Draft technical foundation developed for cannabis growers to request stream flow diversions

Posted January 27, 2023

SCCWRP and its partners have completed the development of a proposed scientific workflow intended to provide the technical foundation for California cannabis growers to demonstrate that the water they are requesting to divert from nearby streams to support cannabis cultivation does not adversely affect the streams’ ecological health.

The draft workflow, submitted in December for review by the State Water Resources Control Board, consists of a process to develop in-stream flow criteria using the recently developed California Environmental Flows Framework, as well as a suite of web-based tools to assess potential ecological risks from diverting stream flows to support cannabis cultivation. Recreational marijuana was legalized in California in 2016.

The workflow will help the State Water Board determine how the individual and cumulative effects of cannabis growers’ proposed stream flow diversions could adversely affect the flow patterns necessary to support aquatic life and ecosystem functioning.

Researchers are initially focusing on developing tools to guide stream-diversion decisions in the North Coast region of California. Eventually, the State Water Resources Control Board’s Division of Water Rights intends to complete similar analyses for each of 14 regions statewide.

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