BRBNA Districts
To fully understand the geographical and ecological complexity of the BRBNA as an assemblage of natural lands extending southward from the Mendocino National Forest, it is helpful to organize the BRBNA in terms of successive districts, or sub-regions, as they unfold from north to south.  One might even imagine a hypothetical southbound winged migration of a golden eagle or the terrestrial journey of a southward-ambling black bear from the well-protected habitats of the Mendocino National Forest and Interior Coast Range toward the southerly expanses of BRBNA extending deep into territory transformed by humans. The five districts within the BRBNA are described below (Figure 3-1) (see Appendix D for a description of BRBNA lands by ownership.)

Indian Valley/Bear Valley District
The first major geographical subdivision our eagle and bear might encounter is the Indian Valley/Bear Valley District (Figure 3-2).  Here the Mendocino National Forest's Douglas fir, ponderosa and knobcone pine give way to the lower elevation chaparral and foothill pine surrounding Indian Valley Reservoir, formed by a dam built in the 1970's by the Yolo County Flood Control and Water Conservation District.  To the west of this territory, towards Clear Lake, lie Long Valley, Wolf Ridge and Wolf Creek.  Indian and Bear Valleys were once home to significant populations of the Pomo and Hill Patwin tribes.  Today, Long Valley is one of the few areas of the BRBNA to contain significant amount of low-density rural development. 

Directly east of Indian Valley Reservoir is the prominent, north-south Walker Ridge, extending to 3,600 feet in elevation at certain points and containing a mosaic of mixed chaparral, serpentine, and pockets of knobcone pine.  This is publicly owned BLM land, and offers spectacular views, interesting and rare plant species, and, to some extent, potential wind energy resources.  Down slope and to the east of Walker Ridge a spectacular working ranch area called Bear Valley.  A showcase of private ranch operations and conservation, Bear Valley is largely protected by private conservation easements and contains a spring brilliance of wildflower displays unsurpassed anywhere in the state.  The area contains the endangered Adobe Lily, and ironically, the lily and the working ranches ensure each other's joint perpetuity and survival, thanks to easements held by the American Land Conservancy.  Bear Valley is also the home of at least one pair of nesting Golden Eagles.

Eastward still (this district is the widest east-west district in the BRBNA) are the private ranching districts of Antelope Valley and Cortina Ridge, both dramatic in topographical relief and containing very little human development. At the extreme eastern edge of this district where Cortina Ridge drops into the Sacramento Valley is the small Indian Rancheria of Cortina, where a number of its residents still speak the native Patwin tongue. 

To the south, the Indian Valley/Bear Valley District transitions to the Cache Creek Natural Area District across State Route 20.

Cache Creek Natural Area District
Our eagle and bear, upon crossing east-west trending Highway 20, would find themselves in good company.  Lands in the Cache Creek Natural Area District (Figure 3-3), located immediately south of the highway, from Clear Lake to the east to parts of the Blue Ridge on the west, are predominately public lands owned by the Bureau of Land Management, with pockets of California Department of Fish and Game (CDFG) lands, and are known as the Cache Creek Natural Area (CCNA).  The Bureau of Land Management has recently completed its CCNA Management Plan.  Central to this district is the proposed Cache Creek Wilderness (currently federally designated as a Wilderness Study Area), which includes more than eighteen miles of Cache Creek's north fork and main stem, an area inaccessible to automobiles, and home to both migratory and resident populations of bald eagles.  It is also a major CDFG tule elk preserve with herds numbering in the hundreds of animals, and has an abundant population of black bear and black-tailed deer as well.  Here in the "wild heart" of the BRBNA lands, native peoples lived for some 10,000 years until the mid 1800's, and critical archaeological sites abound in the region, including the dramatic shallow depressions of former Hill Patwin dwellings and dance lodges.

The Cache Creek district extends from near the community of Clear Lake on the west, to the upper east flank of the Blue Ridge in Yolo County, and southward to include the southern-most tributaries of Cache Creek, including Rocky Creek and Fiske Creek.  The district also contains Yolo County's Cache Creek Canyon Regional Park, with camping, picnicking, and access areas for rafts and kayaks.  The fast-flowing sections of Cache Creek in the canyon area are known nationwide as a blue-ribbon whitewater recreation resource used by thousands of rafters and kayakers each year.  Both the wilderness and the canyon/recreational reaches of Cache Creek are currently being considered for California Wild and Scenic status.

