Flood Inundation Mapping for Susquehanna River in Harrisburg, Pennsylvania - 11-ft to 37-ft


Identification_Information:
Citation:
Citation_Information:
Originator:United States Army Corps of Engineers (USACE)
Publication_Date:20130201
Title:
Flood Inundation Mapping for Susquehanna River in Harrisburg, Pennsylvania - 11-ft to 37-ft
Geospatial_Data_Presentation_Form:vector digital data
Online_Linkage: http://www.pasda.psu.edu/
Description:
Abstract:
This layer was created as part of a Flood Inundation Map Library developed for display within the NOAA National Weather Service's Advanced Hydrologic Prediction Services (AHPS), the SRBC Susquehanna Inundation Map Viewer (SIMV), and the USGS Flood Inundation Mapper (FIM). This data represents the potential flood extent for a stage of 11-ft to 37-ft as recorded at the Harrisburg (Susquehanna River at Harrisburg, PA; USGS ID 01570500) river gage. This data is part of a series of inundation layers meant to correlate observations and forecasts from the river gage with a visual representation of the areas impacted by high water. The data set of flood inundation areas was created from flood scenarios generated by HEC-RAS runs provided by USACE-Baltimore and LiDAR data from PASDA processed to extract bare earth points. A shapefile of inundation area for each stage was created and subsequently merged to form continuous datasets for the main-stem Susquehanna River and backwater areas on its tributaries.This data was developed to assist the public and emergency officials with planning and response to high water episodes at or near a defined National Weather Service river forecast point.
Purpose:
Created riverine flood inundation areas for floods ranging from a stage of 11-ft to 37-ft as recorded at the Harrisburg (Susquehanna River at Harrisburg, PA; USGS ID 01570500) river gage for the main-stem Susquehanna River and backwater areas on its tributaries.
Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date:2013
Currentness_Reference:
publication date
Status:
Progress:Complete
Maintenance_and_Update_Frequency:None planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate:-77.045832
East_Bounding_Coordinate:-76.714319
North_Bounding_Coordinate:40.399386
South_Bounding_Coordinate:40.173108
Keywords:
Theme:
Theme_Keyword_Thesaurus:ISO 19115 Topic Categories
Theme_Keyword:inundation areas
Theme_Keyword:tributary
Theme_Keyword:river
Theme_Keyword:forecasts
Theme_Keyword:inundation mapping
Theme_Keyword:inlandWaters
Theme_Keyword:gage
Theme_Keyword:flood plain mapping
Theme_Keyword:elevation
Theme:
Theme_Keyword_Thesaurus:ISO 19115 Topic Categories
Theme_Keyword:elevation
Theme_Keyword:inlandWaters
Place:
Place_Keyword_Thesaurus:None
Place_Keyword:Pennsylvania
Place_Keyword:Paxton Creek
Place_Keyword:Harrisburg
Place_Keyword:Perry County
Place_Keyword:Swatara Creek
Place_Keyword:Dauphin County
Place_Keyword:Yellow Breeches
Place_Keyword:Susquehanna River
Place_Keyword:York County
Place_Keyword:Cumberland County
Access_Constraints:None
Use_Constraints:
Inundated areas shown are not to be used for navigation, regulatory, permitting, or other legal purposes. The Harrisburg Flood Inundation Mapping Team 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.
Point_of_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization:USACE-Philadelphia District (CENAP)
Contact_Person:Jason F. Miller
Contact_Position:Supervisory Hydraulic Engineer
Contact_Address:
Address_Type:physical address
Address:
100 Penn Square East
Address:
Wanamaker Building
City:Philadelphia
State_or_Province:Pennsylvania
Postal_Code:19107-3390
Country:USA
Contact_Voice_Telephone:215-656-6549
Contact_TDD/TTY_Telephone:jason.f.miller@usace.army
Data_Set_Credit:
USACE, USACE-Philadelphia District (CENAP), USACE-Baltimore District (CENAB), PAMAP, Esri
Native_Data_Set_Environment:
Microsoft Windows Server 2008 R2 Version 6.1 (Build 7600) ; ESRI ArcGIS 10.0.4.4000
Cross_Reference:
Citation_Information:
Originator:PAMAP Program, PA Department of Conservation and Natural Resources, Bureau of Topographic and Geologic Survey
Title:
PAMAP Program 3.2 ft Digital Elevation Model of Pennsylvania
Online_Linkage: http://www.pasda.psu.edu/uci/MetadataDisplay.aspx?entry=PASDA&file=PAMAP_DEM.xml&dataset=1247
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Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report:
Source data has an average error which meets or exceeds +/- 3 meters for well defined points across the full dataset. Data product strives to meet geospatial mapping accuracy standards.
