now Table N-2. 
[April 2005]) 
December 
2004 
Figure N-1 Revised figure. 
December 
2004 
Table - Accepted File 
Formats for Terrain Data 
Added 2-D or to 3-D Polyline shapefile format. 
(Was Table N-2. [Dec. 2004] Now Table N-3. 
[April 2005]) 
December 
2004 
N.2.2.3 Revised title and text to refer to continuous spatial 
files rather than non-tiled terrain files. 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005] 

Date Affected 
Section(s)/Subsection(s) 
Description of Changes 
December 
2004 
Table - Continuous 
Terrain Spatial Files 
Removed S_TileIndex row. (Was Table N-3. [Dec. 
2004] Now Table N-9. [April 2005]) 
December 
2004 
N.2.2.3 and Tables -
S_TileIndex Spatial File 
and 
S_SinkBreach Spatial 
File 
Moved content of S_TileIndex Spatial File to 
Subsection N.2.2.4 and removed duplicated text. 
Moved Table N-4 Subsection N.2.2.4 and labeled as 
Table N-10. (S_SinkBreach Spatial File was Table 
N-4. [Dec. 2004] Now Table N-10. [April 2005]) 
December 
2004 
S_SinkBreach Spatial 
File 
Moved Table N-4 to Subsection N.2.2.4. (Was Table 
N-4. [Dec. 2004] Now Table N-10. [April 2005]) 
December 
2004 
Table - S_TileIndex 
Spatial File 
Revised TileIndex in title and table to 
S_TileIndex and corrected all references to Tile 
Index spatial file. (Was Table N-10. [Dec. 2004] 
Now Table N-4. [April 2005]) 
December 
2004 
Table - S_SinkBreach 
Spatial File 
Changed SinkBreach to S_SinkBreach and 
provided additional information on placing breach 
lines. (Was Table N-4. [Dec. 2004] Now Table N-10. 
[April 2005]) 
December 
2004 
Table - S_NoData 
Spatial File 
Changed NoData to S_NoData. (Was Table N-5. 
[Dec. 2004] Now Table N-11. [April 2005]) 
December 
2004 
Table - S_VoidArea 
Spatial File 
Changed VoidArea to S_VoidArea. (Was Table 
N-6. [Dec. 2004] Now Table N-12 [April 2005]) 
December 
2004 
Table -
S_ExternalBoundary 
Spatial File 
Changed ExternalBoundary to 
S_ExternalBoundary. (Was Table N-7. [Dec. 
2004] Now Table N-13. [April 2005]) 
December 
2004 
Table - S_Island Spatial 
File 
Changed Island to S_Island. (Was Table N-8. 
[Dec. 2004] Now Table N-14. [April 2005]) 
December 
2004 
Table - S_StreamsDEM 
Spatial File 
Changed StreamsDEM to S_StreamsDEM. (Was 
Table N-9. [Dec. 2004] Now Table N-15. [April 
2005]) 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005] 

Date Affected 
Section(s)/Subsection(s) 
Description of Changes 
December 
2004 
N.2.2.4 Changed references to TileIndex to S_TileIndex 
and corrected reference to Table N-2. 
December 
2004 
N.2.3.3 Digital 
Deliverables, Directory 
Structure and Naming 
Conventions 
Changed Submittal_Info table to 
L_Submittal_Info table. 
December 
2004 
N.3.1 Changed Elevation Reference Marks to 
Temporary Bench Marks (or Elevation Reference 
Marks). 
December 
2004 
Table - Database Tables 
and Spatial Files for 
Cross Sections 
Corrected names of referenced tables and revised 
description of L_SXSPht from structure to cross 
section. (Was Table N-13. [Dec. 2004] Now Table 
N-17. [April 2005]) 
December 
2004 
Figure N-4 Revised figure to add color coding and legend to 
indicate the type of shapefile. Corrected figure to 
agree with Table N-14 and the Database Dictionary. 
Removed Easting and Northing. Added 
SOURCE_CIT to shapefile attributes. 
December 
2004 
Table - Attributes for 
Spatial Files for Cross 
Sections 
Corrected names of referenced tables. Corrected 
description for SOURCE_CIT. Deleted WTR_NM 
row. Corrected figure to agree with ERD and 
Database Dictionary. (Was Table N-14. [Dec. 2004] 
Now Table N-26. [April 2005]) 
December 
2004 
Survey Files, Naming 
Convention 
Corrected references to fields and tables. 
December 
2004 
Digital Photographs, 
Attributes 
Corrected reference to table. 
December 
2004 
N.3.2.2 and Attributes 
for Spatial Files for 
Elevation Reference 
Marks 
Changed all references to Elevation Reference 
Mark or ERM to Temporary Bench Mark or 
TBM. Added clarification that a database table is 
not required. (Was Table N-15. [Dec. 2004] Now 
Table N-27. [April 2005]) 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005] 

Date Affected 
Section(s)/Subsection(s) 
Description of Changes 
December 
2004 
Table - Attributes for 
Spatial Files for 
Elevation Reference 
Marks 
Added data type number for ELEV. Added 
description for SOURCE_CIT to shapefile attributes. 
Changeded S_Struc table to S_TBM spatial file. 
(Was Table N-15. [Dec. 2004] Now Table N-27. 
[April 2005]) 
December 
2004 
N.3.2.3 Added clarification that no spatial file is required for 
high water marks and deleted Spatial File subsection. 
December 
2004 
Table - Database Tables 
and Spatial Files for 
High Water Marks 
Updated references to table names. Added Table 
HWMWtnss and revised the description. Corrected 
description for L_HWMPht to refer to photographs 
rather than sketches. Added Table L_HWMSkt. 
(Was Table N-16. [Dec. 2004] Now Table N-28. 
[April 2005]) 
December 
2004 
Figure N-5 Revised figure to agree with the Database Dictionary 
and Table N-17. Added new domain D_Frequency. 
December 
2004 
Table - Database Tables 
and Spatial Files for 
Structures for Detailed 
Studies 
Revised references to table names and corrected 
table to agree with Database Dictionary. (Was Table 
N-17. [Dec. 2004] Now Table N-38. [April 2005]) 
December 
2004 
N.3.2.4 Spatial File Revised culvert description to match the description 
for Limited Detailed Study. 
December 
2004 
Figure N-6 Added SOURCE_CIT to shapefile attributes. 
December 
2004 
Table - Attributes for 
Spatial Files for 
Structures 
Revised Field Name for SOURCE_CIT. (Was Table 
N-18. [Dec. 2004] Now Table N-39. [April 2005]) 
December 
2004 
Survey Files, Attributes Revised text to indicate that each survey file should 
include all survey data. 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005] 

Date Affected 
Section(s)/Subsection(s) 
Description of Changes 
December 
2004 
Table - Database Tables 
and Spatial Files for 
Structures for Limited 
Detail Studies 
Revised references to table names and corrected 
fields to match Database Dictionary. (Was Table N19. [Dec. 2004] Now Table N-73. [April 2005]) 
December 
2004 
Figure N-7 Revised figure to match Database Dictionary. 
December 
2004 
Spatial File, Description Text revised for clarification. 
December 
2004 
Table - Attributes for 
Spatial Files for 
Structures 
Revised references to table names to match Table N21. Added SOURCE_CIT to shapefile attributes. 
Removed TORXS, TOPOXS and GPSPt_ID. Added 
ApxStr_ID as foreign key to SXS table. (Was Table 
N-20. [Dec. 2004] Now Table N-39. [April 2005]) 
December 
2004 
N.3.2.5 Revised dam description revised to a line that is 
aligned to the centerline along the top of the dam. 
Revised culvert description to match that used for 
Detailed Survey. 
December 
2004 
N.3.3 Added SOURCE_CIT to shapefile attributes. 
Corrected references to tables. 
December 
2004 
Table - File Formats for 
Photographs 
Added Tagged Image File Format and corrected 
fields to match Database Dictionary. (Was Table N21. [Dec. 2004] Now Table N-87. [April 2005]) 
December 
2004 
Table - File Formats for 
Spatial Files 
Added table. (Was Table N-21. [Dec. 2004] Now 
Table N-88. [April 2005]) 
December 
2004 
Table - Hydrology 
Database and Spatial 
Data 
Revised references to table names. (Was Table N-25. 
[Dec. 2004] Now Table N-90. [April 2005]) 
December 
2004 
Figure N-8 Revised. 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005] 

Date Affected 
Section(s)/Subsection(s) 
Description of Changes 
December 
2004 
N.4.2.2 Revised references to table names. 
December 
2004 
HydroLink Spatial File Corrected text to indicate that features follow the 
profile baseline wherever available. 
December 
2004 
Table - S_Hydrolink 
Spatial File 
Revised references to table names. (Was Table N-29. 
[Dec. 2004] Now Table N-94. [April 2005]) 
December 
2004 
Table - S_HydroBasin 
Spatial File 
Revised references to table names. (Was Table N-30. 
[Dec. 2004] Now Table N-95. [April 2005]) 
December 
2004 
Table - L_HydroResult 
Table 
Revised references to table names. (Was Table N-31. 
[Dec. 2004] Now Table N-96. [April 2005]) 
December 
2004 
Table - L_ Wtr_Nm 
Table 
Referenced Appendix L of these Guidelines. 
December 
2004 
Table - L_Wtr_Nm 
Table 
Revised references to table names. (Was Table N-32. 
[Dec. 2004] Now Table N-97. [April 2005]) 
December 
2004 
Table - L_HydroEvent 
Table 
Revised table name to include L_.(Was Table N33. [Dec. 2004] Now Table N-98. [April 2005]) 
December 
2004 
N.4.2.3 Revised references to table names. 
December 
2004 
Table - S_HydroGage 
S_Hydro Soil 
S_HydroLandUse 
S_HydroImpervious 
S_HydroTC 
L_HydroEquation 
L_HydroNodeParam 
Revised table names to include S_ or L_. (Were 
Tables N-34N-40. [Dec. 2004] Now Tables N-99 
105. [April 2005]) 
December 
2004 
Table - D_HydroParam 
Table 
Corrected lengths for ShortName and Descript fields. 
Corrected Type of Descript field. (Was Table N-41. 
[Dec. 2004] Now Table N-106. [April 2005]) 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005] 

Date Affected 
Section(s)/Subsection(s) 
Description of Changes 
December 
2004 
Table -
L_HydroCNResult 
L_HydroCNLookup 
L_HydroStormInfo 
L_HydroStormCurve 
Revised table names revised to include L_.(Were 
Tables N-43N-46. [Dec. 2004] Now Tables N-108 
111. [April 2005]) 
December 
2004 
N.5.1 Revised text to reference Appendix C of these 
Guidelines. 
December 
2004 
Table - Hydraulics 
Tables and Spatial Data 
Revised references to table names. (Was Table N-47. 
[Dec. 2004] Now Table N-112. [April 2005]) 
December 
2004 
Table - Minimum 
Required Datasets by 
Model Type 
Revised references to table names. (Was Table N-48. 
[Dec. 2004] Now Table N-113. [April 2005]) 
December 
2004 
N.5.2.2 Revised references to table names. 
December 
2004 
Table - L_HydraModel 
Table 
Revised table name to include L_. Corrected type 
and length for Hydra_LID field. (Was Table N-49. 
[Dec. 2004] Now Table N-114. [April 2005]) 
December 
2004 
Table -
S_StreamCntrLine 
Spatial File 
Revised table name to include S_. Revised 
WATER_LID, CHAN_LID, and WTR_NM_LID 
fields. (Was Table N-50. [Dec. 2004] Now Table N115. [April 2005]) 
December 
2004 
Table -
S_HydraCrossSection 
Spatial File 
Revised table extensively. (Was Table N-51. [Dec. 
2004] Now Table N-116. [April 2005]) 
December 
2004 
Table - S_Stn_Start 
Spatial File 
Changed table name to S_RefPoint Spatial File. 
See following item. 
December 
2004 
Table - S_RefPoint 
Spatial File 
Added primary key RefPtID. (Was Table N-52. 
[Dec. 2004] Now Table N-117. [April 2005]) 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005] 

Date Affected 
Section(s)/Subsection(s) 
Description of Changes 
December 
2004 
Table - L_HydraResult 
Table 
Revised field names and descriptions for Len_LID 
and Length_LID fields. Added V_Datum_LID field. 
(Was Table N-53. [Dec. 2004] Now Table N-118. 
[April 2005]) 
December 
2004 
Table - L_WtrName 
Table 
Revised table name. Revised text to reference 
Appendix L of these Guidelines. (Was Table N-55. 
[Dec. 2004] Now Table N-120. [April 2005]) 
December 
2004 
Table - L_WtrName 
Table 
Revised name, type, and length for WtrNameID 
field. (Was Table N-55. [Dec. 2004] Now Table N120. [April 2005]) 
December 
2004 
N.5.2.3 Revised references to table names. 
December 
2004 
Table -
S_HydraMapping 
Spatial File 
Revised table name and WtrNameID field. (Was 
Table N-56. [Dec. 2004] Now Table N-121. [April 
2005]) 
December 
2004 
Table - S_BFE Spatial 
File 
Added reference to Appendix L of these Guidelines. 
(Was Table N-57. [Dec. 2004] Now Table N-122. 
[April 2005]) 
December 
2004 
N.5.2.4 Revised references to table names. 
December 
2004 
Table -
S_HydraFlowPath 
Spatial File 
Revised table name and WtrNameID field. (Was 
Table N-58. [Dec. 2004] Now Table N-123. [April 
2005]) 
December 
2004 
Table - S_HydraJunction 
Spatial File 
Revised table name and references to other table 
names, and added V_DATM_LID and LEN_ID 
foreign keys. (Was Table N-59. [Dec. 2004] Now 
Table N-124. [April 2005]) 
December 
2004 
Table - L_HydraXsPt 
Table 
Revised table name. (Was Table N-60. [Dec. 2004] 
Now Table N-125. [April 2005]) 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005] 

Date Affected 
Section(s)/Subsection(s) 
Description of Changes 
December 
2004 
Table - S_HydraNvalue 
Spatial File 
Revised table name. (Was Table N-61. [Dec. 2004] 
Now Table N-126. [April 2005]) 
December 
2004 
Table - S_Ovrbnkln 
Spatial File 
Revised field names for Overbnk_ID, WtrName_ID, 
and WtrName. Revised type and length for renamed 
field WTR_NM_LID. (Was Table N-62. [Dec. 2004] 
Now Table N-127. [April 2005]) 
December 
2004 
N.6 Added references for Appendices B and J of these 
Guidelines. 
April 2005 All Sections have been re-arranged in the Terrain 
Section and tables added or deleted throughout. The 
citation in the Affected Section column in this 
chart refers to the previous section numbers. 
April 2005 N.1.1 and a Table Added text and a new table (Table N-1) to describe 
correlation of required tables between Appendices L 
and N. 
April 2005 N.1.6 Minor text revisions to clarify additions to DCS. 
April 2005 N.1.7 Submittal_Info table reference changed to 
L_Submittal_Info. Revised text to indicate that this 
table is required. 
April 2005 Submittal_Info Table Table name changed to L_Submittal_Info. Field 
CASE_ZIP removed.Revised descriptions for 
META_NM, and STUDY_ZIP to remove path and 
add requirement for General folder. Length for 
effective date removed. V_DATM_LID type 
changed to Longand length deleted and reference 
to D_V_Datum domain table added. LG_PAN_NO 
type changed to Text and Length changed to 4. 
(Was Table N-1 [December 2004] Now Table N-2 
[April 2005]) 
April 2005 N.2.2.1 Text revised to specify L_Submittal_Info table in 
Dbase IV or Microsoft Access format and 
requirements. 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005] 

Date Affected 
Section(s)/Subsection(s) 
Description of Changes 
April 2005 Figure - Terrain 
Submittal Flowchart 
Figure deleted. (Was Figure N-1 [December 2004]). 
April 2005 N.2.2.2 and Table 
Accepted File Formats 
for Source Terrain Data 
Section and table renamed. For 3-D Point shapefile 
and 2-D or 3-D Polyline shapefile, prj is also 
required. (Was Table N-2 [December 2004]. Now 
Table N-3 [April 2005]). 
April 2005 N.2.2.3 and Tables  
Supplemental Terrain 
Spatial Files 
Section moved and renumbered. Section and table 
title revised to add Supplemental and requirement 
for Supplemental Info folder. Text revised to clarify 
description of names of tiled data files. (Was Table 
N-3 [December 2004]. Now Table N-9 [April 
2005]). 
April 2005 Figure - File Naming 
Convention 
(Was Figure N-2 [December 2004]. Now Figure N-1 
[April 2005]). 
April 2005 Tables S_SinkBreach, 
S_NoData, S_VoidArea, 
S_ExternalBoundary, 
and S_Island spatial files 
Deleted Decimal Place column. (Were Table N-4, N5, N-6, N-7, N-8 [December 2004]. Now Table N10, N-11, N-12, N-13, N-14 [April 2005]). 
April 2005 Table S_NoData Spatial 
File 
Deleted 0 decimal places for NoDataID. Added 
LEN_LID and V_DATM_LID fields. (Was Table N5 [December 2004]. Now Table N-11 [April 2005]). 
April 2005 N.2.2.3 
Subsection Raster 
Elevation Data 
Revised text to specify that if DEMs are used, they 
must be submitted. 
April 2005 Table S_StreamsDEM 
Spatial File 
LEN_LID field added. (Was Table N-9 [December 
2004]. Now Table N-15 [April 2005]). 
April 2005 N.2.2.4 Now section N.2.2.3. Revised text. 
April 2005 Table Data Types Table renamed to Source Data Types and moved 
under N.2.2.4 Source Terrain Data. (Was Table N-11 
[December 2004]. Now Table N-7 [April 2005]). 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005] 

Date Affected 
Section(s)/Subsection(s) 
Description of Changes 
April 2005 New Section New section N.2.2.4 Source Terrain Data added. 
April 2005 Figure N-2 Prioritization 
of Overlapping Datasets 
Figure added. 
April 2005 Table N-8 Contour 
Spatial File 
LEN_LID and V_DATM_LID fields added. 
April 2005 N.2.2.5 and Raster 
Elevation Data 
Moved into new section, N.2.2.4 Source Terrain 
Data 
April 2005 New Section New section N.2.2.6 Output Terrain Data added. 
Contour Spatial File, Raster (formerly Tiled) 
Elevation Data, Flow Vector Data moved into 
section. 
April 2005 N.2.3.3 Digital 
Deliverables 
Preference for CD_ROM removed. 
April 2005 N.2.3.3 Subsection 
Directory Structure and 
Folder Naming 
Conventions 
Revised text to specify folder structures and names 
and file names in greater detail. 
April 2005 N.3 Table N-24 Data Dictionary has been broken into 
individual tables and inserted into sections. 
April 2005 N.3.1 Revised text to indicate that survey data must specify 
horizontal and vertical datums in the 
L_Submittal_Info table. 
April 2005 N.3.2.1 Re-organized section. Added master table of 
Database Tables for Cross Sections. Moved tables 
for cross sections from Data Dictionary to this 
section. Revised table names and added references to 
tables. 
April 2005 Figure N-4 Entity 
Relationship Diagram 
for Cross Sections 
Revised figure to correspond to tables. 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005] 

Date Affected 
Section(s)/Subsection(s) 
Description of Changes 
April 2005 N.3.2.2 Revised text. Moved tables for TBM from Data 
Dictionary to this section. 
April 2005 N.3.2.3 Re-organized section. Added master table of 
Database Tables for HWM. Moved tables for HWMs 
from Data Dictionary to this section. Revised table 
names and added references to tables. 
April 2005 Figure N-5 Entity 
Relationship Diagram 
for High Water Marks 
Revised figure to correspond to tables. 
April 2005 N.3.2.4 Re-organized section. Added master table of 
Database Tables for Structures for Detailed Studies. 
Moved tables for structures from Data Dictionary to 
this section. Revised table names and added 
references to tables. 
April 2005 Figure N-6 Entity 
Relationship Diagram 
for Structures for 
Detailed Study 
Revised figure to correspond to tables. 
April 2005 N.3.2.5 Re-organized section. Added master table of 
Database Tables for Structures for Limited Detailed 
Studies. Moved tables for structures from Data 
Dictionary to this section. Revised table names and 
added references to tables. 
April 2005 Figure N-7 Entity 
Relationship Diagram 
for Structures for 
Limited Detailed Study 
Revised figure to correspond to tables. 
April 2005 N.3.3.3 Digital 
Deliverables 
Preference for CD_ROM removed. 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005] 

Date Affected 
Section(s)/Subsection(s) 
Description of Changes 
April 2005 N.3.3.3 Subsection 
Directory Structure and 
Folder Naming 
Conventions 
Revised text to specify XML-format metadata file. 
April 2005 Table N-24 Data Dictionary has been broken into individual 
tables and inserted into sections. Revised table 
names to include appropriate prefixes (L_, S_, _D). 
Revised tables to correspond to ERDs and for 
accuracy. 
April 2005 Table - Hydrology 
Database and Spatial 
Data 
S_HydroLink description revised to specify lines. 
(Was Table N-25 [December 2004]. Now Table N90 [April 2005]). 
April 2005 Table - L_HydroModel 
Table 
Lengths for Descript, ZipName, and RPTName 
revised to 254. WtshdFldr, BasinFname, 
NodeFname, LinkFname, SoilFname, and ImpFname 
deleted. IsNew field added. Fields revised to 
eliminate path references and require placement in 
specific folder. (Was Table N-27 [December 2004]. 
Now Table N-92 [April 2005]). 
April 2005 N.4.2.1 Revised text to include spatial projection 
information. 
April 2005 Table - S_HydroNode 
Spatial File 
NodeName length revised to 254 and requirement 
added to Description for uniqueness across a 
watershed. IsPourPt description revised to include 
outlets. (Was Table N-28 [December 2004]. Now 
Table N-93 [April 2005]). 
April 2005 Table - S_HydroLink 
Spatial File 
WTR_NM_LID type revised to Long and length 
removed. LinkName length revised to 254 and 
requirement added to Description for uniqueness 
across a watershed. (Was Table N-29 [December 
2004]. Now Table N-94 [April 2005]). 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005] 

Date Affected 
Section(s)/Subsection(s) 
Description of Changes 
April 2005 N.4.2.2 Subsection 
S_HydroBasin Spatial 
File 
Revised text to include outlet/pour point. 
April 2005 Table - S_HydroBasin 
Spatial File 
BasinName requirement added to Description for 
uniqueness across a watershed. WtshdFldr field 
added. (Was Table N-30 [December 2004]. Now 
Table N-95 [April 2005]). 
April 2005 Table - S_HydroResult 
Spatial File 
Decimal Places column added. Discharge type 
revised to Numeric, 9 as length with 1 decimal 
place. Disch_LID type revised to Long and length 
deleted. (Was Table N-31 [December 2004]. Now 
Table N-96 [April 2005]). 
April 2005 Table - L_Wtr_Nm 
Table 
WTR_NM_LID type revised to Long and length 
deleted. WTR_NM length revised to 254. (Was 
Table N-32 [December 2004]. Now Table N-97 
[April 2005]). 
April 2005 Table - L_HydroEvent 
Table 
Decimal Places column added. ReturnPer type 
revised to Numeric, 6 as length with 1 decimal 
place. (Was Table N-33 [December 2004]. Now 
Table N-98 [April 2005]). 
April 2005 Table - S_HydroGage 
Spatial File 
Lengths for GageDesc and TimeFname revised to 
254. WtshdFldr field required. Gage_LID and 
Time_LID types revised to Long and length 
deleted. Start_PD and End_PD lengths deleted. 
TimeFName revised to eliminate path references and 
require placement in Simulations folder. (Was Table 
N-34 [December 2004]. Now Table N-99 [April 
2005]). 
April 2005 Table -
S_HydroLandUse 
Spatial File 
Field names revised to LUType and LUDesc and 
lengths revised. LUType allows use of abbreviations. 
LUType required, LUDesc not required. (Was Table 
N-36 [December 2004]. Now Table N-101 [April 
2005]). 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005] 

Date Affected 
Section(s)/Subsection(s) 
Description of Changes 
April 2005 Table -
S_HydroImpervious 
Spatial File 
ImpervPerc type revised to Numeric and length 
6 added. (Was Table N-37 [December 2004]. Now 
Table N-102 [April 2005]). 
April 2005 Table - S_HydroTC 
Spatial File 
TC and Time_LID types revised and lengths and 
decimal places revised. (Was Table N-38 [December 
2004]. Now Table N-103 [April 2005]). 
April 2005 Table -
L_HydroEquation Table 
Length for Equation revised to 254. TR type 
revised to Numeric and length and decimal places 
added. (Was Table N-39 [December 2004]. Now 
Table N-104 [April 2005]). 
April 2005 Table -
L_HydroNodeParam 
table 
Field revised to NodeParID. Value type revised to 
Numeric and length and decimal places added. 
Value field renamed to ParamValue. (Was Table 
N-40 [December 2004]. Now Table N-105 [April 
2005]). 
April 2005 Table - D_HydroParam 
Table 
Length for Descript revised to 254. UnitId type 
revised to Long and length deleted. (Was Table N41 [December 2004]. Now Table N-106 [April 
2005]). 
April 2005 Table N-43 
L_HydroCNResult 
Table 
WtshdFldr field added and description revised to 
remove path reference. CN type revised to 
Numeric and length and decimal places added. 
SoilFname and LandFname deleted. (Was Table N43 [December 2004]. Now Table N-108 [April 
2005]). 
April 2005 Table -
L_HydroCNLookup 
Table 
Field names revised to SCSSoil, LUType, and 
SCSLUType. Description for SCSSoil revised. 
Length and description for LUType revised. CN type 
revised to Numeric and length and decimal places 
added. Length for Source revised to 254. (Was 
Table N-44 [December 2004]. Now Table N-109 
[April 2005]). 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005] 

