TERROIR OF THE COLUMBIA GORGE WINE REGION, PACIFIC NORTHWEST, USA

The Columbia Gorge Wine Region (CGWR) is an emerging wine producing area in the Pacific Northwest in which the number of vineyards, wineries and physical terroir conditions has yet to be defined. The region, which includes the Columbia Gorge American Viticulture Area (AVA) and the southwest portion of the Columbia Valley AVA, is home to 82 vineyards, 1268 acres (513 hectares of vines), 37 wineries and 41 different grape varieties. Vineyards range in elevation from 29 to 548 meters (95 to 1799 feet). Vintner responses to a grower’s survey suggest that twenty-eight grape varieties account for 98% of the estimated grape variety acreage, with Pinot Noir being the most widely planted grape variety in both AVAs. In general, planted grape varieties are typical of the three climate regimes represented within the CGWR, allowing for a. All of the soils currently being used to grow grapes are well-drained and within a xeric moisture regime, which are favorable conditions for viticulture. 30 soil series are represented among the vineyard sites, with the Chemawa Series (Underwood Mountain) and Walla Walla Series (eastern portions) being the dominant soil series used to grow grapes. Majority of the soils contain a silt loam texture. Soil Survey data for Oregon and Washington suggest that loess is extensive in the CGWR, with 46% of the total vineyard acreage planted on soils formed in loess. The Missoula Floods also greatly influenced the texture and age of the soil in this region, with skeletal textures being close to the Columbia River. Other common Geological deposits vineyards in the CGWR include, Quaternary Basalt (46.5%), Missoula Flood deposits (9.1%), Columbia River Basalt Group (7.5%), Pliocene Basalt (3.0%), Quaternary Surficial deposits (3.0%), lahars (2.3%) and Quaternary Basaltic Andesite and Andesite (0.9%). Common geological deposits, soil series, and climate conditions at vineyard sites vary spatially in the region, and therefore it is suggested that future work focus on separating the region into separate climatic sub-AVA regimes to better reflect the diversity in terroir conditions.