Flood Control and Water Conservation District - Regular Meeting

So let's get started with our PAC meeting for today. I guess our roll call is the first item of business.

Member Filippelli?

Present.

Member Cooper? Present. Member Shambon? Present. Chair Kolndorf?

Present.

Thank you.

All right. We received public comment from David Graves. Thank you, David, for your thoughtful comments. And we have printed copies of these also, which we can look at further. So thank you very much for that. Any other public comments in the room or online?

We have no callers.

Sorry. Yes, please.

I was just wondering if someone can point to me where the data is for the water quality monitoring in the groundwater wells. I haven't been able to find it. That's my question.

OK. Thanks. I think staff will be able to address your question during the break or right after the meeting. OK. Minutes from our April TAG meeting. Do we have a motion to approve the draft minutes?

So moved. Second.

Second. OK. All in favor of?

Aye. Aye. Aye.

Aye. OK. The minutes are accepted from the last meeting. Do we have reports and announcements from staff?

Sure do. Thank you, Chair Kondolf. First announcement is that all the TAG members have been asked to re-up their appointments and I think you've all received emails from our CEO's office just asking you to check the box if you wish to continue in your role as a technical advisory group member. We would very much appreciate it if you would. I can't believe the time has gone so fast. But yeah, it's time to re-up. So if you please respond to those, you'll be reappointed before the end of July. Second announcement is that we just, county just mailed about 2,600 postcards to groundwater users in the Napa Valley Subbasin, informing people of the presence of a new fee that would be assessed. The very important point about the fee is that it only applies to the Napa Valley Subbasin, which is more or less the valley floor area. I realize for anybody listening that might not answer your question as to if it applies to you, but we have a map on our website as well as really detailed step-by-step instructions for entering your parcel number, your address to determine if you're affected. However, if you didn't receive a postcard, that's a pretty good indication you're not affected. So, we did mail those out. They're already landing in people's mailboxes. The fee applies to three different user groups, agriculture, public water systems, and the so-called self-supplied users, which are more or less domestic users. They each have a different rate and a different unit of measurement, which is included in the postcard along with a lot of other information. Yeah, five things about it. Obviously, if anybody has questions, they can contact staff, and I'll provide information about where to reach us at the end of this. But, yeah, if you have a question about it, if you think that there's a mistake, we absolutely want to hear from you, so please reach out. But there are also a couple other situations that we're asking people to notify us by July 10th, and that is if you're dry farming, we want to hear from you. If you've removed vines, we definitely want to hear from you. You wouldn't pay a fee at all if you've removed vines. If you dry farm, you'd only pay the base rate. If you get a majority of your irrigation water from alternative sources, like reclaimed water or surface water diversion, or if your well is outside the Napa Valley Subbasin. We want to hear from you. And then last but not least, we do have provisions for fee waivers for anybody whose income does not exceed 80% of area median income. We have a lot of detailed information about all of those conditions on our website, really detailed FAQs tailored to each of the three specific user groups, but especially for the folks whose who may be income limited, we absolutely want to hear from you so we can get you a fee waiver and indeed did process one of those just the other day. For more information, you can go to the website is www.nappacounty.gov forward slash 3983. But you can just go to the Napa County homepage and type in groundwater sustainability fee. It will take you to the page where all of the information, the map, the instructions, et cetera, is there. So again, only applies to people in the Napa Valley Subbasin. We're also going to have, last point about it, we're going to have two public virtual workshops related to the fee for anybody, any member of the public. And those will be held on Wednesday, June 16, from 3 to 4.30 in the afternoon. And then two weeks later, on Wednesday, July 1, from 5.30 to 7 in the evening. Again, the registration links to join those meetings are on that main fee web page. I'm sure we will see a lot of people and I hope anybody has questions will join us so that concludes my remarks Mr. Featherston do you have any remarks or announcements okay all right thank you okay thank you very much and I assume that are there any what we would call administrative items in addition to

chair excuse me jameson just a correction that groundwater fee meeting is actually going to be on the 17th not the 16th thank you so much i wrote down the wrong date sorry i should have this burned in my memory by now thank you okay i assume we don't have any further administrative items so we could move on to the fun stuff and uh We'll start with a presentation of the development of concepts for incentives to support implementation of the groundwater pumping reduction and water conservation work plans, as well as a brief update on the Water Quality Certification Partnership Program. Okay.

