History

1950’s — 1970’s

In the Beginning - the 50s
A New Drinking Water Supply
Managing the Floodwaters - the 60s
Meeting a Growing Community’s Water Needs - the 70s

In the Beginning - the 50s Back to top

Old Logo A community that depended largely on farming for its economic livelihood, Sonoma County grew by 1920 into the nation’s eighth-ranked county in agricultural production. In those early days, the majority of the county’s residents lived in rural settings. As of 1947, for example, the county’s population totaled about 73,000, with only 15,000 in Santa Rosa.

One reason for the success of Sonoma County’s agricultural industry was available irrigation water. The Russian River, whose upper reaches slowed to a trickle in most summers, was augmented by diversions from the Eel River beginning in 1906. The increased flows were particularly important to farming in the northern reaches of the county. Residents to the south relied more on groundwater wells, but the water was of generally poor quality.

A series of winter floods between 1935 and 1945 caused $6.1 million in damage in Sonoma County. In 1937 the Sonoma County Board of Supervisors requested that the U.S. Army Corps of Engineers study the Russian River Basin to develop a comprehensive flood control plan. Delayed by World War II and not presented to Congress until 1949, the Corps’ study identified repeated flooding and declining groundwater quality as significant threats to continued economic growth. The U.S. Army Corps recommended construction of Coyote Valley Dam on the east fork of the Russian River, just north of Ukiah, as well as additional flood control and water conservation reservoirs on Dry Creek, Maacama Creek, Big Sulphur Creek, and other Russian River tributaries.

To implement the Corps’ recommendation, Sonoma County was required to create an entity with the legal authority to enter into agreements with federal, state, and local governments. On October 1, 1949, the Sonoma County Water Agency - then known as the Sonoma County Flood Control and Water Conservation District and operating under a board of directors made up of the Sonoma County Board of Supervisors - was established.

Coyote Valley Dam was completed and dedicated in 1959, at a cost of $5.6 million raised by bond election. The dam, creating Lake Mendocino and operated by the U.S. Army Corps of Engineers, both controls winter floods and stores 118,000 acre-feet of water. The Sonoma County Water Agency and the Mendocino County Russian River Flood Control and Water Conservation Improvement District share state water rights permits to store water in the reservoir. However, as the local sponsor for the construction of Coyote Dam, the Sonoma County Water Agency has the exclusive right to control releases from the water supply pool in Lake Mendocino. Once water stored in the lake reaches the flood control pool, the federal sponsor determines releases, the U.S. Army Corps of Engineers. As the local sponsor for the project, the Agency also assumed responsibility for maintaining channelization works on the Russian River constructed along with Coyote Valley Dam.

A New Drinking Water Supply Back to top

The bond election also provided for the construction of the Agency’s water supply and transmission system. The system began simply enough â€” a single diversion facility, called a "Ranney collector," at Wohler Bridge, to collect water from a depth of approximately 60 feet in the gravels next to the Russian River and pump it through the Santa Rosa Aqueduct for 15.6 miles to storage tanks near Lake Ralphine in Santa Rosa. The Santa Rosa Aqueduct formed the backbone of the Agency’s delivery system, with all future aqueducts connecting to it.

The Agency commenced providing water to the City of Santa Rosa on May 24, 1959, under a 1956 agreement that set the fees the city was to pay and the quantities of water the Agency was to provide. To provide sufficient revenues to expand the system, the Agency entered into similar agreements with principal cities and water districts along the route of each ensuing aqueduct before its construction. The Petaluma Aqueduct, completed in 1962, provides water to the cities of Petaluma, Rohnert Park, Cotati, and the North Marin Water District. The Forestville Aqueduct, completed in 1962, provides water to the Forestville Water District; and the Sonoma Aqueduct, completed in 1965, to the City of Sonoma and the Valley of the Moon Water District.

