Final Comments to the Groundwater Sustainability Agency, by the Napa Sierra Club Excom

Dear Supervisors Dillon, Gregory, Pedroza, Ramos, and Wagenknecht,

Available data demonstrate that we are already at an unsustainable level of groundwater usage. The GSP sets the Sustainable Yield at approximately 15,000 AFY.  However, the 2020 Annual Groundwater Report shows that groundwater use in the years 2018-2020, ranging from 17,783 to 17,933 AFY, has exceeded the Sustainable Yield by over 2,700 AFY. We are drawing an increasing volume of water when replenishment is decreasing due to climate change, the increase in the number of wells, and amount taken from the watersheds that feed the subbasin. No amount of modeling, projection, discussion, and report writing can obscure this fact. The subbasin is not infinite; as we are in a climate emergency, we are also in a water emergency. This report and plan should begin with this basic premise. It does not.  

The Sierra Club Napa Group has requested and been denied the opportunity to initiate discussion on what we consider essential actions in the creation of a sustainable plan. We have written letters stating our concerns and request for specific actions. Since our last letter November 15, there have been additional documents published by the GSPAC as well as dissenting members of the GSPAC.  

  • The letter of transmittal submitted by David Graves and Alan Galbraith to the Board of Supervisors which included the pointed to the proposed Technical Working Group, which would be appointed to define and extend actions based on scientific and unbiased advisors who are uninfluenced by political or pecuniary concerns.  
  • The document submitted by Hackett, Manfree, von Rosenberg, and Sauer, (Manfree, et al) Dated December 1, which lists the actions they believe essential for the GSP to be effective. These four were the dissenting votes when the proposed GSP came up for approval by the GSPAC.  
  • The narrative of Mike Hackett, published by NapaVision 2050 (

The Technical Working Group Proposal 

The proposed Technical Working Group (TWG) would consist of credible experts in relevant disciplines who would monitor data input and suggest improvements in data collection, including in surface water/groundwater interactions, streamflow, modeling, forecasts, climate projections, and other tasks.  

We support these functions and consider the proposed responsibilities of the TWG to be essential.  

The TWG adds credibility and dynamic focus to the GSA process. Selection of data, adjusting monitoring programs, and maintaining a rigorous oversight to the implementation process is a means by which the recommendations of the Sierra Club might be implemented.  We strongly support the recommendations of the Manfree, et al on this subject. It can be a significant contribution of rigor and objectivity to the process.  

Without implementation of the recommendations of the Manfree, et al, letter, the TWG is unlikely to remedy the shortcomings of the GSP.  We do not feel that it cures all of the gaps in the process, however. It is necessary, but not sufficient to create a process we would have confidence in implementing an effective sustainability plan. 

The Letter of Dissent 

The letter, with principal author Dr. Manfree, lists concerns and remedies that we find extremely well written and clear. It is rigorous without being arcane. We concur with all of the recommendations and believe they should be endorsed and implemented by the GSA.  

Hackett Narrative 

The Hackett narrative describes the experience and frustration of being on the GSPAC and being in the distinct minority who have primary concern for the sustainability of the environment and of the water. He lists observations and concerns about the process being focused on political expediency rather than objective facts.  He expresses significant concern about the accuracy and objectivity of information provided to the committee. He expresses skepticism over the basic integrity of this process.  

As observers of the process, we have had the same concerns and do not feel that his concerns are overstated. 

Sierra Club Response 

1.      Look at the whole system 

This is repetitive of our prior letter, but it is essential that the domain of discussion, planning, and action be the whole valley, not just the subbasin. There is no prohibition in the SGMA against consideration of dependencies and interactions with other water systems; other jurisdictions have done just that. A distinct impression was created that there was such a prohibition against considering surface water and watershed information. The frequent ruling was “out of scope,” thereby heightening many of our concerns. 

Questions, data, and discussions of the whole valley and the impact of each domain on others should be allowed, encouraged, and taken into consideration.  

The subbasin is one part of a system, and depends on all parts of the system to be sustainable. Developing a subbasin sustainability plan without data and open discussion of all parts of the valley’s water system is not going to lead to productive actions and will still leave the valley vulnerable to ever-increasing water emergencies. 

2.      Revise methods for setting indicators 

The monitoring plans (Section 10) show indicators of adverse conditions of overdrafting. Each of these indicators has a criterion for triggering an alarm. The method is so conservative that it basically answers the question, “Is it bad yet?” The questions that should be asked are “Is it no longer stable?” and “Is it showing signs that it probably will become adverse?” There are statistical methods and tools that are designed to establish such predictive and preventive triggers. Every monitoring indicator should be replaced by statistically derived criteria for action. Action triggers should be a matter of math, not of consensus.  This should be a high priority for the Technical Working Group. 

3.      Collect well data 

We need more data on water pumping and groundwater levels. We need data from the watershed in addition to the subbasin. 

4.      Mandatory metering for all wells, except for domestic wells  

Meters should be installed and checked regularly. We need to know how much groundwater is actually pumped and how much surface water is being diverted. We need data to make better decisions. During the GSPAC discussion, it was stated that metering wells is an action that could be considered if the situation becomes severe. Firstly, we’re closer to ‘severe’ than we may think, and secondly, we need good data. Don’t wait for the emergency to collect useful data.  

5.      Monitoring for all wells  

Depth levels should be taken regularly for all wells. Independent of quantity pumped, we need data on groundwater levels at all locations. In that way, one can detect the impact of new wells on adjacent wells and surface waters.  

6.      Make data public 

Data from well levels and water pumping should be made public. 

7.      Stream monitors 

Groundwater dependent ecosystems (GDEs) include surface water flow sufficient to support dependent flora and fauna. To understand whether there is sufficient water and flow for the GDEs, we need data from stream monitors. There need to be sufficient stream flow monitors to understand the surface flows in the Napa River and tributaries. The number and placement of these monitors should be determined by scientifically qualified and unbiased experts.  

Effort and volume of work and information 

We certainly are aware of the amount of work and dedication contributed to the development of the draft Groundwater Sustainability Plan. Many have pored over every page, commented, and given detailed feedback. The challenge in such a process is that the sheer volume of information, much of it arcane and technical, can be a distraction from the bigger picture and the overall framing of the effort. We express appreciation for those contributors as we express concern for the process itself. 


The Executive Committee,

Sierra Club Napa Group 

Submitted on December 6, 2021