Well, good afternoon. Oh, I can see myself twice here. Let me get the slides up. Is that working for folks in the room?

Yes, it is.

All right, thank you. Well, good afternoon chair called off and tag members. Duncan McEwen with the economics here. Sorry to interrupt.

I'm so sorry to interrupt, but you can you put it in presentation mode? So we can see each slide individually. How about that? Perfect.

Thank you. All right. There we go. Now we're off and running. Anyways, sorry to be virtual today. I think as at least our school district, this is the end of school and graduation stuff. We've got some family activities this afternoon, so I couldn't make it back here in time. So you get me on a computer screen today. Plus, it's like, I don't know, it's a pretty toasty day. So... All right, I'm going to cover four things. Just do a quick update on groundwater pumping reduction work plan implementation. Talk about the Water Certification Partnership pilot program, where that is, and conversations that we've had with a couple of the certification programs. And then spend a little bit of time talking about some concepts for incentives for increasing adoption of water conservation practices and really implementing the GPR work plan. And this is you know, building on conversations that we've had over the last year and really going back to the development of the work plan. So you've all seen this a bunch of times, and just put it up quickly to remember the guiding framework that we set out when we put the groundwater pumping reduction work plan together to focus on voluntary actions, incentive-driven approaches to reduce water, look at the costs and benefits of those, leverage existing programs and opportunities. include adaptive management, and then continue to evaluate more mandatory and therefore more costly measures if the program goals don't achieve the objectives that we've set out for. I think we've largely been on that implementation timeline. The water certification partnership concept, pilot partnership program, you know is working with existing partners and i think is a good example of leveraging some of those existing relationships and it builds off of the analysis of the costs and benefits of different practices and what we're going to talk about today is starting to think about incentives to get more rapid adoption of some of those practices And then here's kind of the overview of the implementation process. And just a reminder that the genesis of the groundwater pumping reduction work plan is to achieve a sub-basin wide, not parcel by parcel, but sub-basin wide 10% reduction in groundwater pumping reduction. And to achieve that, that was laid out in the, and you can see the list of. Management actions for water conservation and groundwater pumping reduction here in blue. We're also continuing to evaluate recharge opportunities, which we presented on at the last tag meeting, although we're not really touching on today. and looking at other supply augmentation approaches and continued outreach with the GSAs and other stakeholders and organizations. And I'll just note that, I mean, I think this has been an important part of the work, getting the word out to people and, you know, the organizations, including the certification programs, but others in the county, you know, RCV, grape growers, others have all been Farm Bureau have all been very responsive to requests and have been helpful in crafting a lot of the ideas that have come into implementation. So a quick update on the Water Certification Partnership pilot program, where that is. We've been meeting with the two partner programs, which is Fish Friendly Farming and Napa Green. And just a quick recap of what the goal for this program is, it would be anonymized data, water data reporting, implementation of best management practices through defined specific practices on a checklist, measurement of what the water conservation savings is, and then development of incentives to give wider adoption and implementation of those practices. So we've met with both programs a number of times and talked through some of the technical and logistical details of these four components that I just went through. And I think at this point we have a concise overview of what the program scope is that both programs have. i've looked at and agreed to so just a concise statement of the data reporting needs the water conservation practices that we're looking for and how we would be tracking those over time and then a concise checklist that lists the practices that are included in the program And again, the goal of the program is to accelerate adoption of those. There's already good water stewardship for certainly on the ag community in the valley. And the idea is to accelerate adoption of those practices and implement more of them and then measure that water savings. And then what we're working on currently is just a short memorandum of understanding that memorializes those items that I just went through between each of the certification programs and the county. So those next steps really include completing that memorandum of understanding and then continued coordination and then starting with implementation. I mean, I think where we are right now, we're hopeful that those are activities that we'll be picking up over the coming several months. I mean, I don't think there's really much to iron out on what the program is or how it would work. We're just going to get the MOU that puts that in writing in place and then move forward with implementation. So one of the ways to accelerate implementation is start to think about incentives. And I think we've talked about these going back to the development of both the water conservation work plan and the groundwater pumping reduction work plan. And so we've been thinking about what are we have a long list of potential incentive approaches ranging from outreach and education type concepts to very specific cost sharing for specific types of practices and data needs. And what we've done today is boil that down into three components that focus on what we think are kind of the lowest hanging fruit for for getting incentives in place. So again, with incentives, the approach is encourage wider adoption of practices. We want to prevent the need for more costly mandatory measures and then integrate across the groundwater pumping reduction work plan program components. So there's three concepts that we put together. These are related. One is like sponsored grower outreach workshops. So where the county is sponsoring or appearing at or presenting to get the word out about these, or one, the need for water conservation and the opportunities that are available both on the technical side and potentially on a financial side and get word out about