nmyrtlb_depth

Raster Dataset

Tags
flood-inundation maps, October 1-5, 2015, North Myrtle Beach, South Carolina, flood, geospatial analysis, elevation, Horry County, high-water marks, Atlantic Ocean, flooded area


Summary

This raster dataset of depth of flood inundation was created to support the development of flood inundation maps for the Federal Emergency Management Agency's (FEMA) response and recovery operations following an October 1-5, 2015 flood event in the City of North Myrtle Beach, South Carolina on the Atlantic Ocean.

Description

Heavy rainfall occurred across South Carolina during October 1-5, 2015, as a result of an upper atmospheric low-pressure system that funneled tropical moisture from Hurricane Joaquin into the State. The storm caused major flooding in the central and coastal parts of South Carolina. Almost 27 inches of rain fell near Mount Pleasant in Charleston County during this period. U.S. Geological Survey (USGS) streamgages recorded peaks of record at 17 locations, and 15 other locations had peaks that ranked in the top 5 for the period of record. During the October 2015 flood event, USGS personnel made about 140 streamflow measurements at 86 locations to verify, update, or extend existing rating curves (which are used to compute streamflow from monitored river stage). Immediately after the storm event, USGS personnel documented 602 high-water marks, noting the location and height of the water above land surface. Later in October, 50 additional high-water marks were documented near bridges for South Carolina Department of Transportation. Using a subset of these high-water marks, 20 flood-inundation maps of 12 communities were created. Digital datasets of the inundation area, modeling boundary, and water depth rasters are all available for download.

The study area covers a 2.4 mile coastal reach in the City of North Myrtle Beach in Horry County, SC. Thirteen high-water marks were used to define the flood extent.

Credits

Use limitations

Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this data, software, or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. This dataset may be redistributed if it is not edited and is properly referenced. The flood boundaries shown were estimated based on high water marks identified following the flooding event in South Carolina and a digital elevation model. Additional areas may have been flooded and were inaccessable due to hazardous conditions preventing access to flooded areas by the USGS field crews identifying HWMs. Although USGS intends to make this server available 24 hours a day, seven days a week, timely delivery of data and products from this server through the Internet is not guaranteed. The USGS provides these maps "as-is" for a quick reference, emergency planning tool but assumes no legal liability, or responsibility resulting from the use of this information.

Extent

West -78.649051   East -78.596509
North 33.845386   South 33.824439

Scale Range
Maximum (zoomed in) 1:5,000
Minimum (zoomed out) 1:150,000,000

ArcGIS Metadata 

Topics and Keywords 

Themes or categories of the resource  elevation


*Content type  Downloadable Data
Export to FGDC CSDGM XML format as Resource Description No

Place keywords  North Myrtle Beach, South Carolina, Horry County, Atlantic Ocean

Temporal keywords  October 1-5, 2015

Theme keywords  flood-inundation maps, flood, geospatial analysis, high-water marks, flooded area

Theme keywords  elevation

Thesaurus
Title ISO 19115 Topic Categories




Citation 

*Title nmyrtlb_depth
Publication date 2016-02-12 00:00:00


Presentation formats* digital map
FGDC geospatial presentation format  Raster Digital Data Set


Series
Name Open File Report
Issue 2016-1019

Citation Contacts 

Responsible party
Organization's name US Geological Survey, South Atlantic Water Science Center
Contact's role  originator


Resource Details 

Dataset languages  English (UNITED STATES)
Dataset character set  utf8 - 8 bit UCS Transfer Format


Status  completed
Spatial representation type* grid


Supplemental information
A GIS application was used to produce a plane representing the flood-water surface. A raster surface was created with the data points using a Topo to Raster interpolation procedure (http://pro.arcgis.com/en/pro-app/tool-reference/3d-analyst/how-topo-to-raster-works.htm, accessed November 2015), forming the estimated flood surface. A flood-depth grid was made by subtracting the DEM from the flood surface. Areas in which the flood surface elevation was greater than the earth's surface elevation value within the defined study area boundary were included in the flood depth grid. This format allows the GIS data to be overlain on maps and aerial photographs, and to be used for various GIS applications, such as FEMA's Hazards U.S. Multi-Hazards (HAZUS-MH) program (Federal Emergency Management Agency, 2010b) to estimate flood damages. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this Federal Geographic Data Committee-compliant metadata file is intended to document the dataset in nonproprietary form, as well as in ArcGIS format, this metadata file may include some ArcGIS-specific terminology.

