During the spring in Sonoma County grape vines begin to come to life after a long winter hibernation and at this time the vines are the most susceptible to a cold freeze. The wineries and vintners usually spray river water onto the vines, which creates a protective frozen shell shielding the new growth from the frigid night temperatures. Many farmers and growers say that the lowest lying crops are the most vulnerable and can sustain severe damage from one night of temperatures that dip 5 to 10 degrees below freezing.
The river water used to protect the vineyards is taken from the main spawning ground for the Coho Salmon, which is a species on the brink of extinction in California. The threat of the Coho salmon's existence has caused the state to take action in Sonoma County by proposing to regulate the pumping of river water by farmers. Although most vineyard growers approve the regulation of water usage, many farmers would like the state to regulate all water usage along the river, not just in Sonoma County. County farmers believe a more accurate regulation system is needed before anything is set in place. The state has said that regulations could begin as soon as 2011, but no specific date has been set.