the pilot certification partnership concept. Second is looking at defining specific incentives. I'll go through what those are. And again, there's a much longer list that we've been working on. We've boiled it down to about four or five concepts that we'd like you all to consider and provide some feedback on. And then the third is how would this actually work? And given the administrative burden of of incentive programs, the least cost approach would be to manage it kind of like a block grant type program concept where, you know, it's done in partnership with the certification program, let's say, through the pilot certification concept or other partner agencies, you know, like RCV or Grape Growers or whoever is appropriate to get the incentives out to folks and actually achieve water conservation, measurable water conservation. So I'll step through these three related components quickly. So the first is, I think this one's pretty straightforward. It would be to, you know, Use staff time and consultant time to continue to get out and be at workshops. Sponsor some of those to get the word out about these programs. And these could include topics at the workshop, could include things from talking about what water conservation opportunities are. I think getting additional information out there about the impacts or the cost of not achieving the voluntary goals that have been set out in the GSP. Promoting early adoption of water conservation practices and then focusing on what can be done now to achieve measurable water savings. The specific practices that could be incentivized, I think we boiled this down and part of this is coming out of work that we've done with the. the certification pilot partners but really kind of fall into five categories here so meters measurement better measurement allows you to be a better you know to do better management it's kind of a fundamental piece of being able to measure water conservation anyways so meters as a big component Anything for vineyard floor management, soil and cover cropping to increase soil moisture holding and infiltration capacity. We've heard extensively, I know Miguel is not here today, but with the RCD and distribution uniformity testing, but then actually following up and implementing recommended corrective actions to improve soil. DU and measure the resulting water savings. So that would be whatever irrigation system repairs would be needed or changes in irrigation practices. And then all of these would be tied to water use tracking and reporting. That's how we actually measure and ensure that any incentives are tied to a measurable reduction in water use. And so the concept would be each practice, each one of these with a clear cost incentive. We already know what estimates of water savings are, best as we can determine them from the existing literature. That information is already in the water conservation work plan and the groundwater pumping reduction work plans. And then this could be set up as like, you know, through a block grant type concept as a cost sharing arrangement. You know, just as an example, it's $500 to $2,000 per practice. And what that specific amount is would need to be set. But the idea would be to define those amounts for specific practices and water savings and then use that to achieve wider adoption and measure the actual savings and start to record that data. And then the third piece, like I mentioned before, is how this could actually work in practice. It would be to work with the partner organizations. We have the pilot certification partnership concept that's up and running. We're working on that. Grape growers, RCV, other local organizations could also be good vehicles to do this. We're thinking internally about what could make sense and then what kind of initial funding could be seed funding to start these program concepts. and the other thing that i note here is that you know the block grant approach is consistent with you know how like the uh hsp and sweep grant programs uh were run on the last iteration and are current and are going to be run on the uh on the current program which i think the solicitation period just closed very recently for those And we've talked to some of the local agencies. I think there's at least two applications that have been submitted that would cover the Napa Valley sub-basin area. So those are programs that are kind of run in the same way. more funding available, obviously, than what we're talking about here for this initial seed funding. But it would also be, so this concept would line up with how those grant funded programs are typically run. And many of those grant opportunities have similarities in best management practices and water conservation that could be achieved through them. So I think we thought it would be a good way to kind of leverage and align with other upcoming potential funding sources that could be leveraged you know next year if those applications are successful and and some of those hsp and sweep grant funds are available And then any of this will be tied to water use reporting. We need to be able to measure. It's important for GSP implementation. It's important for groundwater modeling, as we've heard from Vicki and Nick and her team on prior meetings. And it's how we would actually measure water savings and track how we're doing relative to the 10% target that we're trying to achieve. I think I covered some of these additional details already, so I can skip over this. And I think the last thing that we wanted to note is that a lot of the best management practices that are in the water conservation work plan and the groundwater pumping reduction work plan have been included in the water availability analysis water conservation declaration form, which is like a checklist for these types of best management practices. And so we've been thinking about opportunities to improve understanding for current practices as well as potential planned future water conservation practices. So could this information support more targeted incentives, like where you kind of get best bang for your buck for targeting funding? That's something that we've been thinking about. Could this be accomplished through a survey that's tied to the Water Conservation Declaration form? Are there other ideas to leverage this information and get an improved, more efficient implementation of incentives and the pilot water conservation certification program? and that is the end of the presentation here i think we had just kind of a general prompt that was included in the staff report for for any feedback but i'll stop there and then if jameson if i missed anything or nick on your end that you wanted to add otherwise i'll i'll pause and hand it back over for discussion thanks duncan um comments from the tag

