Using This Application

Map Navigation and Menus

Standard Navigation
Zoom In/Out Incrementally
Zoom To Point
Zoom To Area
Pan
Double-click (quickly) to zoom in one zoom level, centered and click point. Hold down SHIFT key, click map, and drag to zoom to a specific extent. Click map and hold; drag and release.

Menu-Based Navigation

The Search menu provides three options to quickly zoom to an area of interest.

The Address option allows for the input an address and zoom to the location. The tool also allows the user to input additional feature types, as well.

The Beach & City/Town options allow the user to zoom to a beach or municipal area.


NOTE: Submenus for Beach and City/Town are not available on mobile devices. Mobile users should use the Address search, which provides the same search and zoom functionality. Just start typing to see available options.

Change Basemap

This application offers two ESRI® basemap options - Imagery with Labels & Streets.

To change the underlying basemap, click the Change Basemap button. 

Data Access

The Download & Links menu provides access to downloadable OCRM data, links to external data sources, and to the open-source HVA tool and AMBUR software.


Exploring Assessment Results

To begin exploring assessment results, select one of the three result data options.

Once loaded, details about the selected result appear.

View details about the result data inputs by clicking the information icon.  

HVA Rank is the default display parameter, but display of individual input data rankings are available by changing the display parameter.


See details about the display parameter components by clicking the information icon.  

A legend is provided to explain symbology associated with the display parameter.

Layer opacity can be adjusted using the Opacity Slider. This adjusts transparency of the layer (to better see underlying basemap).

Information for specific site or feature can be viewed by clicking on the map.

Inundation Vulnerability

Storm Surge Data Input

Storm surge data is based on the SLOSH (Sea, Lake and Overland Surges from Hurricanes) model, which was developed by the NOAA's National Weather Service. SLOSH produces MEOWs (Maximum Envelope of Water) and MOMs (Maximum of MEOWs). The MEOW is a composite of many hypothetic model runs, with identical hurricane category, speed, and direction, but different landfalls. The maximum value for each grid is plotted. The MOMs (Maximum of MEOWs) is a composite of MEOWs for each category hurricane, plotting the maximum surge for each category. The MOM (AGL) data was used for the Charleston Harbor basin.

Flooding Data Input

Flood data is based on FEMA's DFIRM (Digital Flood Insurance Rate Map) data. The DFIRMS used in this analysis were preliminary. The issue dates for these preliminary DFIRMS are as follows: Charleston County (12/21/2017), Beaufort County (6/30/2017), Jasper County (1/16/2017), Berkeley County (2/12/2016), Dorchester County (11/13/2015), Georgetown County (11/13/2015), and Horry County (9/11/2015). For Colleton County, no DFIRM data were available; therefore, the National Flood Hazard Layer (NFHL) was used, with a latest study effective data of 12/21/2017.

Inundation Result

HVA Rank - Vulnerability rank based on a combination of Q3 RANK and SLOSH RANK; where 1 represents the least risk and 5 represents the most risk.

Flooding (Q3 Rank) - Vulnerability rank based on flood zone derived from FEMA DFIRM/NFHL data where 1 represents the least risk and 5 represents the most risk. The ranks are based on the FEMA flood zone categories. An HVA rank of 5 includes categories V, VE, and Open Water. An HVA rank of 4 includes the following categories: A, AE, and AH. The HVA rank of 3 only includes B. The HVA rank of 2 includes C, X, and X500. The HVA rank of 1 includes D, and 0.2 PCT ANNUAL CHANCE FLOOD HAZARD.

Storm Surge (SLOSH Rank) - Vulnerability rank based on maximum storm surge height during mean tide conditions derived from SLOSH data where rank is based on height exceeding 1 ft for a given hurricane category. A 1 represents the least risk and is assigned in areas where it would take a Category 5 hurricane to reach that level of inundation, and 5 represents the most risk where a Category 1 hurricane would reach that level of inundation based on the data.

Inundation & SoVI® Vulnerability

Inundation (HVA Rank from the Inundation Result) Data Input

Storm surge data is based on the SLOSH (Sea, Lake and Overland Surges from Hurricanes) model, which was developed by the NOAA's National Weather Service. SLOSH produces MEOWs (Maximum Envelope of Water) and MOMs (Maximum of MEOWs). The MEOW is a composite of many hypothetic model runs, with identical hurricane category, speed, and direction, but different landfalls. The maximum value for each grid is plotted. The MOMs (Maximum of MEOWs) is a composite of MEOWs for each category hurricane, plotting the maximum surge for each category. The MOM (AGL) data was used for the Charleston Harbor basin.

Flood data is based on FEMA's DFIRM (Digital Flood Insurance Rate Map) data. The DFIRMS used in this analysis were preliminary. The issue dates for these preliminary DFIRMS are as follows: Charleston County (12/21/2017), Beaufort County (6/30/2017), Jasper County (1/16/2017), Berkeley County (2/12/2016), Dorchester County (11/13/2015), Georgetown County (11/13/2015), and Horry County (9/11/2015). For Colleton County, no DFIRM data were available; therefore, the National Flood Hazard Layer (NFHL) was used, with a latest study effective data of 12/21/2017.