Logical_Consistency_Report:
Inundation areas were reviewed and inconsistencies mitigated by removing disconnected water bodies; eliminating extraneous high spots; and clipping polygons at bridges with their lowest portion not impacted by water and considered to remain usable.
Completeness_Report:
PAMAP LiDAR elevation data were used as the source to determine flood inundation level estimated by the HEC-RAS model. Hydraulically disconnected areas (polygons) were removed. Inundation areas are complete for each flood level. The shapefile includes inundation polygons between the upstream study limit Susquehanna River confluence upstream of Little Juniata Creek and downstream study limit confluence downstream of Swatara Creek.
Lineage:
Source_Information:
Source_Citation:
Citation_Information:
Publication_Date:20130201
Publication_Time:000000
Title:
Susquehanna River Flood Inundation Mapping
Geospatial_Data_Presentation_Form:vector digital data
Source_Scale_Denominator:24000
Type_of_Source_Media:None
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date:20091211
Beginning_Time:000000
Ending_Date:20100410
Ending_Time:000000
Source_Currentness_Reference:
The date when the source data was collected.
Source_Citation_Abbreviation:
inundation_areas
Source_Contribution:
The Bare Earth Digital Elevation Model (DEM) used to generate all mapping products was produced by the PAMAP Program and consists of a raster digital elevation model with a horizontal ground resolution of 3.2-feet. The model was constructed from PAMAP LiDAR (Light Detection and Ranging) elevation points. First, the Bare Earth DEM was used to cut cross-section data which was done in the HEC-GeoRAS environment. HEC-GeoRAS is a set of ArcGIS tools specifically designed to process geospatial data for use with HEC-RAS. HEC GeoRAS first serves as a pre-processor which feeds elevation data to HEC-RAS. The hydraulic modeling is completed using HEC-RAS and once the output is considered satisfactory to the engineer, the results are exported from HEC-RAS to HEC-GeoRAS, which is then used as a post-processor in order to visualize the results in the GIS environment. The HEC-RAS output file contained 28 modeled flood profiles from Stage 11-feet through Stage 37-feet as measured at the USGS Gage ID Number 01570500 (SUSQUEHANNA RIVER AT HARRISBURG, PA). The 28 modeled flood profiles were exported to the GIS environment using HEC-GeoRAS. All GIS data developed during HEC-GeoRAS post-processing is based on the content of the HEC-RAS GIS Export File and the Bare Earth DEM. The HEC-RAS GIS Export File contains GIS coordinate-based information that describe the modeling cross-section locations and the resulting water surface elevations at each modeling cross-section. The Export File is first read into the GIS. The next step is to create water surface TINs for each of the 28 modeled flood profiles. The TIN created is based on the water surface elevation at each cross-section. The water surface TIN is created without considering the Bare Earth DEM. The next step is to delineate a flood plain for each water surface TIN. A floodplain polygon is created based on the corresponding water surface TIN. Each floodplain polygon results from intersecting the water surface TIN with the Bare Earth DEM. The water surface TIN is converted to a grid and compared to the Bare Earth DEM. A depth grid is then created with values where the water surface grid is higher than the Bare Earth DEM. The depth grid is clipped by the bounding polygon to remove any areas outside the hydraulic model. The depth grid is then converted into a floodplain polygon feature class. This process resulted in the Main Stem floodplain polygon and Main Stem depth grids. For the study area, there were four major areas of backwater flooding that had to be mapped independently of the Main Stem. Backwater flooding occurs in the following four descriptive areas: 1) along the Paxton Creek from its confluence with the Susquehanna River to the Harrisburg Area Community College; 2) the area behind the Capital City Airport, which is partially along the Yellow Breeches; 3) the area behind the Harrisburg International Airport SR 230; and 4) the area along the Swatara Creek up until a point approximately 2,000-feet south of Interstate 76. These four areas were modeled separately by necessity. Water surface elevations consistent with the point on the Main Stem Susquehanna River which is generating the backwater elevation were mapped using a process similar to the HEC-GeoRAS post-processing routines. During this process, the backwater elevations were rendered as water surface TINs, which were intersected with the Bare Earth DEM to generate both depth grids and floodplain polygons. At this point in the post-processing, all depth grids and Bare Earth DEM data within the backwater areas were re-sampled from a 3.2-feet horizontal ground resolution to a 5-feet horizontal ground resolution in order to accommodate computing times, transfer of data, and legacy mapping software. Once the backwater areas were mapped, the four backwater areas were merged with the Main Stem Susquehanna River flood areas. This was done for the depth grids and the floodplain polygons. Prior to finalizing the data, the depth grids and floodplain polygons needed to be reviewed and edited. The review and editing process consisted of general smoothing and clean-up plus two major steps: 1) remove any disconnected water bodies and 2) bridge clips. Step 1 involved checking all hydraulically disconnected wet areas. If there was evidence that a wet disconnected pond was hydraulically connected (i.e. an underground pipe connects the Main Stem Susquehanna River flooding to the disconnected pond), no action was taken. If there was no evidence of a hydraulic connection, the disconnected pond was removed. Step 2 involved making the depth grids and floodplain polygons as accurate as possible by clipping bridges if they were still usable during a flood event. A clipped bridge means it is not shown as flooded and will remain usable. For Main Stem Susquehanna River bridges, a bridge was clipped (and shown as being usable) as long as the lowest portion of the bridge was not impacted by water. Once the lowest portion of the bridge was impacted, all subsequent and higher elevation flood profiles would not be clipped. For the non-main stem bridges, if the top elevation of the bridge was not flooded, the bridge was clipped and shown to be usable for that flood profile. Once the top elevation of the bridge was impacted by water, all subsequent and higher elevation flood profiles would not be clipped. Once the review and editing process was complete, the depth grids and floodplain polygons were renamed and projected to their final format.
