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Cannabis Cultivation and Water Shortages in California

In 2016, California voted to legalize recreational cannabis consumption for individuals 21 years or older. While medicinal cannabis had been legal for over 20 years in California, the legalization of recreational cannabis has created a new market, and with the potential for new cannabis businesses, California has seen an increase in legal permits for cultivation and cannabis farms in the state. Considering California’s water shortage, a sudden spike in agriculture in the state certainly poses a concern.

California is the single largest producer of marijuana plants and products in the United States, accounting for about 60-70% of US cannabis supply. Between 2012 and 2016 there was an estimated 183% increase in the number of cannabis plants in the state. Since its complete legalization in 2016, the legal cannabis market is projected to grow into a 7.2 billion dollar industry by 2024. Despite the overwhelmingly positive economic growth expected form the legal cannabis industry in California, there are many environmental concerns resulting from this inevitable market growth, specifically regarding California’s water supply. 

Beginning in the early 2000s, exacerbated by the ensuing threat of climate change, California has experienced serious drought conditions posing threats to its agricultural sector. Between Fall 2011 and Fall 2015, California faced the driest years on record, forcing the state to enforce restrictions on water usage for farmers and citizens alike. With the California cannabis market expanding within those same years of peak drought, many water supply complications emerged as a result of the plant’s demand for water. 

The cannabis plant is highly dependent on water to successfully grow. About 22 litres of water a day are needed a day for a single marijuana plant which approximates to three billion litres per square kilometer for marijuana plants solely grown in greenhouses in a single growing season. During California’s peak drought years, there was a 50 to 100% increase in the amount of watershed lands utilized for cannabis cultivation alone. Most marijuana farming sites are located in remote upper watersheds, relying on irrigation for its water demands, which can have detrimental effects on the water supplies of these regions. 

California’s drought resulted in a lack of surface water, subjugating mairjuana cultivation (and other agricultural industries) to primarily rely on water irrigation from groundwater pumping, an unsustainable method where water deep below the surface is pumped up for agricultural uses. Overpumping groundwater for irrigation is a risky pursuit as it can reduce streamflow, or the amount of water that flows through a stream. Streamflow is necessary for the survival of aquatic ecosystems as it directly alters the water available to aquatic organisms; thus, California’s freshwater ecosystems have declined in biodiversity as a consequence of groundwater overuse. Unfortunately, considering California’s already overstressed water resources, groundwater pumping is a necessary evil if the marijuana industry is to continue its market growth in the state. 

In addition to legal marijuana threatening the state’s water resources, the illegal marijuana industry has posed its own set of risks. In 2018, illegal marijuana cultivators set up over 14,000 grow sites in Humboldt County, California alone. The illegal market for marijuana is projected to be at $6.4 billion by 2024, about $1 billion less than that of the legal market. Many of these illegal cannabis farms are established in watersheds with high biodiversity, also threatening the aquatic ecosystems. Again, the necessity for water is imminent and results in the exacerbation of stress on California’s water resources. 

California has attempted to regulate water resource use for cannabis cultivation through the State Water Board, which created the “Water Boards Cannabis Cultivation Program” in 2017. The program has regulated water quality and quantity issues related to cannabis cultivation; for example, the Cannabis Policy requires cultivators to possess a water right for irrigation. While policies like these offer a small remedy to the water issues from the cannabis industry, it can only apply to legal cultivators, and does not take into account the large illegal marijuana industry in the state. As the marijuna industry continues to prosper in California, questions about how the state can manage its water resources will continue to arise. Furthermore, as climate change continues to globally worsen, water resources will be further depleted, and the industry’s survival will be challenged. 




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