fema region iii storm surge project
DESCRIPTION
FEMA Region III Storm Surge Project. Construction of The Digital Elevation Model The Foundation of a Storm Surge Model FEMA Region III Coastal Storm Surge Project Workshop November 1 2011 Michael F. Forte, Lisa Stillwell, Jason F. Miller, Jeffrey L. Hanson. FEMA Region III Domain. - PowerPoint PPT PresentationTRANSCRIPT
FEMA Region III Storm Surge Project
Construction of The Digital Elevation Model
The Foundation of a Storm Surge Model
FEMA Region III Coastal Storm Surge ProjectWorkshop November 1 2011
Michael F. Forte, Lisa Stillwell, Jason F. Miller, Jeffrey L. Hanson
FEMA Region III Domain
6 StatesPennsylvaniaDelawareMarylandVirginiaNorth CarolinaNew Jersey
Chesapeake and DelawareBays, Numerous Rivers &Atlantic Seaboard
Data Gathering
Over 125 data sets evaluated (~2 TB)
Data types:• TIFF• CSV• ASCII GRID• Raster• FLT• LAS• Shapefile• SID• and more…
Projections:• NJ, DE, MD, VA State Plane• UTM
Datums:• NAD27• NAD83• Tidal (MSL, MLLW, etc.)
USACE District offices of Philadelphia, Baltimore, and Norfolk played critical role in obtaining the most accurate up-to-date datasets for Region
Data Sources
• US Army Corps of Engineers• USGS• NOAA / NGDC• NC Division of Emergency Management Flood
Plain Mapping Program (NCDEM – FMP)• Individual States
Topographic LiDAR Coverage
24 LiDAR Data sets
National Elevation Dataset (NED) covered remaining areas
Bathymetric Data Coverage
SHOWEX Bathymetric Data Set“SHOaling Waves Experiment”
Conversion
Geographic Coordinates Decimal Degrees (NAD83)Elevation/depth relative to North American Vertical Datum 1988 (NAVD88) meters
Horizontal Conversion
Conversion
•Vertical Datum Conversion
•V – Datum (NOAA)
•Unit Conversion
•Mean Lower Low water MLLW
•North American Vertical Datum of 1988 NAVD 88 m
FEMA Region 3 Divided Into 20 Tiles For Efficient Data ManagementCertain Tiles Contain Up To 6 Gigabytes Of Data.
Regional Organization
Weighted Moving Average Algorithm
Search weight – average value of 3-5 used
Grid Cell Size - 0.00011degrees ~10m cell size
Iterative process obtaining best result given data density and Quality
IVS 3-D Fledermaus Interpolation Parameters
Ex. Search Weight
10m ResolutionInterpolation
Result after interpolationObvious errors literally “jump out”
QA/QC
USACE Districts DEM Review
USACE Districts DEM Review
Cross section from tile 8 reveals anomaly Coordinates are defined for peak and Investigated using Google earth.
8NS5 – Google earth search revealed some square areas that may contain higher elevations (possible mining activities).
USACE Districts DEM Review
ARCADIS DEM Review
Tile 3 DEM Reveals Barrier Island not present in Aerial Photograph
Bridge Removal
Tile 3 Bridge serves as impediment to water flow
Tile 3 Delaware River Bridge Impediment
Fledermaus conversion to “PFM” and bridge is manually removed
Bridge Removal
Tile 3 Re-interpolated with bridge removed
Bridge Removal
Lidar Datasets Need Clipping Around land/water interface
Profile displays jump of 2.5m
Land Water Interface
Most Complete up to date seamless DEM available for Mid-Atlantic Region
Comprised of 120 Datasets (~2TB)
Serves a variety of purposes from modeling to sea level rise studies
High Quality DEM for Mid-Atlantic
Documents DEM data, procedures, and USACE District Review
Published as U.S. Army Corps of Engineers ERDC-CHL Technical Report
Available at: dodreports.com/pdf/ada539477.pdf
Documentation /Submittal 1.1