An approach for greenway suitability analysis

Abstract

Greenway analysis is designed to identify and measure the suitability of potential sites for greenway development. This evaluation can be regarded as an extremely difficult task due, in part, to the large number of criteria and large volume of data that may be required for the determination. The purpose of this paper is to present an approach to greenway analysis that integrates suitability analysis with geographic information system (GIS) technology to identify suitable sites for greenway development in the town of Prescott Valley, AZ, USA. This approach identified five major steps involved in the greenway analysis, these include: identification of land-use functions, spatial data collection, development of weighting values, data integration and analysis using GIS, and output evaluation. Land-use function identification, and weighting values were developed from a wide range of resources including the Prescott Valley General Plan, surveys, expert opinion and published literature. Spatial data were obtained from federal, state, and local agencies. Where specific data were not available, these data were collected from the site using inventory techniques. Three land-use functions were identified for the Prescott Valley study area, wildlife habitat, recreation, and riparian corridor. For each of these functions, four or five primary factors were determined. Additionally, for each factor, a land capability rating was established. Results of the surveys indicated that normalized weightings for the functions were 1.0 for wildlife habitat, 0.862 for recreation, and 0.653 for riparian corridor. Rankings for the primary factors within the functions ranged from a high of 0.468 to a low of 0.049, with the sum of weighting values for all factors within a function equal to 1.0. Land capability values for attributes within factors were set as high, moderate, low, and no capability. All data were integrated into a vector-based GIS software and a total of 14 coverages were created, Spatial analysis was performed using an overlay technique combining all factors within a function, and then by combining all resulting factor outputs to produce an overall greenway suitability analysis. The final analysis was then evaluated by a panel of experts to determine its accuracy and potential for use in a greenway development plan.

Introduction

Greenways, sometimes referred to as environmental corridors, landscape linkages, wildlife corridors, or riparian buffers, provide an important means to both protect natural areas and to provide recreation opportunities (Little, 1990; Ahern, 1995). Greenways contribute to many ecological and societal values (Fabos and Ahern, 1995). They help maintain biological diversity, protect water resources, conserve soils, support recreation, enhance community and cultural cohesion, and provide species migration routes during climate or seasonal change (Forman, 1983, Forman, 1995; Forman and Godron, 1986). Greenways can be used to create interconnected networks of open space that may include more traditional non-linear parks and natural areas. They can help to maintain ecological integrity in human-dominated landscapes, especially with regard to sustaining high-quality water reserves and preserving biological diversity (Smith and Hellmund, 1993).

Local officials and citizens frequently advocate the development of greenways and other open spaces to improve environmental quality or their communities. Many citizens, elected officials, and landscape planners seek a better understanding of concepts and procedures for more sustainable greenway development. Greenway planning methods are needed to perpetuate ecological processes and to conserve wildlife populations while affording continued human interaction with the natural landscape.

The most difficult challenge is to design for social and cultural settings which permit people to maximize their needs without generating future social and environmental problems. This dilemma points out the need for new multi-objective greenway planning methods. These planning methods can be applied to the protection of threatened ecosystems and outdoor recreational system as well.

Better research methods are needed to accurately assess and analyze environmental constraints and opportunities. Socio-economic and ecological data must be prepared so that meaningful comparison can occur. Technological developments such as geographic information systems (GIS), when combined with the suitability analysis methods, may provide the necessary tools for the integration of these data into a meaningful database. These databases have the potential to enable planners to integrate both social and ecological interests in multi-objective greenway planning.

The purpose of this paper is to test the hypothesis that the integration of suitability analysis with GIS will provide an effective tool for greenway analysis that blends both socio-economic and ecological data into a comprehensive land management plan. This approach is based on the premise that successful greenway suitability analysis can serve as a foundation for a greenway plan.

The development of suitability analysis has a strong tradition within landscape planning (Hills, 1961; McHarg, 1969; Murray et al., 1971; Steinitz et al., 1976; Steiner, 1983; Linden, 1984; Banai-Kashani, 1989; Searns, 1995; McHarg, 1996). This paper addresses the design of a greenway suitability analysis for a rural area of the American Southwest (Collins, 1996).