GIS Data Catalog

FEMA Cross Sections

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Summary

FEMA Cross Sections

Description

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

Layer information

Layer Name	fema_cross_sections_line
Subject Category	Hydrography
Title	FEMA Cross Sections
Feature Count	2986
Feature Type	Line
Next Update	As needed
Spatial reference	EPSG:2926
Control ID	2854
Place Keywords	None
Theme Keywords	Floodplain, Flood, FEMA, Hydro, Rivers, Environment, Hazard, Elevation
Supplemental Information	None

Table Preview

Attribute information

OBJECTID From Esri	Description Internal feature number. Domain Sequential unique whole numbers that are automatically generated.
XS_LN_ID From FEMA	Description Primary key for table lookup. Assigned by table creator. Domain Not Found
XS_LTR From FEMA	Description 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. Domain Not Found
START_ID From FEMA	Description 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. Domain Not Found
STREAM_STN From FEMA	Description Stream Station. This is the measurement along the profile baseline to the cross section location. This value is used in the FDTs and profiles. Domain Not Found
XS_LN_TYP From FEMA	Description 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. Domain Not Found
WTR_NM From FEMA	Description Surface Water Feature Name. This is the formal name of the surface water feature. Domain Not Found
WSEL_REG From FEMA	Description 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. Domain Not Found
LEN_UNIT From FEMA	Description 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. Domain Not Found
V_DATUM From FEMA	Description 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. Domain Not Found
SOURCE_CIT From FEMA	Description 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. Domain Not Found
Shape From Esri	Description Feature geometry. Domain Coordinates defining the features.
sort_ No Source Noted	Description Not Found Domain Not Found
Shape.STLength() From SQL Server	Description Returns the total length of the elements in a geometry instance. Domain Double

Contact information

Maintained by	DNRP - Water and Land Resources
Primary	Harkeerat Kang Harkeerat.Kang@kingcounty.gov

Terms of Use

License	Terms of use and copyright

Use this Data

Links How to use in ArcGIS Pro
Sharing Status	Public

Summary

FEMA Cross Sections

Description

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.

This information is used in the Floodway Data Tables in the FIS report, as well as on the FIRM panels

Contact information

Maintained by	DNRP - Water and Land Resources
Primary	Harkeerat Kang Harkeerat.Kang@kingcounty.gov

Terms of use and copyright

License	Terms of use and copyright

Change history

5/15/2020	Based on data received from FEMA May 2020