*Processing environment Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS 10.2.2.3552


ArcGIS item properties
*Name nmyrtlb_depth
*Location file://E:\joaquin\publish\ORF2016-1019_DATA\Coastal_North_Myrtle_Beach\nmyrtlb_depth
*Access protocol Local Area Network

Extents 

Extent
Description
ground condition

Temporal extent
Beginning date 2015-10-01
Ending date 2015-10-05

Extent
Geographic extent
Bounding rectangle
West longitude -79.954965346
East longitude -79.922105337
South latitude 32.767871233
North latitude 32.805312181

Extent
Geographic extent
Bounding rectangle
Extent type  Extent used for searching
*West longitude -78.649051
*East longitude -78.596509
*North latitude 33.845386
*South latitude 33.824439
*Extent contains the resource Yes

Extent in the item's coordinate system
*West longitude 2713820.000000
*East longitude 2729610.000000
*South latitude 732910.000000
*North latitude 740170.000000
*Extent contains the resource Yes

Resource Points of Contact 

Point of contact
Organization's name US Geological Survey, South Atlantic Water Science Center
Contact's role  point of contact


Contact information
Phone
Voice 678-924-6700

Address
Type both
Delivery point 1770 Corporate Drive, Suite 500
City Norcross
Administrative area GA
Postal code 30097
Country US



Resource Maintenance 

Resource maintenance
Update frequency  not planned


Resource Constraints 

Legal constraints
Limitations of use
See access and use constraints information.

Other constraints
None. This dataset is provided by USGS as a public service.

Constraints
Limitations of use

Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this data, software, or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. This dataset may be redistributed if it is not edited and is properly referenced. The flood boundaries shown were estimated based on high water marks identified following the flooding event in South Carolina and a digital elevation model. Additional areas may have been flooded and were inaccessable due to hazardous conditions preventing access to flooded areas by the USGS field crews identifying HWMs. Although USGS intends to make this server available 24 hours a day, seven days a week, timely delivery of data and products from this server through the Internet is not guaranteed. The USGS provides these maps "as-is" for a quick reference, emergency planning tool but assumes no legal liability, or responsibility resulting from the use of this information.


Spatial Reference 

ArcGIS coordinate system
*Type Projected
*Geographic coordinate reference GCS_North_American_1983
*Projection NAD_1983_StatePlane_South_Carolina_FIPS_3900_Feet_Intl
*Coordinate reference details
Projected coordinate system
Well-known identifier 2273
X origin -122907600
Y origin -92800700
XY scale 36055449.207017787
Z origin -100000
Z scale 10000
M origin -100000
M scale 10000
XY tolerance 0.0032808398950131233
Z tolerance 0.001
M tolerance 0.001
High precision true
Latest well-known identifier 2273
Well-known text PROJCS["NAD_1983_StatePlane_South_Carolina_FIPS_3900_Feet_Intl",GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Lambert_Conformal_Conic"],PARAMETER["False_Easting",2000000.0],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",-81.0],PARAMETER["Standard_Parallel_1",32.5],PARAMETER["Standard_Parallel_2",34.83333333333334],PARAMETER["Latitude_Of_Origin",31.83333333333333],UNIT["Foot",0.3048],AUTHORITY["EPSG",2273]]

Reference system identifier
*Value 2273
*Codespace EPSG
*Version 8.2.6


Spatial Data Properties 

Georectified Grid
*Number of dimensions 2


Axis dimensions properties
Dimension type  row (y-axis)
*Dimension size 726
*Resolution  10.000000 Foot

Axis dimensions properties
Dimension type  column (x-axis)
*Dimension size 1579
*Resolution  10.000000 Foot

Axis dimensions properties
Dimension type  vertical (z-axis)
Dimension size 1

*Cell geometry  area
*Point in pixel  center


*Transformation parameters are available Yes


*Check points are available No


Corner points
*Point 2713820.000000 732910.000000
*Point 2713820.000000 740170.000000
*Point 2729610.000000 740170.000000
*Point 2729610.000000 732910.000000

*Center point 2721715.000000 736540.000000




ArcGIS Raster Properties
General Information
*Pixel depth 32
*Compression type None
*Number of bands 1
*Raster format GRID
*Source type continuous
*Pixel type floating point
*No data value -3.4028231e+038
*Has colormap No
*Has pyramids Yes




Spatial Data Content 

Image Description
*Type of information  physical measurement
Attribute described by cell values Depth


Band information
*Description Band_1
*Maximum value 11.483271
*Minimum value 0.000007
Units
Symbol [ft_us]

*Number of bits per value 32


Triangulation has been performed No
Radiometric calibration is available No
Camera calibration is available No
Film distortion information is available No
Lens distortion information is available No


Data Quality 

Scope of quality information


Data quality report - Conceptual consistency
Measure description
No formal logical accuracy tests were conducted.





