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Maryland State Highway Administration (MDSHA), Eastern Shore Regional GIS Cooperative (ESRGC), National Oceanic and Atmospheric Administration (NOAA), United States Army Corps of Engineers (USACE), United States Geoglogical Survey (USGS),FHWA, Maryland counties and Metropolitan Planning Organizations |
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In light of the significant damage in the state of North Carolina caused by the storm surge from Hurricane Florence on September 14, 2018, concerns about the vulnerability of the coastal communities on the Atlantic coast of Maryland and in Maryland’s portion of the Chesapeake Bay have come into focus. This project seeks to replicate the storm surge heights seen with Hurricane Florence, to determine a what-if scenario in coastal Maryland.METHODOLOGYCoastal County Analysis:NOAA Tides and Currents provide the flood statistic: 5.72ftFive stations within the area of interest contribute water levels above MSL (Station Name [Station ID]):Springmaid Pier, SC [8661070]Wilmington, NC [8658120]Wrightsville Beach, NC [8658163]Beaufort, Duke Marine Lab, NC [8656483]USCG Station Hatteras, NC [8654467]Station collection process (based on Lat-Long box from NWS-archived-river data website):https://tidesandcurrents.noaa.gov/map/index.htmlZoom to North Carolina5 stations along the coastline between Myrtle Beach, SC and Hatteras, NC.Select station, scroll to “more data” -> “water levels”Times series: 9/11/18 – 9/18/18Confirm tidal datum is MSL and collection interval is 6min or 1hrSelect “Show Data Listing”, export to CSVUnder “Station Info” scroll to “Station Home”, lat/long data available for mappingRepeat process for remaining stationsHAZUS-MH 4.2 [ArcGIS for Desktop 10.5.1] software used to simulate flood scenario. Base elevation data reprojected to WGS84 UTM 18N. Base elevations upsampled to DEM with 2m cell resolution. The flood solution is a depth grid representing stillwater elevations (vertical units: ft).LiDAR collections used in base elevation DEMs are best available at time of project launch (2015).Road Segment AnalysisDepth GRID reclassified using 0.5 foot ranges as [gridcode]:0 = less than or equal to one-tenth of a foot (<= 0.10')1 = greater than one-tenth foot and less than or equal to a half foot (> 0.10' and <= 0.5')2 = greater than a half foot and less than or equal to on foot (> 0.5' and <= 1')3 = greater than one foot and less than or equal to two foot (> 1' and <= 2')4 = greater than two foot (> 2')Hazard Vulnerability Index (HVI) calculated in overlay analysis using roadway characterisitics as [risk]:RISK = (Evacuation Route * 0.5 + 1.0) * ((classified stillwater elevation + .01) / 4.0) * (1.0 / Functional Class) * 0.70HVI classified using Natural Breaks as [HVI_Class]:1 = RISK <= 0.0032 = RISK > 0.003 and RISK <= 0.153 = RISK > 0.15 and RISK <= 0.2644 = RISK > 0.264REPROJECTION:Manual reprojection of county DEMs to common spatial reference, per HAZUS-MH standard - WGS84 UTM 18N - EPSG 32618Applied transformations:Anne Arundel - WGS_1984_(ITRF00)_To_NAD_1983Baltimore - WGS_1984_(ITRF00)_To_NAD_1983Baltimore City - WGS_1984_(ITRF00)_To_NAD_1983Calvert - WGS_1984_(ITRF00)_To_NAD_1983Caroline - WGS_1984_(ITRF00)_To_NAD_1983Cecil - WGS_1984_(ITRF00)_To_NAD_1983Charles - WGS_1984_(ITRF00)_To_NAD_1983Dorchester - WGS_1984_(ITRF00)_To_NAD_1983Harford - WGS_1984_(ITRF00)_To_NAD_1983Kent - WGS_1984_(ITRF08)_To_NAD_1983_2011Queen Anne’s - WGS_1984_(ITRF00)_To_NAD_1983Somerset - NAS_1983_NSRS_2007_To_NAD_1983_2011 + WGS_1984_(ITRF08)_To_NAD_1983_2011St. Mary’s - WGS_1984_(ITRF00)_To_NAD_1983Talbot - WGS_1984_(ITRF08)_To_NAD_1983_2011Wicomico - NAS_1983_NSRS_2007_To_NAD_1983_2011 + WGS_1984_(ITRF08)_To_NAD_1983_2011Worcester - NAS_1983_NSRS_2007_To_NAD_1983_2011 + WGS_1984_(ITRF08)_To_NAD_1983_2011Additional Hurricane Florence Resources:https://www.wunderground.com/hurricane/atlantic/2018/tropical-storm-florencehttps://www.nhc.noaa.gov/data/tcr/index.php?season=2018&basin=atl |