High Valley AVA


High Valley is an American Viticultural Area located in the eastern part of Lake County, California adjacent to the eastern shoreline of Clear Lake. It was established as the nation's 162nd, the state's 92nd and county’s sixth appellation on July 1, 2005 by the Alcohol and Tobacco Tax and Trade Bureau, Treasury after reviewing the petition submitted by Kevin Robinson of the Brassfield Estate, on behalf of the High Valley AVA Committee, local vintners and growers, proposing a viticultural area in Lake County named “High Valley."
‘High Valley’’ is the officially recognized name of the elongated bowl-shaped valley encompassed by the viticultural area, as shown on the Clearlake Oaks, California, USGS Quadrangle map. True to its name, the valley is situated on higher elevations ranging from to, but it actually encompasses two distinct growing regions, the valley floor and the hillsides. The valley itself is a and landform, with an east–west orientation unusual in the California Coastal Range, a result of volcanic activity of Round Mountain, a dormant volcanic cinder cone at the eastern end of the valley. The AVA encompasses, and about under vine. Most are relatively new, but within the area are some of the oldest vines in California. There are 15 struggling Zinfandel and Muscat vines planted by the Ogulin family, which brought them from Slovenia around 1875. Since Slovenia borders Croatia, where cousins of Zinfandel vines are found, this is significance in the history of California Zinfandel. The old vines were stables before Prohibition since Lake County was producing reputable wines before the vineyards were uprooted and replaced with other crops.
Significant vineyards in the AVA include Brassfield Estate Winery, whose estate sits on the valley floor and Shannon Family of Wines. The plant hardiness zone ranges from 8b to 9b.

History

The High Valley area was first settled by Native American Indian descendants of the Pomo tribes, the Elam and Kamdots. The peaceful tribes lived on opposite ends of High Valley and referred to it as "kas". Numerous sites found on steep rock ledges on the southern and western slopes of High Valley were winter high ground camps. This area was also an important transportation route between lake shore tribes and tribes in neighboring Long Valley to the north and Cache Creek to the east. An essential food supply of acorns, wild oats, wild game including deer, rabbit, bear, and quail could be found throughout the valley and surrounding hills.
High Valley remained Pomo territory until the arrival of European settlers in the 1850's. Hemy L. Wildegrube was the first white man to settle in High Valley. In 1856 at the age of 21 he settled in what is now Upper Lake and established its first general store. Three years later in 1859 he purchased in High Valley after selling his portion of what is now the town of Lucerne to his partner.
Soon after Wildegrube settled in High Valley other settlers began to arrive. At the peak of the 1850's about a dozen small ranches occupied the valley forcing most of the Pomo Indian tribes out of the valley and up into the hillsides and ridges. High Valley Ridge was once the dividing line between Lake and Colusa Counties until 1868 when Long Valley and Indian Valley were added to Lake County moving the boundary further north. Over the next several decades the valley contained a schoolhouse, post office and a stagecoach stop that provided essential supplies and rest to the many travelers utilizing High Valley as a transportation route between Upper Lake and Sacramento. Before their steep climb up High Valley Ridge horses were changed in High Valley at the "Foutch Stage Station" for visitors from San Francisco on there way to the mineral baths at Bartlett Springs.
The history of grape and wine production in Lake County is fairly dramatic. The County boasted one of the largest growing areas in California until Prohibition replaced the vineyards with pears, walnuts, prunes, green beans and other crops. However, a few of these old-vine vineyards still exist in a few locations throughout parts of the County. Testimony to this is a derelict vineyard of with about 25 "centennial vines" of perhaps Zinfandel variety on a southeast ridge above High Valley at the Ogulin Ranch.
Since the late 1800's the area has witnessed little change. Ranching still exists along the valley floor although vineyards now occupy a large portion of the moderate to steep slopes, and to a lesser degree, the valley floor to the west. There were nearly producing or are under development during the early 2000s. Many wineries in the North Coast over the past several years have created vintages using Upper Lake fruit displaying extraordinary qualities. As a result of the high quality wines coming from the High Valley area several local winery projects started construction or were in the planning phase.

