By Kelsey J. Rydland and Dan Currier, Central Vermont Regional Planning

Possible build-out locations randomly generated and placed within the development potential.

The Central Vermont Regional Planning Commission (CVRPC) is a planning organization in the heart of Vermont's Green Mountains. Formed in 1967, CVRPC is one of Vermont's 11 regional planning commissions. CVRPC works with 23 municipalities in central Vermont to assist with effective local governance and planning by providing a range of services from policy advisement to GIS analysis. The most recent project on which CVRPC's GIS staff has been working is the future development of Montpelier, the state's capital city.

Historically, growth in large metropolitan areas of a state influences development pressures within other parts of the state. This phenomenon is currently taking place in Vermont. Population increases in Vermont's largest county, Chittenden County, home of Vermont's largest city, Burlington, have spurred regional planners and state and federal agencies to take a closer look at Vermont's future growth. As a result, the state of Vermont, U.S. Environmental Protection Agency, Vermont Transportation Department, and Federal Highway Administration have funded the innovative Northwest Vermont Project. The goal of the project is to estimate future development, evaluate the ability of towns to plan for future growth, and provide tools and training to plan for that future growth.

The completed model with a roads layer and river lay, showing the best areas for development.

Vermont has a rich planning tradition. Act 250, Vermont's 25-year-old landmark development review law, and Act 200, also known as the Growth Management Act of 1988, have provided the Green Mountain State with some of the nation's most progressive and up-to-date planning laws. The Northwest Project builds upon this legacy. One of the regions outlined in the project is Washington County, home of Vermont's statehouse. According to the 2000 census, Montpelier is the least populous state capital, with a population of 8,035. The city encompasses an area of approximately 10.3 square miles, or 26.6 square kilometers, and has a history of placing emphasis on the forethought and quality of future development.

CVRPC has been using Esri mapping software since 1989. CVRPC has stayed with Esri over the years for its reputation as a leader in the GIS industry. The commission chose ArcView specifically for this application for its straightforward interface, which allowed CVRPC to navigate through large amounts of build-out data to deliver simplified and readable maps to Montpelier's planning community.

ArcView 9 with the included ModelBuilder application and ArcView 3 with the ArcPress extension are integral parts of CVRPC's planning for future development in Montpelier through the Northwest Project. Using the ModelBuilder environment, CVRPC created a development potential model that utilizes a set of weighted factors:

• House point locations to determine existing development
• The grade of slopes
• Flood zones
• Presence of city water and sewer in an area
• The areas that have already been built upon
• Natural constraints, such as stream buffers, deeryards, agricultural soil, and the ability of soil to handle septic systems

Each factor is appropriately weighted by CVRPC's staff of planners and GIS technicians. The result is a geographic dataset that represents development potential.

The shapefiles are broken down by value into areas where development potential is high, medium, low, or not possible. Areas where development is highly likely are designated by the color green. Regions where moderate growth is possible are colored yellow. Areas where growth is least likely are colored red. Dark gray is used in areas where development cannot occur because of conservation status or the existence of cemeteries. The final coverage is a light gray area representing existing development that does not allow for infill.

CVRPC utilized ArcView 3 to run a build-out scenario incorporating the development potential data that was generated for Montpelier. The build-out analyzes a municipality based on its zoning regulations by using minimum and maximum lot sizes along with respective zoning acreage, parcel, and Montpelier development potential overlay data.

A visual representation of where growth can and cannot occur has proven to be a great asset to city officials, planning professionals, academics, and builders. Without ArcView 9 ModelBuilder and ArcView 3, the aggregation of multiple constraints and the visualization of development potential would be daunting. ArcView 9 with ModelBuilder gives CVRPC professionals the ability to run complex models in relatively short intervals. ArcView 9 with ModelBuilder and ArcView 3 provide CVRPC and the city of Montpelier with tools that deepen the state's progressive planning heritage and give individuals an idea of what the future Montpelier will look like.

For more information, contact Dan Currier, GIS planner (e-mail: currier@cvregion.com), or Kelsey J. Rydland, GIS associate (e-mail: rydland@cvregion.com), or visit the Central Vermont Regional Planning Commission Web site (www.centralvtplanning.com).