Process_Step:
Process_Description:
Detailed in Source Description section
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Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method:Vector
Point_and_Vector_Object_Information:
SDTS_Terms_Description:
SDTS_Point_and_Vector_Object_Type:GT-polygon composed of chains
Point_and_Vector_Object_Count:0
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Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Planar:
Map_Projection:
Other_Projection's_Definition:
PROJCS["WGS_1984_Web_Mercator_Auxiliary_Sphere",GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Mercator_Auxiliary_Sphere"],PARAMETER["False_Easting",0.0],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",0.0],PARAMETER["Standard_Parallel_1",0.0],PARAMETER["Auxiliary_Sphere_Type",0.0],UNIT["Meter",1.0],AUTHORITY["EPSG",3857]]-20037700-30241100148923141.92838538-10000010000-100000100000.0010.0010.001true3857
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method:coordinate pair
Coordinate_Representation:
Abscissa_Resolution:0.000000006714873101998366
Ordinate_Resolution:0.000000006714873101998366
Geodetic_Model:
Horizontal_Datum_Name:D WGS 1984
Ellipsoid_Name:WGS 1984
Semi-major_Axis:6378137.0
Denominator_of_Flattening_Ratio:298.257223563
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Entity_and_Attribute_Information:
Detailed_Description:
Entity_Type:
Entity_Type_Label:bound_326
Attribute:
Attribute_Label:FID
Attribute_Definition:
Internal feature number.
Attribute_Definition_Source:
ESRI
Attribute_Domain_Values:
Unrepresentable_Domain:
Sequential unique whole numbers that are automatically generated.
Attribute:
Attribute_Label:Shape
Attribute_Definition:
Feature geometry.
Attribute_Definition_Source:
ESRI
Attribute_Domain_Values:
Unrepresentable_Domain:
Coordinates defining the features.
Attribute:
Attribute_Label:MBG_Width
Attribute:
Attribute_Label:MBG_Length
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Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization:Pennsylvania Spatial Data Access (PASDA)
Contact_Address:
Address_Type:mailing and physical address
Address:
115 Land and Water Building
City:University Park
State_or_Province:Pennsylvania
Postal_Code:16802
Country:United States
Contact_Voice_Telephone:(814) 865 - 8792
Contact_Electronic_Mail_Address:pasda@psu.edu
Distribution_Liability:
The USER shall indemnify, save harmless, and, if requested, defend those parties involved with the development and distribution of this data, their officers, agents, and employees from and against any suits, claims, or actions for injury, death, or property damage arising out of the use of or any defect in the FILES or any accompanying documentation. Those parties involved with the development and distribution excluded any and all implied warranties, including warranties or merchantability and fitness for a particular purpose and makes no warranty or representation, either express or implied, with respect to the FILES or accompanying documentation, including its quality, performance, merchantability, or fitness for a particular purpose. The FILES and documentation are provided "as is" and the USER assumes the entire risk as to its quality and performance. Those parties involved with the development and distribution of this data will not be liable for any direct, indirect, special, incidental, or consequential damages arising out of the use or inability to use the FILES or any accompanying documentation.
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Metadata_Reference_Information:
Metadata_Date:20130415
Metadata_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization:USACE-Philadelphia District (CENAP)
Contact_Person:Jason F. Miller, P.E.
Contact_Position:Supervisory Hydraulic Engineer
Contact_Address:
Address_Type:physical address
Address:
100 Penn Square East
Address:
Wanamaker Building
City:Philadelphia
State_or_Province:Pennsylvania
Postal_Code:19107-3390
Country:US
Contact_Voice_Telephone:215-656-6549
Contact_Electronic_Mail_Address:jason.f.miller@usace.army.mil
Metadata_Standard_Name:FGDC Content Standard for Digital Geospatial Metadata
Metadata_Standard_Version:FGDC-STD-001-1998
Metadata_Time_Convention:local time
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