TERROIR OF THE COLUMBIA GORGE WINE REGION

This thesis aimed to characterize the terroir for the growing and recently established Columbia Gorge Wine Region. The Columbia Gorge Wine Region consists of the Columbia Gorge American Viticultural Area (AVA) and the southwest portion on the Columbia Valley AVA. This wine region is roughly 45 minutes east of the Portland metropolitan area and consists of a 96.5-kilometer stretch along the Columbia River. Although the oldest vineyard site was planted in 1892, majority of vineyard plantings have taken place since the early 1900’s, almost a century later. The climate in the region is well known to range from a wet, cool climate in the northwestern portion near Underwood, WA to a very warm, dry climate in the eastern portion near The Dalles, OR. The diversity of other terroir-related factors (grape variety, soils, topography and geology) and an update of the current vineyard locations has not yet been characterized for the region. It was concluded that there are 84 vineyard sites (5.1 km²), 37 wineries and 41 different grape varieties throughout the region. The main types of planted grape varieties include Pinot Noir (1.6 km²), Syrah (0.30 km²) and Chardonnay (0.30 km²). The wine region can be broken up into 7 different soil sub-regions, based off of different soil series throughout the region. Distributions of the soil orders are the following: Mollisols (2.9 km²), Andisols (0.90 km²), Alfisols (0.94 km²), Inceptisols (0.20 km²), Entisols (0.23 km²). Soil textures range from skeletal (0.18 km²), and sandy (0.23 km) to loamy (3.4 km²) and silt loamy(1.8 km²). The geological influences on the terroir include the Missoula Flood deposits, lahars, young Pleistocene volcanics, alluivum and loess. Growing degree days and average growing season temperautres are also modeled for the region to depict boundaries of different climatic regimes.