REGIONAL DEVELOPMENT SUITABILITY MODEL

The Standard and Compact Development Models

The idea behind the differing scenarios was to show how growth policy decisions can affect the suitability of land for development. In the standard/compact pairings, the standard scenario showed what might be expected given status quo development patterns; i.e. sprawling development with limited regard for existing infrastructure particularly public water and sewer systems. In the compact scenario the effects of altering development policy so that growth is enticed to locate in a more dense fashion around existing infrastructure are shown. The visual results are obvious but the model allows one to identify geographically the effects of such a policy and to quantify the impact statistically.

The Standard Development Model, also known as "Trends Extended," assumes the continuation of the existing sprawling pattern of development.

The Compact Development Model adopts a strategy of less sprawl through more efficient use of existing infrastructure. Factors such as proximity to sewer and water lines, are given higher weights. Emphasis on infrastructure means that land becomes more suitable for development around existing infrastructure while land away from existing infrastructure becomes even less attractive.

Factor Weights

In order to derive scenarios, each factor is assigned a weight as an indicator of its relative importance to the type of development being modeled. The following weighting schemes were developed through careful consideration in consultation with planners and lay people.

Trends Extended Alternative

For large lot/"suburban" development, the presence of sewer primarily impacts cost of land and impacts density to a slightly lesser impact. Assume that each new household requires 2 acres per dwelling unit. Retail acres are calculated by taking 25% [or the approximate number of retail jobs compared to total jobs] of the anticipated new jobs and 50 employees per acre, and Office-industrial acres are determined by taking 75% of new jobs at a density of 20 employees per acre.

______________________________________

Compact Development Alternative

Ranking, for denser development. Relatively dense development requires sewer, sewer capacity, and absence of steep slopes. For residential uses, these add to 30%, which exceeds the school ranking factor. Residential land demands are calculated at 2/3 per dwelling unit (but 10% of the required units are located in existing structures or "reused"), and retail and office industrial using the same factors as the conventional, but 25% of the needed land would be found in existing structures or on previously developed land.

______________________________________