Even keen students of geography may struggle to locate Shasta Lake and Lake Oroville on a map of the United States, but these two bodies of water are important. With respective capacities of 5.6bn and 4.4bn cubic metres, they are the largest reservoirs in California. And, at a time of the year when the water in them should be at its deepest, they are worryingly empty.
According to the May 3rd US Drought Monitor report, Lake Oroville is at 55% of its capacity and Shasta lake is at just 40%. Both levels are described as "critically low”.
Shasta Lake is part of the Central Valley Project, a 400 mile (644 km) long system of canals that from north to south of the state, drawing water from the Sacramento and San Joaquin river basins. Its importance to the region’s agriculture is illustrated by the fact that it supplies seven of California’s most productive farming counties
Lake Oroville is part of the separate California's State Water Project which supplies water to 750,000 acres of land and 27m Californians. Last year, its levels dropped to 24% of capacity, causing the the Edward Hyatt hydroelectric power plant to shut down for the first time since 1967.
Crucially, California’s water projects are interconnected, so even if some other reservoirs have benefited from winter storms, the low levels in Shasta and Oroville will affect the state as a whole.
2021 was California’s second driest year in what is described as a 22-year ‘megadrought’. With little rain – and January and February were even drier than usual this year – the state relies heavily on snow melt from the Sierra Nevada mountains where, again, despite record snowfall in December, there is over a third less snow than average for the time of year.
Ryan Endean, a spokesperson for the California Department of Water Resources (DWR) told CNN that the low levels of Lake Oroville's may mean that water agencies will only get five percent of the water they have asked for this year. They are, he said “being urged to enact mandatory water use restrictions in order to stretch their available supplies through the summer and fall."
The prospect of another drought year will focus the minds of grape growers across the state, but particularly in the Central Valley where there is a history of overproduction. Around five percent of the average 4m ton harvests remained unpicked. Problems of smoke taint (from drought-linked fires) in 2020 and a short crop last year helped to bring the industry back into balance but, as the Allied Grapoe Growers Winter 2022 report says “make no mistake – any series of 4-million ton crushes in a row will challenge that balance once again”.
Alongside the issues of possible overproduction, drought and of course fire, growers are also concerned about rising costs of everything from wages and energy to steel and fertlisers. Assuming the 2022 harvest is 'balanced', “buyers” the AGG report states, “should be prepared for growers to make some pretty convincing and legitimate arguments for higher grape prices.”
Given the volumes of wine Australia now has to sell, those grape growers may have to polish up their powers of persuasion.