Date Affected 
Section(s)/Subsection(s) 
Description of Changes 
April 2005 Table -
L_HydroStormInfo 
Table 
Storm_LID type revised to Long and length 
deleted. (Was Table N-45 [December 2004]. Now 
Table N-110 [April 2005]). 
April 2005 Table -
L_HydroStormCurve 
Table 
Revised Time_LID, Depth, Len_LID, Intensity, 
Vel_LID types, length, and decimal places. (Was 
Table N-46 [December 2004]. Now Table N-111 
[April 2005]). 
April 2005 N.4.3.3 Digital 
Deliverables 
Preference for CD_ROM removed. 
April 2005 N.4.3.3 Subsection Data 
Directory Structure and 
Folder Naming 
Conventions 
Revised text to specify XML-format metadata file 
and folders and file names. Supplemental Info folder 
and L_Submittal_Info table added. 
April 2005 N.5.2.1 Revised text to include spatial projection 
information. 
April 2005 Hydraulics Tables and 
Spatial Data 
S_RefPoint revised for downstream point. 
April 2005 Table - L_HydraModel 
Table 
Lengths for Descript, ZipName, RptName, and 
TimeFname revised to 254. Hydra_LID type 
revised to Long and length deleted. StreamFldr 
and IsNetwork fields added. MapFname, BfeFname, 
FlowFname, JunctFname, NvalFname, and 
OverFname fields deleted. Descriptions revised to 
eliminate path references and require placement in 
specific folders. (Was Table N-49 [December 2004]. 
Now Table N-114 [April 2005]). 
April 2005 Table -
S_StreamCntrLine 
Spatial File 
WATER_LID, CHAN_LID, and WTR_NM_LID 
types changed to Long and length deleted. Length 
for SegName revised to 254 and requirement 
added to description that SegName be unique to a 
stream. (Was Table N-50 [December 2004]. Now 
Table N-115 [April 2005]). 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005] 

Date Affected 
Section(s)/Subsection(s) 
Description of Changes 
April 2005 Table - S_HydraCross 
Section Spatial File 
XS_LTR not required. RefPtID, WTR_NM_LID, 
LEN_LID, and V_DATM_LID types revised to 
Long and length deleted. WSEL_REG, 
TOP_WIDTH, XS_AREA, AREA_LID, 
VELOCITY, and VEL_LID fields deleted. Length 
for XS_LTR changed to 10. STREAM_STN 
description revised to add reference point. 
BED_ELEV description revised to add Lowest. 
(Was Table N-51 [December 2004]. Now Table N116 [April 2005]). 
April 2005 Table - S_RefPoint 
Spatial File 
RefPtID type revised to Long and length deleted. 
(Was Table N-52 [December 2004]. Now Table N117 [April 2005]). 
April 2005 Table -
L_HydraFloodResult 
Table 
Elevation field deleted. WSEL_Model, WSEL_Reg, 
TOP_WIDTH, XS_AREA, AREA_LID, 
VELOCITY, and VEL_LID fields added. 
DISCH_LID, LEN_LID and V_DATM_LID types 
revised to Long and length deleted. Description for 
Discharge revised to delete cfs. (Was Table N-53 
[December 2004]. Now Table N-118 [April 2005]). 
April 2005 Table - L_Wtr_Nm 
Table 
WTR_NM_LID type revised to Long and length 
deleted. Length for WTR_NM revised to 254. 
(Was Table N-55 [December 2004]. Now Table N120 [April 2005]). 
April 2005 Table -
S_HydraMapping 
Spatial File 
WTR_NM_LID type revised to Long and length 
deleted. HydraID field added. (Was Table N-56 
[December 2004]. Now Table N-121 [April 2005]). 
April 2005 Table - S_BFE Spatial 
File 
BFE_LN_ID, LEN_LID, and V_DATM_LID types 
revised to Long and length deleted. HydraID field 
added. (Was Table N-57 [December 2004]. Now 
Table N-122 [April 2005]). 
April 2005 N.5.2.3 Stream Profiles Text revised for clarification and to specify 
RASPLOT layer. 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005] 

Date Affected 
Section(s)/Subsection(s) 
Description of Changes 
April 2005 N.5.2.3 Floodway Data 
Tables 
Text revised for clarification and to reference 
Appendix J. Removed reference to template. 
April 2005 Table -
S_HydraFlowPath 
Spatial File 
WTR_NM_LID, Water_LID, and Len_LID types 
revised to Long and length deleted. Length for 
PathName revised to 254. (Was Table N-58 
[December 2004]. Now Table N-123 [April 2005]). 
April 2005 Table - S_HydraJunction 
Spatial File 
LEN_LID and V_DATM_LID types revised to 
Long, lengths deleted, and these are only required 
if Invert is populated. (Was Table N-59 [December 
2004]. Now Table N-124 [April 2005]). 
April 2005 Table - L_HydraXsPt 
Table 
XsectID required. Len_LID type revised to Long 
and length deleted. Station description expanded to 
include orientation. (Was Table N-60 [December 
2004]. Now Table N-125 [April 2005]). 
April 2005 Table - S_HydraNvalue 
Spatial File 
All fields now are required. (Was Table N-61 
[December 2004]. Now Table N-126 [April 2005]). 
April 2005 Table - S_Ovrbnkln 
Spatial File 
Field name revised to OVRBNK_ID. 
OVRBNK_ID and WTR_NM_ID types revised to 
Long and lengths deleted. (Was Table N-62 
[December 2004]. Now Table N-127 [April 2005]). 
April 2005 N.5.3.3 Subsection Data 
Directory Structure and 
Folder Naming 
Conventions 
Revised text to specify XML-format metadata file, 
file names, and Supplemental Info folder. 
Supplemental Info folder added. Hydraulic 
Databases files include L_Submittal_Info table. 
May 2005 N.1.1 Introduction Revised text to clarify that DCS tables are in addition 
to Appendix L tables and can be used to populate 
Appendix L tables. 
May 2005 N.2.2.2 Accepted File 
Formats 
Revised text to delete source and specify accepted 
for terrain data. 
May 2005 N.2.3.1 Metadata Revised text to clarify metadata requirements. 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005] 

Date Affected 
Section(s)/Subsection(s) 
Description of Changes 
May 2005 N.2.3.3 Digital 
Deliverables 
Revised requirements for Output/DEM_xx folder by 
deleting Any files that dont fit into the other 
categories. 
May 2005 Figure N-7 Entity 
Relationship Diagram 
for Structures for 
Limited Detailed Study 
Removed fields ExPpDia and RsrDia and renamed 
ExPpPpHt to ExPpRise to be consistent with changes 
to Table N-79, L_ApxRsr Table. 
May 2005 Table N-77. L_ApxRsr 
Table 
Removed fields ExPpDia and RsrDia. Field ExPpHt 
renamed to ExPpRise and description revised to 
include diameter. Descriptions for fields RsrHlLn 
and RsrLn revised to include diameter. 
May 2005 Table N-109 
L_HydroCNLookup 
Revised field name in description from Soil_Type 
to SoilType. 
May 2005 N.3.3.1 Metadata Revised text to clarify metadata requirements. 
May 2005 N.3.3.3 Digital 
Deliverables 
Revised text in the Metadata subsection to remove 
reference to Appendix L. 
May 2005 N.4.3.1 Metadata Revised text to clarify metadata requirements. 
May 2005 N.5.3.1 Metadata Revised text to clarify metadata requirements. 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

Table of Contents 

N.1 Overview........................................................................................................................ 1 


N.1.1 Introduction [May 2005]....................................................................................... 1 


N.1.2 Terrain [December 2004]...................................................................................... 2 


N.1.3 Survey [December 2004] ...................................................................................... 2 


N.1.4 Hydrology [December 2004] ............................................................................... 3 


N.1.5 Hydraulics [December 2004].............................................................................. 3 


N.1.6 Updates [December 2004] ..................................................................................... 4 


N.1.7 Submittal Information [April 2005]...................................................................... 4 


N.1.8 Future Vision [December 2004] ........................................................................... 6 


N.2 Terrain Submittal Standards ........................................................................................... 7 


N.2.1 Overview [April 2005].......................................................................................... 7 


N.2.2 Requirements [April 2005] .................................................................................... 8 


N.2.2.1 Data Files [April 2005] ..................................................................................... 8 


N.2.2.2 Accepted File Formats [May 2005] .................................................................. 8 


N.2.2.3 Tiled Terrain Spatial Files [April 2005] .......................................................... 9 


N.2.2.4 Source Terrain Data [April 2005]..................................................................... 11 


N.2.2.5 Output Terrain Data [April 2005]..................................................................... 17 


N.2.3 Deliverables [May 2005] ..................................................................................... 18 


N.2.3.1 Metadata [May 2005]........................................................................................ 18 


N.2.3.2 Hard Copy Deliverables [December 2004]..................................................... 18 


N.2.3.3 Digital Deliverables [May 2005] ...................................................................... 19 


N.3 Survey Submittal Standards.......................................................................................... 22 


N.3.1 Overview [December 2004].................................................................................. 22 


N.3.2 Requirements [April 2005] ................................................................................ 23 


N.3.2.1 Cross Sections [April 2005].............................................................................. 23 


N.3.2.2 Temporary Bench Marks [April 2005] .......................................................... 30 


N.3.2.3 High Water Marks [April 2005] ...................................................................... 31 


N.3.2.4 Structures for Detailed Study [April 2005]..................................................... 38 


N.3.2.5 Structures for Limited Detailed Study [April 2005]....................................... 62 


N.3.3 Deliverables [May 2005] ...................................................................................... 73 


N.3.3.1 Metadata [May 2005]................................................................................... 73 


N.3.3.2 Hard Copy Deliverables [December 2004].................................................. 73 


N.3.3.3 Digital Deliverables [May 2005] ................................................................. 73 


N.4 Hydrology Submittal Standards.................................................................................... 77 


N.4.1 Overview [December 2004]............................................................................. 77 


N.4.2 Requirements [April 2005] ................................................................................... 78 


N.4.2.1 Data Files [April 2005] ................................................................................... 78 


N.4.2.2 Required Hydrologic Data [April 2005]...................................................... 82 


N.4.2.3 Other Hydrologic Data [April 2005]............................................................. 86 


N.4.3 Deliverables [May 2005] ................................................................................... 94 


Ni Table of Contents 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

N.4.3.1 Metadata [May 2005]................................................................................... 94 


N.4.3.2 Hard Copy Deliverables [December 2004].................................................. 95 


N.4.3.3 Digital Deliverables [April 2005] ................................................................ 95 


N.5 Hydraulics Submittal Standards.................................................................................... 97 


N.5.1 Overview [December 2004]............................................................................. 97 


N.5.2 Requirements [April 2005] ................................................................................... 98 


N.5.2.1 Data Files [April 2005] ................................................................................ 98 


N.5.2.2 Required Hydraulic Data [April 2005] ...................................................... 102 


N.5.2.3 Work Map Products [April 2005]................................................................. 107 


N.5.2.4 Required If Utilized [April 2005] .............................................................. 110 


N.5.3 Deliverables [May 2005] ................................................................................. 113 


N.5.3.1 Metadata [May 2005]................................................................................. 113 


N.5.3.2 Hard Copy Deliverables [December 2004].................................................. 113 


N.5.3.3 Digital Deliverables [April 2005] .................................................................. 114 


N.6 References [December 2004]............................................................................. 116 


List of Figures 

Figure N-1. File Naming Convention .......................................................................................... 10
Figure N-2. Prioritization of Overlapping Datasets..................................................................... 11 
Figure N-3. Flow Direction Values ............................................................................................. 18 
Figure N-4. Entity Relationship Diagram for Cross Sections...................................................... 24 
Figure N-5. Entity Relationship Diagram for High Water Marks ............................................... 33 
Figure N-6. Entity Relationship Diagram for Structures for Detailed Studies............................ 41 
Figure N-7. Entity Relationship Diagram for Structures for Limited Detailed Study................. 63 
Figure N-8. Entity Relationship Diagram for Hydrology............................................................ 81 
Figure N-9. Placement of HydroNodes and HydroLinks ............................................................ 84 
Figure N-10. Entity Relationship Diagram for Hydraulics........................................................ 101 


List of Tables 

Table N-1. Correlation of Required Tables between Appendices L and N................................... 2 
Table N-2. L_Submittal_Info Table ..............................................................................................5
Table N-3. Accepted File Formats for Terrain Data...................................................................... 8 
Table N-4. S_TileIndex Spatial file............................................................................................... 9 
Table N-5. S_Perimeter Spatial File ............................................................................................ 12 
Table N-6. L_PerimFile Table..................................................................................................... 12 
Table N-7. Source Data Types..................................................................................................... 13 
Table N-8. Contour Spatial file.................................................................................................... 13 
Table N-9. Supplemental Terrain Spatial Files............................................................................ 14 
Table N-10. S_SinkBreach Spatial File....................................................................................... 14
Table N-11. S_NoData Spatial File ............................................................................................. 15 


Nii Table of Contents 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

Table N-12. S_VoidArea Spatial File.......................................................................................... 15 
Table N-13. S_ExternalBoundary Spatial File ............................................................................ 16 
Table N-14. S_Island Spatial File................................................................................................ 16 
Table N-15. S_StreamsDEM Spatial File.................................................................................... 17 
Table N-16. Output Data Types................................................................................................... 17 
Table N-17. Database Tables and Spatial Files for Cross Sections............................................. 23 
Table N-18. L_SXS Table ........................................................................................................... 25 
Table N-19. L_SXSPht Table...................................................................................................... 26 
Table N-20. L_SXSSkt Table...................................................................................................... 26 
Table N-21. L_Sketch Table........................................................................................................ 26 
Table N-22. L_Wtr_Nm Table .................................................................................................... 27 
Table N-23. S_Photo Spatial File ................................................................................................ 27 
Table N-24. D_DatTyp Table...................................................................................................... 28 
Table N-25. Domain Values for D_DatTyp ................................................................................ 28 
Table N-26. S_SXS Spatial File .................................................................................................. 28 
Table N-27. S_TBM Spatial File................................................................................................. 31 
Table N-28. Database Tables and Spatial Files for High Water Marks....................................... 32 
Table N-29. S_HWM Spatial File ............................................................................................... 34 
Table N-30. L_HWMWtns Table................................................................................................ 35 
Table N-31. L_HWMPht Table ................................................................................................... 35 
Table N-32. L_HWMSkt Table ................................................................................................... 35 
Table N-33. L_Sketch Table........................................................................................................ 36 
Table N-34. L_Wtr_Nm Table .................................................................................................... 36 
Table N-35. S_Photo Spatial File ................................................................................................ 36 
Table N-36. D_HWLnTp Table................................................................................................... 37 
Table N-37. Domain Values for D_HWLnTp ............................................................................. 37 
Table N-38. Database Tables and Spatial Files for Structures for Detailed Studies .................. 39 
Table N-39. S_Struc Spatial File ................................................................................................. 42 
Table N-40. L_Brdg Table........................................................................................................... 44 
Table N-41. L_CulPp Table......................................................................................................... 45 
Table N-42. L_Dam Table........................................................................................................... 46 
Table N-43. L_LChrd Table ........................................................................................................ 47 
Table N-44. L_Levee Table......................................................................................................... 48 
Table N-45. L_Orfc Table ........................................................................................................... 49 
Table N-46. L_OtlPp Table ......................................................................................................... 50 
Table N-47. L_Pier Table ............................................................................................................ 51 
Table N-48. L_Rail Table............................................................................................................ 51 
Table N-49. L_RsrBrl Table........................................................................................................ 52 
Table N-50. L_Sketch Table........................................................................................................ 52 
Table N-51. L_StrPht Table......................................................................................................... 53 
Table N-52. L_StrSkt Table......................................................................................................... 53 
Table N-53. L_SWy Table........................................................................................................... 53 
Table N-54. L_SXS Table ........................................................................................................... 54 
Table N-55. L_Wtr_Nm Table .................................................................................................... 55 
Table N-56. S_Photo Spatial File ................................................................................................ 55 


Niii Table of Contents 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

Table N-57. D_AbtTyp Table...................................................................................................... 56 
Table N-58. Domain Values for D_AbtTyp ................................................................................ 56 
Table N-59. D_ShpTyp Table...................................................................................................... 56 
Table N-60. Domain Values for D_ShpTyp................................................................................ 56 
Table N-61. D_PpTyp Table........................................................................................................ 57 
Table N-62. Domain Values for D_PpTyp.................................................................................. 57 
Table N-63. D_MtlTyp Table...................................................................................................... 57 
Table N-64. Domain Values for D_MtlTyp ................................................................................ 57 
Table N-65. D_ClsTyp Table ...................................................................................................... 58 
Table N-66. Domain Values for D_ClsTyp................................................................................. 58 
Table N-67. D_LevTyp Table...................................................................................................... 58 
Table N-68. Domain Values for D_LevTyp................................................................................ 58 
Table N-69. D_SwyTyp Table..................................................................................................... 59 
Table N-70. Domain Values for D_SwyTyp ............................................................................... 59 
Table N-71. D_DamTyp Table.................................................................................................... 59 
Table N-72. Domain Values for D_DamTyp .............................................................................. 59 
Table N-73. Database Tables and Spatial Files for Structures for Limited Detail Studies ........ 62 
Table N-74. S_ApxStr Spatial File .............................................................................................. 65 
Table N-75. L_ApxCul Table...................................................................................................... 66 
Table N-76. L_ApxDam Table.................................................................................................... 67 
Table N-77. L_ApxRsr Table ...................................................................................................... 68 
Table N-78. L_ApxSwy Table..................................................................................................... 69 
Table N-79. L_ApxPht Table ...................................................................................................... 69 
Table N-80. L_ApxBrdg Table.................................................................................................... 70 
Table N-81. S_Photo Spatial File ................................................................................................ 70 
Table N-82. L_Wtr_Nm Table .................................................................................................... 71 
Table N-83. D_MtlTyp Table...................................................................................................... 71 
Table N-84. Domain Values for D_MtlTyp ................................................................................ 71 
Table N-85. D_ShpTyp Table...................................................................................................... 72 
Table N-86. Domain Values for D_ShpTyp................................................................................ 72 
Table N-87. File Formats for Photographs .................................................................................. 74 
Table N-88. File Formats for Spatial Files .................................................................................. 74
Table N-89. File Formats for Sketches........................................................................................ 75 
Table N-90. Hydrology Database and Spatial Data..................................................................... 79 
Table N-91. Minimum Required Datasets*................................................................................. 80 
Table N-92. L_HydroModel Table.............................................................................................. 82
Table N-93. S_HydroNode Spatial File....................................................................................... 83 
Table N-94. S_HydroLink Spatial File........................................................................................ 83
Table N-95. S_HydroBasin Spatial File ...................................................................................... 85 
Table N-96. L_HydroResult Table .............................................................................................. 85 
Table N-97. L_Wtr_Nm Table .................................................................................................... 86 
Table N-98. L_HydroEvent Table ............................................................................................... 86 
Table N-99. S_HydroGage Spatial File....................................................................................... 87 
Table N-100. S_HydroSoil Spatial File....................................................................................... 88
Table N-101. S_HydroLandUse Spatial File............................................................................... 88 


Niv Table of Contents 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

Table N-102. S_HydroImpervious Spatial File ........................................................................... 89 
Table N-103. S_HydroTC Spatial File ........................................................................................ 89 
Table N-104. L_HydroEquation Table........................................................................................ 90 
Table N-105. L_HydroNodeParam Table.................................................................................... 90 
Table N-106. D_HydroParam Table............................................................................................ 91 
Table N-107. Sample Domain Values for D_HydroParam ......................................................... 91 
Table N-108. L_HydroCNResult Table....................................................................................... 91 
Table N-109. L_HydroCNLookup Table .................................................................................... 92 
Table N-110. L_HydroStormInfo Table...................................................................................... 93 
Table N-111. L_HydroStormCurve Table................................................................................... 94 
Table N-112. Hydraulics Tables and Spatial Data....................................................................... 99 
Table N-113. Minimum Required Datasets by Model Type ..................................................... 100 
Table N-114. L_HydraModel Table .......................................................................................... 102 
Table N-115. S_StreamCntrLine Spatial File............................................................................ 103 
Table N-116. S_HydraCrossSection Spatial File....................................................................... 104 
Table N-117. S_RefPoint Spatial File ....................................................................................... 105
Table N-118. L_HydraFloodResult Table ................................................................................. 106 
Table N-119. L_HydraEvent Table ........................................................................................... 107 
Table N-120. L_Wtr_Nm Table ................................................................................................ 107
Table N-121. S_HydraMapping Spatial File ............................................................................. 108 
Table N-122. S_BFE Spatial File .............................................................................................. 109 
Table N-123. S_HydraFlowPath Spatial File ............................................................................ 110 
Table N-124. S_HydraJunction Spatial File .............................................................................. 111 
Table N-125. L_HydraXsPt Table............................................................................................. 112
Table N-126. S_HydraNvalue Spatial File ................................................................................ 112 
Table N-127. S_Ovrbnkln Spatial File ...................................................................................... 113 


Nv Table of Contents 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004, Sections 
Updated May 2005]

Appendix N 

Data Capture Standards for Mapping Partners 

N.1 Overview 
N.1.1 Introduction [May 2005] 
The purpose of the Data Capture Standards (DCS) in this Appendix is to provide a consistent 
framework for collection, analysis, storage and retrieval of the data needed for a Flood Insurance 
Study (FIS) or Flood Insurance Rate Map (FIRM) revision. Providing this framework is 
intended to make the study assessment process more efficient; make the data more available for 
future use; and preserve the investment made in the data. It is part of a 5-year plan to collect and 
provide data to the Mapping Information Platform (MIP) for sharing through the data federation. 

For those Mapping Partners that use the engineering and mapping tools provided by FEMA, the 
required data will be automatically archived in the recommended format. In the case of Mapping 
Partners who have developed other automated processes for performing production style flood 
mapping, these data standards serve as the mechanism for collecting and archiving the required 
data. 

These data standards are the vehicles used to help collect and manage the engineering 
deliverables that result from the flood insurance study process. The DCS also facilitate the 
building of an Enhanced Digital Flood Insurance Rate Map (DFIRM) database by providing 
information that is needed in manageable pieces during the progression of the mapping process. 
The DCS will also support queries to the MIP that will track and evaluate progress metrics on 
studies and report these metrics to the process stakeholders. 

Similarities have been drawn between the DCS in this Appendix and Appendix L of these 
Guidelines. The clear difference between Appendix L and the DCS is that the DCS is a 
collection of databases for use as part of the intermediate processes of creating a DFIRM. 
Appendix L is associated with the output and final deliverables of the flood hazard mapping. 

There is some overlap between the two data standards, specifically in areas where the DCS, once 
capture points have been reached, reports end result data. There are also places where the two 
datasets have no overlap at all. Examples of this would be how Appendix L captures data such 
as planimetric data and pre-/post-Preliminary DFIRM mapping information. Conversely, the 
DCS stores data types such as terrain processing and field survey information, neither of which 
are stored in Appendix L tables. 

As a part of the ongoing review and refinement of all FEMA datasets, Appendix L of these 
Guidelines and the DCS will undergo a review to specifically see how best to account for the 
data stored in the two datasets and how this can be made clearer to all Mapping Partners. The 

N1 Section N.1 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004, Sections 
Updated May 2005]

result of this review could involve refinements to the datasets or the joining of the data into one 
comprehensive dataset. 

In the interim, Mapping Partners should submit DCS tables defined in this appendix for all remodeled areas. All Standard Appendix L tables should be submitted for the entire community or 
county being mapped. The correlations between required tables defined by Appendices L and N 
are listed in Table N-1. The records stored in the DCS tables listed in Table N-1 are usually a 
subset of the total number of records required for Appendix L and so should be used to help 
populate the corresponding Appendix L tables. 

Table N-1. Correlation of Required Tables between Appendices L and N 

DFIRM Tables in Appendix L DCS Tables in Appendix N 
S_XS S_HydraCrossSection 
S_Wtr_Ln S_StreamCntrLine 
L_Stn_Start S_RefPoint 
S_Riv_Mark S_RefPoint 
S_Fld_Haz_Ln S_HydraMapping 
S_Gen_Struct 
S_Struc and S_ApxStr (and associated lookup 
tables) 

The data standards are provided in subsections. Each subsection corresponds to major 
engineering data capture points and includes guidance on collecting terrain, survey, hydrologic, 
and hydraulic data. These sections describe the minimum dataset of deliverables established by 
FEMA for floodplain mapping submittals. These data standards will serve in addition to the 
Technical Support Data Notebook and other standards detailed in other parts of these Guidelines. 

N.1.2 Terrain [December 2004] 
The Terrain section describes what is needed for capture of the digital topographic data that was 
used to create the elevation data representing the terrain environment of a watershed and/or 
floodplain. It allows for flexibility in the types of information provided while describing in 
detail the specifics of the deliverables. Once this type of data is provided, FEMA will be able to 
account for the origins of the flood study elevation data. The requirements in Appendix A of 
these Guidelines must still be met to define the quality of the topographic data used. 

N.1.3 Survey [December 2004] 
The Survey section describes those spatial datasets and data tables necessary to digitally 
represent data collected in the survey phase of the study. The survey phase has traditionally been 
one of the most expensive portions of the study. These standards describe how the survey data 
shall be submitted for features such as dams, culverts, bridges, and channels. 

N2 Section N.1 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

In an effort to aid the Mapping Partner in disseminating the data requirements to field surveyors, 
FEMA has prepared Data Capture Guidelines for survey data. This manual will guide surveyors 
in collecting the type of information the engineer requires to create a digital representation of a 
floodplain hydraulic structure. The Data Capture Guidelines are considered guidelines 
because they describe how to collect data and are not required data submittal. The tables in the 
Survey section of the DCS serve the purpose of archiving the data needed for the application of 
hydraulic models. 

N.1.4 Hydrology [December 2004] 
The Hydrology section describes those spatial datasets and data tables necessary for 
documenting the hydrologic procedures for estimating flood discharges for the flood insurance 
study. The goal of this section is to describe the format and type of hydrologic data expected by 
FEMA for new riverine studies. The objective is to archive the hydrologic data in a database so 
that this data can be revised and used with minimum effort in future flood insurance studies or 
map revisions. Another objective is to collect sufficient data on hydrologic procedures to 
populate the Enhanced DFIRM database. 