All right.

I'm first, Duncan. So on the incentive slide, it seems like a lot of those are really focused on sort of post-establishment incentives. So, you know, what's your cover crop in an established vineyard? How are you irrigating it? What's your irrigation system efficiency? And I'm wondering if there's, given the fact that there are currently many vineyards that are out of production, if we could explore incentives for planting decisions, because planting decisions will then determine water demand of block for the life of the vineyard and so if we could incentivize things around you know rootstock selection if we could incentivize things around like if you're actually doing some soil mapping to look at water holding capacity and then how you're aligning that with your planting decisions yeah so that's my first question

I think the short answer to that is yes. I mean, I think that's something we could add. It's on the longer list we can pull up. I think related to that, which we've talked about as a program incentive concept before, is also incentives to rest land longer, you know, to keep it out for an additional year. I think it was like three tag meetings ago we presented some estimates of land at that time that has been, you know, vineyards that have been removed. I assume that number might have gone up a little bit since then, but thinking about how to keep that

out a little bit longer through incentives so yeah i think yeah or if your footprint was you know instead of going in with a hundred percent footprint of the previous block going in at eighty percent footprint right so if those types of things can also make the incentive list because you know, while those are on the minds of the tag, because we have heard this information, you know, many iterations, you know, we've interacted with it quite a bit. There's a lot of people in the community who have not interacted with this near the frequency that we have. And so I think having those on the list from the start to allow people to actually really consider them as part of their options will be important.

Thank you.

And then I'm curious so you sort of glossed over it but and I know that the agricultural water users were the you know first priority for some of these rollout of these programs but what is the timeline for sort of incentive plans or are these types of this type of sort of laid out design for other users?

yeah thanks and i think i meant to mention that and my opening remarks is that you know today is all focused this presentation is all focused on ag water conservation because it's things that are tied to the water conservation certification partnership and then you know we you know continued to lay out work on the best management practices for for rural domestic and other pumpers and I think similar types of incentive programs could be rolled out. We've just been working on the ag programs first.

But like Napa Green certifies vineyards and wineries, right?

Oh, sorry. Yeah, on vineyards, at wineries, we've included those in the certification partnership concepts in our conversations with Napa Green. I thought you were talking more broadly about the rest of the vineyards.

I was, but then also we didn't see any winery ones here today either. But then we also didn't see other users either. It was both.

