Enhanced Landscape Evaluation and Site Assessment (ELESA)
Brian Lee, Department of Landscape Architecture
Collin Linebach, Department of Landscape Architecture
An established framework for making land-use decisions was implemented in ModelBuilder to provide a more holistic approach to community planning.
Land-use decision making is an increasingly important capability for many local governments. The Land Evaluation and Site Assessment (LESA) framework, developed by the Natural Resources Conservation Service, has been used by hundreds of communities across the country to help make decisions, particularly in the context of farmland protection programs. Land evaluation (LE) and site assessment (SA) are the two aspects of this approach. The LESA framework aids land-use decision makers by rating lands based on land evaluation and site assessment rating factors. The factor rating system is determined by a committee composed of local people who are familiar with the landscape and analysis objectives. A key benefit of using LESA is that it provides a clear and consistent decision tree-type framework for land rating.
LE primarily rates soils. For this Central Kentucky study region, most of the data was obtained from the Kentucky Geography Network, and soil data came from the NRCS Soil Data Mart. The best soils were given a high ordinal rating (10), while less agriculturally rated soils were assigned a lower rating (1). The SA section is often more complex and can consist of three general categories: nonsoil agricultural factors, development pressures (e.g., road and sewer proximity), and other public values (e.g., historic, scenic). Like the LE portion, each SA factor described in this article was rated relative to agricultural generalization to demonstrate the functionality of this approach.
In this Enhanced LESA (ELESA) implementation, The Environmental Systems Research Institute's (ESRI) ModelBuilder was used to automate the rating as well as factor weighting as described in the LESA guidebook by Pease and Coughlin. The model can be thought of in terms of three primary components: Land Evaluation (LE) factors, Site Assesment (SA) factors, and overall factor weighting. Raster-based ELESA allows the landscape to be thought of as a continuous surface of LESA process rating. This rating visualization can help identify suitable acreage for people interested in agricultural land for a variety of reasons. The factor rating and weighting can be tailored to meet the desires of an individual or an entire community. The introduction of ModelBuilder benefits the process by allowing different rating and weighting combinations to be explored during public meetings depending on land-use problems. The model has the ability to include land protected by land trusts or other entities under agreements such as conservation easements and purchase of development rights programs. The model can also visualize how ELESA ratings change relative to agricultural uses when urbanization proposals are anticipated.
GIS has enhanced the power of LESA for landscape analysis and participatory planning/decision making. The regional/landscape scale analysis performed in this ELESA model allows for broad scale and flexible analysis. ELESA has the potential for areawide planning applications, and this model could be adapted for watershed-based applications and modified for use with ArcGIS Server.