The CCNA offers ample public hiking venues, including the popular Redbud Trail, the challenging Blue Ridge Trail, and the lesser known but highly scenic Cache Creek Ridge Trail.  Opportunities exist for equestrian and off-road bicycle travel in and out of the wilderness study areas, respectively.  As more people come to appreciate the dramatic scenery and the wild values of the Cache Creek Natural Area, user pressure will necessarily grow, making conservation, wilderness preservation and sound management a necessity.

Knoxville District
Still southward on our migratory path down the Blue Ridge "spine" of the BRBNA, our eagle and bear would encounter the Knoxville District (Figure 3-4) in the upper reaches of Eticuera Creek in the Putah Creek basin.  Here at the intersection of Lake, Yolo and Napa Counties lies land originally mined in the late 19th century for quicksilver (mercury) to be used in processing during California's gold rush.  In Knoxville geology is king, with some of the most complex associations and dynamic origins of rocks and minerals in the western U.S.  Dominated by ophiolite sequences forged deep within former seafloor vents and surrounded by two types of volcanic rock (Sonoma and Clear Lake volcanics), the Knoxville District is home to the McLaughlin Gold Mine, whose operations subsumed several more historic mercury mines and provided for the safe extraction of nearly 3.45 million ounces of gold.  While the open pits, tailings pond and other working elements of the mines' lands are being reclaimed according to state-mandated standards, considerable land owned by the company has been transferred to the University of California Natural Reserve System for management as the preeminent serpentine-based natural reserve in the United States.  The Donald and Sylvia McLaughlin Reserve is home to numerous scientific studies by geologists, ecologists, atmospheric scientists, fisheries biologists, and others.

By an artifact of circumstance, just southwest of the McLaughlin Reserve is the Bureau of Land Management's Knoxville Off-Road Vehicle Recreation Area.  This labyrinthine system of dirt trails for off-highway vehicles courses throughout hilly serpentine lands.  It is managed by the Bureau of Land Management and partly funded by Green Sticker funds from fees on registration of off-highway vehicles.

To the south of the McLaughlin Reserve and southeast of the Knoxville Recreation Area lies the State Fish and Game owned Knoxville Wildlife Area.  This 20,000-acre habitat forms the western slope of the Blue Ridge south of the dividing saddle between the Cache Creek drainage and the Putah Creek Drainage.  The recent addition of the Napa Ranch acquisition was made possible by the combined funding effort of the State Wildlife Conservation Board, the State Coastal Conservancy, the Resources Legacy Fund Foundation, and The Nature Conservancy, and has considerable potential as an expansion area for tule elk and many other species of wildlife.  South and west of the Knoxville Wildlife Area are a number of large private ranches, including the Gamble Ranch, known for its locally prized, premium grass-fed beef. 

Berryessa District
Lake Berryessa, a 1.9 million acre-foot reservoir formed in 1957 by the construction of Monticello Dam on Putah Creek, dominates the Berryessa District (Figure 3-5) in the southward journey of our bear and eagle.  Managed by the federal Bureau of Reclamation (BOR), Lake Berryessa provides both irrigation and drinking water for Solano County as well as water-based recreation to a potential population in the millions within a two-hour drive of the reservoir. One of two significant recreational hubs in the BRBNA (the other being BLM's Cache Creek), Lake Berryessa is best known for fishing, water skiing and wake boarding, and a series of controversial, privatized resorts which have existed on public lands for nearly half a century.  A major portion of the accessible areas of the lake is fronted with private resort development and there are, as yet, no public campgrounds and only a few short hiking trails. Only one of the eleven existing boat ramps is public (the rest are privately managed), and the only public picnic area is an extensive complex located on the western shore north of the BOR headquarters.

West of Lake Berryessa is Cedar Roughs, a unique forested area dominated by Sargent and McNabb cypress, and managed by BLM.  Sargent cypress occur only in California and this stand is unique due to its 3000-acre size, the largest stand of Sargent cypress in the state. Cedar Roughs is also a federally designated Wilderness Study Area.

