Cannabis Water Use in Northern California - Dr. Ted Grantham
Channel: UC Berkeley Events
Date: 2020-06-26

There is growing concern over the impacts of cannabis on the environment and water resources in particular, yet data on cannabis water use are scarce. In this presentation, we analyze data reported by enrollees in California’s North Coast Regional Water Quality Control Board Cannabis Program to understand how variation in cultivation practices and the use of stored water affect the timing and amount of water extracted from the environment and applied to cannabis plants. We found that supplemental use of stored water resulted in a seasonal pattern of water extraction (water withdrawals from the environment) that was distinct from water demand (water applied to plants). Although water input to storage in the off-season months (November through March) reduced water extraction in the growing season (April through October), farms generally did not have sufficient storage to avoid surface water extraction during the growing season. Our findings indicate that water extraction from groundwater wells generally occurs during the dry season and highlight the need to assess their potential impacts to connected surface water in streams.