The minimum required dataset for documenting the hydrologic procedures is described in this 
section of the DCS. This minimum requirement includes input and output files for all hydrologic 
models and spatial datasets that are needed to implement the models. Because of the frequent 
use of hydrologic models such as HEC-1 and HEC-HMS that utilize a design storm event and the 
Natural Resources Conservation Service hydrologic procedures and regional regression 
equations, more detailed data is requested to describe these methodologies. Detailed information 
on continuous simulation models like HSPF, SWMM and MIKE 11 RR are not required but the 
input and output files and supporting spatial data files are archived. As metrics are collected on 
the types of hydrologic models used most frequently by Mapping Partners, additional tables will 
be added in the future to capture this data in more detail. 

N.1.5 Hydraulics [December 2004] 
The development of a hydraulic model to provide water-surface elevations for floodplain 
mapping requires a significant investment in time and resources to obtain and process 
topographic survey data including cross-section and bridge surveys. Recent developments in 
digital terrain and geospatial database management technology make it possible to protect this 
investment for existing and future projects to a much greater extent than was possible in the past. 
This section describes the format and type of hydraulic data to be provided to FEMA for new 
riverine flood insurance studies. 

The minimum required dataset for documenting the hydraulic procedures is described in this 
section of the DCS. This minimum requirement includes input and output files for all hydraulic 
models and spatial datasets that are needed to implement the models. As with hydrology, there is 
a focus on HEC hydraulic models such as HEC-2 and HEC-RAS due to their frequency of use 
and the intent is to capture the data required to populate the Enhanced DFIRM database. 
Detailed information on one- and two-dimensional unsteady flow models like FEQ, ICPR, FLO2D, and MIKE 11 HD are not required but the input and output files and supporting spatial data 

N3 Section N.1 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

files are archived. As metrics are collected on the frequency of use of hydraulic models, 
additional tables will be added to capture the data from these models in a true database format. 

N.1.6 Updates [December 2004] 
It is the intention of the NSP to provide yearly management reports as a part of the data standards 
process. These reports will detail metrics collected on study types and other key study factors 
associated with flood mapping. Coastal data is currently not included in the data standards. 
Methodologies for coastal studies are presently being reviewed and developed. Once this 
process is complete, detailed description of coastal data submittal as dictated by the study 
process will be included in the data standards. Data capture standards for other more specialized 
flow regimes and processes (for example alluvial fans, closed system pipe flow and 
interconnected pond hydraulics) will also be evaluated for inclusion in the future. These updates 
will be done on a yearly basis. 

N.1.7 Submittal Information [April 2005] 
The L_Submittal_Info table is a required database table. This table holds essential information 
about the FEMA Case, datums and projections, and location of metadata and study-related zip 
files. This table is submitted along with the data given in the four subsections to describe who 
collected the data and where the data is coming from. 

The L_Submittal_Info table contains the attributes shown in Table N-2. 

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Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

Table N-2. L_Submittal_Info Table 

Field Type Length Required Description 
SubInfoID Long Yes Primary key for this table. 
CASE_NO Text 12 Yes FEMA Case Number for study. 
CASE_DESC Text 254 Yes General description of the study. 
EFF_DATE Date Yes Effective date of the case. 
STUDY_PRE Text 20 No Study prefix, i.e. City of. 
STUDY_NM Text 50 Yes Study name. 
STATE_NM Text 50 Yes State name. 
CNTY_NM Text 50 Yes County name. 
JURIS_TYP Text 50 No Political jurisdiction type. 
LG_PAN_NO Text 4 Yes Largest panel number. 
OPP_TF Boolean Yes Only panel printed? 
H_DATUM Text 10 Yes Horizontal datum. Valid Entries include NAD27 or 
NAD83. 
V_DATM_LID Long Yes Vertical datum lookup identification and foreign key 
to D_V_Datum domain table (see Appendix L of 
these Guidelines). 
PROJECTION Text 50 Yes Map projection used for the hard copy FIRM 
publication. 
PROJ_ZONE Text 10 No Projection zone. 
CW_TF Boolean Yes Countywide? 
SW_TF Boolean Yes Statewide? 
CBRS_PHONE Text 15 No Coastal Barrier Resources System (CBRS) Phone 
number. 
CBRS_REG Text 1 No CBRS Coordinators region. 
RTROFT_TF Boolean Yes Retrofit? 
META_NM Text 50 Yes Metadata file name. Must be stored in General 
folder. 
STUDY_ZIP Text 254 No File name of the zipped file that contains the FIS 
report or auxiliary data that is relevant to the entire 
study. Must be stored in General folder. 
SUBMIT_BY Text 100 Yes Company name of Mapping Partner who is 
submitting this dataset. 
SUBMIT_CON Text 100 Yes Contact person for this submittal. 
SUBMIT_PHO Text 15 Yes Phone number of Mapping Partner 
Restricted Boolean Yes Some data in this submittal cant be distributed 
freely. See the metadata file. 

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Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

N.1.8 Future Vision [December 2004] 
This document presents an interim solution to enable data capture in the short term. The long-
term objective is to adopt an approach to data exchange that is open and vendor independent. 
This release of the standards mandates specific file naming and folder structure. In upcoming 
versions, the plan is to require a metadata file (read me file) that describes file names and their 
location in the folder structure of the submittal. This will enable Mapping Partners to submit data 
without restrictions on file naming and folder structure. 

The vision of FEMA is to establish an Interoperable Framework for Open Data Exchange 
Standards (OpenDES) that enables the full potential of its information holdings in all mission 
areas. This framework will consist of common information models and tools for data sharing and 
exchange based on adopted information technology standards such as: OGC/ISO Geography 
Markup Language (GML), FGDC/ISO (Federal Geographic Data Committee/International 
Organization for Standardization) Metadata, and W3C Web Service technologies such as 
eXtensible Markup Language (XML) and Simple Object Access Protocol (SOAP). 

The objectives of this open standards-based approach are to: 

 Eliminate interoperability barriers to sharing hazard resources managed by different 
organizations using different technologies 
 Enable Mapping Partners to share and exchange data irrespective of their underlying 
technologies 
 Define secure and robust formats for data capture and exchange for use across multiple 
platforms, applications and devices 
 Realize the full integration of resources with Web enabled technologies 
 Deploy the framework to enhance processes and tools for hazard data production, 
management and dissemination 
 Leverage related private, local, State, Federal, and international initiatives, such as: 
o E-Government (e.g. Geospatial One-Stop, DHS, FGDC NSDI, etc) 
o Industry-driven standards consortia that rapidly seed the market with certified 
Standards-based Commercial Off The Shelf (SCOTS) products and tools 
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Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

N.2 Terrain Submittal Standards 
N.2.1 Overview [April 2005] 
The goal of this subsection is to describe the format and type of terrain data expected by FEMA 
for new Flood Insurance Studies. The Mapping Partner should refer to Appendix A of these 
Guidelines for guidance on terrain data production. 

There is a broad range of methods that Mapping Partners can use to gather terrain data and 
extract useful information for hydraulic and hydrologic models. The simplest method, but least 
accurate, is to use hard copy U.S. Geological Survey (USGS) quadrangles with contours and 
streams. Using an engineering scale, planimeter, and map wheel, Mapping Partners can 
calculate cross-section geometries and basin areas. The main disadvantage of this technique is 
that the underlying terrain data is not captured in a digital format for potential future use. 

Other Mapping Partners may have aerial photography performed and receive contours digitally. 
This data is useful for automating many hydraulic and hydrologic computations. Its main 
disadvantage is that the contour maps leave out the details of what is happening in between 
adjacent contours. This is especially troublesome in coastal areas. 

The best type of terrain data is based on three-dimensional spot elevations and breaklines. Many 
commercial software packages can use this type of data to create Triangular Irregular Networks 
(TINs). A TIN is the most precise approximation of the earths surface, but it is also the most 
costly in terms of storage size. A TIN can be used to create digital elevation models (DEMs) 
that are evenly spaced elevations. DEMs are useful for hydrologic analysis and for generating 
approximate floodplain boundaries rapidly; however, like contours, they are still approximations 
of a better data source and should only be used when necessary. 

The rest of this subsection will explain the data requirements for a terrain submittal. 

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Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

N.2.2 Requirements [April 2005] 
N.2.2.1 Data Files [April 2005] 
The minimum required data for a terrain submission is the source terrain data. This data can be 
contained in a single file, or more commonly, a tiled set of files. If any terrain processing has 
been performed, the intermediate and final files are to be submitted as well. Examples of these 
additional files are spatial files used to indicate locations for breaching sinks, flow vectors files, 
and hydrologically correct DEMs. 

Certain spatial features, as indicated below, must be stored in an ESRI shapefile or Open GML 
document with the necessary attribute fields and spatial projection information. Other terrain 
data must be submitted in the file formats specified in Table N-3. All database tables must be 
populated in Dbase IV format or Microsoft Access format. 

N.2.2.2 Accepted File Formats [May 2005] 
Table N-3 shows the file formats that are accepted for terrain data. This data can be contained in 
a single file or a tiled set of files. If the data is tiled, it is important to note that DTM files must 
not overlap each other. Any tiled data must have an accompanying index spatial file. 

Airborne Light Detection and Ranging (LIDAR)-generated data shall be submitted as two series 
of files: one for bare earth only, one for all returns. 

Table N-3. Accepted File Formats for Terrain Data 

Format Extension References 
ArcInfo Tin Generate (line) LIN See ESRI support: www.esri.com 
ArcInfo Tin Generate (point) PNT See ESRI support: www.esri.com 
AutoCAD DXF version 12 DXF www.autodesk.com 
ESRI Grid Ascii ASC See ESRI support: www.esri.com 
Comma delimited point text XYC 
Space delimited point text XYS 
LAS Binary LIDAR points LAS http://www.lasformat.org/ 
3-D Point shapefile SHP (include 
shx,dbf and prj) 
See ESRI support: www.esri.com 
2-D or 3-D Polyline shapefile SHP (include 
shx,dbf and pdf 
See ESRI support: www.esri.com 

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Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

N.2.2.3 Tiled Terrain Spatial Files [April 2005] 
All tiled terrain data shall be submitted with an accompanying S_TileIndex polygon spatial file. 
Tiles must have only one part and cannot self-intersect (must be simple). Adjacent tiles must not 
overlap or have gaps between them. The tile shape must completely contain the DTM data in the 
associated file. The attributes of the S_TileIndex Spatial File are provided in Table N-4. 

Table N-4. S_TileIndex Spatial file 

Field Type Length Required Description 
GridID Text 20 Yes Primary key for table. Used to identify tiled data 
sources. Example: G05, F1254. 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata file when 
describing the source information. 

The names of tiled data files will be constructed using the GridId, an underscore, the data type 
suffix (see Table N-7), and the file format extension (see Table N-3). The format is 

GridId_datatype.FileformatExtension. 

For example, file G104_CNT.DXF would be the AutoCAD contour file for panel G104, and file 
G104_DEM_50.ASC would be the 50-foot cell size DEM for panel G104. 

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Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

Figure N-1. File Naming Convention 


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Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

N.2.2.4 Source Terrain Data [April 2005] 
The minimum required data for a terrain submission is the source terrain data. This data can be 
contained in a single file, or more commonly, a tiled set of files. Data of various types can be 
grouped together into datasets and prioritized based on accuracy. 

Perimeter Information 

A dataset contains all terrain data files from each source of digital terrain data. A typical 
submittal could contain one dataset for LIDAR, another dataset for DEM data, and a third dataset 
for private developer data. The spatial perimeters of datasets can overlap each other. 

A name is assigned to each dataset to describe the source of digital terrain data (such as 2001 
LIDAR Aerial Data). This name will be stored in a perimeter bounding polygon for each 
dataset. This perimeter polygon delineates the outer boundary of data from one dataset 

A user prioritizes the datasets by arranging them according to their importance for the submittal, 
and entering a priority number from 1 to x into the S_Perimeter spatial file (where 1 is highest 
priority and x is the number of polygons). This, in effect, produces a set of rules that are used for 
the TIN creation. 

As an example, assume that a submittal has DEM data, aerial LIDAR data, and a private 
developers point and breakline data. The level of confidence in the LIDAR data is highest but 
the data is only available at one location. The developers data is good but may not cover the 
entirecounty or watersheds of interest. The DEM data may cover the entire state but it is less 
accurate than the other available sources. 

To use the best available data, prioritize the data from highest (LIDAR data) to lowest (DEM 
data). Without prioritization, all the points and break lines overlap each other. After the datasets 
have been prioritized, only the most accurate data is utilized at any location within the submittal. 
Figure N-2 illustrates how prioritization is used to resolve overlapping datasets. 

Figure N-2. Prioritization of Overlapping Datasets 


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Updated May 2005]

S_Perimeter Spatial File 

This polygon spatial file is required. These polygons define the perimeter of a dataset and can be 
irregularly shaped. Perimeters must have only one part and cannot self-intersect (must be 
simple). Perimeter polygons can overlap, because each polygon represents a different dataset. 
The attributes of the S_Perimeter Spatial File are provided in Table N-5. 

Table N-5. S_Perimeter Spatial File 

Field Type Length Required Description 
PerimID Long Yes Primary key for table 
Priority Long Yes A value from 1 to X where 1 is highest 
priority. No duplicates allowed. 
Descript Text 50 Yes Unique descriptive name of a dataset (i.e. 
City of Matthews 2001 LIDAR) 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata file 
when describing the source information. 

L_PerimFile Table 

The L_PerimFile table is a database table. It is required for all terrain submittals. This table 
defines the list of files that are contained by each perimeter polygon in S_Perimeter. The 
L_PerimFile table contains the elements presented in Table N-6. 

Table N-6. L_PerimFile Table 

Field Type Length Required Description 
PerimID Long Yes Foreign key to S_Perrimeter spatial file 
FileName Text 254 Yes File title, i.e. G04_3DL.shp 
Folder Text 50 Yes Submittal folder, i.e. Source\3DL 

Source Data Types 

Terrain files are organized for submittal under folders corresponding to each available data type 
in Table N-7. 

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Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

Table N-7. Source Data Types 

Submittal Folder Data Type Description 
Source\ARL ARL LIDAR  All Returns 
Source\BE BE Bare Earth Points (LIDAR and non-LIDAR) 
Source\3DL 3DL 3D Breaklines 
Source\2DL 2DL 2D (soft) Breaklines 
Source\CNT CNT Elevation contours 
Source\DEM_xx DEM_xx DEM with the minor cell spacing of xx 
Source\HDEM_xx HDEM_xx Hydrologically corrected DEM with minor cell 
spacing of xx 
Source\Supplemental 
Spatial Files 
Other Any files that dont fit in the other categories 

Contour Spatial File 

These linear spatial files shall be submitted if used. The file naming convention in the 
TileIndex section should be used (i.e. G04_CNT.shp). Contours cannot self-intersect (must be 
simple). The attributes of the Contour Spatial File are provided in Table N-8. 

Table N-8. Contour Spatial file 

Field Type Length Decimal 
Places 
Required Description 
ContourID Long Yes Primary key for table 
Elev Numeric 10 3 Yes Elevation in feet 
LEN_LID Long Yes A foreign key to the D_Length_Units 
table (see Appendix L). 
V_DATM_LID Long Yes A foreign key to the D_V_Datum table 
(see Appendix L). 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata file 
when describing the source 
information. 

Raster Elevation Data 

If DEMS are used, they must be submitted. The standard ESRI Grid ASCII format can be used 
to create a tile of elevations at a uniform spacing interval. These elevations can represent both 
uncorrected and hydrologically corrected DEMs. 

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Updated May 2005]

Supplemental Spatial Files 

Supplemental spatial files for a terrain submittal are listed in Table N-9. These files are 
continuous over an entire project area, unlike the Tiled Data. These files are not required in all 
cases, but if they are used, they shall be submitted in the Source/Supplemental Spatial Files 
folder. 

Table N-9. Supplemental Terrain Spatial Files 

Spatial File Description 
S_SinkBreach A linear spatial file representing sink breaches 
used to hydrologically correct terrain models. 
S_NoData A polygon spatial file that is used to modify DEM 
elevations. 
S_VoidArea A polygon spatial file used to delete unwanted 
points before building TINs. 
S_ExternalBoundary A polygon spatial file used to define the outer 
extents of a TIN model. 
S_Island A polygon spatial file used to represent an island 
within a void area. 
S_StreamsDEM A linear spatial file used for enforcing flow 
directions. 

S_SinkBreach Spatial File 

This linear spatial file shall be submitted if used. Sink breach polylines are used to breach sinks 
in the DEM in order to create a hydrologically correct DEM. Breach lines are placed at the toe 
of fill of culverts and other depressions that need to be breached (drained). Breaches must have 
only one part and cannot self-intersect (must be simple). The attributes of the S_SinkBreach 
Spatial File are provided in Table N-10. 

Table N-10. S_SinkBreach Spatial File 

Field Type Length Required Description 
BreachID Long Yes Primary key for table 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata file 
when describing the source information. 

S_NoData Spatial File 

This polygon spatial file shall be submitted if used. NoData zones are used primarily for 
applying a no data value like 9999 to specific areas of a DEM. These areas are usually at the 
fringes of a dataset, where the TIN may be inaccurate. This spatial file can also be used to 

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Updated May 2005]

enforce elevations in other areas such as lakes. NoData zones must have only one part and 
cannot self-intersect (must be simple). NoData zones should not overlap. The attributes of the 
S_NoData Spatial File are provided in Table N-11. 

Table N-11. S_NoData Spatial File 

Field Type Length Decimal 
Places 
Required Description 
NoDataID Long Yes Primary key for table 
Elev Numeric 10 3 No Elevation to use other than 9999. Useful 
for elevation enforcement in lakes, quarries, 
etc. 
LEN_LID Long No A foreign key to the D_Length_Units table 
(see Appendix L). Required if an elevation 
is used. 
V_DATM_LID Long No A foreign key to the D_V_Datum table (see 
Appendix L). Required if an elevation is 
used. 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata file when 
describing the source information. 

S_VoidArea Spatial File 

This polygon spatial file shall be submitted if used. VoidArea polygons are used to delete 
unwanted points before building TINs, usually in obstructed areas. VoidAreas must have 
only one part and cannot self-intersect (must be simple). VoidAreas should not overlap. The 
attributes of the S_VoidArea Spatial File are provided in Table N-12. 

Table N-12. S_VoidArea Spatial File 

Field Type Length Required Description 
VoidID Long Yes Primary key for table 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata file when 
describing the source information. 

S_ExternalBoundary Spatial File 

This polygon spatial file shall be submitted if used. ExternalBoundary polygons can be used to 
define the outer extents of a TIN model. ExternalBoundary polygons must have only one part 
and cannot self-intersect (must be simple). ExternalBoundary polygons should not overlap. The 
attributes of the S_ExternalBoundary Spatial File are provided in Table N-13. 

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Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

Table N-13. S_ExternalBoundary Spatial File 

Field Type Length Required Description 
BoundaryID Long Yes Primary key for table 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata file when 
describing the source information. 

S_Island Spatial File 

This polygon spatial file shall be submitted if used. Island polygons can be used to represent an 
area within a void area where it is desired to build TINs. An example would be the case where a 
Void Area is used to represent a lake, but an Island polygon is used to build the TIN model for 
an island within the lake. Islands must have only one part and cannot self-intersect (must be 
simple). Islands should not overlap. The attributes of the S_Island Spatial File are provided in 
Table N-14. 

Table N-14. S_Island Spatial File 

Field Type Length Required Description 
IslandID Long Yes Primary key for table 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata file when 
describing the source information. 

S_StreamsDEM Spatial file 

This linear spatial file shall be submitted if used. These single-line streams are a typical by-
product of cartography but are also useful during the hydro-correction process. These same 
streams are often used in the hydraulics portion of a submittal as a modeling baseline. Streams 
must have only one part and cannot self-intersect (must be simple). Streams should be drawn 
upstream to downstream and connect endpoint to endpoint. The attributes of the S_StreamsDEM 
Spatial File are provided in Table N-15. 

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Updated May 2005]

Table N-15. S_StreamsDEM Spatial File 

Field Type Length Decimal 
Places 
Required Description 
StreamID Long Yes Primary key for table 
InvAdjust Numeric 10 3 No Elevation offset of line. 
LEN_LID Long No A foreign key to the D_Length_Units 
table (see Appendix L). Required if 
InvAdjust is used. 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata file 
when describing the source information. 

N.2.2.5 Output Terrain Data [April 2005] 
Any intermediate and final files are to be submitted, if created. Examples include flow vectors 
calculated from hydrologically corrected DEMs or contours created from a TIN surface. 

Output Data Types 

Terrain files are organized for submittal under folders corresponding to each available data type 
in Table N-16. 

Table N-16. Output Data Types 

Submittal Folder Data Type Description 
Output\CNT CNT Elevation contours 
Output\DEM_xx DEM_xx DEM with the minor cell spacing of xx 
Output\HDEM_xx HDEM_xx Hydrologically corrected DEM with minor cell 
spacing of xx 
Output\VEC VEC Flow vectors 
Supplemental Info Other Any files that dont fit in the other categories 

Contour Spatial File 

These linear spatial files shall be submitted if used. The file naming convention in the 
TileIndex section should be used (i.e. G04_CNT.shp). Contours cannot self-intersect (must be 
simple). The attributes of the Contour Spatial File are provided in Table N-8. 

Raster Elevation Data 

If DEMs are generated, they must be submitted. The standard ESRI Grid ASCII format can be 
used to create a tile of elevations at a uniform spacing interval. These elevations can represent 
both uncorrected and hydrologically corrected DEMs. 

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Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

Flow Vector Data 

Flow vector raster files shall be submitted if available. They should follow the D-8 format 
shown in Figure N-3. The standard ESRI Grid ASCII format can be used to create a tile of 
vectors at a uniform spacing interval. 

Figure N-3. Flow Direction Values 

2 

04 
1 3 
9 
6 
7 
8 

N.2.3 Deliverables [May 2005] 
N.2.3.1 Metadata [May 2005] 
A metadata file that complies with the FEMA/FGDC Metadata Profiles (available under separate 
cover from FEMA Headquarters) in XML-format shall be included with the submittal. The 
profiles follow the FGDC Content Standard for metadata and define additional domains and 
business rules for some elements and those elements that are mandatory for FEMA based on the 
specific submittal type. 

There are specific items in the FGDC metadata standards that the submitter shall address. For 
each spatial data source in the metadata file, the Mapping Partner shall assign a Source Citation 
Abbreviation. The overview description subsection of the entity and attribute information of the 
metadata file must include a list of all DCS database tables included in the submittal. 

N.2.3.2 Hard Copy Deliverables [December 2004] 
There are no hard copy deliverables for submittal of terrain data. 

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Updated May 2005]

N.2.3.3 Digital Deliverables [May 2005] 
Transfer Media 

Mapping Partners must submit files on one of the following electronic media: 

 CD-ROM 
 DVD 
 Upload to the Mapping Information Platform (MIP) (http://www.hazards.fema.gov) 
As technology changes or in special situations, other media may be acceptable if coordinated 
with FEMA. 

Directory Structure and Folder Naming Conventions 

A metadata file compliant with FEMA/FGDC Metadata Profiles shall be placed in the General 
folder on the root directory of Disk1. Database files are stored in a Database folder. If 
submitting in Microsoft Access format, this file will be named Terrain.mdb. If submitting in 
Dbase IV format, each table will be stored in its own file (i.e. L_Submittal_Info.dbf). The 
Mapping Partner is required to submit the source terrain data as well as any files used to process 
this data. Any additional data used to assist in the modeling of this study not described in these 
specifications can be submitted in the Supplemental Info folder. 

Terrain files are arranged into appropriate directories based on data type. The index spatial file 
used for each data type must be placed in each applicable directory (if the files are tiled). For 
example, the file G104_CNT.DXF, which is an indexed contour output file, should be placed in 
the Output\CNT directory, along with the appropriate index spatial file. The source file 
G104_DEM_50.ASC would be placed in the Source\DEM_50 directory, along with the 
appropriate index spatial file. 

\General 

o XML_format metadata file 
\Database 
o Database file(s), including the L_Submittal_Info and L_PerimFile tables 
\Source\Perimeter Info 

o S_Perimeter spatial file 
\Source\ARL 

o LIDAR data  All Returns 
o LIDAR S_TileIndex spatial file (if used) 
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\Source\BE 

o LIDAR data  Bare Earth Points 
o LIDAR S_TileIndex spatial file (if used) 
\Source \3DL 

o 3D breakline spatial files 
o 3D breakline S_TileIndex spatial file (if used) 
\Source \2DL 

o 2D breakline spatial files 
o 2D breakline S_TileIndex spatial file (if used) 
\Source \CNT 

o Contour spatial files 
o Contour S_TileIndex spatial file (if used) 
\Source \DEM_xx 

o Uncorrected DEM files with a minor cell spacing of xx (i.e.DEM_50) 
o S_TileIndex spatial file (if used) 
\Source \HDEM_xx 

o Hydrologically correct DEM files with a minor cell spacing of xx (i.e. 
HDEM_50) 
o S_TileIndex spatial file (if used) 
\Source\Supplemental Spatial Files 

o Continuous spatial files (i.e. S_SinkBreach.shp) 
o Any files that dont fit into the other categories 
\Output \CNT 

o Contour spatial files 
o Contour S_TileIndex spatial file (if used) 
\Output \DEM_xx 

o Uncorrected DEM files with a minor cell spacing of xx (i.e. DEM_50) 
o S_TileIndex spatial file (if used) 
\Output \HDEM_xx 

o Hydrologically correct DEM files with a minor cell spacing of xx (i.e. 
HDEM_50) 
o S_TileIndex spatial file (if used) 
\Output\VEC 

o Flow vectors 
o S_TileIndex spatial file (if used) 
\Supplemental Info 

o Any files that dont fit into the other categories 
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Updated May 2005]

Data Identification Requirements 

All digital media submitted must be labeled with at least the following information: 

 Mapping Partner name 
 Community name and state for which the FIS was prepared 
 Terrain Data 
 Date of submission (formatted mm/dd/yyyy) 
 Disk [sequential number] of [number of disks] 
The media must be numbered sequentially, starting at Disk 1. The [number of disks] is the total 
number of disks in the submission. 

