Wine without irrigation: evaluating geographic information systems as a tool to identify potential dryland viticulture sites

This study attempts to assess whether or not geographic information systems (GIS) is an effective tool for identifying potential sites for growing wine grapes without the use of supplemental irrigation water. Using spatial analysis techniques with GIS technology, this study evaluated the Walla Walla Valley American Viticultural Area (AVA) and the immediate region in Washington and Oregon for dryland-farmed viticulture site potential. Cabernet Sauvignon was used as a test variety as an exercise in siting a potential new vineyard planting. The areas where environmental factors were estimated to be both sufficient for vines to survive without irrigation and the best potential for producing quality wine grapes were categorized into a suitability area. This site selection identified approximately 2000 hectares of land suitable for dryfarming Cabernet Sauvignon. Of these 2000 hectares, about 60 hectares are currently planted with vineyards, leaving 1940 hectares of suitable lands in the study area. This area was compared against the rest of the study area in the occurrence of existing dryland vineyards to evaluate the effectiveness of GIS in this application. The majority of known dryland vineyards in the area were found within or immediately adjacent to the suitability area. Results from this study suggest that geographic information systems may be used to identify dryland vineyard site potential