Managing the Floodwaters - the 60s Back to top

Flood control continued to be an important aspect of the Agency’s work, particularly after large areas in Sonoma County were inundated repeatedly in the mid-1950s. The Agency again requested the U.S. Army Corps of Engineers survey the Russian River basin to evaluate flood control and water resources in the region. To provide financing for flood management projects, the Board of Directors in 1958 proposed the creation of nine flood control zones, each encompassing a major watershed, which could be activated at the request of 25 percent of the property owners within its boundaries to allow assessments for flood control projects. Today, six of the nine zones are funded. Activation of Zone 1A led to channel improvements in the Laguna de Santa Rosa, a natural waterway and overflow basin flowing to Mark West Creek and ultimately the Russian River. The Laguna de Santa Rosa was once very effective at reducing flooding on the lower Russian River, but silt and debris, as well as encroaching development, have begun to reduce its capacity.

Additional structures, known collectively as the Central Sonoma Watershed Project and aimed at preventing flooding in Santa Rosa, were planned for other tributaries to the Russian River. This project includes five water diversion structures built in the late 1960s on Santa Rosa Creek, Matanzas Creek, Paulin Creek, Brush Creek, and Spring Creek.

In 1962, following the second survey report by the U.S. Army Corps of Engineers, Congress authorized a flood control structure and reservoir with recreational facilities on Dry Creek, a major tributary to the Russian River, near Cloverdale. Called Warm Springs Dam, the project was designed to provide 212,000 acre-feet of water supply storage and 130,000 acre-feet of flood control storage in a reservoir to be known as Lake Sonoma.

Warm Springs Dam proved to be very controversial. Design and construction were suspended several times by litigation over financing and environmental effects, and ballot initiatives to halt the dam were presented to voters - and defeated - on three occasions. In 1983, more than four decades after the Corps’ initial 1937 survey, Lake Sonoma began storing water.

Meeting a Growing Community’s Water Needs - the 70s Back to top

New freeways and commuter routes to San Francisco and Oakland, combined with the building and baby booms following World War II, drew businesses and families to Sonoma County. The demand for water grew apace. In the first year of operation for the Santa Rosa Aqueduct, 1959/60, the Agency pumped a little over 6,000 acre feet of water. By the end of the decade, with an additional Ranney collector and expanded aqueduct system, the Agency was delivering 18,000 acre-feet of water annually, a threefold increase in only 10 years, and the system was stretched to its limit. The Agency was faced with meeting demands that the existing system could not accommodate. The contracting communities needed assurances of a continued water supply. To provide for those needs, the Agency proposed the Russian River to Cotati Intertie Project. The project was conducted with the authority the Agency was given in the 1974 Agreement for Water Supply with the goal of continuing to provide water supplies for the contracting communities - or water contractors, as they are known - through the year 2000.

The 1974 Agreement for Water Supply obligated the Agency to operate, maintain, and expand the water supply and transmission system. Expansion included the intertie pipeline from the Russian River to Cotati, additional diversion facilities at the Russian River, an inflatable dam at the diversion site to fill infiltration ponds, booster pumps, storage tanks, emergency wells, a hydroelectric plant at Warm Springs Dam, corrosion control facilities, a water quality "early warning" system, and computerized telemetry systems. The 1974 Agreement for Water Supply fixed the amount of water to be delivered to the water contractors based on their own estimated needs. The signatories to the 1974 Agreement for Water Supply were the cities of Santa Rosa, Petaluma, Rohnert Park, Sonoma, and Cotati; North Marin Water District; Valley of the Moon Water District; and Forestville Water District.

An additional feature of the 1974 Agreement for Water Supply was the formation of the Water Advisory Committee. The committee includes representatives from each of the eight signatories to the 1974 Agreement for Water Supply and makes recommendations to the Agency’s Board of Directors on water supply and policy issues.

The Agreement for Water Supply has been amended 11 times since 1974. The Marin Municipal Water District has also executed two agreements with the Agency for water supply contingent upon the entitlements of the water contractors being met.

For a more complete overview and for the 1980's and 1990's history, click here to view our Biennial Report