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Updated May 2005]

N.3 Survey Submittal Standards 
N.3.1 Overview [December 2004] 
The purpose of this section is to provide guidance and specifications to the Mapping Partner that 
prepares digital data for DFIRM production. This section is not intended to specify in-process 
compilation or procedures, but rather to present the specifications and requirements for output 
and deliverables. The Mapping Partner should refer to Appendix A of these Guidelines for 
guidance on the performance of surveying. 

This section will focus on the data that is obtained during the survey of the following features: 

 Cross Sections 
 Temporary Bench Marks (or Elevation Reference Marks) 
 High Water Marks 
 Structures for Detailed Study 
o Bridges 
o Channels 
o Culverts 
o Dams 
o Levees 
 Structures for Limited Detail Study 
o Bridges 
o Culverts 
o Dams 
A major aspect of a Geographic Information System (GIS) is horizontal and vertical position on 
the earth. Survey data must be referenced to a standard coordinate system, employ a standard 
projection, and specify in the L_Submittal_Info table both the horizontal and the vertical datums 
used. These positional references are established prior to the field data collection and 
topographic mapping phase of the project. All planimetric and topographic features must be 
collected and referenced to this coordinate system and projection. A detailed discussion of aerial 
mapping and surveying specifications, which includes horizontal and vertical control for new 
mapping is provided in Appendix A of these Guidelines. A discussion of vertical datum selection 
and conversion is provided in Appendix B of these Guidelines. 

Considerations for transfer of digital data also must include the file structure of the data, the 
transfer medium, and acceptable data formats. The organization and accepted formats for the 
intermediate submittal of survey data are discussed in Subsection N.3.3. 

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Updated May 2005]

N.3.2 Requirements [April 2005] 
N.3.2.1 Cross Sections [April 2005] 
The following deliverables are required whenever cross sections are shown on the Flood Profile: 

.. Database Tables and Spatial Files 
.. Survey Files 
.. Digital Photographs 
.. Digital Sketches 
The following subsections detail the requirements for each deliverable. 
Database Tables and Spatial Files 
The database tables and spatial files needed for cross sections are provided in Table N-17. 

Table N-17. Database Tables and Spatial Files for Cross Sections 

Table Description 
L_SXS A database table of survey data related to cross sections. 
L_SXSPht A look up table for the photos associated with the cross 
sections. 
L_SXSSkt A look up table for the sketches associated with the cross 
sections. 
L_Sketch A lookup database table of data about that contains 
information related to sketches that were created during 
the survey. 
L_Wtr_Nm This is a lookup table of stream names. 
S_Photo A point spatial file used to represent the locations where 
of photos were taken. 
S_Struc A linear spatial file used to represent surveyed 
structures. 
D_DatTyp A domain table used to store the valid lookup 
identification keys to identify cross section type. 
S_SXS A point spatial file used to represent the survey shots or 
points of the cross sections. 
S_TBM A point spatial file used to represent the locations of 
temporary bench marks or elevation reference marks. 

See Figure N-4 for an entity relationship diagram of the tables and spatial files for cross sections. 

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Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

Figure N-4. Entity Relationship Diagram for Cross Sections 


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Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

The L_SXS table is a database table. It is required for all surveyed cross sections. The L_SXS 
table contains the attributes presented in Table N-18. 

Table N-18. L_SXS Table 

Field Type Length Decimal 
Places 
Required Description 
SXS_ID Long Yes Primary key for table. 
CLEasting Numeric 12 2 Yes X-coordinate at stream crossing. 
CLNorthing Numeric 12 2 Yes Y-coordinate at stream crossing. 
CLStn Numeric 8 2 Yes Cross section station at intersection of 
cross section and stream centerline. 
Comments Text 254 No General comments or notes. 
DatTyp_LID Long Yes Cross section or data type lookup 
identification. A code that provides a 
valid link to a valid entry from 
D_DatTyp. 
Invert Numeric 8 2 Yes Lowest elevation in cross section. 
Len_LID Long Yes Units of linear measure. A code that 
provides a valid link to a valid entry 
from D_Length_Units. See Appendix L. 
Location Text 254 Yes Description of location. 
Orient Text 1 Yes Direction in which survey shots were 
taken. From left to right, looking 
downstream - D, or looking 
upstream  U. 
StreamStn Numeric 12 2 Yes Distance along stream. 
Struc_ID Long No Foreign key to S_Struc. Note: Required 
if cross section is associated with a 
structure. 
SurveyDt Date Yes Date and time of survey. 
Wtr_Nm_LID Long Yes Foreign key to L_Wtr_Nm. Surface 
water feature name. 
XSNm Text 65 Yes Cross Section Name. This is the name 
of the cross section and the name that 
will be shown on the hardcopy FIRM. 
SurveyFile Text 254 No Name of the survey text file. Not 
required for cross sections associated 
with structures. 
TBM_ID Long Yes Foreign key to S_TBM. Elevation 
reference point of cross section. 

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Updated May 2005]

The L_SXSPht is a lookup table for the photos associated with the cross sections. The L_SXSPht 
table contains the attributes presented in Table N-19. 

Table N-19. L_SXSPht Table 

Field Type Length Required Description 
SXSPht_ID Long Yes Primary key for table. 
Photo_ID Long Yes Foreign key to S_Photo. 
SXS_ID Long Yes Foreign key to S_SXS. 

The L_SXSSkt is a lookup table for the sketches associated with the cross sections. The 
L_SXSSkt table contains the attributes presented in Table N-20. 

Table N-20. L_SXSSkt Table 

Field Type Length Required Description 
SXSSkt_ID Long Yes Primary key for table. 
Sketch_ID Long Yes Foreign key to L_Sketch. 
SXS_ID Long Yes Foreign key to L_SXS. 

The L_Sketch table is a database table that contains information related to sketches that were 
created during the survey. The L_Sketch table contains the elements presented in Table N-21. 

Table N-21. L_Sketch Table 

Field Type Length Required Description 
Sketch_ID Long Yes Primary key for table. 
Comments Text 254 No General comments or notes. 
FileNm Text 254 Yes Name of the sketch file. 
SketchDt Date Yes Date the sketch was created. 

The L_Wtr_Nm table is a lookup table. This table identifies the unique list of stream names used 
in the submittal. This is the same table defined in Appendix L of these Guidelines, but it is listed 
here for completeness. 

The L_Wtr_Nm table contains the attributes presented in Table N-22. 

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Updated May 2005]

Table N-22. L_Wtr_Nm Table 

Field Type Length Required Description 
Wtr_Nm_LID Long Yes Unique identifier for L_Wtr_Nm. Primary 
key. 
Wtr_Nm Text 254 Yes Name of surface water feature. 

The S_ Photo is a spatial file used to represent the locations of the digital photographs that were 
taken during the survey. The S_Photo attribute table contains the information presented in Table 
N-23. 

Table N-23. S_Photo Spatial File 

Field Type Length Decimal 
Places 
Required Description 
Photo_ID Long Yes Primary key for table. 
Azimuth Numeric 6 2 No Horizontal angle of the bearing for the 
photo. 
Comments Text 254 No General comments or notes. 
FileNm Text 254 Yes Name of the photo file. 
Location Text 254 Yes A description of the geographic 
location where the picture was taken. 
PhotoDt Date Yes The date that the picture was taken. 
Source_Cit Text 11 Yes Source Citation. Abbreviation used in 
the metadata file when describing the 
source information for the S_STRUC 
spatial file. 
Subject Text 50 Yes Description of feature or view. 

The S_Struc table contains general data about structures surveyed for detailed studies and 
includes the attributes presented in Table N-39. If the cross section is associated with a structure, 
the field Struc_ID should be populated in L_SXS. Struc_ID is the unique identifier for the 
structure and is included in the S_Struc spatial file. See Table N-39 for a list of attributes 
included in the S_Struc spatial file. 

The D_DatTyp is a domain table that contains the valid lookup identification keys that may be 
used to identify cross section type. The D_DatTyp table contains the attributes presented in 
Table N-24. Table N-25 contains the domain values for D_DatType 

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Updated May 2005]

Table N-24. D_DatTyp Table 

Field Type Length Required Description 
DatTyp_LID Long Yes Primary key - Data type look-up 
identification key. 
DatTypDes Text 50 Yes Describes different type of cross sections: 
Field or Top Of Road (TOR). 

Table N-25. Domain Values for D_DatTyp 

DatTyp_LID DatTypDes 
1 Field 
2 Top of Road 

S_SXS is a spatial file that contains location information and also relates to the data table, 
L_SXS. Each survey shot or entry in the survey text file for a cross section should be represented 
spatially by a single point (See section 3.2.1 Survey Files). The spatial file containing the 
locational information for the cross sections will be named S_SXS and the extension appropriate 
for the file format. For example, the components of a shapefile would be named S_SXS.shp, 
S_SXS.dbf, S_SXS.shx, and S_SXS.prj. 

The S_SXS attribute table contains the information presented in Table N-26. 

Table N-26. S_SXS Spatial File 

Field Type Length Decimal 
Places 
Required Description 
SXSPT_ID Long Yes Primary key for table. 
SXS_ID Long Yes Foreign key to L_SXS. 
CLStn Numeric 8 2 Yes Station of surveyed shot or point 
(referencing profile view of cross 
section). 
Descript Text 100 Yes Description of surveyed cross section 
shot or point. 
Elev Numeric 8 2 Yes Elevation of surveyed cross section 
shot or point. 
Len_LID Long Yes Units of linear measure. A code that 
provides a valid entry from 
D_Length_Units. See Appendix L. 
Source_Cit Text 11 Yes Source Citation. Abbreviation used in 
the metadata file when describing the 
source information for the S_SXS 
spatial file. 

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Updated May 2005]

The S_TBM is a spatial file used to represent the locations of the temporary benchmarks or 
elevation reference marks that were used during the survey. All TBMs that were used during the 
survey of cross sections should be included in S_TBM. 

See Table N-27 for a list of attributes included in the S_TBM spatial file. 

Survey Files 

Description 

A separate survey file must be submitted for each surveyed cross section, unless the cross section 
is associated with a structure. If the cross section is associated with a structure and the survey 
data for the cross section has been included with the survey files for the structure, then a separate 
survey file is not required for the cross section. 

Naming Convention 

The file name for the survey file will be based upon the name of the cross section, which is found 
in the XSNm field in L_SXS table. However, the file name will use underscores to indicate 
spaces in the name of the cross section. In a submission, each survey file must have a unique file 
name. 

For example, XS_1.TXT 

The file name of the survey file for a cross section must be populated in the SurveyFile field in 
the L_SXS table, in the record corresponding to that cross section. 

Attributes 

Each survey file should include all survey data for a cross section. 

Digital Photographs 

Description 

A minimum of two digital photographs must be submitted for each cross section. The required 
aspects or view of the photographs include: 

 Standing at cross section, looking upstream at the channel (USC) 
 Standing at cross section, looking downstream at the channel (DSC) 
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Updated May 2005]

Naming Convention 

The file name of the digital photograph will be based on the name of the cross section (with 
underscores rather than spaces), an underscore, the aspect or view of the photograph, and the 
extension. In a submission, each digital photograph must have a unique file name. 

For examples, XS_1_USC.PNG 
XS_1_DSC.PNG 

Attributes 

A record must be populated in the S_Photo table for each photograph. The file name of the 
photograph must be populated in the FileNm field in the S_Photo table, corresponding to that 
photograph. In addition, a record must be populated in the L_SXSPht table for each photograph. 

See Table N-19 for a list of attributes included in the L_SXSPht table. 

See Table N-23 for a list of attributes included in the S_Photo spatial file. 

Digital Sketches 

Description 

Any sketch that is prepared during the survey of a cross section must be submitted in digital 
format. If a sketch is drawn on paper in the field, it must be scanned into digital format. Each 
sketch must be in a separate digital file. 

Naming Convention 

The file name of the digital sketch will be based on the name of the cross section (with 
underscores rather than spaces), an underscore, SK and a number, and the extension. In a 
submission, each sketch file must have a unique file name. 

For example, XS_1_SK1.PNG 

Attributes 

A record must be populated in the L_Sketch table for each sketch. The file name of the sketch 
must be populated in the FileNm field in the L_Sketch table, corresponding to that sketch. In 
addition, a record must be populated in the L_SXSSkt table for each sketch. 

See Table N-19 for a list of attributes included in the L_SXSSkt table. 

N.3.2.2 Temporary Bench Marks [April 2005] 
The S_TBM is a spatial file used to represent the locations of the temporary benchmarks (TBMs) 
or elevation reference marks that were used during the survey. Each TBM is to be represented 
spatially by a single point. A database table is not required for TBMs. The spatial files for the 

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Updated May 2005]

TBMs are to be named S_TBM and the extension appropriate for the file format. For example, 
the components of a shapefile would be named S_TBM.shp, S_TBM.dbf, S_TBM.shx, and 
S_TBM.prj. 

The S_TBM attribute table contains the information presented in Table N-27. 

Table N-27. S_TBM Spatial File 

Field Type Length Decimal 
Places 
Required Description 
TBM_ID Long Yes Primary key for table. 
Descript Text 254 Yes Description of directions to location 
Temporary Benchmark. 
Elev Numeric 8 2 Yes Elevation of Temporary Benchmark. 
Len_LID Long Yes Units of linear measure. A code that 
provides a valid link to a valid entry 
from D_Length_Units. See Appendix L. 
Owner Text 50 Yes Agency or municipality owns or 
maintains the monument. 
Source_Cit Text 11 Yes Source Citation. Abbreviation used in 
the metadata file when describing the 
source information for the S_TBM 
spatial file. 
SurveyDt Date Yes Date the Temporary Benchmark was 
surveyed. 
TBMNm Text 50 Yes Temporary Benchmark Name. This is 
the name of the temporary benchmark 
and the name that will be shown on the 
hard copy FIRM. 

N.3.2.3 High Water Marks [April 2005] 
The following deliverables are required whenever high water marks have been identified and 
surveyed during the performance of a Flood Insurance Study: 

 Database Tables and Spatial Files 
 Digital Photographs 
 Digital Sketches 
The following subsections detail the requirements for each deliverable. 
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Updated May 2005]

Database Tables and Spatial Files 

The database tables and spatial files used for high water marks are provided in Table N-28. 

Table N-28. Database Tables and Spatial Files for High Water Marks 

Table Description 
S_HWM A point shapefile containing information about High 
Water Marks (HWM). 
L_HWMWtns Contains information about witnesses associated with 
high water marks. 
L_HWMPht A look up table for the photos associated with each high 
water mark. 
L_HWMSkt A look up table for the sketches associated with each 
high water mark. 
L_Sketch A database table that contains information related to 
sketches that were created during the survey. 
L_Wtr_Nm A look up table for streams. 
S_Photo A point spatial file used to represent the locations where 
photos were taken. 
D_HWLnTp A domain table used to store the valid lookup 
identifcation keys used to identify types of high water 
marks. 

See Figure N-5 for an entity relationship diagram of the tables for high water marks. 

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Updated May 2005]

Figure N-5. Entity Relationship Diagram for High Water Marks 


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Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

S_ HWM is a spatial file that contains attributes and the locations of the high water marks 
(HWMs) that were surveyed. Each HWM is to be represented spatially by a single point. The 
spatial files for the HWMs are to be named S_ HWM and the extension appropriate for the file 
format. For example, the components of a shapefile would be named S_HWM.shp, S_ 
HWM.dbf, S_ HWM.shx, and S_ HWM.prj. 

The S_HWM attribute table contains the information presented in Table N-29. 

Table N-29. S_HWM Spatial File 

Field Type Length Decimal 
Places 
Required Description 
HWM_ID Long Yes Unique identifier for L_HWM. Primary 
key. 
Wtnss_ID Long Yes Foreign key to L_HWMWtns table. 
Wtr_Nm_LID Long Yes Foreign key to L_Wtr_Nm. Surface 
water feature name. 
Comments Text 254 No General comments or notes. 
Elev Numeric 8 2 Yes Elevation of water mark. 
EventDt Date Yes Date of the storm. 
Freq_LID Long Yes Lookup identification for the frequency 
of the storm event. A code that 
provides a valid link to a valid entry 
from D_Frequency. See Appendix L. 
HWMNm Text 50 Yes Name of high water mark. 
IntrviewDt Date Yes Date of interview with witness to high 
water mark. 
Len_LID Long Yes Units of linear measure. A code that 
provides a valid link to a valid entry 
from D_Length_Units. See Appendix L. 
LnTyp_LID Long Yes HWM type lookup identification. A 
code that provides a valid link to a valid 
entry from D_HWLnTp. 
Location Text 254 Yes Location of the high water mark. 
Source_Cit Text 11 Yes Source Citation. Abbreviation used in 
the metadata file when describing the 
source information for the S_HWM 
spatial file. 
StormNm Text 50 No Name of storm. 
SurvPrmt Yes/No Yes Do the surveyors have permission to 
survey? Yes/No. 

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Updated May 2005]

The L_HWMWtns table is a database table. This table contains information about each witness 
to high water marks that occurred during flooding events. The L_HWMWtns table contains the 
attributes presented in Table N-30. 

Table N-30. L_HWMWtns Table 

Field Type Length Required Description 
Wtnss_ID Long Yes Primary key for table. 
Address Text 254 Yes Physical address of witness to high water 
mark. 
Phone Text 20 Yes Telephone number of witness to high 
water mark. 
ResLngth Long Yes The length of time a witness has lived at a 
particular residence. 
Time_LID Long Yes Units of temporal measure. A code that 
provides a valid link to a valid entry from 
D_Time_Units. See Appendix L. 
WtnssNm Text 60 Yes Name of witness to high water mark. 

The L_ HWMPht is a lookup table for the photos associated with the high water marks. The 
L_ HWMPht table contains the attributes presented in Table N-31. 

Table N-31. L_HWMPht Table 

Field Type Length Required Description 
HWMPht_ID Long Yes Primary key for table. 
HWM_ID Long Yes Foreign key to S_HWM. 
Photo_ID Long Yes Foreign key to S_Photo. 

The L_ HWMSkt is a lookup table for the sketches associated with the high water marks. The 
L_ HWMSkt table contains the attributes presented in Table N-32. 

Table N-32. L_HWMSkt Table 

Field Type Length Required Description 
HWMSkt_ID Long Yes Primary key for table. 
HWM_ID Long Yes Foreign key to S_HWM. 
Sketch_ID Long Yes Foreign key to L_Sketch. 

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Updated May 2005]

The L_Sketch table is a database table that contains information related to sketches that were 
created during the survey. The L_Sketch table contains the attributes presented in Table N-33. 

Table N-33. L_Sketch Table 

Field Type Length Required Description 
Sketch_ID Long Yes Primary key for table. 
Comments Text 254 No General comments or notes. 
FileNm Text 254 Yes Name of the sketch file. 
SketchDt Date Yes Date the sketch was created. 

The L_Wtr_Nm table is a database lookup table. This is the same table defined in Appendix L of 
these Guidelines, but it is listed here for completeness. 

The L_Wtr_Nm table contains the attributes presented in Table N-34. 

Table N-34. L_Wtr_Nm Table 

Field Type Length Required Description 
Wtr_Nm_LID Long Yes Unique identifier for L_Wtr_Nm. Primary 
key. 
Wtr_Nm Text 254 Yes Name of surface water feature. 

S_Photo is a point spatial file used to represent the locations where photos were taken. The 
S_Photo attribute table contains the attributes presented in Table N-35. 

Table N-35. S_Photo Spatial File 

Field Type Length Decimal 
Places 
Required Description 
Photo_ID Long Yes Primary key for table. 
Azimuth Numeric 6 2 No Horizontal angle of the bearing for the 
photo. 
Comments Text 254 No General comments or notes. 
FileNm Text 254 Yes Name of the photo file. 
Location Text 254 Yes A description of the geographic 
location where the picture was taken. 
PhotoDt Date Yes The date that the picture was taken. 
Source_Cit Text 11 Yes Source Citation. Abbreviation used in 
the metadata file when describing the 
source information for the S_STRUC 
spatial file. 
Subject Text 50 Yes Description of feature or view. 

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Updated May 2005]

The D_ HWLnTp is a domain table that contains the valid lookup identification keys that may be 
used to identify the types of high water marks. 

The D_HWLnTp table contains the attributes presented in Table N-36. Table N-37 contains the 
domain values for D_HWLnTP. 

Table N-36. D_HWLnTp Table 

Field Type Length Required Description 
LnTyp_LID Long Yes Primary key - High water mark line type 
look-up identification key. 
LnTypDes Text 20 Yes Type of line: mud, debris, etc. 

Table N-37. Domain Values for D_HWLnTp 

LnTyp_LID LnTypDes 
1 Mud 
2 Debris 
3 Other 

Digital Photographs 

Description 

A minimum of one digital photograph is to be submitted for each high water mark. The 
photographs should be in color. The required aspects or view of the photograph include standing 
approximately 20 feet away from the high water mark. 

Naming Convention 

The file name of the digital photograph is to be based on the name of the high water mark (with 
underscores rather than spaces), an underscore and a number, and the extension. In a 
submission, each digital photograph must have a unique file name. For example, 
HWM_1_1.PNG 

Attributes 

A record must be populated in the S_Photo spatial file for each photograph. The file name of the 
photograph must be populated in the FileNm field in the S_Photo attribute table, corresponding 
to that photograph. In addition, a record must be populated in the L_HWMPht table for each 
photograph. 

See Table N-31 for a list of attributes included in the L_HWMPht table. 

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Updated May 2005]

Digital Sketches 

Description 

Any sketch that is prepared during the survey of a high water mark must be submitted in digital 
format. If a sketch is drawn on paper in the field, it must be scanned into digital format. Each 
sketch must be in a separate digital file. 

Naming Convention 

The file name of the digital sketch will be based on the name of the high water mark (with 
underscores rather than spaces), an underscore, SK and a number, and the extension. In a 
submission, each sketch file must have a unique file name. For example, HWM_1_SK1.PNG 

Attributes 

A record must be populated in the L_Sketch table for each sketch. The file name of the sketch 
must be populated in the FileNm field in the Sketch table, corresponding to that sketch. In 
addition, a record must be populated in the L_HWMSkt table for each sketch. 

See Table N-33 for a list of attributes included in the L_Sketch table. 

See Table N-32 for a list of attributes included in the L_HWMSkt table. 

N.3.2.4 Structures for Detailed Study [April 2005] 
These deliverables are required whenever hydraulic structures have been surveyed to support 
Detailed Studies. They are also required if levees are shown on the FIRM, channels containing 
the flooding are shown on the FIRM, or any other structure that impacts the areas flood risk is 
shown on the FIRM. 

 Database Tables and Spatial Files 
 Survey Files 
 Photographs 
 Sketches 
For cross sections related to structures, refer to Subsection N.3.2.1 and to the Data Capture 
Guidelines. The following subsections detail the requirements for each deliverable. 

Database Tables and Spatial Files 

The database tables and spatial files needed for structures surveyed for detailed studies are 
provided in Table N-38. 

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Updated May 2005]

Table N-38. Database Tables and Spatial Files for 
Structures for Detailed Studies 

Table Description 
S_Struc The S_Struc table contains information about the 
hydraulic structures that have been surveyed within the 
study area. It should include all structures shown in the 
flood profiles. In addition, levees, sea walls, channels 
that contain flooding and other significant flood control 
structures shown on the Digital Flood Insurance Rate 
Map (DFIRM) should be included. 
L_Brdg Each record in this contains information specific to a 
bridge, such as abutment stations. 
L_CulPp Each record in this table contains information about one 
pipe, at a culvert crossing. 
L_Dam Each record in this table contains information specific to 
a dam, such as embankment type or location of a drain 
valve. 
L_LChrd Each record in this table contains information about a low 
chord shot. Only bridges may have low chord shots. 
L_Levee Each record in this table contains information specific to 
a levee, such as type of levee. 
L_Orfc Each record in this table contains information specific to 
the size and number of similar orifices clustered together 
on a riser barrel. 
L_OtlPp Each record in this table contains information specific to 
one outlet pipe, at the bottom of a riser barrel, which 
transports water underneath the dam structure. 
L_Pier This table contains information on piers, such as pier 
width and shape. Only bridges may have related records 
to this table. 
L_Rail Each record in this table contains information about a top 
of rail shot. 
L_RsrBrl Each record in this table contains information specific to 
one riser barrel, such as size and trash rack information. 
L_Sketch A database table that contains information related to 
sketches that were created during the survey. 
L_StrPht This table is a look up table for the photos of each 
structure. 
L_StrSkt This table is a look up table for the sketches of each 
structure. 
L_SWy Each record in this table contains information about a 
relief device (e.g. spillway) at a dam, used to prevent 
overtopping during a large flood. 

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Table Description 
L_SXS A database table of survey data related to cross sections. 
L_Wtr_Nm This is a look up table for streams. 
S_Photo A point spatial file used to represent the locations where 
photos were taken. 
S_TBM A point spatial file used to represent the locations of 
temporary bench marks or elevation reference marks. 
D_AbtTyp A domain table used to store valid abutment types. 
D_ShpTyp A domain table used to store valid shape types. 
D_PpTyp A domain table used to store valid types used to describe 
the ends of pipes or culverts. 
D_MtlTyp A domain table used to store valid types of material used. 
D_ClsTyp A domain table used to store valid types of closures 
required to operate structure. 
D_LevTyp A domain table used to store valid types of levees. 
D_SwyTyp A domain table used to store valid types of spillways. 
D_DamTyp A domain table used to store valid types of dams. 

See Figure N-6 for an entity relationship diagram of the tables for structures surveyed for 
detailed studies. 

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Updated May 2005]

Figure N-6. Entity Relationship Diagram for Structures for Detailed Studies 


N41 Section N.3 


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Updated May 2005]

S_Struc is a spatial file that contains attributes and locational information for each structure. 
Each structure is to be represented spatially by a single line. Each line is to represent the primary 
characteristic of the structure. 