Yeah. And so the wineries have been part of the Napa green discussions. We have been focused on vineyards. And I think I could just say that, you know, We've taken the program concept to like a program outline and now trying to get it implemented and just working through kind of the details. We'd be like, all right, well, let's start with vineyards and then we can figure out how to apply this more broadly to wineries. And then we don't have a similar concept for the certification partnership that would apply to non-agricultural users, but the same incentive concepts could be applied. And I think that's something that we need to work on next.

Yeah, I think we've had some previous assessments around landscaping selection, and that would apply to both domestic users and also to other winery or commercial buildings.

Yeah, we did review kind of the model efficient landscape ordinance that was earlier this year. And so bringing in some of those best management practices and updating those concepts.

Staying on the incentive slides and jab it up, I'm curious about How, like, this is meant to incentivize growers who are not using these tools to conserve water, so it incentivized them to use them. Is there a plan to incentivize, to account for those growers who are already using these? You know, someone who, say, installed a meter two years ago.

So the concepts that we've put together were definitely more forward-looking, you know, and I think that's something that we've talked about. certainly going back to the work plan development, is that there's already been a lot of investments and how do you account for those and where do we draw the line for historical investments that have been made? I think what we've been focused on is let's do more and get more investments. It's good that folks have made those investments, but we weren't thinking as a concept for this program to retroactively pay for things that say were implemented in prior years, even if those are achieving some water savings. Maybe something to think about, though. I mean, if there's an opportunity for a partnership and some data sharing. I'd also kind of be curious to hear what our certification program partners think about that and some of their members, if that might be of interest. So it's a good question, but this, this, everything that we were thinking about here was, was definitely more forward looking to get more adoption of new practices.

Thank you.

I was just gonna say, I, I think it's a really good point because yes, you want more adoption of new practices, but at the same time, people who are already. you know, being responsible stewards, you want them to continue to do that and so not to feel sort of penalized in any way just because they put their meter in two years ago or five years ago, right? Because, oh, they already realized this was important.

Well, they should be recognized for that.

They should be recognized for that, right? So how does the program do that? Or does it only recognize bad actors who now have decided to change their mind because they have to?

Yeah, I definitely think it's worth digging into, like just spitballing from the meter part of it. Most of these flow meters are not just install and go. So for that in particular, maybe rather than just installation, there's some calibration or maintenance incentives, things like that.

This is good feedback. Thank you.

And I think I'm curious if there has been any discussion on how those incentives could be either linked or combined with the fee that we were just talking about, which is an annual fee. And so that's where has there been any talk of having those incentives kind of used to decrease the fee if you are implementing some of those practices and whether the postcard included any information on the water conservation practices and whether maybe those public meeting would be a good forum to talk about it but it would make more impact if people here at the same time that they have some opportunity to maybe decrease the fee I mean you got people's attention I think with them having to pay a fee so it might be a good opportunity to follow up on how the could either be reduced or other thing with implementing some of those water conservation practices.

Yes, I mean, I think some of that might be more Jameson in your wheelhouse. I know that those conversations have come up. I think there's kind of like legally what you can do with, you know, directly related to the fee. But I mean, I think that's something that we've definitely discussed and thought about, like, how do you tie this to make it clear that there's a direct savings, ideally, that relates to that? or other savings on your operation from making these investments? And if you use less water, that's a savings on input costs. And how can we tie that back directly to costs related to the fee?

Yeah, I can just offer that there is a little bit of an incentive already built into the fee now in that the base rate of whatever it is, $32 per planted acre, only applies to dry farmed acres. So if you're dry farming, you're paying about one-third of the total fee. If you're irrigating, it's almost $99. per irrigated acre. So there's a little bit of a baked in incentive there. I realize dry farming is still not common, although we've already gotten a number of comments from people and emails indicating that they are, some of whom we were already aware of and I think at least one or two two or three new ones that we were not aware of. So there is a little bit of a baked-in incentive there, but as Duncan mentioned, there is also a legal hurdle to I wish that we could offer a direct individual rebate, if you would, for the adoption of certain incentives to an individual, but you can't. legal technical reasons what you what we could perhaps do is establish some kind of threshold where if we had a certain threshold number or acreage of voluntary adoption of certain measures that we could talk to the GSA about okay could we establish for this amount of voluntary participation that links to X amount number of dollars of contribution from the general fund. Because right now the fee is subsidized, if you will, or matched, if you will, with a $500,000 contribution from the county board of supervisors from our general fund. They'll make their final decision about that in the budget hearing so they could actually elect to contribute more. So we could establish some kind of thresholds there, but it would mean providing that break to everyone, irrespective of whether they implemented the measures. So it's tricky, but we've just started down this, so we're not out of ideas either. So I think there's potential to develop further.

