Water Allocation

Water Allocation

Sonoma County's Water Supply

There are eight major water contractors who buy water from the Sonoma County Water Agency:

They have legal contracts with the Agency to provide them with certain water allocations as long as water is available. During drought periods the contractual allocations get cut back and the contractors need to rely on conservation and local supplies (usually groundwater) to provide as much as half of their supply. The Agency has a permit from the State Water Resources Control Board allowing them to withdraw up to 76,000 acre feet a year (AFY), from the Russian River at various points. Each acre-foot has about 325,000 gallons. 76,000 AFY is about 25 billion gallons. For the last fifteen years the Agency has been trying to get that amount increased to 101,000 AFY to no avail.

Needless to say, the situation is even more complicated by extensive water use by wineries and other property owners, some of whom have their own water rights, yet many are guilty of illegal water diversions because there is a fifteen year backup in the State Board’s water permit allocations and little enforcement. There is nothing to be lost by simply taking the water.

The complexities of the Eel River diversion and the Potter Valley Project involve power generation by PG&E, and have resulted in 33% less water being delivered to Lake Mendocino, from which most of our supplies come, and further complicates the situation.

Follow the flow of our water supply on Sonoma County Water Agency's Interactive Map.

Read more in this Sonoma Gazette article.

Russian River Hydrology

The Russian River drains an area of 1,485 square miles that is approximately 100 miles long and from 12 to 32 miles wide. From its source, about 16 miles north of Ukiah, the river flows southward for 90 miles through Redwood, Ukiah, Hopland, and Alexander Valleys, and through the northwestern part of the Santa Rosa Plains.

It is estimated that there are presently over 600 diversions by various entities along the mainstem of the Russian River and approximately 800 other diversions along the tributaries of the Russian River (SCWA 1996b). The uses of diverted water include municipal, domestic, agricultural, and industrial.
Read more...