In one of the final steps to complete a Groundwater Sustainability Plan (GSP) for the Colusa Subbasin, the Colusa Groundwater Authority (CGA) and the Glenn Groundwater Authority (GGA) hosted a virtual public meeting on Wednesday to review the plan and gather community input. 

The GSP is a roadmap for how groundwater will be managed over the next two decades, according to meeting facilitator Dave Ceppos, and is being prepared by the CGA and GGA in response to the Sustainable Groundwater Management Act of 2014, which requires locals agencies to form groundwater sustainability agencies for the high and medium priority basins such as the Colusa Subbasin. 

“The GSP describes groundwater conditions and how groundwater management will avoid adverse impacts to beneficial users, including domestic, municipal, tribal, agricultural, industrial and environmental uses,” said Ceppos. 

According to Ceppos, avoiding adverse impacts is based on the evaluation of six sustainability indicators, including surface water depletion, reduction of storage, regraded quality, land subsidence and lowering groundwater levels. The final indicator, seawater intrusion, was determined to not be applicable in the Colusa Subbasin. 

The development of the Colusa Subbasin GSP, like many others throughout California, has coincided with one of the most severe and extensive droughts that has ever gripped the western United States, with drought conditions throughout most of California, including the area in and around the Colusa Subbasin, classified as “exceptional” –  the most extreme classification, according to the U.S. Drought Monitor. 

During the meeting John Amaro, chairperson of the GGA, said at this point in time it is likely too late to make any major and immediate changes to the way aquifers are managed within the Colusa Subbasin and the entire Sacramento Valley region to mitigate the effects of the current drought. 

“We will have to work collaboratively together through this current water emergency and then prepare for the next drought with the lessons we learned and the tools we’ve built as a result of our new, almost completed, groundwater sustainability plan,” said Amaro. 

According to the draft, technical work and related public involvement processes supporting development of the Colusa Subbasin GSP began in earnest in May 2020 and is now nearing completion. 

“Development of the GSP  has  utilized  the  best  available  science  and  tools, with the most  sufficient  and  credible  information and data available for the decisions being made and the time frame available for making those decisions,” read the draft. “Current and historical groundwater conditions and water budgets have been evaluated for the subbasin in  alignment  with  the  GSP  regulations.  The  technical  work  is  based  primarily  on  historical  records  of surface water and groundwater conditions from 1966 through 2015, which includes the prior 2014-2015 drought, but not the current 2020- 2021 drought.”

The Colusa Subbasin has been designated by the Department of Water Resources as a high priority subbasin, which means Colusa Subbasin GSAs must develop, adopt, and submit a GSP covering the entire subbasin to DWR by January 31, 2022.

Another public meeting to discuss the Public Draft Colusa Subbasin Groundwater Sustainability Plan will be held in person today (Friday) at the Sites Project Authority office, 122 Old Highway 99W, Maxwell, from 5:30-8 p.m. 

“Your participation today andover the past few years has been incredibly important to guide our approach as we prepare the GSP in a way that reflects your needs, “ said Amaro. “Of many things we are proud of, one and most particular is the unprecedented opportunities we have had for you to participate in this process.” 

According to Amaro, the GCA and the GGA have collectively sponsored, publicized and conducted 236 separate meetings in various formats since Jan. 2016 to give the community the opportunity to learn about this “challenging law and the steps to comply with it.”

The Draft GSP is available for public review and comment through Oct. 31. 

Those located in the Glenn Groundwater Authority can get more information by contacting Lisa Hunter, program manager for the Glenn Groundwater Authority, by emailing Those in the Colusa Groundwater Authority  can get more information by contacting Mary Fahey, program manager for the Colusa Groundwater Authority, by emailing

To view the Draft GSP, visit or

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