Regional MapThe certified and enrolled farms are presented by watershed or drainage area. Each farm produces either fruit or winegrapes and the quality of these products is the result of the particular natural features of the farm as well as the management practices of the grower.

The natural features of these watersheds vary greatly. The largest drainage, the Russian River, is a “big valley” river with a series of major alluvial river valleys with numerous creeks draining steep mountains flanking each valley. The Napa River is similar, coursing through the alluvial Napa Valley. In contrast, the Gualala and Navarro River watersheds are primarily steep and mountainous. In the Navarro River watershed, Anderson Valley is the only flat valley in an otherwise hilly landscape. In most instances earthquake faults define these valleys.

Besides these topographic differences each watershed has a distinct geology, producing unique soil

Franciscan Formation
Large slide in Franciscan Formation.

types and drainage features and supporting characteristic native vegetative cover. In the north, the Gualala, Navarro, and Russian River watersheds consist primarily of Franciscan Formation, an ancient seafloor formed 200 to 65 million years ago and uplifted through crustal plate movements into steep and very erodible slopes. The Franciscan Formation is highly variable with areas of dense clay, gravelly substrates, very large hard rocks, and many other features. Franciscan Formation has very little stored water with springs occurring at geologic contacts and along faults and cracks.

Serpentinite rock is a unique feature of the California landscape. Usually found along fault zones, this rock type produces soil with magnesium levels so high that few plants can grow. Only certain specialized native species can tolerate serpentine soils.

On the Napa/Solano County border, in the Napa River, Pope Valley, and Suisun Creek watersheds, lies Great Valley Formation. This formation was deposited in deep water between the ancestral Sierra Nevada to the east and the Franciscan rocks, to the west between 140-65 million years ago. The Great Valley Formation is comprised mostly of sandstone and shale and, like the Franciscan Formation, holds little water.

The Sonoma Creek and Suisun Creek watersheds, and parts of the Russian and Napa River watersheds, are made up of Sonoma Volcanics. Two to six million years ago the Sonoma Volcanic field covered a 350 sq. mile-wide area stretching from Fairfield to Sonoma and north to St. Helena and the Geysers. These volcanoes produced large ash flows and pyroclastic explosions rather than extruding molten lava. The Sonoma Volcanics often have copious springs and may be found layered over a foundation of Franciscan or Great Valley Formation rock.

Petrified rock

The petrified forest preserves remnants of an ancient forest blown down and buried in volcanic ash during a pyroclastic explosion.

rainfall photo

Rainfall varies a great deal between coastal and inland watersheds.

Another great difference between these watersheds is the amount of rainfall each receives. In the Cazadero area of the western Russian River watershed, total rainfall can surpass 100 inches per year, while eastern Napa County can average only 23 inches of rain per year.

The combination of geology, soil and climate make for very different types of vegetation over these watersheds. For example, on the east side of the Napa and Ukiah valleys are blue oaks. Blue oak is one of the most drought resistant species in California and covers the dry eastern hillsides of these valleys. Along the valley floor where groundwater is more abundant are large valley oaks, a deciduous riparian oak that grows to great size. Like the oaks and their different forms winegrapes from these two environments will have unique and different qualities.

Blue Oak Photo

Blue oak and adjacent vineyard in the Stags Leap area of Napa.

Valley Oak Photo

Valley oak on the floor of Napa Valley.

These variations in geology, topography, and climate create numerous microclimates and lend credence to the concept of terroir central to the production of fine wine. Terroir embodies the idea that the characteristics of each watershed are unique and require the use of site-specific information to direct environmental management and restoration. Just as the vineyard manager and winemaker create wine by understanding the land and growing conditions, the Fish Friendly Farming program uses site-specific review to restore and revegetate each property and implement management practices suited to the natural features of each watershed. This approach assures the greatest level of success for both the farmers and the fish.

terroir photo

Certified farms have completed the Fish Friendly Farming certification and are in good standing and up-to-date with their re-certification.

Enrolled farms have completed the workshops and a farm conservation plan and are actively involved in achieving certification.

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