Local growers in the Russian River watershed in Mendocino and Sonoma ounties, titled Russian River Water Users for the Environment, filed a lawsuit against the State Water Resources Control Board (SWRCB) on Oct. 20 in the Sacramento Superior Court for an unprecedented regulation targeting winegrape growers’ use of water for frost protection purposes. What is frost protection?
During the spring months, as vines emerge from dormancy, they begin to form tiny buds which later produce the bountiful crops seen in fall. If spring temperatures drop below freezing (31°F or below), the buds will freeze, killing the bud and subsequent grapes. A mere one to two degrees can result in the difference between a productive crop and a complete crop loss. In order to protect against such a freeze, misted water is placed over the buds, providing a reduced risk of damage, with excess returning and replenishing the groundwater table below. The regulation
The regulation declares all frost protection diversions downstream of Lake Mendocino (Coyote Dam) and Lake Sonoma (Warm Springs Dam) between March 15 and May 15 of the year are “unreasonable” unless the diverter is complying with a Water Demand Management Program (WDMP). Anyone who uses water for frost protection in the watershed, regardless of water right held or method of diversion (e.g. riparian, appropriative, “hydraulically connected groundwater”) is subject to the regulation. The watershed is approximately 100 miles long and from 12 to 32 miles wide.
The catalyst for the regulation was a letter sent to SWRCB from the National Oceanic Atmospheric Administration (NOAA) Fisheries Service on Feb. 27, 2009, “expressing concern over the threat to federally threatened and endangered salmonids of frost protection irrigation by vineyard owners in the Russian River watershed.” In 2008, two strandings occurred which were allegedly linked to frost protection — one in Sonoma and one in Mendocino County. Local efforts
One of the most notable examples of growers altering practices in recent decades to improve fishery resources is converting from tilled (plowed) soils between the rows, to non-tillaged (mowing) between the rows, reducing the amount of sediment which reaches streams. No law or regulation demands this sustainable practice, yet there is no doubt it has improved fishery resources.
Growers have engaged in other local efforts such as spearheading a frost protection ordinance to collect data on the watershed, identifying any risk zones to salmonid habitat; erecting offstream storage ponds so frost water may be pumped from storage rather than directly from streams and rivers; and coordinating diversions with the Sonoma County Water Agency during peak frost seasons. Local efforts, by all indication, have proven successful.Alternatives covered
SWRCB, as is required under the California Environmental Quality Act (CEQA), stated alternative options for growers in its Environmental Impact Report (EIR). The EIR expressly states the status quo and local grower voluntary efforts are the environmentally superior alternative. Amongst those cited as the most probable alternative to frost water are orchard heaters and wind machines. The agency, while admitting these alternatives are not environmentally superior to water, fails to address they do not achieve the same results as water.
According to a California State University, Fresno study, water is a viable option to protect vines when temperatures drop to 25°F. When there is a temperature inversion layer, heaters in combination with wind machines, allow for protection down to approximately 26°F. When there is no inversion layer, or what is known as advective freezes, water is simply the only option to protect vines. Common to the area are advective freezes and was precisely the type of freeze that occurred in 2008.Growers’ arguments and hope