To the north of Cedar Roughs and west of Lake Berryessa lies Pope Valley, a highly scenic agricultural region now dominated by livestock grazing but increasingly being converted to grape vineyards.  It is home to the Wantrup Wildlife Sanctuary, a 730 acre oak woodland preserve managed by the Land Trust of Napa County that supports studies in reforestation and ecological research.  At the south end of Lake Berryessa is the Quail Ridge Reserve, another holding of the University of California Natural Reserve System.  Quail Ridge Reserve occupies most of a peninsula surrounded on three sides by Lake Berryessa and harbors outstanding remnants of rare native grassland, savannah, and oak woodland habitats.

The east shore of Lake Berryessa also features a Fish and Game managed wildlife area between the shoreline and an access road to several private ranches.  Large cattle ranches occupy nearly all the land on the western flank of Blue Ridge between the north-south ridgeline and Lake Berryessa.  BRBNA conservation efforts on private lands focus on these large, intact cattle ranches that form a remote, wild contrast to the highly peopled western edge of Lake Berryessa.  Likewise, the eastern flank of Blue Ridge down to the Sacramento Valley floor in Yolo County is also largely a mosaic of several large stock ranches, with the notable exception of an island of inaccessible federal BLM land surrounding the Blue Ridge's highest point, Berryessa Peak.  Both the eastern and western flanks of the Blue Ridge are significant working landscapes worthy of conservation.  From Cache Creek to Putah Creek, along both flanks of the Blue Ridge, the working ranches and BLM holdings represent a significant wild habitat corridor for eagles, bears, mountain lions, and hundreds of other species, as well as providing the scenic backdrops to the Capay Valley and Lake Berryessa.  These working ranches are among the most critical conservation opportunities in the entire BRBNA 

Cold Canyon District
As the BRBNA extends southward, its width narrows somewhat, yet the hypothetical southbound eagle and bear have covered a continuous unbroken corridor of wild land since the Mendocino National Forest. Just southeast of the Monticello Dam that forms Lake Berryessa, the last major BRBNA district begins – that of Cold Canyon (Figure 3-6), the inter-dam reach of Putah Creek, and the southernmost Blue Ridge.

Between Monticello Dam and the Solano Diversion Dam is an approximately six-mile reach on public and private lands which contains waters released from the cold bottom layers of Lake Berryessa, yielding a trout fishery known statewide and rivaling many at higher-altitude Sierra locations.  Putah Creek rushes over boulders and rapids amidst alder and willow trees, and the waters of Lake Solano, impounding Putah Creek behind the diversion dam, are home to otter, beaver, muskrat, numerous osprey, egrets and herons, as well as recreating non-motorized boaters, fishers and picnickers.  Lake Solano Park, managed by Solano County, has one of the only public, organized campgrounds in the BRBNA (the other being Canyon Park in upper Cache Creek), as well as a well-loved picnic site and remote, group campground.  The Putah Creek Discovery Corridor, an active member of the Partnership, is an association of stakeholders along the inter-dam reach united by a desire to share education and outreach.

Just downhill from Monticello Dam and south of Route 128, which is the border between Yolo and Solano County, lies the inconspicuous entrance to yet another holding in the University of California Natural Reserve System - Stebbins Cold Canyon Preserve. This research facility also contains the most popular hiking trail in the BRBNA.  The Stebbins Loop Trail connects the western ridgeline to the Cold Creek Canyon floor via an old homestead.  Steep lands containing the canyon make home for a surprising divergence of plants and wildlife, including rare peregrine falcons.

Southward and surrounding Cold Canyon are more BLM lands, as the Blue Ridge extends southward out of public and into more private lands punctuated by a second prominent ridgeline peak, Mt. Vaca.  South of here, the BRBNA narrows and tapers to its southern terminus, nearly to Interstate 80 – more than sixty miles, as the eagle flies or the bear walks, from the southernmost connection to the Mendocino National Forest.  The sixty linear miles along the Blue Ridge spine of the BRBNA form a critical corridor and extension of wild lands deep into the growing populations of the Bay Area and Sacramento Valle