Sonoma County is a county located in the U.S. state of California. As of the 2020 United States Census, its population was 488,863. Its county seat and largest city is Santa Rosa. It is to the north of Marin County and the south of Mendocino County. It is west of Napa County and Lake County.
Lake Sonoma is a reservoir west of Cloverdale in northern Sonoma County, California, created by the construction of Warm Springs Dam. Access from U.S. Route 101 is by way of Canyon Road from Geyserville, or Dutcher Creek Road from Cloverdale.
Coyote Creek is a river that flows through the Santa Clara Valley in Northern California. Its source is on Mount Sizer, in the mountains east of Morgan Hill. It eventually flows into Anderson Lake in Morgan Hill and then northwards through Coyote Valley to San Jose, where it empties into San Francisco Bay.
The Mokelumne River is a 95-mile (153 km)-long river in northern California in the United States. The river flows west from a rugged portion of the central Sierra Nevada into the Central Valley and ultimately the Sacramento–San Joaquin River Delta, where it empties into the San Joaquin River-Stockton Deepwater Shipping Channel. Together with its main tributary, the Cosumnes River, the Mokelumne drains 2,143 square miles (5,550 km2) in parts of five California counties. Measured to its farthest source at the head of the North Fork, the river stretches for 157 miles (253 km).
The Yuba River is a tributary of the Feather River in the Sierra Nevada and eastern Sacramento Valley, in the U.S. state of California. The main stem of the river is about 40 miles (64 km) long, and its headwaters are split into three major forks. The Yuba River proper is formed at the North Yuba and Middle Yuba rivers' confluence, with the South Yuba joining a short distance downstream. Measured to the head of the North Yuba River, the Yuba River is just over 100 miles (160 km) long.
Cache Creek is an 87-mile-long (140 km) stream in Lake, Colusa and Yolo counties, California.
The Gualala River is a river on the northern coast of California. Most of the river is in Sonoma County, but a portion is in Mendocino County. The headwaters of the 40-mile-long (64 km) river are high in the Coast Range, and it empties into the Pacific Ocean. For its last few miles, it forms the boundary between Sonoma County and Mendocino County.
Lake Mendocino is a large reservoir in Mendocino County, California, northeast of Ukiah. It covers 1,922 acres (7.78 km2) and was formed by the construction of Coyote Valley Dam in 1958. The lake and dam provide flood control, water conservation, hydroelectric power, and recreation. The dam also includes a fallout shelter built during the Cold War era to protect against the radiation from nuclear attacks from the Soviet Union.
The Russian River is a southward-flowing river that drains 1,485 sq mi (3,850 km2) of Sonoma and Mendocino counties in Northern California. With an annual average discharge of approximately 1,600,000 acre feet (2.0 km3), it is the second-largest river flowing through the nine-county Greater San Francisco Bay Area, with a mainstem 115 mi (185 km) long.
Matanzas Creek is an 11.4-mile-long (18.3 km) year-round stream in Sonoma County, California, United States, a tributary of Santa Rosa Creek.
The Santa Clara Valley Water District provides stream stewardship, wholesale water supply and flood protection for Santa Clara County, California, in the southern San Francisco Bay Area. The district encompasses all of the county's 1,300 square miles (3,400 km2) and serves the area's 15 cities, 2 million residents and more than 200,000 commuters. In terms of acres, the district includes 138,000 acres, and 120,700 of those acres are lands that people have built cities, roads or cultivate farms on. Almost 2,000 pumping wells supply the districts fields, houses and businesses with a clean reliable source of water. The water district has about 150 miles of pipelines and operates 10 dams and reservoirs, three treatment plants, many groundwater recharge basins, three pump stations and an advanced water purification plant. The district's three water treatment plants can produce as much as 210,000,000 US gallons (800,000 m3) of drinking water a day.
Spring Lake Regional Park is a 320-acre (130 ha) public park in southeastern Santa Rosa, Sonoma County, California, United States. Centered on the Santa Rosa Creek Reservoir, the park is administered by the Sonoma County Regional Parks Department. Its coordinates are 38.45°N 122.65°W, and its official address is 391 Violetti Drive.
The Central Utah Project is a US federal water project that was authorized for construction under the Colorado River Storage Project Act of April 11, 1956, as a participating project. In general, the Central Utah Project develops a portion of Utah's share of the yield of the Colorado River, as set out in the Colorado River Compact of 1922.
East Fork Russian River is a 15 mi (24 km) long tributary of the Russian River in Mendocino County, California artificially connected to the Eel River via an interbasin diversion at the Potter Valley Project hydroelectric facility. It forms in the north of Potter Valley, flows south through this valley, then southwest through a mountain pass to Lake Mendocino, an artificial reservoir that empties into Russian River. At one time Clear Lake to the east drained through Cold Creek then along the lower part of East Fork Russian River through Coyote Valley to the Russian River proper. A few hundred years ago a massive landslide blocked this channel, and Clear Lake found a new outlet to the Sacramento River.
The Marin Municipal Water District is the government agency that provides drinking water to southern and central Marin County, California. Chartered in 1912, it became California's first municipal water district. It serves 191,000 customers in a 147-square-mile (380 km2) area that includes ten towns and cities.
Lake Van Arsdale, also known as Van Arsdale Reservoir, is a reservoir on the Eel River in California, part of the Potter Valley Project. Located in Mendocino County, 4 miles (6.4 km) north of the town of Potter Valley, California, the reservoir supplies water to users as far south as Marin County.
The Potter Valley Project is an hydroelectric project in Northern California in the United States, delivering water from the Eel River basin to turbines in the headwaters of the Russian River. The project is owned and operated by Pacific Gas and Electric Company (PG&E). The main facilities are two dams on the Eel River, a diversion tunnel and hydroelectric plant. Average annual throughput is 159,000 acre⋅ft (196,000,000 m3), although this figure varies significantly with both the amount of precipitation in the Eel River basin and the demand on the Russian River.
The Mojave Forks Dam, most often known as the Mojave River Dam, is an earth-fill dry dam across the Mojave River in San Bernardino County, California in the United States. Completed in 1974 by the U.S. Army Corps of Engineers (USACE), the dam is located at the confluence of the West Fork Mojave River and Deep Creek, and can store approximately 179,400 acre⋅ft (221,300,000 m3) of water.
The 2017 California floods affected parts of California in the first half of the year. Northern California saw its wettest winter in almost a century, breaking the record set in 1982–83. The same storm systems also flooded parts of western Nevada and southern Oregon. The damage was estimated at $1.55 billion ($1,713,501,222 today), including damage to California roads and highways estimated at more than $1.05 billion.