.. Each bridge is to be represented by a single line that is aligned to the transportation 
centerline carried by the bridge. 
.. Each culvert is to be represented by a single line that is aligned to the transportation 
centerline carried by the culvert. 
.. Each dam is to be represented by a single line aligned to the centerline along the top of 
the dam. 
.. Each levee is to be represented by a single line aligned to the top or crest of levee. 
The spatial files containing the locational information for the general structures are to be named 
S_Struc and the extension appropriate for the file format. For example, the components of a 
shapefile would be named S_Struc.shp, S_Struc.dbf, S_Struc.shx, and S_Struc.prj. S_Struc 
must contain the attributes shown in Table N-39. 

Table N-39. S_Struc Spatial File 

Field Type Length Decimal 
Places 
Required Description 
Struc_ID Long Yes Primary key for table. 
CLEasting Numeric 12 2 No Easting or X-coordinate of centerline 
station. Required for bridges, culverts, 
and dams. 
CLNorthing Numeric 12 2 No Northing or Y-coordinate of centerline 
station. Required for bridges, culverts, 
and dams. 
CLStn Numeric 8 2 No Cross section station, in profile view, 
along structure of intersection of 
structure and stream centerline. Note: 
Required for bridges, culverts, and 
dams. 
Comments Text 254 No General comments or notes. 
DSInvert Numeric 8 2 No Elevation of the lowest point in stream, 
under structure on downstream side. 
Note: Required for bridges, culverts, 
and dams. 
Len_LID Long Yes Units of linear measure. A code that 
provides a valid link to a valid entry 
from D_Length_Units. See Appendix L. 
Lngth Numeric 8 2 Yes Distance from beginning of structure to 
end. Measured across stream for 
bridges, culverts and dams. Measured 
along crest of levee or centerline of 
channel. 

N42 Section N.3 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

Field Type Length Decimal 
Places 
Required Description 
MtlBed_LID Long No Bed material type lookup identification. 
A code that provides a valid link to a 
valid entry from D_MtlTyp. Required for 
bridges, culverts, and dams. 
MtlFil_LID Long No Fill material type lookup identification. 
A code that provides a valid link to a 
valid entry from D_MtlTyp. Note: 
Required for bridges, culverts, and 
dams. 
Orient Text 1 No Direction in which survey shots were 
taken. From left to right, looking 
downstream - D, or looking upstream - 
U. Note: Required for bridges, 
culverts, and dams. 
RailAvgHt Numeric 8 2 No Average rail height. Note: Required for 
bridges, culverts, and dams. 
RoadNm Text 254 Yes Road name or location of structure. 
Skew Numeric 8 4 No Angle of structure, if not perpendicular 
to stream. Note: Required for bridges, 
culverts, and dams. 
Source_Cit Text 11 Yes Source Citation. Abbreviation used in 
the metadata file when describing the 
source information for the S_STRUC 
spatial file. 
StreamStn Numeric 12 2 No Distance along stream from a user-
defined reference point to where 
structure intersects stream. Note: 
Required for bridges, culverts, and 
dams. 
Struct_LID Long Yes Structure Type Lookup Identification. 
A code that provides a link to a valid 
entry from the D_Struct_Typ table. See 
Appendix L. 
Struct_Nm Text 50 Yes Field name of the structure. 
SurveyDt Date Yes Date and time of survey 
SurveyFile Text 254 Yes Name of the survey text file. 
TBM_ID Long Yes TBM_ID of benchmark provides link to 
spatial file S_TBM. 
USInvert Numeric 8 2 No Elevation of the lowest point in stream, 
under structure on upstream side. 
Note: Required for bridges, culverts, 
and dams. 
Wdth Numeric 8 2 Yes For bridges, culverts and dams, the 
hydraulic distance from one edge of 
structure to the other, parallel to 
stream. For other structures, average 

N43 Section N.3 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

Field Type Length Decimal 
Places 
Required Description 
width of structure. 
Wtr_Nm_LID Long Yes Foreign key to L_Wtr_Nm. Surface 
water feature name. 

L_Brdg is a database table. Each record in this table contains information specific to a bridge, 
such as abutment stations. The L_Brdg table contains the attributes presented in Table N-40. 

Table N-40. L_Brdg Table 

Field Type Length Decimal 
Places 
Required Description 
Brdg_ID Long Yes Primary key for table. 
Struc_ID Long Yes Foreign key to S_Struc. 
AbtTyp_LID Long Yes Abutment type lookup identification. A 
code that provides a valid link to a valid 
entry from D_AbtTyp. 
DeckThick Numeric 8 2 Yes Measurement from top of road to 
bottom of bridge. 
LAbtmntStn Numeric 8 2 Yes Left station of abutment, input from 
survey data (referencing profile view of 
structure). 
Len_LID Long Yes Units of linear measure. A code that 
provides a valid link to a valid entry 
from D_Length_Units. See Appendix L. 
LFillStn Numeric 8 2 Yes Station of left toe of fill (referencing 
profile view of structure). 
LSideSlope Numeric 5 2 Yes Slope of left fill station. 
RAbtmntStn Numeric 8 2 Yes Right station of abutment, input from 
survey data (referencing profile view of 
structure). 
RFillStn Numeric 8 2 Yes Station of right toe of fill (referencing 
profile view of structure). 
RSideSlope Numeric 5 2 Yes Slope of right fill station. 

N44 Section N.3 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

L_CulPp is a database table. Each record in this table contains information about one pipe or 
box, at a culvert crossing. The L_CulPp table contains the attributes presented in Table N-41. 

Table N-41. L_CulPp Table 

Field Type Length Decimal 
Places 
Required Description 
CulPp_ID Long Yes Primary key for table. 
Struc_ID Long Yes Foreign key to S_Struc. 
CLStn Numeric 12 2 Yes Centerline station of pipe (referencing 
profile view of structure). 
DSInvert Numeric 8 2 Yes Elevation at bottom of downstream 
pipe opening. 
InTyp_LID Long Yes Type of inlet. A code that provides a 
valid link to a valid entry from 
D_PpTyp. 
Len_LID Long Yes Units of linear measure. A code that 
provides a valid link to a valid entry 
from D_Length_Units. See Appendix L. 
MtlTyp_LID Long Yes Pipe material. A code that provides a 
valid link to a valid entry from 
D_MtlTyp. 
OutTyp_LID Long Yes Type of outlet. A code that provides a 
valid link to a valid entry from 
D_PpTyp. 
PipeLn Numeric 8 2 Yes Length of pipe. 
Rise Numeric 8 2 Yes Height or diameter of pipe. 
ShpTyp_LID Long Yes Lookup identification for the c ross 
sectional shape of culvert. A code that 
provides a valid link to a valid entry 
from D_ShpTyp. 
USInvert Numeric 8 2 Yes Elevation at bottom of upstream pipe 
opening. 
Wdth Numeric 8 2 Yes Width or span of pipe. 

N45 Section N.3 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

L_Dam is a database table. Each record in this table contains information specific to one dam. 
The L_Dam table contains data specific to dams. The L_Dam table contains the attributes 
presented in Table N-42. 

Table N-42. L_Dam Table 

Field Type Length Decimal 
Places 
Required Description 
Dam_ID Long Yes Primary key for table. 
Struc_ID Long Yes Foreign key to S_Struc. 
Area_LID Long Yes Units of area measure. A code that 
provides a valid link to a valid entry 
from D_Area_Units. See Appendix L. 
DamHt Numeric 8 2 Yes Height of Dam. 
DamTopElv Numeric 8 2 Yes Elevation at top of dam. 
DamTyp_LID Long Yes Dam type lookup identification. A code 
that provides a valid link to a valid 
entry from D_DamTyp. 
EmbSlope Numeric 5 2 Yes Slope of embankment. 
Len_LID Long Yes Units of linear measure. A code that 
provides a valid link to a valid entry 
from D_Length_Units. See Appendix L. 
NormalArea Numeric 10 2 Yes Area of pool at normal water surface 
elevation. 
NWSElv Numeric 8 2 Yes Normal water surface elevation (level 
pool elevation). 
ValveEasting Numeric 12 2 No Easting or X-coordinate of drain valve. 
ValveNorth Numeric 12 2 No Northing or Y-coordinate of drain 
valve. 

N46 Section N.3 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

The L_Chrd table is a database table. Each record in L_Chrd contains information about a low 
chord shot. Only bridges may have low chord shots. The L_LChrd table contains the attributes 
presented in Table N-43. 

Table N-43. L_LChrd Table 

Field Type Length Decimal 
Places 
Required Description 
LChrd_ID Long Yes Primary key for table. 
Brdg_ID Long Yes Foreign key to L_Brdg. 
Easting Numeric 12 2 Yes X-coordinate. 
Elev Numeric 8 2 Yes Feet above sea level. 
Len_LID Long Yes Units of linear measure. A code that 
provides a valid link to a valid entry 
from D_Length_Units.See Appendix L. 
Northing Numeric 12 2 Yes Y-coordinate. 
Station Numeric 8 2 Yes Cross section station (referencing 
profile view of structure). 

N47 Section N.3 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

The L_ Levee table contains data specific to levees. The L_Levee table contains the attributes 
presented in Table N-44. 

Table N-44. L_Levee Table 

Field Type Length Decimal 
Places 
Required Description 
Levee_ID Long Yes Primary key for table. 
Accredit Text 50 Yes Accreditation or verification: Meets 
FEMA policy - FEMA, credited prior to 
FEMA's policy - PRIOR, or certified by 
another Federal agency as providing 
100-year protection - FEDERAL 
Area_LID Long Yes Units of area measure. A code that 
provides a valid link to a valid entry 
from D_Area_Units. See Appendix L. 
Bank Text 1 Yes Side of channel on which structure is 
located, when looking downstream: 
Left - L, or right  R. 
ClsTyp_ID Long Yes Closure type lookup identification. A 
code that provides a valid link to a valid 
entry from D_ClsTyp. 
FreeBoard Numeric 8 2 Yes Minimum freeboard of structure. 
HasFailed Yes/No Yes Have failures occurred? Yes/No. 
IsMaint Yes/No Yes Is there a FEMA-approved 
maintenance plan? Yes/No. 
IsOpPlan Yes/No Yes Is there an approved operational plan? 
Yes/No. 
Len_LID Long Yes Units of linear measure. A code that 
provides a valid link to a valid entry 
from D_Length_Units. See Appendix L. 
LevTyp_LID Long Yes Levee type lookup identification. A 
code that provides a valid link to a valid 
entry from D_LevTyp. 
ProtectAr Numeric 10 2 Yes Area protected. 
ProtectLU Text 1 Yes Area protected by structure is primarily 
developed - D, or undeveloped  U. 
ProtectYr Long Yes Exceedence frequency in years that 
flood structure was designed to protect 
against. 
SideSlope Numeric 5 2 Yes Average side slope. 
Struc_ID Long Yes Foreign key to S_Struc. 
TopElv Numeric 8 2 Yes Average top elevation of levee. 

N48 Section N.3 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

The L_Orfc table contains specific information about the orifices of the riser. The L_Orfc table 
contains the attributes presented in Table N-45. 

Table N-45. L_Orfc Table 

Field Type Length Decimal 
Places 
Required Description 
Orfc_ID Long Yes Primary key for table. 
RsrBrl_ID Long Yes Foreign key to L_RsrBrl. 
CLElv Numeric 8 2 Yes Elevation at center of orifice. 
Diameter Numeric 8 2 Yes Diameter of orifice. 
Height Numeric 8 2 Yes Height of orifice. 
Len_LID Long Yes Units of linear measure. A code that 
provides a valid link to a valid entry 
from D_Length_Units. See Appendix L. 
OrfcCnt Integer Yes Number of same size orifices at a 
given elevation. 
ShpTyp_ID Long Yes Orifice shape type lookup identification. 
A code that provides a valid link to a 
valid entry from D_ShpTyp. 
Wdth Numeric 8 2 Yes Width of orifice. 

N49 Section N.3 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

The L_ OtlPp table contains specific information about the outlet pipes from each riser. The 
L_OtlPp table contains the attributes presented in Table N-46. 

Table N-46. L_OtlPp Table 

Field Type Length Decimal 
Places 
Required Description 
OtlPp_ID Long Yes Primary key for table. 
RsrBrl_ID Long Yes Foreign key to L_RsrBrl. 
CLStn Numeric 12 2 Yes Centerline station where outlet pope is 
located. 
Diameter Numeric 8 2 Yes Diameter of outlet pipe. 
DSInvert Numeric 8 2 Yes Elevation at downstream invert of 
outlet pipe. 
Height Numeric 8 2 Yes Height of outlet pipe. 
InTyp_LID Long Yes Inlet type lookup identification. A code 
that provides a valid link to a valid entry 
from D_PpTyp. 
Len_LID Long Yes Units of linear measure. A code that 
provides a valid link to a valid entry 
from D_Length_Units. See Appendix L. 
Lngth Numeric 8 2 Yes Length of outlet pipe. 
MtlTyp_LID Long Yes Pipe material type lookup identification. 
A code that provides a valid link to a 
valid entry from D_MtlTyp. 
OutTyp_LID Long Yes Outlet type lookup identification. A 
code that provides a valid link to a valid 
entry from D_PpTyp. 
ShpTyp_LID Long Yes Pipe shape type lookup identification. 
A code that provides a valid link to a 
valid entry from D_ShpTyp. 
USInvert Numeric 8 2 Yes Elevation at upstream invert of outlet 
pipe. 
Wdth Numeric 8 2 Yes Width of outlet pipe. 

N50 Section N.3 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

The The L_ Pier table is a database table. Each record in L_ Pier contains information about a 
pier. Only bridges may have piers. The L_Pier table contains the attributes presented in Table 
N-47. 

Table N-47. L_Pier Table 

Field Type Length Decimal 
Places 
Required Description 
Pier_ID Long Yes Primary key for table. 
Brdg_ID Long Yes Foreign key to L_Brdg. 
CLStn Numeric 8 2 Yes Station at centerline of pier 
(referencing profile view of structure). 
ColumnCnt Integer Yes Number of columns of piers occurring 
at one station. 
Easting Numeric 12 2 Yes X-coordinate. 
Northing Numeric 12 2 Yes Y-coordinate. 
Len_LID Long Yes Units of linear measure. A code that 
provides a valid link to a valid entry 
from D_Length_Units. See Appendix L. 
ShpTyp_LID Long Yes Pier shape type lookup identification. 
A code that provides a valid link to a 
valid entry from D_ShpTyp. 
Wdth Numeric 8 2 Yes Width or span of pier, measured 
perpendicular to the streamflow. 

The L_Rail table contains information about the surveyed rail shots. The L_Rail table contains 
the attributes presented in Table N-48. 

Table N-48. L_Rail Table 

Field Type Length Decimal 
Places 
Required Description 
Rail_ID Long Yes Primary key for table. 
Struc_ID Long Yes Foreign key to S_Struc. 
CLStn Numeric 8 2 Yes Station at centerline of rail (referencing 
profile view of structure). 
Easting Numeric 12 2 Yes X-coordinate. 
Elev Numeric 8 2 Yes Elevation at top of rail. 
Height Numeric 8 2 Yes Height of rail. 
Len_LID Long Yes Units of linear measure. A code that 
provides a valid link to a valid entry 
from D_Length_Units. See Appendix L. 
Northing Numeric 12 2 Yes Y-coordinate. 

N51 Section N.3 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

The L_RsrBrl table contains data specific to risers. The L_RsrBrl table contains the attributes 
presented in Table N-49. 

Table N-49. L_RsrBrl Table 

Field Type Length Decimal 
Places 
Required Description 
RsrBrl_ID Long Yes Primary key for table. 
Dam_ID Long Yes Foreign key to L_Dam. 
BaseElv Numeric 8 2 Yes Elevation at the bottom of the riser 
barrel. 
CLStn Numeric 8 2 Yes Station where riser barrel is located. 
Len_LID Long Yes Units of linear measure. A code that 
provides a valid link to a valid entry 
from D_Length_Units. See Appendix L. 
Lngth Numeric 8 2 Yes Length of the riser barrel. 
MtlTyp_LID Long Yes Riser material type lookup 
identification. A code that provides a 
valid link to a valid entry from 
D_MtlTyp. 
ShpTyp_LID Long Yes Riser shape type lookup identification. 
A code that provides a valid link to a 
valid entry from D_ShpTyp. 
TopElv Numeric 8 2 Yes Elevation at the top of riser barrel. 
TrHt Numeric 8 2 Yes Height of trashrack. 
TrLn Numeric 8 2 Yes Length of trashrack. 
TrTopElv Numeric 8 2 Yes Elevation at top of trashrack. 
TrWd Numeric 8 2 Yes Width of trashrack. 
Wdth Numeric 9 2 Yes Width of the riser barrel. 

The L_Sketch table is a database table that contains information related to sketches that were 
created during the survey. The L_Sketch table contains the attributes presented in Table N-50. 

Table N-50. L_Sketch Table 

Field Type Length Required Description 
Sketch_ID Long Yes Primary key for table. 
Comments Text 254 No General comments or notes. 
FileNm Text 254 Yes Name of the sketch file. 
SketchDt Date Yes Date the sketch was created. 

N52 Section N.3 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

The L_StrPht is a lookup table for the photos associated with the structures. The L_StrPht table 
contains the attributes presented in Table N-51. 

Table N-51. L_StrPht Table 

Field Type Length Required Description 
StrPht_ID Long Yes Primary key for table. 
Photo_ID Long Yes Foreign key to S_Photo. 
Struc_ID Long Yes Foreign key to S_Struc. 

The L_ StrSkt is a lookup table for the sketches associated with the structures. The L_StrSkt 
table contains the attributes presented in Table N-52. 

Table N-52. L_StrSkt Table 

Field Type Length Required Description 
StrSkt_ID Long Yes Primary key for table. 
Sketch_ID Long Yes Foreign key to L_Sketch. 
Struc_ID Long Yes Foreign key to S_Struc. 

The L_ SWy table contains specific information about the spillways for each dam. The L_SWy 
table contains the attributes presented in Table N-53. 

Table N-53. L_SWy Table 

Field Type Length Decimal 
Places 
Required Description 
SWy_ID Long Yes Primary key for table. 
Dam_ID Long Yes Foreign key to L_Dam. 
BotWd Numeric 8 2 Yes Width at the bottom of spillway. 
CLStn Numeric 8 2 Yes Centerline station of spillway. 
CrestElv Numeric 8 2 Yes Elevation at crest of spillway. 
Len_LID Long Yes Units of linear measure. A code that 
provides a valid link to a valid entry 
from D_Length_Units. See Appendix L. 
SWyTyp_LID Long Yes Spillway type lookup identification. A 
code that provides a valid link to a valid 
entry from D_SWyTyp. 
TopElv Numeric 8 2 Yes Elevation at top of spillway. 
TopWd Numeric 8 2 Yes Width at top of spillway. 

N53 Section N.3 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

The L_SXS is a database table that contains general information about each surveyed cross 
section. The L_SXS table contains the attributes presented in Table N-54. 

Table N-54. L_SXS Table 

Field Type Length Decimal 
Places 
Required Description 
SXS_ID Long Yes Primary key for table. 
CLEasting Numeric 12 2 Yes X-coordinate at stream crossing. 
CLNorthing Numeric 12 2 Yes Y-coordinate at stream crossing. 
CLStn Numeric 8 2 Yes Cross section station at intersection of 
cross section and stream centerline. 
Comments Text 254 No General comments or notes. 
DatTyp_LID Long Yes Cross section or data type lookup 
identification. A code that provides a 
valid link to a valid entry from 
D_DatTyp. 
Invert Numeric 8 2 Yes Lowest elevation in cross section. 
Len_LID Long Yes Units of linear measure. A code that 
provides a valid link to a valid entry 
from D_Length_Units. See Appendix L. 
Location Text 254 Yes Description of location. 
Orient Text 1 Yes Direction in which survey shots were 
taken. From left to right, looking 
downstream - D, or looking 
upstream - U 
StreamStn Numeric 12 2 Yes Distance along stream. 
Struc_ID Long No Foreign key to S_Struc. Note: Required 
if cross section is associated with a 
structure. 
SurveyDt Date Yes Date and time of survey. 
SurveyFile Text 254 No Name of the survey text file. Note: Not 
required for cross sections associated 
with structures. 
TBM_ID Long Yes Foreign key to S_TBM. Elevation 
reference point of cross section. 
Wtr_Nm_LID Long Yes Foreign key to L_Wtr_Nm. Surface 
water feature name. 
XSNm Text 65 Yes Cross Section Name. 

N54 Section N.3 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

The L_Wtr_Nm table is a database lookup table. This is the same table defined in Appendix L of 
these Guidelines, but it is listed here for completeness. 

The L_Wtr_Nm table contains the attributes presented in Table N-55. 

Table N-55. L_Wtr_Nm Table 

Field Type Length Required Description 
Wtr_Nm_LID Long Yes Unique identifier for L_Wtr_Nm. Primary 
key. 
Wtr_Nm Text 254 Yes Name of surface water feature. 

The S_ Photo is a spatial file used to represent the locations of the digital photographs that were 
taken during the survey. The S_Photo table contains the attributes presented in Table N-56. 

Table N-56. S_Photo Spatial File 

Field Type Length Decimal 
Places 
Required Description 
Photo_ID Long Yes Primary key for table. 
Azimuth Numeric 6 2 No Horizontal angle of the bearing for the 
photo. 
Comments Text 254 No General comments or notes. 
FileNm Text 254 Yes Name of the photo file. 
Location Text 254 Yes A description of the geographic 
location where the picture was taken. 
PhotoDt Date Yes The date that the picture was taken. 
Source_Cit Text 11 Yes Source Citation. Abbreviation used in 
the metadata file when describing the 
source information for the S_STRUC 
spatial file. 
Subject Text 50 Yes Description of feature or view. 

S_TBM is a spatial file used to represent the locations of the temporary benchmarks or elevation 
reference marks that were used during the survey. All TBMs that were used during the survey of 
structures for detatiled studies should be included in S_TBM. 

See Table N-27 for a list of attributes included in the S_TBM spatial file. 

N55 Section N.3 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

D_AbtTyp is a domain table that lists the valid abutment types. The D_AbtTyp table contains the 
attributes presented in Table N-57. Table N-58 contains the domain values for D_AbtTyp. 

Table N-57. D_AbtTyp Table 

Field Type Length Required Description 
AbtTyp_LID Long Yes Primary key - Abutment type look-up 
identification key. 
AbtTypDes Text 20 Yes Type of abutment: Spill through or vertical 
wall. 

Table N-58. Domain Values for D_AbtTyp 

AbtTyp_LID AbtTypDes 
1 Spill Through 
2 Vertical Wall 
3 Other 
4 Unknown 

D_ShpTyp is a domain table that lists the valid shape types. The D_ShpTyp table contains the 
attributes presented in Table N-59. Table N-60 contains the domain values for D_ShpTyp. 

Table N-59. D_ShpTyp Table 

Field Type Length Required Description 
ShpTyp_LID Long Yes Primary key - shape type look-up 
identification key. 
ShpTypDes Text 20 Yes Shape of feature: Circular, Box, 
Rectangular, Elliptical, 
Octagonal,Trapezoidal, etc. 

Table N-60. Domain Values for D_ShpTyp 

ShpTyp_LID ShpTypDes 
1 Circular 
2 Box 
3 Rectangular 
4 Elliptical 
5 Octagonal 
6 Other 
7 Trapezoidal 
9 Unknown 

N56 Section N.3 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

D_PpTyp is a domain table that lists the valid types used to describe the ends of pipes or 
culverts. The D_PpTyp table contains the attributes presented in Table N-61. Table N-62 
contains the domain values for D_PpTyp. 

Table N-61. D_PpTyp Table 

Field Type Length Required Description 
PpTyp_LID Long Yes Primary key - pipe inlet or outlet type lookup identification key. 
PpTypDes Text 20 Yes Inlet or outlet type: Socket, Projecting 
from fill, Bell, etc. 

Table N-62. Domain Values for D_PpTyp 

PpTyp_LID PpTypDes 
1 Socket 
2 Projecting from fill 
3 Bell 
4 Other 
5 Unknown 

The D_MtlTyp is a domain table that lists the valid descriptions for construction material. 
D_MtlTyp table contains the attributes presented in Table N-63. Table N-64 contains the 
domain values for D_MtlTyp. 

Table N-63. D_MtlTyp Table 

Field Type Length Required Description 
MtlTyp_LID Long Yes Primary key - material type look-up 
identification key. 
MtlTypDes Text 20 Yes Type of material: Gravel, Silt, Clay, 
Earthen, Concrete, etc. 

Table N-64. Domain Values for D_MtlTyp 

MtlTyp_LID MtlTypDes 
1 Gravel 
2 Silt 
3 Clay 
4 Earthen 
5 Concrete 
6 Other 
7 Unknown 

N57 Section N.3 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

D_ClsTyp is a domain table that lists the valid types used to describe the closure required to 
operate a structure. The D_ClsTyp table contains the attributes presented in Table N-65. Table 
N-66 contains the domain values for D_ ClsTyp. 

Table N-65. D_ClsTyp Table 

Field Type Length Required Description 
ClsTyp_ID Long Yes Primary key - Closure type look-up 
identification key. 
ClsTyp Text 20 Yes Type of closure: Sandbags, Stop logs, 
Floodgates, Combination, etc. 

Table N-66. Domain Values for D_ClsTyp 

ClsTyp_ID ClsTypDes 
1 Combination 
2 Floodgates 
3 Other 
4 Sandbags 
5 Stop logs 
6 None 

D_LevTyp is a domain table that lists the valid types of levees. The D_LevTyp table contains 
the attributes presented in Table N-67. Table N-68 contains the domain values for D_ ClsTyp. 

Table N-67. D_LevTyp Table 

Field Type Length Required Description 
LevTyp_LID Long Yes Primary key - levee type look-up 
identification key. 
LevTypDes Text 20 Yes Type of levee: Levee & floodwall, Levee, 
Floodwall, Ring Levee, Road 
embankment, RR Embankment, etc. 

Table N-68. Domain Values for D_LevTyp 

LevTyp_LID LevTypDes 
1 Floodwall 
2 Levee 
3 Levee & floodwall 
4 Ring levee 
5 Road embankment 
6 RR embankment 
7 Other 

N58 Section N.3 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

D_SwyTyp is a domain table that lists the valid types of levees. The D_SwyTyp table contains 
the attributes presented in Table N-69. Table N-70 contains the domain values for D_ SwyTyp. 

