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FEMA Cross Sections

Description | Contacts | Attribute Information | Constraints

Data layer thumbnail image


Layer name:
Subject category:
Title: FEMA Cross Sections
Feature Count: 2943
Feature Type: Line
Abstract: Normally, any FIRM that has associated flood profiles has cross sections. The S_XS table contains information about cross section lines. These lines usually represent the locations of channel surveys performed for input into the hydraulic model used to calculate flood elevations. Sometimes cross sections are interpolated between surveyed cross sections using high accuracy elevation data. Depending on the zone designation (Zone AE, Zone A, etc.), these locations may be shown on Flood Profiles in the FIS report and can be used to cross reference the Flood Profiles to the planimetric depiction of the flood hazards. This information is used in the Floodway Data Tables in the FIS report, as well as on the FIRM panels
Purpose: FEMA Cross Sections
Status: Complete
Updated: As needed
Time period of content: (single date,as YYYYMMDD):: 20200515
Time period of content: (date range, as YYYYMMDD):: -
Spatial reference: WA State Plane North
FGDC Documentation: Classic or FAQ
Open Data Availability: Unknown
Theme Keywords: Floodplain, Flood, FEMA, Hydro, Rivers, Environment, Hazard, elevation,
Lineage: Available


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Secondary: KCGIS Center; This mailbox is monitored during business hours.

Attribute Information

_XS_LN_ID_Primary key for table lookup. Assigned by table creator.
_XS_LTR_Cross Section Letter. This is the letter or number that is assigned to the cross section on the hardcopy FIRM and in the FIS Report. This field is populated when the cross section is lettered.
_START_ID_Station Start Identification. This is the foreign key to the S_Stn_Start layer. The station start describes the origin for the measurements in the STREAM_STN field. This value is used in the FDTs and profiles.
_STREAM_STN_Stream Station. This is the measurement along the profile baseline to the cross section location. This value is used in the FDTs and profiles.
_XS_LN_TYP_Cross-Section Line Type. This attribute should contain ‘LETTERED, MAPPED’ for cross sections that are shown on the hardcopy FIRM and are given a letter. If the cross section will be shown on the FIRM but not lettered, the attribute should contain ‘NOT LETTERED, MAPPED’ to indicate that it is a cross section shown on the hardcopy FIRM, but not on the FDTs or profiles. If the cross section will not be shown on the hardcopy FIRM, this attribute should contain ‘NOT LETTERED, NOT MAPPED’ to indicate that the cross section is part of the backup data for the Flood Risk Project but is not shown on the FIRM. All cross sections used in the development of effective hydraulic models shall be stored in this table, regardless of the flood hazard zone depicted on the effective panels. Acceptable values for this field are listed in the D_XS_Ln_Typ table.
_WTR_NM_Surface Water Feature Name. This is the formal name of the surface water feature.
_WSEL_REG_Regulatory Water Surface Elevation for the 1-Percent-Annual-Chance Flood Event. This the regulatory water-surface elevation for the 1-percent-annual-chance flood event in the stream channel at this cross section. In the case of levee(s) associated with a cross section, it is assumed that the levee(s) holds. For cross sections in the coastal floodplain, this value should be coded “-8888”. For cross sections in the combined coastal and riverine floodplain, this value should reflect the results of the combined rate of occurrence analysis. This field is stored here and in L_XS_Elev to simplify annotation of the FIRM panel water-surface elevation at this cross section. This value and the corresponding value in L_XS_Elev should match.
_LEN_UNIT_Water-Surface and Streambed Elevation Units. This unit indicates the measurement system used for the water-surface and streambed elevations. Normally, this would be feet. Acceptable values for this field are listed in the D_Length_Units table.
_V_DATUM_Vertical Datum. The vertical datum indicates the reference surface from which the flood and streambed elevations are measured. Normally, this would be NAVD88. Acceptable values for this field are listed in the D_V_Datum table.
_SOURCE_CIT_Source Citation. Abbreviation used in the metadata file when describing the source information for the feature. The abbreviation must match a value in L_Source_Cit.


Access: Access Constraint: Data is available on GIS Data Portal:

Use: None