I have a question that you could defer to the meetings that are upcoming, but just out of curiosity, what's the process for verifying the dry farm claims?

Yeah, the dry farm claims, we will notify Miguel Garcia of the Resource Conservation District and he will schedule a meeting with the grower to go out and verify the dry farm practices. Yeah, the practices in the acreage. I mean, we're not looking at like, are you doing this, this, this, this? It's a very quick kind of thing.

It's more of a technical question. It might be for Miguel, but my question kind of revolves around is that if there's no irrigation infrastructure, check. But if there is irrigation infrastructure and the grower says, well, we don't water, how do you kind of deal with that situation?

Yeah, having irrigation infrastructure in itself is not like, okay, you're not dry farming. In fact, we talk about that in our FAQs. If you're only applying water for frost protection or heat spikes, that would not disqualify you from being a dry farmed vineyard. For the years in which you're establishing a new dry farm, like two or three years you're irrigating to establish, yeah, you wouldn't get the dry farm rate during those years. But once you convert, then you would. And if there is a definition that we're going on, it's what was provided by the California Sustainable Wine Growing Alliance. It's on our website. And when, in fact, we used their database of dry farm vineyards as kind of our baseline of who we think is dry farming, But again, we could be missing some people, so we're asking them to write in. And even the people that are on the database, we're asking them to contact us anyway because maybe it's not correct in terms of the number of acres. So, yeah.

Last two follow-up questions.

Sure. Yeah, keep going.

What if there's a parcel that has... I mean, this is probably simple, but if there's an acreage that is dry farmed and other that's not, it would just be split in regard?

Correct. Yep. You'd only pay the base rate on the ones that are dry farmed, and any that are whatever portion of the parcel that's irrigated would pay the irrigated rate.

And then the last is to verify an assumption. Since it's an annual fee and an annual certification, a grower could be dry farmed one year, irrigated the next, and then dry farmed the following.

Correct. Yes. And we do, we say that in the FAQs that we will require that re-verification, if you will, every year. Okay. Yeah.

Good questions.

Just Duncan just kind of back to spitballing some of these additional incentives There are many vineyards that either have like irrigation team or an individual who's sort of on irrigation like duty, right? Checking to make sure the emitters are right, you know, all that are not broken and fixing them and then, you know, turning systems on and off or whatever. And so I'm just wondering if an incentive could be related to education or specific to those certain individuals. So if you're either you have dedicated teams that are have additional training around Irrigation that that I know I know the education piece is separate from the incentive piece But if you were doing some very specific education around like certain individuals with very specific job duties That could be a potential incentive and then also like irrigation system repairs well in places where you have an established vineyard and then you have replants or In those cases, we're installing a second irrigation line just to water those replants. And many people do that as standard practice, but not everyone does. And so if you're not doing that, you're either severely underwatering your replants or you're overwatering your established vines. And so that's another thing where there may be some situations where, like, you know, putting a second double line in could allow for some water efficiency.

Thank you. Yeah, I like the outreach and training stuff. I think that fits nicely under some of those kind of item one concepts, and we can definitely expand on that, see what some of the partner programs are interested in.

Like I train the trainer almost.

All right, do we have any public comment on this item?