Table N-69. D_SwyTyp Table 

Field Type Length Required Description 
SWyTyp_LID Long Yes Primary key - Spillway type look-up 
identification key. 
SWyTypDes Text 20 Yes Type of spillway: Auxiliary/Emergency, 
Service/Principal, etc. 

Table N-70. Domain Values for D_SwyTyp 

SWyTyp_LID SWyTypDes 
1 Auxiliary/Emergency 
2 Service/Principal 
3 Other 
4 Unknown 

D_LevTyp is a domain table that lists the valid types of dams. The D_DamTyp table contains 
the attributes presented in Table N-71. Table N-72 contains the domain values for D_ SwyTyp. 

Table N-71. D_DamTyp Table 

Field Type Length Required Description 
DamTyp_LID Long Yes Primary key - Dam type look-up 
identification key. 
DamTypDes Text 20 Yes Engineering descriptor: Concrete Arch, 
Masonry, Rubber, Timber Crib, RCC, 
Rockfill, Earthen, etc. 

Table N-72. Domain Values for D_DamTyp 

DamTyp_LID DamTypDes 
1 Concrete Arch 
2 Concrete Gravity 
3 Earthfill 
4 Masonry 
5 RCC 
6 Rockfill 
7 Rubber 
8 Timber Crib 
9 Other 
10 Unknown 

N59 Section N.3 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

Survey Files 

Description 

A separate survey file must be submitted for all bridges, culverts, and dams. Survey files are not 
required for channels or levees. 

Naming Convention 

The file name for the survey file is to be based on the name of the structure, which is found in the 
StrucNm field in the S_Struc table. However, the file name is to use underscores to indicate 
spaces in the name of the structure. In a submission, each survey file must have a unique file 
name. For example, SOMEWHERE_RD.TXT 

The file name of the survey file for a structure must be populated in the SurveyFile field in the 
S_Struc table, in the record corresponding to that structure. 

Attributes 

Each survey file is to include all survey data for a structure. The file name of the survey file for 
a structure must be populated in the SurveyFile field in the S_Struc table, in the record 
corresponding to that structure. 

Digital Photographs 

Description 

A minimum of four digital photographs will be submitted for each bridge, culvert, and dam. The 
required aspects or view of the photographs include: 

.. Standing upstream of structure, looking downstream at structure (USF) 
.. Standing on or below the structure, looking upstream at the channel (USC) 
.. Standing on or below the structure, looking downstream at the channel (DSC) 
.. Standing downstream of structure, looking upstream at structure (DSF) 
A minimum of two digital photographs are to be submitted for each channel and levee. The 
required aspects or view of the photographs include: 

.. Standing at midpoint of the structure, looking upstream at the channel or levee (USC) 
.. Standing at midpoint of the structure, looking downstream at the channel or levee (DSC) 
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Naming Convention 

The file name of the digital photograph is to be based on the name of the structure (with 
underscores rather than spaces), an underscore, the aspect or view of the photograph, and the 
extension. In a submission, each digital photograph must have a unique file name. 

For examples, SOMEWHERE_RD_USF.PNG 

SOMEWHERE_RD_USC. PNG 

SOMEWHERE_RD_DSC. PNG 

SOMEWHERE_RD_DSF. PNG 

Attributes 

A record must be populated in the S_Photo table for each photograph. The file name of the 
photograph must be populated in the FileNm field in the S_Photo table, in the record 
corresponding to that photograph. In addition, a record must be populated in the L_StrPht table 
for each photograph. 

See Table N-56 for a list of attributes included in the S_Photo spatial file. 

Digital Sketches 

Description 

All sketches that are prepared during the survey of a structure must be submitted in digital 
format. If a sketch is drawn on paper in the field, it must be scanned into digital format. Each 
sketch must be in a separate digital file. 

Naming Convention 

The file name of the digital sketch is to be based on the name of the structure (with underscores 
rather than spaces), an underscore, SK and a number, and the extension. In a submission, each 
sketch files must have a unique file name. For example, SOMEWHERE_RD_SK1.PNG 

Attributes 

A record must be populated in the L_Sketch table for each sketch. The file name of the sketch 
must be populated in the FileNm field in the L_Sketch table, corresponding to that sketch. In 
addition, a record must be populated in the L_StrSkt table for each sketch 

See Table N-50 for a list of attributes included in the L_Sketch table. 

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Updated May 2005]

N.3.2.5 Structures for Limited Detailed Study [April 2005] 
The following deliverables are required whenever hydraulic structures have been surveyed to 
support Limited Detailed Studies; levees are shown on the FIRM, channels containing the 
flooding are shown on the FIRM; or any other structure that impacts the areas flood risk is 
shown on the FIRM: 

 Database tables and Spatial Files 
 Digital Photographs 
The following subsections detail the requirements for each deliverable. 

Database Tables and Spatial Files 

Description 

The database will contain the tables related to survey data for structures listed in Table N-73. 

Table N-73. Database Tables and Spatial Files 
for Structures for Limited Detail Studies 

Table Description 
S_ApxStr The ApxStr table contains information about the hydraulic 
structures that have been surveyed within the study area in 
support of limited detailed studies. 
L_ApxCul Each record in this table contains information about one pipe, 
at a culvert crossing. 
L_ApxDam Each record in this table contains information specific to a 
dam. 
L_ApxRsr Each record in this table contains information specific to one 
riser barrel. 
L_ApxSWy Each record in this table contains information about a relief 
device at a dam. 
L_ApxPht This table is a look up table for the photos of each structure. 
L_ApxBrdg Each record in this table contains information specific to a 
bridge. 
S_Photo A point spatial file used to represent the locations where 
photos were taken. 
L_WtrNm This is a look up table for streams. 
D_MtlTyp A domain table used to store the valid types of construction 
material. 
D_ShpTyp A domain table used to store the valid shape of a 
culvert/riser/exit pipe. 

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Updated May 2005]

See Figure N-7 for an entity relationship diagram of the tables for structures surveyed for limited 
detailed studies. 

Figure N-7. Entity Relationship Diagram for Structures for Limited Detailed Study 


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Updated May 2005]

The S_ApxStr spatial file contains general data and locational information about structures 
surveyed for limited detailed studies. Each structure is to be represented spatially by a single 
line. Each line is to represent the primary characteristic of the structure. 

.. Each bridge is to be represented by a single line that is aligned to the transportation 
centerline carried by the bridge. 
.. Each culvert is to be represented by a single line that is aligned to the transportation 
centerline carried by the culvert. 
.. Each dam is to be represented by a single line that is aligned to the centerline along the 
top of the dam. 
The spatial files are to be named S_ApxStr and the extension appropriate for the file format. For 
example, the components of a shapefile would be named S_ApxStr.shp, S_ApxStr.dbf, 
S_ApxStr.shx, and S_ApxStr.prj. 

S_ApxStr must contain the attributes shown in Table N-74. 

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Table N-74. S_ApxStr Spatial File 

Field Type Length Decimal 
Places 
Required Description 
ApxStr_ID Long Yes Primary key for table. 
Wtr_Nm_LID Long Yes Foreign key to L_Wtr_Nm. Surface 
water feature name. 
CBElv Numeric 8 2 Yes Average channel bank elevation. 
ChnlBotWd Numeric 8 2 Yes Width at the bottom of channel. 
ChnlTopWd Numeric 8 2 Yes Width at the top of channel. 
Comments Text 254 No General comments or notes. 
Len_LID Long Yes Units of linear measure. A code that 
provides a valid link to a valid entry 
from D_Length_Units. See Appendix L. 
MinElv Numeric 8 2 Yes Minimum elevation at structure. 
RoadNm Text 100 Yes Road name or location of structure 
Source_Cit Text 11 Yes Source Citation. Abbreviation used in 
the metadata file when describing the 
source information for the S_ApxStr 
spatial file. 
StreamStn Numeric 12 2 Yes Distance along stream where structure 
intersects stream. 
Struct_LID Long Yes Structure Type Lookup Identification. 
A code that provides a link to a valid 
entry from the D_Struct_Typ table. See 
Appendix L. 
Struct_Nm Text 50 Yes Field name of the structure. 
SurveyDt Date Yes Date of survey. 
TORElv Numeric 8 2 Yes Maximum top of road elevation at 
structure. 
Wdth Numeric 8 2 Yes Hydraulic distance from one edge of 
structure to the other, parallel to 
stream. 

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L_ApxCul is a database table. Each record in this table contains information about one pipe or 
box, at a culvert crossing. The L_ApxCul table contains the attributes presented in Table N-75. 

Table N-75. L_ApxCul Table 

Field Type Length Decimal 
Places 
Required Description 
ApxCul_ID Long Yes Primary key for table. 
ApxStr_ID Long Yes Foreign key to S_ApxStr. 
ShpTyp_LID Long Yes Culvert shape type lookup 
identification. A code that provides a 
valid link to a valid entry from 
D_ShpTyp. 
CLStn Numeric 8 2 Yes Cross section station, in profile view, 
along structure of intersection of 
structure and stream centerline. 
Invert Numeric 8 2 Yes Elevation at bottom of upstream pipe 
opening. 
Len_LID Long Yes Units of linear measure. A code that 
provides a valid link to a valid entry 
from D_Length_Units. See Appendix L. 
Rise Numeric 8 2 Yes Height or diameter of pipe. 
Span Numeric 8 2 Yes Width or span of pipe. 

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Updated May 2005]

The L_ApxDam is a database table. Each record in this table contains information specific to 
one dam. The L_ApxDam table contains the attributes presented in Table N-76. 

Table N-76. L_ApxDam Table 

Field Type Length Decimal 
Places 
Required Description 
ApxDam_ID Long Yes Primary key for table. 
ApxStr_ID Long Yes Foreign key to S_ApxStr. 
Area_LID Long Yes Units of area measure. A code that 
provides a valid link to a valid entry 
from D_Area_Units. See Appendix L. 
DamTopElv Numeric 8 2 Yes Elevation at top of dam. 
DamTyp_LID Long Yes Dam type lookup identification. A code 
that provides a valid link to a valid entry 
from D_DamTyp. 
Len_LID Long Yes Units of linear measure. A code that 
provides a valid link to a valid entry 
from D_Length_Units. See Appendix L. 
MtlTyp_LID Long Yes Material type lookup identification. A 
code that provides a valid link to a valid 
entry from D_MtlTyp. 
NormalArea Numeric 10 2 Yes Area of pool at normal water surface 
elevation. 

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Updated May 2005]

The L_ApxRsr contains data specific to risers. The L_ApxRsr table contains the attributes 
presented in Table N-77. 

Table N-77. L_ApxRsr Table 

Field Type Length Decimal 
Places 
Required Description 
ApxRsr_ID Long Yes Primary key for table. 
ApxDam_ID Long Yes Foreign key to L_ApxDam. 
ExPpRise Numeric 8 2 Yes Diameter or height of the exit pipe. 
ExPpLn Numeric 8 2 Yes Length of the exit pipe. 
ExPpTopElv Numeric 8 2 Yes Elevation at the top of the exit pipe. 
ExPpWd Numeric 8 2 Yes Width of the exit pipe. 
ExPShpT_ID Long Yes Exit pipe shape type lookup 
identification. A code that provides a 
valid link to a valid entry from 
D_ShpTyp, field ShpTyp_LID. 
Len_LID Long Yes Units of linear measure. A code that 
provides a valid link to a valid entry 
from D_Length_Units. See Appendix 
L. 
RsrHlCnt Integer Yes Number of riser holes. 
RsrHlSp_ID Long Yes Riser hole shape type lookup 
identification. A code that provides a 
valid link to a valid entry from 
D_ShpTyp, field ShpTyp_LID. 
RsrHlLn Numeric 8 2 Yes Length or diameter of riser holes. 
RsrHlSpc Numeric 8 2 Yes Spacing between riser holes. 
RsrHlWd Numeric 8 2 Yes Width of riser holes. 
RsrHt Numeric 8 2 Yes Height of riser. 
RsrLn Numeric 8 2 Yes Length or diameter of riser top 
opening. 
RsrShpT_ID Long Yes Riser shape type lookup identification. 
A code that provides a valid link to a 
valid entry from D_ShpTyp, field 
ShpTyp_LID. 
RsrTopElv Numeric 8 2 Yes Elevation at the top of the riser. 
RsrWd Numeric 8 2 Yes Width of riser. 
TrTopElv Numeric 8 2 Yes Elevation at the top of trashrack. 
TrLn Numeric 8 2 Yes Length of the trashrack. 
TrWd Numeric 8 2 Yes Width of the trashrack. 

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Updated May 2005]

The L_ApxSWy table contains specific information about the spillways for each dam. The 
L_ApxSWy table contains the attributes presented in Table N-78. 

Table N-78. L_ApxSwy Table 

Field Type Length Decimal 
Places 
Required Description 
ApxSWy_ID Long Yes Primary key for table. 
ApxDam_ID Long Yes Foreign key to L_ ApxDam. 
BotWd Numeric 8 2 Yes Width at bottom of spillway. 
Height Numeric 8 2 Yes Height of spillway. 
Len_LID Long Yes Units of linear measure. A code that 
provides a valid link to a valid entry 
from D_Length_Units. See Appendix L. 
TopElv Numeric 8 2 Yes Elevation at top of spillway. 
TopWd Numeric 8 2 Yes Width at top of spillway. 

The L_ApxPht table is a lookup table for the photos associated with structures that have been 
surveyed to support limited detailed studies. The L_ApxPht table contains the attributes 
presented in Table N-79. 

Table N-79. L_ApxPht Table 

Field Type Length Required Description 
ApxPht_ID Long Yes Primary key for table. 
ApxStr_ID Long Yes Foreign key to S_ApxStr. 
Photo_ID Long Yes Foreign key to S_Photo. 

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The L_ ApxBrdg is a database table. Each record in this table contains information specific to 
one bridge. The L_ApxBrdg table contains the attributes presented in Table N-80. 

Table N-80. L_ApxBrdg Table 

Field Type Length Decimal 
Places 
Required Description 
ApxBrdg_ID Long Yes Primary key for table. 
ApxStr_ID Long Yes Foreign key to S_ApxStr. 
DeckThick Numeric 8 2 Yes Measurement from top of road to 
bottom of bridge. 
Len_LID Long Yes Units of linear measure. A code that 
provides a valid link to a valid entry 
from D_Length_Units. See Appendix 
L. 
NumPiers Integer Yes Number of piers. 
PierWd Numeric 8 2 Yes Average width or span of piers, 
measured perpendicular to the 
streamflow. 
ToeWd Numeric 8 2 Yes Width of a structure, measured 
between the abutments. 
TopWd Numeric 8 2 Yes Width of structure, measured between 
outermost low chords. 

The S_ Photo is a spatial file used to represent the locations of the digital photographs that were 
taken during the survey. The S_Photo table contains the attributes presented in Table N-81. 

Table N-81. S_Photo Spatial File 

Field Type Length Decimal 
Places 
Required Description 
Photo_ID Long Yes Primary key for table. 
Azimuth Numeric 6 2 No Horizontal angle of the bearing for the 
photo. 
Comments Text 254 No General comments or notes. 
FileNm Text 254 Yes Name of the photo file. 
Location Text 254 Yes A description of the geographic 
location where the picture was taken. 
PhotoDt Date Yes The date that the picture was taken. 
Source_Cit Text 11 Yes Source Citation. Abbreviation used in 
the metadata file when describing the 
source information for the S_STRUC 
spatial file. 
Subject Text 50 Yes Description of feature or view. 

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Updated May 2005]

The L_Wtr_Nm table is a database lookup table. It is required for all types of hydraulic analyses. 
This table identifies the unique list of stream names used in the submittal. This is the same table 
defined in Appendix L of these Guidelines, but it is listed here for completeness. 

The L_Wtr_Nm table contains the attributes presented in Table N-82. 

Table N-82. L_Wtr_Nm Table 

Field Type Length Required Description 
Wtr_Nm_LID Long Yes Unique identifier for L_Wtr_Nm. Primary 
key. 
Wtr_Nm Text 254 Yes Name of surface water feature. 

D_MtlTyp is a domain table that lists the valid types used to describe construction material. The 
D_MtlTyp table contains the attributes presented in Table N-83. Table N-84 contains the 
domain values for D_MtlTyp. 

Table N-83. D_MtlTyp Table 

Field Type Length Required Description 
MtlTyp_LID Long Yes Primary key - material type look-up 
identification key. 
MtlTypDes Text 20 Yes Type of material: Gravel, Silt, Clay, 
Earthen, Concrete, etc. 

Table N-84. Domain Values for D_MtlTyp 

MtlTyp_LID MtlTypDes 
1 Gravel 
2 Silt 
3 Clay 
4 Earthen 
5 Concrete 
6 Other 
7 Unknown 

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D_ShpTyp is a domain table that lists the valid types used to describe the shape. The D_ShpTyp 
table contains the attributes presented in Table N-85. Table N-86 contains the domain values for 
D_ ShpTyp. 

Table N-85. D_ShpTyp Table 

Field Type Length Required Description 
ShpTyp_LID Long Yes Primary key - shape type look-up 
identification key. 
ShpTypDes Text 20 Yes Shape of feature: Circular, Box, 
Rectangular, Elliptical, 
Octagonal,Trapezoidal, etc. 

Table N-86. Domain Values for D_ShpTyp 

ShpTyp_LID ShpTypDes 
1 Circular 
2 Box 
3 Rectangular 
4 Elliptical 
5 Octagonal 
6 Other 
7 Trapezoidal 
9 Unknown 

Digital Photographs 

Description 

A minimum of one digital photograph is to be submitted for each structure. The required aspects 
or view of the photographs include standing upstream of structure, looking downstream at 
structure (USF). 

Naming Convention 

The file name of the digital photograph is to be based on the name of the structure (with 
underscores rather than spaces), an underscore, the aspect or view of the photograph, and the 
extension. In a submission, each digital photograph must have a unique file name. For example,

 SOMEWHERE_RD_USF.PNG 

Attributes 

A record must be populated in the S_Photo table for each photograph. The file name of the 
photograph must be populated in the FileNm field in the S_Photo table, in the record 

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Updated May 2005]

corresponding to that photograph. In addition, a record must be populated in the L_ApxPht table 
for each photograph. 

See Table N-81 for a list of attributes included in the S_Photo spatial file. 

N.3.3 Deliverables [May 2005] 
N.3.3.1 Metadata [May 2005] 
A metadata file that complies with the FEMA/FGDC Metadata Profiles (available under separate 
cover from FEMA Headquarters) in XML-format shall be included with the submittal. The 
profiles follow the FGDC Content Standard for metadata and define additional domains and 
business rules for some elements and those elements that are mandatory for FEMA based on the 
specific submittal type. 

There are specific items in the FGDC metadata standards that the submitter shall address. For 
each spatial data source in the metadata file, the Mapping Partner shall assign a Source Citation 
Abbreviation. The overview description subsection of the entity and attribute information of the 
metadata file must include a list of all DCS database tables included in the submittal. 

N.3.3.2 Hard Copy Deliverables [December 2004] 
There are no hard copy deliverables for submittal of inventory data. 

N.3.3.3 Digital Deliverables [May 2005] 
Transfer Media 

Mapping Partners must submit files on one of the following electronic media or via the internet: 

 CD-ROM 
 DVD 
 Upload to Mapping Information Platform (MIP) (http://www.hazards.fema.gov) 
As technology changes or in special situations, other media may be acceptable if coordinated
with FEMA and the Mapping Partner receiving the data. 
Files must not be compressed. 


Data Format 

Metadata 

Each submittal of survey data must include one metadata file. 

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Updated May 2005]

Database 

Each submittal will include only one database. The database must be a Microsoft Access 2000 
database (mdb) or dBASE IV files. The file name for the database will be based upon the name 
of the study name. No spaces will be allowed in the file name. 

For example, FLOODUSA.MDB. 

Photographs 

The photographs must be in color and must be submitted digitally. Table N-87 provides the file 
formats acceptable for submittal of digital photographs. 

Table N-87. File Formats for Photographs 

Format Extension References 
JPEG JPG Joint Photographics Experts Group. 
Bitmap BMP Microsoft Corporation. 
Portable Network 
Graphic 
PNG 
Tagged Image File 
Format 
TIFF 

Spatial Files 

Most spatial features can be stored in an ESRI shapefile or Open GML document, with the 
necessary attribute fields. Table N-88 provides the file formats acceptable for data submittal. 

Table N-88. File Formats for Spatial Files 

Format Extension Vendor Information 
Shapefile SHP (including related files such as 
.SHX, .DBF, and .PRJ) 
See ESRI support: www.esri.com. 
Sketches 

Each sketch must be in a separate digital file. Table N-89 provides the file formats acceptable 
for submittal of survey files. 

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Updated May 2005]

Table N-89. File Formats for Sketches 

Format Extension References 
Portable document PDF See Adobe support: www.adobe.com. 
JPEG JPG Joint Photographics Experts Group. 
Portable Network 
Graphic PNG 

Survey Files 

The survey file must be an ASCII-formatted file. 

Directory Structure and Folder Naming Conventions 

A metadata file compliant with FEMA/FGDC Metadata Profiles shall be placed in the General 
folder on the root directory of Disk1. These directories must be located in the root directory of 
the disk(s). No sub-folders or sub-directories will be allowed under these directories. Data must 
be located in the appropriate directory, as follows. The General folder must be located on the 
first disk. 

\Database 

o Database file(s), including the L_Submittal_Info table 
\General 

o XML-format metadata file 
\Photos 

o All digital photographs 
\Sketches 

o All digital sketches 
\Spatial 

o Cross section spatial file (S_SXS) 
o Temporary Benchmarks or Elevation Reference Marks spatial file (S_TBM) 
o Structures for detailed study spatial file (S_Struc) 
o Structures for limited study spatial file (S_ApxStr) 
o High water marks spatial file (S_HWM) 
o Photos spatial file (S_Photo) 
\Survey 

o All survey files 
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Updated May 2005]

Data Identification Requirements 

All digital media submitted must be labeled with at least the following information: 

 Mapping Partner name 
 Community name and state for which the FIS was prepared 
 Survey Data 
 Date of submission (formatted mm/dd/yyyy) 
 Disk [sequential number] of [number of disks] 
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Updated May 2005]

N.4 Hydrology Submittal Standards 
N.4.1 Overview [December 2004] 
The goal of this section is to describe the format and type of hydrologic data expected by FEMA 
for new riverine flood insurance studies. The objective is to archive the hydrologic data in a 
database so that these data can be revised and used with minimum effort in future flood 
insurance studies or map revisions. New techniques such as digital terrain analysis, geospatial 
database management, and digital hydrologic and hydraulic models make it possible to protect 
the data investment and make these data available for reuse in existing and future studies to a 
much greater extent than in the past. 

As described in Appendix C of these Guidelines, there are three broad categories of hydrologic 
procedures used in the National Flood Insurance Program (NFIP): 

.. flood-frequency analyses for gaged streams using Bulletin 17B, Guidelines For 
Determining Flood Flow Frequency (Interagency Advisory Committee on Water Data, 
1982) 
.. Regional regression equations for ungaged streams, generally those developed by USGS 
(http://water.usgs.gov/software/nff.html) 
.. Rainfall-runoff models for ungaged streams that utilize rainfall data to estimate flood 
discharges. 
Within the category of rainfall-runoff models, the HEC-1 and HEC-HMS models developed by 
the U.S. Army Corps of Engineers (USACE), Hydrologic Engineering Center (HEC), are used 
most frequently in the NFIP. In addition to the two USACE models, FEMA accepts hydrologic 
results from over a dozen other rainfall-runoff models (for a list of accepted models see 
http://www.fema.gov/fhm/en_hydro.shtm) and it is likely that new models will be added in the 
future. Considering the widely varying data requirements for these models, initial efforts to 
archive the hydrologic data will concentrate on a minimum dataset required to describe the 
hydrologic procedures. 

In recent years, pre- and post-processors have been developed that automate the application of 
hydrologic models and provide links to Geographic Information Systems, hydraulic models, and 
floodplain mapping procedures. Some examples of pre- and post processor systems that 
implement rainfall-runoff models include the Watershed Modeling System (WMS) developed by 
Brigham Young University, the Modular Modeling System (MMS) developed by USGS, 
BASINS developed by the U.S. Environmental Protection Agency, and the Watershed 
Information System (WISE) developed by Watershed Concepts. These automated systems 
create input and output files that can be easily archived. 

Using FEMA-accepted hydrologic modeling methods such as flood-frequency analyses for 
gaged streams, application of regional regression equations or a rainfall-runoff model, the 

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Updated May 2005]

Minimum Required Dataset is described in detail in this section and includes the following 
items: 

 A georeferenced/projected hydrologic link network (typically the same as the stream 
channel network) 
 A georeferenced point dataset showing the locations of computed discharges and the 
design discharges obtained from the hydrologic analysis that can be converted to a FIS 
Discharge Summary Table 
 Input and output files for an approved hydrologic model where used (see 
http://www.fema.gov/fhm/en_hydro.shtm for an updated list of these models) 
 A series of database tables summarizing key data 
 A design hydrology report 
 A georeferenced /projected polygon feature class of watershed areas contributing runoff 
to the stream channel network, subdivided into the subcatchments, if utilized for 
hydrologic modeling 
 Optional geospatial datasets and database tables utilized for parameter calculation 
A detailed description of each of these data requirements is provided in the body of this section. 
Because of the frequent use of applications such as HEC-1 and HEC-HMS that utilize a design 
rainfall event and the Natural Resources Conservation Service runoff curve number and time of 
concentration approach, these data are requested in the tables described in this section. 
Additional tables will be added in the future to capture data from other methods as well. 

N.4.2 Requirements [April 2005] 
N.4.2.1 Data Files [April 2005] 
The following deliverables are required for a hydrology submittal: 

 Database Tables 
 Spatial Files 
 Hydrology Model Input and Output Files 
Most spatial features can be stored in an ESRI shapefile or Open GML document, with the 
necessary attribute fields and spatial projection information. Other domain and hydrologic 
results tables will be populated in Dbase IV format or Microsoft Access. All spatial data must be 
georeferenced and elevation data must include datum information. 

