There are many ways to conduct a buildout analysis. Methodologies are chosen based on the time and data available. Generally, the more accurate an analysis is, the more time it takes. Here is a list of some buildout methodologies and how they compare to the methodology that was used for Charlestown:

Parcel Buildout: Parcel buildout analyses estimate the number of units that can fit on each parcel individually. The buildout presented in this study is a parcel level buildout. In the methodology used for Charlestown the amount of constrained land is subtracted from the total land in the parcel, to determine the land that is developable.
However, not all parcel level buildout analyses use this exact method. In some situations, it is necessary to analyze each parcel in terms of "development potential" as described below. The following is an outline of the steps taken in this methodology:

1. Determine the size of the parcel.
2. Reduce the size of the parcel by the percentage that would have to be taken out for roads.
3. Divide that size by the zoning.
4. Determine the constraints that exist, and assign a constraint value to each of these constraints. For example, if a wetland exists, a constraint value of 0.7 can be given to the parcel. This will reduce the number of units that can be built on the parcel by 30%.
5. Multiply the density determined in step 2 by the development potential value. This will give the number of units that can be built on the parcel.

The major difference between this method, and the method used for Charlestown is that the size of the constraint is not taken into account. The method discussed above assigns one value for a constraint, regardless of its size. This methodology is effective in towns where the constrained land is not taken out of the total buildable land in the parcel under the zoning definition. Because this is not the case in Charlestown, I believe that the methodology used in this study was more affective than the one described above.

Landuse Buildout: A land use buildout analysis is much simpler than a parcel buildout. Land use buildout analyses are generally done when parcel data are not available. An outline of the methodology used in landuse buildout analyses is presented below:

1. The amount of land in each zoning district in the town is determined.
2. The amount of land within that zoning district that cannot be built on is determined. This includes areas that are unbuildable due to physical constraints, and areas that have legal limits on building (e.g. conservation easements and parks).
3. The amount of buildable land is determined by subtracting the total land, from the land that cannot be built on.
4. A percentage of this land is taken out for roads and infrastructure.
5. The buildable land, minus the percentage taken out for roads, is then divided by the minimum lot size, and the number of units is then estimated.

This method does not account for the size and the configuration of the existing parcels. It also does not produce a clear picture of where development will go in the town. Additionally, this method does not have a strong spatial aspect because it shows the distribution of density in large zoning districts, making it difficult to plan on a neighborhood level.

Site Design Level Buildout: Site design level buildout analyses are extremely accurate, and extremely time consuming. The basic process is to draw potential site designs for every vacant parcel, and then add up the total number of units for each site. This method will not only produce an accurate picture of how much development there will be in a town, but it also shows the types of development that may occur. It has a strong spatial aspect because it allows planners to pin point parcels, and portions of parcels that are suitable for development. This method has many advantages over the method used for Charlestown but it was not possible due to time constraints.

Links to other web sites that have information about buildout analyses:

• Description of a build-out analysis and potential effects on wildlife habitat in the Lower Blue Planning Basin, Summit County, Colorado
• MassGIS Scope of Services for Build-Out Analysis
• How will buildout affect wildfire losses in El Dorado County?
• NEMO - GIS Buildout Analysis
• Fairfax County Housing Information (Virginia)
• The Southeast Gateway Area Plan
• City of Clemson Comprehensive Plan
• Westminister Colorado Land Use Plan
• Franklin Massachusetts Buildout Analysis