Document generated on 09/30/2021 5:15 a.m. Geoscience Canada Geology and Wine 11. Terroir of the Western Snake River Plain, Idaho, USA Virginia S. Gillerman, David Wilkins, Krista Shellie and Ron Bitner Volume 33, Number 1, March 2006 Article abstract This article explores the unique combination of factors that shape the terroir of URI: https://id.erudit.org/iderudit/geocan33_1ser01 Idaho's principal wine grape-growing district. Most Idaho wine grape vineyards are located in the Western Snake River Plain (WSRP) rift basin See table of contents (~43°N, ~117°W) on soils derived from lake, river, volcanic and wind-blown sediments. The underlying Tertiary and Quaternary rocks record the geologic history of ancient Lake Idaho, its interaction with basaltic volcanism, and Publisher(s) subsequent Pleistocene fluvial processes and catastrophic floods. The arid to semi-arid, mid-latitude steppe climate of the WSRP provides fewer growing The Geological Association of Canada degree days than American Viticultural Areas (AVAs) in Walla Walla, Washington and Napa Valley, California, but still allows cultivation of Vitis ISSN vinifera grapes. Other differences include lower precipitation, higher solar radiation during the growing season, and greater threat of cold injury. Wine 0315-0941 (print) grapes grown in the WSRP require irrigation, and irrigation is used to manage 1911-4850 (digital) canopy size and manipulate vine physiology. Wine grape acreage in Idaho has increased dramatically since 1993 and is estimated, in 2003, at about 500 ha Explore this journal with the white wine cultivars Riesling, Chardonnay, and Gewürztraminer comprising about 60% of production, and Cabernet Sauvignon, Merlot and Syrah as principal red wine cultivars. Cite this article Gillerman, V. S., Wilkins, D., Shellie, K. & Bitner, R. (2006). Geology and Wine 11. Terroir of the Western Snake River Plain, Idaho, USA. Geoscience Canada, 33(1), 37–48. All rights reserved © The Geological Association of Canada, 2006 This document is protected by copyright law. Use of the services of Érudit (including reproduction) is subject to its terms and conditions, which can be viewed online. https://apropos.erudit.org/en/users/policy-on-use/ This article is disseminated and preserved by Érudit. Érudit is a non-profit inter-university consortium of the Université de Montréal, Université Laval, and the Université du Québec à Montréal. Its mission is to promote and disseminate research. https://www.erudit.org/en/ GEOSCIENCE CANADA Volume 33 Number 1 March 2006 37 SERIES sequent Pleistocene fluvial processes and Washhington et de la vallée de Napa de catastrophic floods. The arid to semi- l’État de Californie, il permet tout de arid, mid-latitude steppe climate of the même la culture des raisins de Vitis WSRP provides fewer growing degree vinifera. De plus, cette région reçoit days than American Viticultural Areas moins de précipitations, plus d’en- (AVAs) in Walla Walla, Washington and soleillement durant la saison de crois- Napa Valley, California, but still allows sance, et elle est davantage exposée aux cultivation of Vitis vinifera grapes. Other meurtrissures du froid. Les vignes de differences include lower precipitation, raisins de cuve cultivés dans la WSRP higher solar radiation during the growing doivent être irriguées, l’irrigation perme- season, and greater threat of cold injury. ttant d’agir sur l’ampleur du feuillage et Geology and Wine 11. Wine grapes grown in the WSRP require sur la physiologie du vin. La superficie irrigation, and irrigation is used to man- de culture du raisin de cuve en Idaho Terroir of the Western age canopy size and manipulate vine s’est considérablement accrue depuis Snake River Plain, Idaho, physiology. Wine grape acreage in 1993 pour atteindre 500 ha environ en USA Idaho has increased dramatically since 2003, les cultivars à vin blanc de 1993 and is estimated, in 2003, at about Riesling, Chardonnay, et 500 ha with the white wine cultivars Gewürztraminer constituant 60 % de la Virginia S. Gillerman1, David Riesling, Chardonnay, and production, et ceux du Cabernet Wilkins2, Krista Shellie3 and Ron Gewürztraminer comprising about 60% Sauvignon, du Merlot et du Syrah con- Bitner4 of production, and Cabernet Sauvignon, stituant les principaux cultivars à vin 1Idaho Geological Survey, Boise State Merlot and Syrah as principal red wine rouge. University, Boise, ID 83725-1535, cultivars. [email protected] INTRODUCTION 2Department of Geosciences, Boise State RÉSUMÉ Best known for scenic beauty, white- University, Boise, ID 83725-1535, Le présent article porte sur la combinai- water rivers, and quality potatoes, the [email protected] son particulière de facteurs qui définit le state of Idaho is receiving medals for 3USDA-ARS Horticultural Crops Research terroir du principal district viticole de premium red, white, and ice wines pro- Laboratory, Parma, ID 83660, l’État d’Idaho. La plupart des vignobles duced from Idaho-grown Vitis vinifera L. [email protected] de l’Idaho sont situés dans le