Database tables and spatial datasets needed for hydrologic submittal are provided in Table N-90. 

N78 Section N.4 


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Updated May 2005]

Table N-90. Hydrology Database and Spatial Data 

Table Name Description 
L_HydroModel A database table. The highest level representation of a hydrology 
model. Contains important information on geometry and results files. 
S_HydroNode A spatial dataset consisting of points showing the locations of 
computed discharge values. 
S_HydroLink A spatial dataset consisting of lines showing the hydrologic 
connectivity network. 
S_HydroBasin A spatial dataset consisting of polygons depicting basin boundaries. 
L_HydroResult A database table. Identifies one or more flood events per model at 
each point of the HydroNode spatial data. 
L_Wtr_Nm A database table. A lookup table of stream names. 
L_HydroEvent A database table. A lookup table of flood events. 
S_HydroGage A point spatial file of flow and precipitation gage locations. Required 
if utilized for calibration, regression, or frequency analysis. 
S_HydroSoil A polygon spatial file of soils. Required if utilized for model 
parameterization. 
S_HydroLanduse A polygon spatial file of land-use classifications. Required if utilized 
for model parameterization. 
S_HydroImpervious A polygon spatial file of impervious areas. Required if utilized for 
model parameterization. 
L_HydroEquation A database table. Lookup table of regression equations. Required if 
regression analysis utilized. 
L_HydroNodeParam A database table. Used for storing regression equation parameter 
values. Required if regression analysis is utilized. 
D_HydroParam A domain table used for storing regression equation parameter 
types. Required if regression analysis is utilized. 
S_HydroTC A linear spatial file of time of concentration calculations. Required if 
utilized for rainfall runoff model parameterization. 
L_HydroCNResult A database table. Contains curve numbers for subbasins. Required 
if utilized for rainfall runoff model parameterization. 
L_HydroCNLookup A database table. Lookup of curve numbers by soil and land use. 
Required if utilized for rainfall runoff model parameterization. 
L_HydroStormInfo A database table. Describes precipitation patterns. Required if 
utilized for rainfall runoff model parameterization. 
L_HydroStormCurve A database table. Used for storing DDF and IDF curves. Required if 
utilized for rainfall runoff model parameterization. 

N79 Section N.4 


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Updated May 2005]

Depending on the scope of work, the Mapping Partner may develop a new hydrologic model 
with all the associated input files, may modify an existing model developed for the effective 
flood insurance study or a related study, or simply utilize an existing model or adopt the effective 
flood discharges. Table N-91 describes the minimum required datasets for each study approach 
and the three hydrologic modeling approaches described earlier, watershed model, regression 
equations and gage analysis. If existing models are not available in digital format, the hard copy 
output from the model or analysis should be scanned into a PDF file. 

Table N-91. Minimum Required Datasets* 

Watershed Model Regression Analysis Gage Analysis 
New Model Spatial File: 
 S_HydroBasin 
 S_HydroNode 
 S_HydroLink 
Table: 
 L_HydroModel 
 L_HydroResult 
 L_HydroEvent 
 L_Wtr_Nm 
Spatial File: 
 S_HydroNode 
 S_HydroLink 
Table: 
 L_HydroModel 
 L_HydroResult 
 L_HydroEvent 
 L_Wtr_Nm 
 L_HydroEquation 
 L_HydroNodeParam 
 D_HydroParam 
Spatial File: 
 S_HydroNode 
 S_HydroLink 
 S_HydroGage 
Table: 
 L_HydroModel 
 L_HydroResult 
 L_HydroEvent 
 L_Wtr_Nm 
Modification / 
Reference of existing 
model 
Spatial File: 
 S_HydroNode 
 S_HydroLink 
Table: 
 L_HydroModel 
 L_HydroResult 
 L_HydroEvent 
 L_Wtr_Nm 
Spatial File: 
 S_HydroNode 
 S_HydroLink 
Table: 
 L_HydroModel 
 L_HydroResult 
 L_HydroEvent 
 L_Wtr_Nm 
 L_HydroEquation 
 L_HydroNodeParam 
 D_HydroParam 
Spatial File: 
 S_HydroNode 
 S_HydroLink 
 S_HydroGage 
Table: 
 L_HydroModel 
 L_HydroResult 
 L_HydroEvent 
 L_Wtr_Nm 

*Additional datasets (such as S_HydroLanduse) are still required if utilized. 

N80 Section N.4 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

Figure N-8. Entity Relationship Diagram for Hydrology 


N81 Section N.4 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

N.4.2.2 Required Hydrologic Data [April 2005] 
L_HydroModel Table 

The L_HydroModel table is a database table. It is required for all types of hydrologic analyses. 
This table identifies the model(s) and hydrologic result file(s) related to a particular watershed. 

The L_HydroModel table contains the attributes provided in Table N-92. 

Table N-92. L_HydroModel Table 

Field Type Length Required Description 
HydroID Long Yes Primary key for table. AutoNumber field. 
Hydro_LID Long Yes A foreign key to the D_Hydro domain table. 
Descript Text 254 Yes Model description. 
ZipName Text 254 No File name of a compressed hydrologic model, 
including inputs and outputs, stored in the 
Simulations folder for this watershed. 
WtshdFldr Text 254 Yes Folder that stores all files for this watershed. 
SubInfoID Long Yes Foreign key to L_Submittal_Info table. 
RPTName Text 254 Yes File name of the design hydrology report stored 
in the General folder. 
CNGroupID Long No Foreign key to L_HydroCNLookup table used to 
identify a set of curve numbers. 
IsNew Boolean Yes Specifies whether this is a new model or 
modification/reference of an existing model. 

S_HydroNode Spatial File 

The S_HydroNode spatial file is required for all types of hydrologic analyses. Each point in this 
spatial data can have computed discharge values (in L_HydroResult table) associated with it, 
when paired with a HydroModel. The points must lie on the stream centerlines as shown in the 
S_HydroLink spatial dataset. HydroNodes can represent subbasin pour points or HydroLink 
confluences.

 The S_HydroNode spatial file contains the attributes presented in Table N-93. 

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Updated May 2005]

Table N-93. S_HydroNode Spatial File 

Field Type Length Required Description 
NodeID Long Yes Primary key for table. 
NodeName Text 254 Yes Description of the location. This information will be 
included in the FIS text. Must be unique across a 
watershed. 
IsPourPt Boolean Yes Nodes can be either basin outlets/pour points or 
confluences. 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata file when 
describing the source information. 

S_HydroLink Spatial File 

The S_HydroLink spatial file(s) is required for all types of hydrologic analysis. This dataset is 
used as the base for delineation of basin boundaries and identification of discharge locations. 
The features in the S_HydroLink spatial file connect HydroNodes and follow the profile baseline 
wherever available. All link segments are to be drawn upstream to downstream and must not be 
multi-part shapes. 

The S_HydroLink attribute table contains the information presented in Table N-94. 

Table N-94. S_HydroLink Spatial File 

Field Type Length Required Description 
LinkID Long Yes Primary key for table. 
WTR_NM_LID Long Yes A foreign key to the L_Wtr_Nm table. 
LinkName Text 254 No An optional identification string for each reach. If 
used, LinkName must be unique across a 
watershed. 
UpNodeID Long No A foreign key to the S_HydroNode table. The 
upstream node of a link. 
DownNodeID Long No A foreign key to the S_HydroNode table. The 
downstream node of a link. 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata file when 
describing the source information. 

Figure N-9 illustrates the proper placement of HydroNodes and HydroLinks. Note that 
HydroNodes are required at basin pour points and confluences. 

N83 Section N.4 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

Figure N-9. Placement of HydroNodes and HydroLinks 


S_HydroBasin Spatial File 

The S_HydroBasin spatial file is required whenever basins have been utilized for hydrologic 
analyses. Basins must have only one part and cannot self-intersect (must be simple). Adjacent 
basins should not overlap or have gaps between them. Each basin must overlay a corresponding 
stream segment in the S_HydroLink spatial dataset and must have a HydroNode representing the 
outlet/pour point. 

 The S_HydroBasin spatial file contains the attributes presented in Table N-95. 

N84 Section N.4 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

Table N-95. S_HydroBasin Spatial File 

Field Type Length Required Description 
BasinId Long Yes Primary key for table. 
BasinName Text 100 Yes An alpha-numeric name. Must be unique across a 
watershed. 
WTR_NM_LID Long Yes A reference to L_Wtr_Nm table. 
NodeID Long Yes A foreign key to the S_HydroNode table. 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata file when 
describing the source information. 

L_HydroResult Table 

The L_HydroResult table is a database table. It is required for all types of hydrologic analyses. 
This table identifies one or more flooding events associated with a node in the S_HydroNode 
table. A typical example would be four records for a 10-year, 50-year, 100-year, and 500-year 
flood, corresponding to one particular method/model. 

The L_HydroResult table contains the attributes presented in Table N-96. 

Table N-96. L_HydroResult Table 

Field Type Length Decimal 
Places 
Required Description 
ResultID Long Yes Primary key for table. 
HydroID Long Yes A reference to L_HydroModel. 
EventID Long Yes A reference to L_HydroEvent, which 
identifies the return period for this result. 
Discharge Numeric 9 1 Yes Calculated discharge. 
Disch_LID Long Yes A foreign key to the D_Discharge_Units 
domain table. 
Cumulative Boolean Yes Specifies whether this result is for a subbasin 
discharge or a cumulative discharge. 
HydEqID Long No A reference to L_HydroEquation table. 
NodeID Long Yes A reference to S_HydroNode table. 
BasinID Long No A reference to S_HydroBasin table. 

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Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

L_Wtr_Nm Table 

The L_Wtr_Nm table is a database domain table. It is required for all types of hydrologic 
analyses. This table identifies the unique list of stream names used in the submittal. This is the 
same table as defined in Appendix L of these Guidelines, but it is listed here for completeness. 

The L_Wtr_Nm table contains the attributes presented in Table N-97. 

Table N-97. L_Wtr_Nm Table 

Field Type Length Required Description 
WTR_NM_LID Long Yes Primary key for table. 
WTR_NM Text 254 Yes Unique alpha-numeric name (i.e. Crooked 
Creek). 

L_HydroEvent Table 

The L_HydroEvent table is a database table. It is required for all types of hydrologic analyses. 
This table identifies flooding events used in HydroModels. 

The L_HydroEvent table contains the attributes presented in Table N-98. 

Table N-98. L_HydroEvent Table 

Field Type Length Decimal 
Places 
Required Description 
EventID Long Yes Primary key for table. AutoNumber field. 
ReturnPer Numeric 6 1 Yes The recurrence interval of the event in years 
(i.e. 10, 27, 100). 
Descript Text 32 Yes Brief description of flood event (i.e. 10-year 
or Hurricane Hugo). 

N.4.2.3 Other Hydrologic Data [April 2005] 
S_HydroGage Spatial File 

The S_HydroGage spatial file is a spatial file that is used to locate precipitation and flow gages. 
It is required if it is utilized for calibration, regression, or frequency analysis. 

 The S_HydroGage spatial file contains the attributes presented in Table N-99. 

N86 Section N.4 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

Table N-99. S_HydroGage Spatial File 

Field Type Length Required Description 
GageID Long Yes Primary key for table. 
GageName Text 100 Yes An alpha-numeric name. 
GageDesc Text 254 Yes Information describing the location of the 
gage (i.e. Black River at I-95). 
Gage_LID Long Yes Foreign key to D_Gage domain table. 
Gage_ID Text 25 Yes Gage Identification. Assigned by the agency 
maintaining the gage. 
Agency Text 150 Yes Agency. Name of agency maintaining the 
gage. 
Rec_Intvl Text 11 Yes Recording Interval. Recording interval for the 
gage. 
Time_LID Long Yes Recording Interval Time Unit Lookup 
Identification. A code that provides a link to a 
valid entry from the D_Time_Units table. This 
attribute establishes the unit of measure of 
the recording interval. 
Start_PD Date/Time Yes Start Period. This value is the start of the 
earliest period of record used in the gage 
analysis. 
End_PD Date/Time Yes End Period. This value is the end of the 
latest period of record used in the gage 
analysis. 
TimeFname Text 254 No File name of database file with time series 
data (i.e. USGS WATSTORE-formatted peak 
discharge file, WDM files for HSPF, etc.). File 
should be stored in Simulations folder for this 
watershed. 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata file when 
describing the source information. 

S_HydroSoil Spatial File 

The S_HydroSoil spatial file is a polygon spatial file of soil types. It is required if utilized for 
model parameterization. Soil polygons must have only one part and cannot self-intersect (must 
be simple). Adjacent soils should not overlap or have gaps between them. 

The S_HydroSoil spatial file contains the attributes presented in Table N-100. 

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Updated May 2005]

Table N-100. S_HydroSoil Spatial File 

Field Type Length Required Description 
SoilID Long Yes Primary key for table. 
SoilType Text 20 Yes Soil Type (dependent on classification system 
utilized  to be referenced in metadata). 
SoilAbbrev Text 20 No Abbreviation (i.e. Ch, Wg, Chcr). 
SoilDesc Text 100 No Example: Watauga Silty Clay Loam. 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata file when 
describing the source information. 

S_HydroLanduse Spatial File 

The S_HydroLanduse spatial file is a polygon spatial file of land-use classifications. It is 
required if utilized for model parameterization. Land-use polygons must have only one part and 
cannot self-intersect (must be simple). Adjacent land uses should not overlap or have gaps 
between them. 

 The S_HydroLanduse spatial file contains the attributes presented in Table N-101. 

Table N-101. S_HydroLandUse Spatial File 

Field Type Length Required Description 
LUID Long Yes Primary key for table. 
LUType Text 50 Yes Alpha-numeric name or abbreviation used to 
ID this land use type (i.e. Industrial, Residential 
Half-Acre, R4, etc.). 
LUDesc Text 100 No Detailed description of this land use. 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata file when 
describing the source information. 

S_HydroImpervious Spatial File 

The S_HydroImpervious spatial file is a polygon spatial file of impervious areas. It is required if 
utilized for model parameterization. Impervious areas must have only one part and cannot self-
intersect (must be simple). Adjacent areas should not overlap. 

 The S_HydroImpervious spatial file contains the attributes presented in Table N-102. 

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Updated May 2005]

Table N-102. S_HydroImpervious Spatial File 

Field Type Length Decimal 
Places 
Required Description 
ImpID Long Yes Primary key for table. 
ImpervPerc Numeric 6 2 Yes Percent of impervious areas in the 
polygon. 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata file 
when describing the source information. 

S_HydroTC Spatial File 

The S_HydroTC spatial file is a linear spatial file representing Time of Concentration flowpaths. 
It is required if utilized for rainfall runoff model parameterization. Time of Concentration 
polylines must have only one part and cannot self-intersect (must be simple). TCs are associated 
to a basin, and there can be one or more TCs per basin, if the engineer wishes to divide the 
overall path into channel, swale and overland parts. 

 The S_HydroTC spatial file contains the attributes presented in Table N-103. 

Table N-103. S_HydroTC Spatial File 

Field Type Length Decimal 
Places 
Required Description 
TCID Long Yes Primary key for table. 
BasinID Long Yes A foreign key to the S_HydroBasin table. 
TC Numeric 6 3 Yes Time of concentration (time is by segment, 
not total for a basin). 
Time_LID Long Yes Foreign key to D_Time_Units domain table. 
Regime Text 10 Yes Flow regime (i.e. Channel, Swale, Lake, 
Overland, Pipe, etc.). 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata file 
when describing the source information. 

L_HydroEquation Table 

The L_HydroEquation table is a database table used to store basic regression equations utilized 
in regression analysis. It is required whenever basic regression equations are used in the 
modeling process. Variable names used in regression equations should correspond to parameter 
ShortNames in D_HydroParam. 

The L_HydroEquation table contains the attributes presented in Table N-104. 

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Updated May 2005]

Table N-104. L_HydroEquation Table 

Field Type Length Decimal 
Places 
Required Description 
HydEqID Long Yes Primary key for table. AutoNumber field. 
Equation Text 254 Yes Textual depiction of equation (i.e. Q10 = 
622*DA^0.75). 
TR Numeric 6 1 Yes Recurrence interval. 
Descript Text 50 Yes Details about the equation (2000 NC 
Regression Equations). 

L_HydroNodeParam Table 

The L_HydroNodeParam table is a database table used to store parameter values at nodes 
utilized in regression analysis. It is required whenever regression equations are used in the 
modeling process. 

The L_HydroNodeParam table contains the attributes presented in Table N-105. 

Table N-105. L_HydroNodeParam Table 

Field Type Length Decimal 
Places 
Required Description 
NodeParID Long Yes Primary key for table. AutoNumber field. 
NodeID Long Yes Foreign key to S_HydroNode. 
ParamID Long Yes Foreign key to D_HydroParam. 
ParamValue Numeric 16 6 Yes Value for this parameter at this node. 

D_HydroParam Table 

The D_HydroParam table is a domain table used to store a list of node parameters utilized in 
regression analysis. It is required whenever regression equations are used in the modeling 
process. A sample domain table is included, but D_HydroParam is designed to expand as the 
users needs expand, so this is not a comprehensive list. 

The D_HydroParam table contains the attributes presented in Table N-106. Table N-107 
contains the domain values for D_HydroParam. 

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Updated May 2005]

Table N-106. D_HydroParam Table 

Field Type Length Required Description 
ParamID Long Yes Primary key for table. AutoNumber field. 
ShortName Text 50 Yes Name of parameter. Used in regression 
equation. 
Descript Text 254 No Details about this parameter. 
UnitType Text 10 Yes Type of unit. Used to specify which domain 
table the UnitID field references. Values are 
Time, Length, Velocity, Volume, Area, 
None. The corresponding domain tables are 
D_Time_Units, D_Length_Units, 
D_Velocity_Units, D_Volume_Units, 
D_Area_Units, and none. 
UnitID Long No Foreign key to corresponding domain table. 

Table N-107. Sample Domain Values for D_HydroParam 

ParamID ShortName Descript UnitType UnitID 
1 DA Drainage Area Area 1000 
2 BDF Basin Development Factor None 
3 Slope Main Channel Slope None 
4 AvgBasinElev Average Basin Elevation Length 1010 

L_HydroCNResult Table 

The L_HydroCNResult table is a database table used for describing SCS curve numbers used in 
models such as HEC-1 and HEC-HMS. It is required if utilized for rainfall runoff model 
parameterization. 

The L_HydroCNResult table contains the attributes presented in Table N-108. 

Table N-108. L_HydroCNResult Table 

Field Type Length Decimal 
Places 
Required Description 
CNID Long Yes Primary key for table. AutoNumber field. 
BasinID Long Yes A foreign key to S_HydroBasin. 
CN Numeric 6 2 Yes Calculated SCS curve number. 
CNGroupID Long Yes A foreign key to the L_HydroCNLookup table. 
WtshdFldr Text 254 No The folder of the watershed containing the 
spatial files (soil and/or land use) used to 
calculate these results. 

N91 Section N.4 


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Updated May 2005]

L_HydroCNLookup Table 

The L_HydroCNLookup table is a database table that relates various combinations of soil and 
land use types, to provide an appropriate curve number. It is required if curve numbers are 
utilized. 

The L_HydroCNLookup table contains the attributes presented in Table N-109. 

Table N-109. L_HydroCNLookup Table 

Field Type Length Decimal 
Places 
Required Description 
CNLookupID Long Yes Primary key for table. AutoNumber field. 
CNGroupID Long Yes Used to identify a set of Curve Number lookups. 
SCSSoil Text 2 Yes SCS Hydrologic Soil Type (A, B, C, D). If 
S_HydroSoil spatial file is submitted, these 
values should correspond to those in the spatial 
file field SoilType. 
LUType Text 50 Yes Land use name. If S_HydroLandUse spatial file 
is submitted, these values should correspond to 
those in the spatial file field LUType. 
CN Numeric 6 2 Yes SCS curve number established for this land use 
/ soil combination. 
AMC Integer Yes Antecedent moisture condition (1,2 or 3). 
SCSLUType Text 50 No Example: Open Space  Fair condition. 
Source Text 254 Yes SCS TR-55, etc. 

L_HydroStormInfo Table 

The L_HydroStormInfo table is a database table that is useful for describing precipitation 
distributions used in the hydrologic analysis. It contains basic descriptions of precipitation 
patterns. It is required if utilized for rainfall runoff model parameterization. 

The L_HydroStormInfo table contains the attributes presented in Table N-110. 

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Updated May 2005]

Table N-110. L_HydroStormInfo Table 

Field Type Length Required Description 
StormID Long Yes Primary key for table. AutoNumber field. 
Storm_LID Long Yes Storm Type Lookup Identification. A code that 
provides a link to a valid entry from the 
D_Storms table. This attribute establishes the 
storm type. 
Storm_Desc Text 254 No Storm Description. Brief text description/note for 
the storm. 
BasinID Long Yes A foreign key to the S_HydroBasin table. 

L_HydroStormCurve Table 

The L_HydroStormCurve table is a database table that is useful for describing precipitation data 
used in the hydrologic analysis. It accommodates descriptions of Depth-Duration-Frequency 
(DDF) and Intensity-Duration-Frequency (IDF) relationships, as well as durations of design 
storms and precipitation patterns of historical storms. It is required if utilized for rainfall runoff 
model parameterization. 

The L_HydroStormCurve table contains the attributes presented in Table N-111. 

N93 Section N.4 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

Table N-111. L_HydroStormCurve Table 

Field Type Length Decimal 
Places 
Required Description 
CurveID Long Yes Primary key for table. AutoNumber 
field. 
StormID Long Yes Storm Identification. A code that 
provides a link to a valid entry from the 
L_HydroStormInfo table. 
Duration Text 11 Yes Duration. Duration of precipitation 
event. The duration is that of a design 
or historical storm, or of a point on a 
DDF or IDF curve. 
Time_LID Long Yes Duration Unit Lookup Identification. A 
code that provides a link to a valid entry 
from the D_Time_Units table. This 
attribute establishes the unit of measure 
of the corresponding duration entry. 
Depth Numeric 5 2 No Precipitation Depth. This field is 
populated only if entering data for a 
DDF curve. 
Len_LID Long No Precipitation Depth Unit Lookup 
Identification. A code that provides a 
link to a valid entry from the 
D_Length_Units table. This attribute 
establishes the unit of measure for the 
precipitation depth. This field is 
populated only if a precipitation depth is 
entered. 
Intensity Numeric 5 2 No Rainfall intensity. This field is populated 
only if entering data for an IDF curve. 
Vel_LID Long No Rainfall Intensity Unit Lookup 
Identification. A code that provides a 
link to a valid entry from the 
D_Velocity_Units table. This attribute 
establishes the unit of measure for 
precipitation intensity. This field is 
populated only if precipitation intensity 
is entered. 
EventID Long No A foreign key to L_HydroEvent table. 

N.4.3 Deliverables [May 2005] 
N.4.3.1 Metadata [May 2005] 
A metadata file that complies with the FEMA/FGDC Metadata (available under separate cover 
from FEMA Headquarters) Profiles in XML-format shall be included with the submittal. The 
profiles follow the FGDC Content Standard for metadata and define additional domains and 
business rules for some elements and those elements that are mandatory for FEMA based on the 
specific submittal type. 

N94 Section N.4 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

There are specific items in the FGDC metadata standards that the submitter shall address. For 
each spatial data source in the metadata file, the Mapping Partner shall assign a Source Citation 
Abbreviation. The overview description subsection of the entity and attribute information of the 
metadata file must include a list of all DCS database tables included in the submittal. 

N.4.3.2 Hard Copy Deliverables [December 2004] 
Supplemental information may be delivered in hard copies. 

N.4.3.3 Digital Deliverables [April 2005] 
Transfer Media 

Mapping Partners must submit files on one of the following electronic media, or via the internet: 

 CD-ROM 
 DVD 
 Upload to Mapping Information Platform (MIP) (http://www.hazards.fema.gov) 
As technology changes or in special situations, other media may be acceptable if coordinated 
with FEMA. 

Directory Structure and Folder Naming Conventions 

A metadata file compliant with FEMA/FGDC Metadata Profiles shall be placed in the General 
folder on the root directory of Disk1. 

The Mapping Partner is required to submit the input and output files for any study using detailed 
hydrologic models such as HEC-1 or HEC-HMS. If the data that was used to estimate the 
hydrologic parameters is available, it shall be submitted as well. 

Models are organized by watershed, with all model files in the Simulations folder and support 
spatial files in the Spatial Files folder. Database files are stored in a Hydrology Databases 
folder. If submitting in Microsoft Access format, this file will be named Hydrology.mdb. If 
submitting in Dbase IV format, each table will be stored in its own file (i.e. 
L_HydroModel.dbf). Any additional data used to assist in the modeling of this study not 
described in these specifications can be submitted in the Supplemental Info folder. Data must be 
located in the appropriate directory, as follows. 

N95 Section N.4 


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Updated May 2005]

\General 

o XML-format metadata file 
o Hydrology design report in PDF format 
\Hydrology Databases 

o Database file(s), including L_Submittal_Info table 
\Hydrology Models\Watershed Name\Simulations 

o Model input and output files by watershed 
\Hydrology Models\Watershed Name\Spatial Files 

o Spatial files by watershed 
\Supplemental Info 

o Any additional supplemental info used in this study 
Data Identification Requirements 

All digital media submitted must be labeled with at least the following information: 

 Mapping Partner name 
 Community name and state for which the FIS was prepared 
 Hydrologic Data 
 Date of submission (formatted mm/dd/yyyy) 
 Disk [sequential number] of [number of disks] 
N96 Section N.4 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

N.5 Hydraulics Submittal Standards 
N.5.1 Overview [December 2004] 
The development of a hydraulic model to provide water surface elevations for floodplain 
mapping requires a significant investment in time and resources to obtain and process 
topographic survey data including cross section and bridge surveys. Recent developments in 
digital terrain and geospatial database management technology make it possible to protect this 
investment for existing and future projects to a much greater extent than was possible in the past. 
This Appendix describes the format and type of hydraulic data to be provided to FEMA for new 
riverine flood insurance studies. Information on the proper procedures to create hydraulic models 
is provided in Appendix C of these Guidelines. 