Data quality report - Completeness omission
Measure description
Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details.





Data quality report - Quantitative attribute accuracy
Measure description
Input data for the water-level surface were obtained from the HWMs identified and leveled by the USGS following the flooding event and verified with high-resolution imagery.





Data quality report - Absolute external positional accuracy
Dimension horizontal


Measure description
Horizontal accuracy to the input DEM dataset.





Data quality report - Absolute external positional accuracy
Dimension vertical


Measure description
Vertical accuracy to the input DEM dataset.





Lineage 

Process step
When the process occurred 2015-11-01
Description
Created Grid of only inundated areas (positive numbers/wet area): Spatial Analyst Tool: Conditional: Con (Expression: difference "VALUE" >0) (depth grid)





Process step
When the process occurred 2015-11-01
Description
Extracted depth grid to wetpoly_edit for final Depth surface.





Process step
When the process occurred 2015-11-01
Description
Create a polygon of flooded area:Raster to Polygon=(wetpoly feature class)





Process step
When the process occurred 2015-11-01
Description
Clipped inundated area grid to extent boundary: Extraction by Mask: depth grid and the mask is the boundary extent= (depthclip grid)





Process step
When the process occurred 2015-11-01
Description
Edit wetpoly by removing small holes and other outliers due to small variations and artifacts that can not be substaniated by LiDAR data. (Removed 4 cell size or smaller holes within the flooded area) (wetpoly_edit feature class)





Process step
When the process occurred 2015-11-01
Description
Converted clipped depth grid to a grid of all 1 so a flooded area extent polygon could be created:Raster Calculator (Con("depthclip,1,0))= (wet grid)





Process step
When the process occurred 2015-11-01
Description
Interpolation Method: Topo to Raster used to create water-surface raster **Boundary extent: boundary feature dataset (Geographic restriction or limit placed on interpolation extent of inital surface. Based on distribution of HWMs in relation to understanding of natural hydrologic flow in region.) ** Environmental Variables: Processing Extent- Snap grid to LiDAR (DEM) **Resulting dataset( surface)





Process step
When the process occurred 2015-11-01
Description
Create difference grid between DEM and water surface: Raster Calculator: surface - DEM = (difference grid)





Distribution 

Distributor
Contact information
Organization's name US Geological Survey, South Atlantic Water Science Center
Contact's role  distributor


Available format
Name Raster Digital Data Set


Ordering process
Terms and fees None. No fees are applicable for obtaining the data set.



Distribution format
*Name Raster Dataset


Transfer options
Online source
Locationhttp://water.usgs.gov/floods/events/2015/Joaquin/data_ofr20161019/
Name Data download location

References 

Aggregate Information
Association type  larger work citation


Aggregate resource name
Title Flood-Inundation Maps of Selected Areas Affected by the Flood of October 2015 in Central and Coastal South Carolina
Publication date 2016-02-12 00:00:00


Series
Name Open File Report
Issue 2016-1019

Resource location online
Locationhttp://dx.doi.org/10.3133/ofr20161019



Metadata Details 

Metadata language English (UNITED STATES)
Metadata character set  utf8 - 8 bit UCS Transfer Format


Scope of the data described by the metadata  dataset
Scope name* dataset


*Last update 2016-02-19


ArcGIS metadata properties
Metadata format ArcGIS 1.0
Metadata style FGDC CSDGM Metadata
Standard or profile used to edit metadata FGDC


Created in ArcGIS for the item 2015-12-10 07:50:36
Last modified in ArcGIS for the item 2016-02-19 16:43:21


Automatic updates
Have been performed Yes
Last update 2016-02-19 16:43:21


Metadata Contacts 

Metadata contact
Organization's name US Geological Survey, South Atlantic Water Science Center
Contact's role  point of contact


Contact information
Phone
Voice 678-924-6700

Address
Type both
Delivery point 1770 Corporate Drive, Suite 500
City Norcross
Administrative area GA
Postal code 30097
Country US



Metadata Maintenance 

Maintenance
Update frequency  not planned