Terroir

Topography

High Valley is an elongated, bowl-shaped basin, which is largely enclosed and topographically isolated from surrounding regions by high surrounding mountain ridges. As shown on USGS maps, the valley floor is generally between in elevation, while, to the north, High Valley Ridge rises to over. To the east, south, and west, the surrounding ridges average between in elevation. The lowest elevation within the High Valley viticultural area is at the contour line, which forms part of the area’s southern boundary. The only drainage outlet from High
Valley is Schindler Creek, which flows south through a gap in the mountain ridge between the valley and Clear Lake on the viticultural area’s southern side.
In addition to its topographic isolation, High Valley has an east and west orientation, which is rarely found in the northern Californian coastal range. This
orientation contributes to some of the distinctive climatic features of the High
Valley area.

Climate

High Valley viticultural area’s climate is cooler than the surrounding viticultural areas of Lake County, according to weather station data collected from several locations within the High Valley viticultural area, including vineyards on the area’s
southeastern and western mountain ridges, and on the eastern and western portions of the valley floor. The Winkler degree-day heat summation method of climate classification classifies High Valley as a Region 3 climate and occasionally as a cooler Region 2, depending upon the year and a vineyard’s location within the area.
(Each degree of a day’s mean temperature that is above 50 degrees F, which is the minimum temperature required for grapevine growth, is counted as one degree day. Amber Knolls, a grape-growing region approximately west of High Valley’s boundary line, has consistently warmer growing season temperatures, and is frequently a Region 4 climate in the degree-day classification system. High Valley’s cool growing climate
results from the valley’s east-west orientation, the surrounding ridge topography, and the perpetual "wind machine" generated from the Clear Lake basin. The high east-west ridges above the valley trap the cooling afternoon breezes as they blow in from the Clear Lake basin. Also, the cooling mountain-valley winds from the higher northern
elevations of the Mendocino National Forest drift down the ridges to the valley floor. The High Valley area is one of the coolest grape-growing regions in Lake County, with a frost season that frequently extends into June. The grape
varietals planted in the High Valley area reflect this cooler and shorter growing
season. The petition noted the wide variation in annual precipitation in High Valley
between the years 2000 and May 2003, and did not provide extensive rainfall
data to show it as a distinguishing viticultural factor. The High Valley area
received of precipitation in both 2000 and 2001, in 2002, and from January through
May 2003. In recent years, other Lake County grape-growing regions received
more precipitation than the High Valley viticultural area, and the petition listed the following average precipitation amounts: Red Hills, ; Kelseyville, ; and the Putah Creek basin,.

Geology

Originally a small east-west trending fault basin with drainage to the east, volcanic activity altered High Valley’s shape and created a series of high ridges along its eastern side, forming the valley’s largely enclosed basin and redirecting the valley’s drainage southward into Clear Lake. This volcanic activity also created Tule Lake,
a small lake on the valley’s central floor, as well as Round Mountain, once an
active volcanic cinder cone rising above the northern valley floor. The dominant rock types in the proposed High Valley viticultural area
are Jurassic sedimentary rocks of the Franciscan Complex, basalt flows, and Quaternary volcanic deposits. The Franciscan Complex forms the base material and most of the exposed rock in the southern ridges and western portions of High Valley, while the Quaternary volcanics overlay the basalts found throughout the valley’s eastern half. Round Mountain is a prominent High Valley feature of the Quaternary volcanics.

Soils

The two primary soil types of High Valley are weathered volcanic residue and Franciscan Complex weathered sandstone, shale, or phyllitic rocks. The east side of the area contains soils derived primarily from volcanics, while the west side contains soils from Jurassic to Cretaceous sedimentary and
phyllitic source material. The four basic soil formations within the High Valley viticultural area include: The Franciscan Hills along the area’s southern and western boundaries, the alluvial basin of High Valley, the alluvial terrace along the southeast boundary, and the volcanic ridges along the area’s
northeastern boundary near Round Mountain.
Wolfcreek loam soil, a very deep well-drained clay to sandy loam with
moderately slow permeability, covers most of the High Valley floor. The eastern half of the High Valley viticultural area contains Konocti variants, Konocti, Hambright, Benridge, and Sodabay Series soils. The Maymen, Hopland, and Mayacama Series soils
dominate the southeast region of the High Valley area. The western hills and
ridges contain primarily Millsholm, Bressa, Hopland, Estel, and Maymen Series soils. While the High Valley soils are permeable in mild and moderately-warm to warm temperatures, soils in the nearby Big Valley allow only moderately-warm to warm temperature permeation. The soils of High Valley’s slopes and ridges permit excellent
drainage, unlike Big Valley’s less favorable soil drainage characteristics.
Further, the vine-planted slopes of the High Valley area incline about 30
percent, comparatively steeper than the 0 to 2 percent incline of Big Valley
Vineyards.