bassin de grapevines. Idaho normally is associated 4Bitner Vineyards, Caldwell, ID 83607, fossé tectonique (~43°N, ~117°O) de la with high mountains and cold tempera- [email protected] Western Snake River Plain (WSRP), sur tures, but southwestern Idaho’s low ele- des sols formés de sédiments lacustres, vation and relatively moderate climate is SUMMARY fluviatiles, volcaniques et éoliens. Les suitable for growing European wine This article explores the unique combi- couches tertiaires et quaternaires sous- grapes. The Snake River Plain (SRP) is a nation of factors that shape the terroir jacentes témoignent des événements crescent-shaped belt of sagebrush-cov- of Idaho’s principal wine grape-growing constitutifs de l’histoire géologique de ered volcanic rocks ranging in width district. Most Idaho wine grape vine- l’ancien lac Idaho, de phénomènes inter- from 65 to 100 km, and stretching yards are located in the Western Snake actifs dont il a été le théâtre, soit un vol- roughly 600 km across southern Idaho; River Plain (WSRP) rift basin (~43°N, canisme basaltique, ainsi que des proces- the principal wine grape-growing district ~117°W) on soils derived from lake, sus fluviatiles et des inondations cata- is located in the Western part of the river, volcanic and wind-blown sedi- strophiques pléistocènes. Bien que le Snake River Plain (WSRP, Figs 1, 2). ments. The underlying Tertiary and climat aride à semi-aride de steppe en Geologically, the WSRP is distinguished Quaternary rocks record the geologic altitude moyenne de la WSRP comporte from the Eastern Snake River Plain history of ancient Lake Idaho, its inter- moins de degrés-jours de croissance que (ESRP, Fig. 1) by the much greater pro- action with basaltic volcanism, and sub- les zone les zones viticoles étasuniennes portion of sedimentary rocks relative to (AVA) de Walla Walla de l’État de basalts and a more fault-bounded, rift- 38 Figure 1. Map showing the location of the Western Snake River Plain (WSRP) relative to other major grape-growing regions and tectonic elements in the Pacific Northwest. Hells Canyon of the Snake River lies along the Idaho-Oregon border from the WSRP north to Lewiston. Physiographic and structural features (Ball and bar symbols indicate the downthrown side of the fault): BFZ, Brothers Fault Zone; ESRP, Eastern Snake River Plain; IdB, Idaho Batholith; O-WL, Olympic-Wallowa Lineament; Ow M, Owyhee Mountains; Stn M, Steens Mountains; VFZ, Vale Fault Zone; WSRP, Western Snake River Plain; YC, Yellowstone Caldera. Cities: B, Boise; L, Lewiston; R, Roseburg; P, Portland; TF, Twin Falls; WW, Walla Walla. AVA refers to American Viticultural Area, as designated by the Alcohol and Tobacco Tax and Trade Bureau (TTB) formerly called the Bureau of Alcohol, Tobacco and Firearms (BATF). Geology modified from Wood and Clemens (2002). basin geometry. Yellowstone and Grand and Spain, and chapters of its geologic production did not recover until around Teton National Parks lie at the eastern history are similar to the history of the 1970. Idaho created a state commission terminus of the SRP and contain the neighbouring states of Washington and in 1984 to promote growth and develop- headwaters of the Snake River, which Oregon (Meinert and Busacca, 2000). ment of the grape and wine industry. drains about 283,000 km2 during its In Idaho, European wine grape produc- Acreage and number of wineries ~1120 km trek across the SRP and tion north (~47°N) or east (~114°W) of increased steadily such that by 1998, down Hells Canyon, before joining the the WSRP is limited by low winter mini- wine grapes were Idaho’s fourth largest Columbia River en route to the Pacific mum temperatures and limited length of fruit crop (USDA, Idaho Agricultural Ocean (Fig. 3). Irrigation from the growing season. Statistics Service, 1999). Between 1993 Snake River has been instrumental for The history of wine production and 1999, the latest year for which offi- much of Idaho agriculture, including in Idaho is similar to that of neighbour- cial statistics are available, acreage and viticulture. ing states and the province of British number of vineyards doubled to 262 ha The WSRP includes parts of 10 Columbia, Canada (Meinert and in 27 vineyards. An informal 2003 sur- Idaho counties and a small part of Busacca, 2000; Taylor et al., 2002), dat- vey by the Idaho Grape Growers and Oregon, but 75% of commercial wine ing to the mid-1800s when French and Wine Producers Commission of 35 of grape acreage, including the largest vine- German immigrants cultivated European its ~50 grower members, suggested fur- yard at 150 ha, is located in Idaho’s grapes and produced wines near the ther doubling of acreage to about 489 Canyon County [United States confluence of the Snake and Columbia ha with > 50% of vineyards at < 6 ha. Department of Agriculture (USDA), rivers. Native North American grape Cultivar acreage, based on 65% of esti- Idaho Agricultural Statistics Service, species that host pests detrimental to mated total acreage, suggests a predomi- 1999; Fig.