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NATURAL HERITAGE

Vulnerability Model

map image of VCLNA vulnerability model

The Virginia Vulnerability Model was developed in an effort to map predicted growth in Virginia . The growth prediction may be used as an indication of potential land use change from the current use to an urban or suburban use. In an effort to map the predicted growth in Virginia, four models were developed:

  • Virginia Urban Vulnerability Model which shows predicted urban growth
  • Virginia Urban Fringe Vulnerability Model which shows the predicted urban fringe, or metropolitan fringe growth (suburban growth).
  • Virginia Vulnerability the Urban Fringe Model which shows the predicted growth beyond the urban fringe (ex-urban or rural growth)
  • Virginia Vulnerability Model which shows a composite of all the vulnerability models integrated into one model representing growth pressures across the urban, suburban and rural landscape.

The Virginia Vulnerability Model methodology was based on the Chesapeake Bay Program's Resource Lands Assessment Vulnerability Model. The Virginia model was run with Virginia specific datasets and methodology was altered to reflect Virginia specific needs.

The Vulnerability models show where predicted growth patterns are in the landscape and it is incumbent on the end user to assess what growth represents in terms of sprawl (E. H. Wilson et al. 2003). Growth that continues in an unplanned fashion, particularly into previously undeveloped areas, typically has a negative effect on the environment, ecologically, economically and socially (E. H. Wilson et al. 2003, R. E. Heimlich and W. D. Anderson, 2001). As unplanned growth and subsequent development continues across the state, remaining resources are being damaged and irretrievably lost.

The development of a Virginia GIS vulnerability model puts growth into context in relation to the state; it provides a large scale picture of growth patterns across jurisdictional boundaries. Traditionally state and local government has been reactive to population growth, and while some efforts are being made to control growth, often "strategically directing development to the most favorable areas well in advance of urban pressures" does not happen (R. E. Heimlich and W. D. Anderson, 2001).

The models, detailed above, represent different growth effects. The only model showing all predicted growth effects is the Virginia Vulnerability Model. The Urban Vulnerability Model shows the predicted urban growth into the landscape, it does not include the suburban or rural growth pressures. The Urban Fringe Vulnerability Model shows the predicted urban fringe, also typically called suburban, growth into the landscape, it does not include urban or rural growth pressures. The Beyond the Urban Fringe Vulnerability Model shows predicted growth outside of the urban fringe, or rural growth pressures, it does not include urban or suburban growth pressures. Urban, suburban and rural designations were determined with the use of the Rural Area Community Codes. For a comprehensive description of the definitions of how urban, suburban and rural areas are defined for purposes of this project, please see:
http://www.ers.usda.gov/Briefing/Rurality/RuralUrbanCommutingAreas/.

The Vulnerability model may serve as a guide to state and local government, consultants, and developers as to the location of growth patterns, particularly in relation to the current environment. The model can be used alone or integrated with other datasets, such as the Virginia ConservationVision Cultural Model or Ecological Model, to identify which cultural resources or ecological cores are most at risk to these growth pressures. The model may also be used to help guide local land use planners in the development of their comprehensive plans in an effort to control growth and subsequent development within their jurisdiction. It is important to look at the landscape as a whole and assess how growth may impact the environment, what remaining farmland or timberland is available or how water quality will be affected, before more development is introduced.

The models serve as part of a larger green infrastructure plan, which aims to model where Virginia 's conservation priorities are located to facilitate an integrated approach to planning and development. To view the report on the Virginia Vulnerability Model, click here. For information on the Virginia ConservationVision and the Green Infrastructure Modeling effort, please visit the Virginia ConservationVision website at : http://www.dcr.virginia.gov/natural_heritage/vaconvision.shtml.

References

Heimlich, R. E. and W. D. Anderson. 2001. Development at the urban fringe and beyond: impacts on agriculture and rural land. U.S. Department of Agriculture, Agricultural Economic Report 803, Washington, D.C., USA.

Wilson, E. H. et al. 2003. Development of a geospatial model to quantify, describe and map urban growth. Remote Sensing of Environment 82: 275-285.

Application of the Vulnerability Model

Some general categories of uses to which the vulnerability model data can be applied include:

  • Targeting - to identify targets for protection activities
  • Prioritizing - to provide primary or additional justification for key conservation land purchases and other protection activities.
  • Local planning - guidance for comprehensive planning and local ordinance and zoning development.
  • Assessment - to review the state of the land and assess growth in context of the landscape
  • Land management - to guide property owners and public and private land managers in making land management decisions that enhance ecological, social and economic services
  • Public education - to inform the citizenry about the development and growth of their community, helping them stay informed about the state of growth of their area.

The Vulnerability Model serves as a base model, upon which local datasets can be added, such as zoning information, comprehensive plans, parcel data, septic suitability information and any other datasets which may help drive local decision making processes. The constraints of a statewide model include the incorporation of existing, statewide GIS datasets. Incorporation of datasets such as individual locality septic sewer information may not be available statewide and are not included in the model since the effect would skew overall model results. Individuals should use the Vulnerability Models and incorporate any additional datasets as needed to make informed decisions. It is at this local level the end user may be able to draw his / her own conclusions on growth, sprawl and the impending consequences.

Products

Maps have been produced for the entire Coastal Zone and the Planning District Commissions and included as part of the final report. The report and data are available via FTP and on this site as well as the Land Conservation Data Explorer and include:

  • Maps showing:
    o  Virginia Urban Vulnerability Model
    o  Virginia Urban Fringe Vulnerability Model
    o  Virginia Vulnerability outside the Urban Fringe Model
    o  Virginia Vulnerability Model which shows a composite of all the vulnerability models integrated into one model representing growth pressures across the urban, suburban and rural landscape.
  • A report detailing the methodology
  • Metadata
  • Four (4) GRID coverages representing the above detailed models.
  • Four (4) shapefiles representing the above detailed models.
  • An ArcGIS geodatabase with threat feature classes.

Data Download

For more information about the Virginia Vulnerability Model(s), please contact Jason Bulluck at jason.bulluck@dcr.virginia.gov or 804-786-8377.

Page last updated 2/11.