SoVI® Data Input

The social and economic vulnerability component was represented by the Social Vulnerability Index (SoVI®), which measures social vulnerability to environmental hazards. This index is produced by the University of South Carolina's Hazards & Vulnerability Research Institute (USC HVRI). This is a relative index which incorporates 29 socioeconomic variables. DHEC-OCRM contracted with the Institute to run a SoVI® analysis specific to the study area of this project.

Inundation & SoVI® Result

HVA Rank - Vulnerability rank based on a combination of Inundation Rank and SoVI®; where 1 represents the least risk and 5 represents the most risk.

Inundation Rank (Q3 Rank & SLOSH Rank) - Vulnerability rank based on a combination of Q3 Rank and SLOSH Rank; where 1 represents the least risk and 5 represents the most risk.

SoVI® Rank - SoVI® rank where 1 represents the least risk and 5 represents the most risk. SoVI® values are relative. This dataset includes the SoVI® scores only for our project area. The ranking of SoVI® scores is based on standard deviations from the mean. An HVA rank of 5 represents SoVI® scores >+2 standard deviations from the mean. An HVA rank of 4 represents SoVI scores +1 to +2 standard deviations from the mean. An HVA rank of 3 represents SoVI® scores +/- 1 standard deviation from the mean. An HVA rank of 2 represents SoVI® scores -1 to -2 standard deviations from the mean. An HVA Rank of 1 represents SoVI® scores <-2 standard deviations from the mean.

Shoreline Change Vulnerability

Shoreline Change Data Input

The South Carolina Department of Health and Environmental Control's Office of Ocean and Coastal Resource Management (DHEC-OCRM) is the source for the shoreline change data. This dataset represents shoreline change for the critical area of the South Carolina coast. It was created using an open-source geospatial tool called AMBUR (Analyzing Moving Boundaries Using R). The shoreline change analysis used three time steps: 1800s, 1930s, and 2000s. The change rate utilized with the HVA tool was the End Point Rate (EPR).

Shoreline Change Result

HVA Rank - Vulnerability rank based on a combination of SCR Rank, TSCRV Rank, and SSCRV Rank; where 1 represents the least risk and 5 represents the most risk.

Shoreline Change Rate (SCR Rank) - Vulnerability rank based on end-point shoreline change rate. There are 5 categories; very high, high, medium (no significant change), low, and very low. Very High includes shoreline change values less than -1 m/yr. High includes shoreline change values between -0.2 to -1 m/yr. Medium includes shoreline change values between -0.2 to 0.2 m/yr. Low includes shoreline change values between 0.2 to 1 m/yr. Very Low includes shoreline change values greater than 1 m/yr.

Temporal Variation (TSCRV Rank) - Vulnerability rank based on standard deviation of end-point shoreline change rates between each historical shoreline for consecutive eras. There are 3 categories: high, medium, and low. High includes standard deviation values greater than 0.5. Medium includes standard deviation values between 0.2 to 0.5. Low includes standard deviation values less than 0.2.

Spatial Variation (SSCRV Rank) - Vulnerability rank based on standard deviation of end-point shoreline change rates of adjacent transects within a 150-meter buffer radius. There are 3 categories: high, medium, and low. High includes standard deviation values greater than 0.16. Medium includes standard deviation values between 0.074 to 0.16. Low includes standard deviation values less than 0.074.

About HVA

The Hazard Vulnerability Assessment (HVA) tool is an open-source geospatial tool that can be used by coastal managers, planners, and researchers to improve hazard mitigation planning, emergency management, post-disaster redevelopment, and to determine areas best suited for restoration and mitigation. The HVA Tool was developed through the Governors' South Atlantic Alliance using a grant funded by NOAA.

The HVA tool evaluates coastal hazard vulnerability from four components: 1.) Storm surge, 2.) Shoreline change rate (erosion or accretion), 3.) Flooding, and 4.) Social/economic vulnerability (SoVI®). HVA produces several combination products including the following: 1.) Inundation (surge + flooding), 2.) Inundation + SoVI®, and 3.) Shoreline Change (rate, plus temporal and spatial variations). Users can examine each hazard component to see which has the most impact in any given area. The final products are vulnerability indices on a scale of 1 to 5, with 1 being the least risk, and 5 being the most risk.

The shoreline change component of the HVA tool was created using the AMBUR (Analyzing Moving Boundaries Using R) tool. This is an open-source geospatial tool which analyzes shoreline change and other boundary movements.

AMBUR & AMBUR-HVA packages are available on R-Forge.

Additional AMBUR & HVA references:


If you have questions about the Coastal Hazard Vulnerability Assessment, please contact DHEC - OCRM at 843-953-0200.