FEMA accepts ten one-dimensional steady flow, nine one-dimensional unsteady flow, and four 
two-dimensional steady/unsteady flow hydraulic models for the delineation of floodplains and 
two models specifically developed for the delineation of floodways for any location within the 
United States. In addition, three models that have been developed for specific geographic 
locations have been approved for use by FEMA. 

If the past is any indication of future trends, new-generation hydraulic models (with significantly 
different data requirements) will be added to the FEMA list of acceptable models in the future. 
Considering the widely varying data requirements for these models, the FEMA database for 
supporting hydraulics must be flexible. 

The Minimum Required Dataset, which is described in detail in the body of this Appendix, 
includes the following items: 

.. A georeferenced/projected stream channel network, which is used for floodplain mapping 
.. A georeferenced line dataset showing the locations of cross sections used for the 
computation of water surface profiles for one-dimensional models, or a DTM file of 
water depths or other appropriate file structure for two-dimensional models 
.. A georeferenced line dataset showing draft regulatory floodway, 100-year floodplain, and 
500-year floodplain boundaries, where calculated 
.. Input and output files for an approved hydraulic model (an updated list of these models 
can be obtained from http://www.fema.gov/fhm/en_hydra.shtm) 
.. All geospatial datasets used for parameter calculation without further processing (e.g. a 
spatial file of n-value polygons but not the land use polygons that they are based upon) 
.. An FIS narrative report 
.. A series of database tables summarizing key data 
.. Some additional geospatial and database tables if utilized (i.e. overbank distances are 
used in certain models such as HEC-RAS and HEC-2) 
N97 Section N.5 


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Updated May 2005]

N.5.2 Requirements [April 2005] 
N.5.2.1 Data Files [April 2005] 
The following deliverables are required for a hydraulics submittal: 
.. Database tables 
.. Spatial files 
.. Hydraulic models 

Most spatial features can be stored in an ESRI shapefile or Open GML document, with the 
necessary attribute fields and spatial projection information. Other domain and hydraulic results 
tables will be populated in dBASE IV format or Microsoft Access. 

The database tables and spatial files used in a hydraulics submittal are shown in Table N-112. 

N98 Section N.5 


Guidelines and Specifications for Flood Hazard Mapping Partners [April 2004; Sections 
Updated May 2005]

Table N-112. Hydraulics Tables and Spatial Data 

Table Name Description 
L_HydraModel A database table. The highest level representation of a 
hydraulic model. Contains important information on 
geometry and results files. 
S_StreamCntrLine A spatial dataset showing the centerlines of the stream 
network. Used for backwater models such as HECRAS. 
S_HydraCrossSection A linear spatial file of cross sections. 
S_RefPoint Spatial file that describes the downstream point where 
a riverine model starts. 
L_HydraFloodResult A database table. Stores flood elevations and 
discharges for a cross section. 
L_HydraEvent A database table. Identifies flood events. 
L_Wtr_Nm A database table. A lookup table of stream names. 
S_HydraMapping A linear spatial file containing draft floodway 
boundaries, 100-year and 500-year flood boundaries. 
S_BFE A linear spatial file containing work map BFEs. 
Stream Profiles A CAD drawing file containing stream profiles. Used in 
the FIS narrative. 
Floodway Data Tables Microsoft Word documents used in the FIS narrative. 
S_HydraFlowPath A linear spatial file that can represent streams and/or 
more complicated features like bridges, culverts, dams, 
pipes or trapezoid channels. 
S_HydraJunction A point spatial file that identifies confluences or 
transition points along a stream. 
L_HydraXsPt A database table for detailed profile calculations. 
S_HydraNvalue A polygon spatial file used to assign roughness 
coefficients. 
S_Ovrbnkln A linear spatial file used for measuring overbank flow 
distances. See Appendix L of these Guidelines. 

Depending on the scope of work, the Mapping Partner may develop a new hydraulic model with 
all the associated input files, may modify an existing model developed for the effective flood 
insurance study or a related study, or simply utilize an existing model or adopt the effective flood 
elevations. Table N-113 describes the minimum required datasets for each study approach and 
the two primary hydraulic modeling approaches: backwater models (i.e. HEC-RAS) or network 
models (i.e. SWMM and ICPR). If existing models are not available in digital format, the hard 
copy output from the model or analysis is to be scanned into a PDF file. 

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Table N-113. Minimum Required Datasets by Model Type 

Hydraulic Study Type Backwater Model Network Model 
New Model, Modified 

Spatial File: 

Spatial File: 

FEMA Model, or 

 S_StreamCntrLine 
 S_StreamCntrLine 
Capture of a FEMA 

 S_HydraCrossSection 
 S_HydraCrossSection 
Model 

 S_RefPoint 
 S_RefPoint 
Table: 

 S_HydraFlowPath 
 L_HydraModel 
 S_HydraJunction 
 L_HydraFloodResult 
Table: 

 L_HydraEvent 
 L_HydraModel 
 L_Wtr_Nm 
 L_HydraFloodResult 
Work Map Products: 

 L_HydraEvent 
 S_HydraMapping 
 L_Wtr_Nm 
 S_BFE 
Work Map Products: 

 Stream Profiles 
 S_HydraMapping 
 Floodway Data Tables 
 S_BFE 
 Stream Profiles 
 Floodway Data Tables 
Figure N-10 is a schematic view of the relational database files required for the minimum 
hydraulic submittal. A detailed description of each of these data requirements is provided in the 
body of this section. 

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Updated May 2005]

Figure N-10. Entity Relationship Diagram for Hydraulics 


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Updated May 2005]

N.5.2.2 Required Hydraulic Data [April 2005] 
L_HydraModel Table 

The L_HydraModel table is a database table. It is required for all types of hydraulic analyses. 
This table identifies the models used for the floodplain delineation study. 

The L_HydraModel table contains the elements presented in Table N-114. 

Table N-114. L_HydraModel Table 

Field Type Length Required Description 
HydraID Long Yes Primary key for table. 
Hydra_LID Long Yes A foreign key to D_Hydra. See Appendix L of 
these Guidelines. 
SubInfoID Long Yes Foreign key to L_Submittal_Info table. 
Descript Text 254 Yes Model description. 
ZipName Text 254 Yes File name of a compressed hydraulic model 
including inputs and outputs, stored in the 
Simulations folder. 
RptName Text 254 Yes File name of the FIS narrative report, stored in 
the General folder. 
StreamFldr Text 254 Yes Folder that stores all files for this stream. 
IsNetwork Boolean Yes Specifies whether this is a network model or a 
backwater model. 

S_StreamCntrLine Spatial File 

The S_StreamCntrLine spatial file(s) is required for locating all cross-sections and for 
referencing the data from the hydrologic study. This dataset is used as the base for locating 
cross-section alignments and for the location of discharge locations. Stream centerlines are not 
be multipart or self-intersecting. Streams are to be drawn upstream to downstream, and 
connected endpoint to endpoint with adjacent streams. 

The S_StreamCntrLine attribute table contains the information presented in Table N-115. 

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Updated May 2005]

Table N-115. S_StreamCntrLine Spatial File 

Field Type Length Required Description 
StrmLineID Long Yes Primary key for table. 
WATER_LID Long Yes A foreign key to the D_Water_Typ table. See 
Appendix L of these Guidelines. 
CHAN_LID Long Yes A foreign key to the D_Chan_Rep table. See 
Appendix L of these Guidelines. 
WTR_NM_LID Long Yes A foreign key to the L_Wtr_Nm table. 
SegName Text 254 No An optional identification string for each reach. If 
used, this must be unique for a stream. 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata file when 
describing the source information. 

S_HydraCrossSection Spatial File 

The S_HydraCrossSection spatial file is required for models that utilize cross sections. This file 
will not be submitted for two-dimensional models that do not employ cross sections for 
simulating water surfaces. Cross sections are associated to one stream flow path and must 
intersect that flow path at only one point. Stream station is used to match these sections to the 
hydraulic results table, so there must be a one-to-one match with the results. All cross sections 
must be drawn left to right facing downstream. Multi-part shapes are not allowed. 

Where submitted, the S_HydraCrossSection spatial file contains the elements presented in Table 
N-116. 

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Updated May 2005]

Table N-116. S_HydraCrossSection Spatial File 

Field Type Length Decimal 
Places 
Required Description 
XsectID Long Yes Primary key for table. 
XS_LTR Text 10 No Example: B, AQ 
RefPtID Long Yes A foreign key to the S_RefPoint.. 
STREAM_STN Numeric 12 2 Yes Distance from the reference point 
along the stream. 
XS_LN_TYPE Text 20 Yes LETTERED or NOT LETTERED. 
WTR_NM_LID Long Yes A foreign key to the L_Wtr_Nm table. 
LEN_LID Long Yes A foreign key to the D_Length_Units 
table (see Appendix L). 
V_DATM_LID Long Yes A foreign key to the D_V_Datum table 
(see Appendix L). 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata file 
when describing the source 
information. 
BED_ELEV Numeric 8 2 Yes Lowest stream bed elevation, from 
profile. 
XsName Text 100 Yes Unique alpha-numeric name. 
DataType Text 12 Yes Top of Road or Natural. 
CenterStat Numeric 9 2 Yes The cross section station used in the 
model that corresponds to the 
intersection point of the stream and 
cross section. 

S_RefPoint Spatial File 

The S_RefPoint spatial file(s) is required. These points indicate the reference point that was 
used as the origin for distance measurements along streams and rivers. 

The S_RefPoint attribute table contains the information presented in Table N-117. 

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Table N-117. S_RefPoint Spatial File 

Field Type Length Required Description 
RefPtID Long Yes Primary key for table. 
Start_Desc Text 254 Yes Description of the location of the station starting 
point. For example, Feet upstream of 
Mecklenburg County line. 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata file when 
describing the source information. 

L_HydraFloodResult Table 

The L_HydraFloodResult table is a database table. It is a required table that is used to store one 
or more flood elevations and discharges per cross section. The L_HydraFloodResults table 
contains the elements presented in Table N-118. 

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Table N-118. L_HydraFloodResult Table 

Field Type Length Decimal 
Places 
Required Description 
ResultId Long Yes Primary key for table. 
HydraID Long Yes A foreign key to the L_HydraModel table. 
XsectID Long Yes A foreign key to the 
S_HydraCrossSection spatial file. 
EventId Long Yes A foreign key to the L_HydraEvent table. 
WSEL_Model Numeric 8 2 Yes Modeled flood elevation. 
WSEL_Reg Numeric 8 2 Yes Regulatory flood elevation that matches 
profile (and floodway data table for 
Floodway event). 
Discharge Numeric 9 1 Yes Discharge. 
DISCH_LID Long Yes A foreign key to the D_Discharge_Units 
table (see Appendix L). 
TOP_WIDTH Numeric 9 2 No Floodway width, used in floodway data 
table. Required for Floodway event. 
XS_AREA Numeric 10 2 No Underwater cross section area used in 
floodway data table. Required for 
Floodway event. 
AREA_LID Long No A foreign key to the D_Area_Units table 
(see Appendix L). Required if XS_Area is 
populated. 
VELOCITY Numeric 8 2 No Mean velocity, used in the floodway data 
table. Required for Floodway event. 
VEL_LID Long No A foreign key to the D_Vel_Units table 
(see Appendix L). Required if Velocity is 
populated. 
LEN_LID Long Yes A foreign key to the D_Length_Units table 
(see Appendix L). 
V_DATM_LID Long Yes A foreign key to the D_V_Datum table 
(see Appendix L). 

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Updated May 2005]

L_HydraEvent Table 

The L_HydraEvent table is a database table. It is required for all types of hydraulic analyses. 
This table defines a list of modeled floods. The L_HydraEvent table contains the elements 
presented in Table N-119. 

Table N-119. L_HydraEvent Table 

Field Type Length Decimal 
Places 
Required Description 
EventId Long Yes Primary key for table. AutoNumber field. 
ReturnPer Numeric 6 1 Yes The recurrence interval of the event in years 
(i.e. 10, 26.5, 100). 
Descript Text 32 Yes Brief description of flood event (i.e. 10-year 
or Hurricane Hugo). 
IsFW Boolean Yes Identifies a floodway simulation. 

L_Wtr_Nm Table 

The L_Wtr_Nm table is a database domain table. It is required for all types of hydraulic 
analyses. This table identifies the unique list of stream names used in the submittal. This is the 
same table as defined in Appendix L of these Guidelines, but it is listed here for completeness. 
The L_Wtr_Nm table contains the elements presented in Table N-120. 

Table N-120. L_Wtr_Nm Table 

Field Type Length Required Description 
WTR_NM_LID Long Yes Primary key for table. 
WTR_NM Text 254 Yes Unique alpha-numeric name (i.e. Crooked 
Creek). 

N.5.2.3 Work Map Products [April 2005] 
Work map products are used to assist in quality control of the hydraulic models. Some items 
listed below, such as S_HydraMapping and S_BFE will also be part of a subsequent Mapping 
Submittal, with any necessary modifications. Stream profiles and floodway data tables are direct 
products of a hydraulic model, so they are incorporated into the Hydraulics DCS. 

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Updated May 2005]

S_HydraMapping Spatial File 

The S_HydraMapping spatial file is a linear spatial file submittal. It contains draft floodway, 
100-year and 500-year boundaries that are a pre-cursor to the preliminary maps. Because the 
EventID is an attribute of each line, it is possible to store flood boundaries for storms other 
than the 100-year and 500-year. The S_HydraMapping spatial file contains the elements 
presented in Table N-121. 

Table N-121. S_HydraMapping Spatial File 

Field Type Length Required Description 
MapID Long Yes Primary key for table. 
WTR_NM_LID Long Yes A foreign key to L_Wtr_Nm table. 
EventID Long Yes A foreign key to L_HydraEvent table. 
HydraID Long Yes A foreign key to L_HydraModel table. 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata 
file when describing the source 
information. 

S_BFE Spatial File 

The Base Flood Elevation (BFE) spatial file is required for any digital data where BFE lines will 
be shown on the corresponding Flood Insurance Rate Map (FIRM). Normally, if there are any 
riverine AE zones, BFE lines are required. This is the same table as defined in Appendix L of 
these Guidelines, but it is listed here for completeness. 

The S_BFE spatial file contains information about the BFEs within a study area, as well as 
locational information. BFE lines indicate the rounded whole-foot water-surface elevation of the 
1-percent-annual-chance flood. 

The S_BFE spatial file contains the attributes listed in Table N-122. 

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Updated May 2005]

Table N-122. S_BFE Spatial File 

Field Type Length Decimal 
Places 
Required Description 
BFE_LN_ID Long Yes Primary key for table. Assigned by table 
creator. 
ELEV Numeric 13 2 Yes Base Flood Elevation. The rounded, whole 
foot elevation of the 1-percent-annualchance flood. 
LEN_LID Long Yes Length Unit Lookup Identification. See 
D_Length_Units table (Appendix L). 
V_DATM_LID Long Yes Vertical datum lookup identification. A 
foreign key to the D_V_Datum table (see 
Appendix L). 
HydraID Long Yes A foreign key to L_Hydramodel table. 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata file when 
describing the source information. 

Stream Profiles 

Stream profiles are used in the Flood Insurance Study narrative and are a direct product of a 
hydraulic model. The NSP provides tools to convert HEC-RAS and HEC-2 models to AutoCAD 
DXF files. These DXF files can be imported into a template AutoCAD drawing file (DWG), and 
edited for content. 

For the Hydraulics DCS, all stream profiles will be submitted as AutoCAD DWG files, named 
StreamName_Profile.dwg. These files are to be located in the Profiles folder of this submittal. 
Additional format information on Flood Profiles is provided in Appendix J of these Guidelines. 
The RASPLOT layer specification should be followed, regardless of the modeling method. 

Floodway Data Tables 

Floodway Data Tables are used in the Flood Insurance Study report narrative and are a direct 
product of a hydraulic model. These tables are required to be submitted in a Microsoft Word 
format, named StreamName_FWDT.doc. These files are to be located in the FWDTs folder of 
this submittal. The specifications for the Floodway Data Table are provided in the sample report 
in Appendix J, Section J.6, of these Guidelines. 

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Updated May 2005]

N.5.2.4 Required If Utilized [April 2005] 
S_HydraFlowPath Spatial File 

The S_HydraFlowPath spatial file is required for hydraulic models other than HEC-RAS and 
HEC-2, such as SWMM or ICPR. Flow paths can be associated to one or more L_HydraModels. 
All flow paths must be drawn upstream to downstream. Multipart shapes are not allowed. 
S_HydraFlowPath can also be used to store modeling base lines, similar to S_Profil_Basln (see 
Appendix L of these Guidelines), when the stream centerline differs from the model baseline. 
The S_HydraFlowPath spatial file contains the attributes presented in Table N-123. 

Table N-123. S_HydraFlowPath Spatial File 

Field Type Length Decimal 
Places 
Required Description 
PathId Long Yes Primary key for table. 
WTR_NM_LID Long Yes Foreign key to L_Wtr_Nm table. 
Water_LID Long Yes A foreign key to the D_Water_Typ table. See 
Appendix L of these Guidelines. 
PathName Text 254 Yes Unique alphanumeric identifier (i.e. CC-1). 
PathType Text 15 Yes Stream, Structure, Pipe, Simple 
Channel. 
InvenID Long No A foreign key to an inventory table (only used 
for non-stream path types). 
UpNodeID Long Yes Foreign key to S_HydraJunction table. 
DownNodeID Long Yes Foreign key to S_HydraJunction table. 
DsStation Numeric 12 2 Yes Distance measured from a prominent location, 
such as a confluence or county line. 
UsStation Numeric 12 2 Yes Distance measured from a prominent location, 
such as a confluence or county line. 
DsInvert Numeric 8 2 No Downstream thalweg elevation. 
UsInvert Numeric 8 2 No Upstream thalweg elevation. 
TopoOffset Numeric 4 1 No For Stream path types, this is the average 
difference between the true thalweg and the 
lowest profile elevation derived from the 
terrain. Useful for limited detail studies. 
Example: True thalweg is 98.2, Topo Invert = 
100, so TopoOffset = -1.8. 
Len_LID Long Yes A foreign key to the D_Length_Units table 
(see Appendix L). 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata file when 
describing the source information. 

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Updated May 2005]

S_HydraJunction Spatial File 

The S_HydraJunction spatial file is required for hydraulic models other than HEC-RAS and 
HEC-2, such as SWMM or ICPR. Junctions are associated to a particular S_HydraFlowPath. 
These junctions can represent confluences of streams or a transition point between a stream and a 
structure. Junctions can also represent more detailed inventory, such as manholes or curb inlets. 

The S_HydraJunction spatial file contains the elements presented in Table N-124. 

Table N-124. S_HydraJunction Spatial File 

Field Type Length Decimal 
Places 
Required Description 
JunctionId Long Yes Primary key for table. 
JunctName Text 50 Yes Unique alphanumeric identifier (i.e. A201). 
JunctType Text 50 Yes Transition, Manhole, Curb Inlet, 
Slab Inlet, Junction Box, Pipe 
Junction 
InvenID Long No Foreign key to an inventory table. Not 
used for junctions on most models 
(HEC-RAS and HEC-2) 
Invert Numeric 8 2 No Lowest elevation at junction 
LEN_LID Long No A foreign key to the D_Length_Units 
table (see Appendix L). Required if 
Invert is populated. 
V_DATM_LID Long No A foreign key to the D_V_Datum table 
(see Appendix L). Required if Invert is 
populated. 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata file 
when describing the source information. 

L_HydraXsPt Table 

The L_HydraXsPt table is a database table. It can be used to store intermediate terrain profiles, 
which are typically used as a major part of a cross section definition in a HEC-RAS or HEC-2 
model. This database table is required for any modeling approaches that do not store 3-D cross 
section geometries explicitly in the model inputs. HEC-RAS and HEC-2 models store this 
information in geometry files, so the terrain profiles are not required for those model types. 

The L_HydraXsPt table contains the elements presented in Table N-125. 

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Updated May 2005]

Table N-125. L_HydraXsPt Table 

Field Type Length Decimal 
Places 
Required Description 
XsPtID Long Yes Primary key for table. 
XsectID Long Yes Foreign key to the 
S_HydraCrossSection table. 
Station Numeric 8 2 Yes Distance from start of section to profile 
point. Cross section must be oriented 
from left to right looking downstream. 
Elevation Numeric 8 2 Yes Elevation. 
Easting Numeric 12 2 Yes X-coordinate. 
Northing Numeric 12 2 Yes Y-coordinate. 
PointNum Long Yes Useful for ordering points when there is 
a vertical step. Integer values. 
Len_LID Long Yes A foreign key to the D_Length_Units 
table (see Appendix L). 

S_HydraNvalue Spatial File 

The S_HydraNvalue spatial file is made up of polygons. It is required when utilized for 
calculating the distribution of the roughness coefficients along the cross sections. The 
S_HydraNvalue Spatial File contains the elements presented in Table N-126. 

Table N-126. S_HydraNvalue Spatial File 

Field Type Length Decimal 
Places 
Required Description 
NvalueID Long Yes Primary key for table. AutoNumber field. 
Nvalue Numeric 5 3 Yes Mannings n-value. Usually a number 
between 0.01 and 0.20. 
LandCover Text 50 Yes A brief description of the land cover, i.e. 
(short grass, boulders, dense brush, fine 
silty clay, etc.). 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata file 
when describing the source information. 

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Updated May 2005]

S_Ovrbnkln Spatial File 

The S_Ovrbnkln spatial file is a linear spatial file submittal. This spatial file contains features 
representing the overbank flow distances between two adjacent cross sections. HEC-2 and 
HEC-RAS models require this information when the overbank distances are not equal to the 
distances measured along the stream centerline. 

The S_Ovrbnkln spatial file contains the attributes presented in Table N-127. 

Table N-127. S_Ovrbnkln Spatial File 

Field Type Length Required Description 
OVRBNK_ID Long Yes Primary key for table. 
WTR_NM_LID Long Yes A foreign key to L_Wtr_Nm table. 
OBNK_SIDE Text 1 Yes L or R, indicates Left or Right. 
SOURCE_CIT Text 11 Yes Abbreviation used in the metadata 
file when describing the source 
information. 

N.5.3 Deliverables [May 2005] 
N.5.3.1 Metadata [May 2005] 
A metadata file that complies with the FEMA/FGDC Metadata Profiles (available under separate 
cover from FEMA Headquarters) in XML-format shall be included with the submittal. The 
profiles follow the FGDC Content Standard for metadata and define additional domains and 
business rules for some elements and those elements that are mandatory for FEMA based on the 
specific submittal type. 

There are specific items in the FGDC metadata standards that the submitter shall address. For 
each spatial data source in the metadata file, the Mapping Partner shall assign a Source Citation 
Abbreviation. The overview description subsection of the entity and attribute information of the 
metadata file must include a list of all DCS database tables included in the submittal. 

N.5.3.2 Hard Copy Deliverables [December 2004] 
Supplemental information may be delivered in hard copies. 

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Updated May 2005]

N.5.3.3 Digital Deliverables [April 2005] 
Transfer Media 

Mapping Partners must submit files on one of the following electronic media or via the internet: 

 CD-ROM 
 DVD 
 Upload to Mapping Information Platform (MIP) (http://www.hazards.fema.gov) 
As technology changes or in special situations, other media may be acceptable if coordinated 
with FEMA. 

Directory Structure and Folder Naming Conventions 

A metadata file compliant with FEMA/FGDC Metadata Profiles will be placed in the General 
folder on the root directory of Disk1. 

The Mapping Partner is required to submit the input and output files for any study using detailed 
hydraulic computer models such as HEC-2 or HEC-RAS. If the data that was used to estimate 
the hydraulic parameters is available, it shall be submitted as well. 

Models are usually organized by stream, with all model files in the Simulations folder and 
support spatial files in the Spatial Files folder. One set of database tables is stored in a 
Hydraulic Databases folder, for all streams. If submitting in Microsoft Access format, this file 
will be named Hydraulics.mdb. If submitting in Dbase IV format, each table will be stored in 
its own file (i.e. L_HydraModel.dbf). Any additional data used to assist in the modeling of 
this study not described in these specifications can be submitted in the Supplemental Info folder. 
Data must be located in the appropriate directories, as follows. 

\General 

o XML-format metadata file 
o Hydraulics design report in PDF format 
\Hydraulic Models\Stream Name\Simulations 

o Model input and output files by stream 
\Hydraulic Models\Stream Name\Spatial Files 

o Spatial files by stream 
\Hydraulic Databases 

o Database file(s), including L_Submittal_Info table 
\Profiles 

o CAD profile(s) by stream (i.e.StreamName_profile.dwg) 
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Updated May 2005]

\FWDTs 

o Microsoft Word floodway data tables by stream (i.e StreamName_fwdt.doc) 
\Supplemental Info 

o Any additional supplemental info used in this study 
Data Identification Requirements 

All digital media submitted must be labeled with at least the following information: 

 Mapping Partner name 
 Community name and state for which the FIS was prepared 
 Hydraulic Data 
 Date of submission (formatted mm/dd/yyyy) 
 Disk [sequential number] of [number of disks] 
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Updated May 2005]

N.6 References [December 2004] 
Federal Geographic Data Committee, FGDC-STD-001-1998. Content Standard for Digital 
Geospatial Metadata (version 2.0), FGDC, c/o USGS, Reston, VA 

http://www.fgdc.gov/metadata/metadata.html 

U.S. Department of the Army, Corps of Engineers, Hydrologic Engineering Center, HEC-1 
Flood Hydrograph Package, Users Manual, Davis, CA, 1990. 
U.S. Department of the Army, Corps of Engineers, Hydrologic Engineering Center, HEC-RAS, 
River Analysis System, Users Manual, Version 3.0, Davis, CA, 2001. 
U.S. Department of the Army, Corps of Engineers, Hydrologic Engineering Center, Hydrologic 
Modeling System, HEC-HMS, Users Manual, Version 2.1, Davis, CA, 2001. 
Watershed Concepts, Guidelines and Specifications for Collecting Survey Data for Flood 
Insurance Studies, Greensboro, North Carolina, November 2003. 

N116 Section N.6