Hi, my name is Chris Malen. I'm the Executive Director of the Institute for Conservation Advocacy Research and Education. We've been following SGMA since 2014 and the Groundwater Sustainability Plans and the updates and the implementation. I know that in SGMA, we're supposed to be considering the recharge areas in the whole equation of what's happening in the aquifer. And I'm just wondering if we're overlooking that there could be an opportunity to help with recharge on the valley floor if we actually looked at the sub-watersheds, because what's happening on the valley floor is actually what's happening throughout each sub-watershed. So if you have a creek that's dry and the water never reaches the valley floor, that impacts the groundwater recharge. And I just think the onus of recovering the aquifer really involves everybody in the watershed. And so if the watershed was divided up into the sub-watersheds, and then everybody who's impacting the groundwater was part of that equation for restoring the aquifer, it takes the onus off of all the people on the valley floor. And I know that, again, I know that SGMA says we should be looking at recharge. And I think those people higher in the watershed could have incentives as well and be a part of this recovery. Having said that, to get right down to the incentives in the presentation, I'm wondering about meter installation, vineyard floor management, and all of that under incentives for water conservation. I know the state is putting a lot of money. When I say the state, I mean the State Water Resources Control Board has got telemetry research going on, and they've implemented that on the Russian River, and they're going to roll it out in other rivers. And I've made a recommendation that they do it on the Napa River, and they're considering it. They want other watersheds. But I love that telemetry because it informs you like in real time what is happening with stream flow in real time. And I'm wondering, I know Hotspot Ag did a presentation to our nonprofit on the technologies there. I mean, people can be informed. if they're exceeding their share of groundwater extraction. And the best way to manage that is in real time. So the technology is there. And if the public's going to be paying for these block grants the matches and all that. It should be working. It should be effective. It should be efficacious. So I would really like to see real-time data coming in that is those hundreds of teachable moments to the growers. Yeah, and I didn't really understand if the block grant people have to show their outcomes. I would really like to see how that works on those block grants that they could make presentations to us. Thank you.

Thanks, Chris. Any other public comments?

David, you will have three minutes.

Thank you. David Graves here. I will not surprise anyone by asking about the self-supplied pumper outreach. I have sort of an epistemological question, fancy way of saying, what do we know and why do we think we know it? Why do we think we know how much groundwater is pumped by self-supplied pumpers, number one? And number two, It strikes me that there may be some easy, as it were, low hanging fruit by making water use more efficient on those parcels. And I'm wondering if there's any, I realize it's hard to have outreach to those folks as a group compared to growers, but I still think that they represent a pretty big chunk of groundwater use and my belief is Golly, they may be amenable to some metering to find out what they are using. I don't know to what extent we perfected remote sensing to figure out what they use and also pretty easy to come up with some ideas of how one might help them reduce their groundwater pumping. Because after all, most of their water use is not related to any economic activity. It's because they want to have a nice garden. That's all. Thank you.

Any other comments?

We have no other callers.

Well, thank you, David. And at this point, we can move on to refinements to the Napa Valley Integrated Hydrologic Model. Nick Newcomb from Udorph and Scalmanini will make that presentation.

Perfect. Yeah, thank you for having me. I'm Nick Newcomb. I'm a hydrogeologist with Ludorfin Scavanini. I'm going to be giving an update on some of the refinements we've been making to the Napa Valley integrated hydrologic model. A lot of this ties into the periodic evaluation that is currently being prepared for the Napa Valley subbasin. And that, I think, will be coming out in a draft that will be coming out in the next few months. But updates to the numerical model, water budgets, things like that are going to play a role in that update as well. So just to give... A BRIEF OUTLINE AND SOME INFORMATION, JUST BACKGROUND INFORMATION ON HOW THE MODEL IS SET UP AGAIN JUST AS A REFRESHER. THAT FIGURE ON THE RIGHT-HAND SIDE OF THE SLIDE, IT SHOWS OUR APPROACH. WE HAVE THE NAPA VALLEY INTEGRATED HYDROLOGIC MODEL WHICH COVERS MOST OF THE VALLEY FLOOR WHERE MUCH OF THE AGRICULTURE HAPPENS IN THE WATERSHED. and where most of the groundwater pumping is happening. And then outside of that, where it's kind of more rural and kind of wild land, we represent that using what's called the basin characterization model, which is just a watershed model to calculate the tributary inflows and the tributaries, and then any underflow or mountain block recharge coming in from the upper watershed. So as far as updates to the model, I'm just going to touch on a few of them. One is updates to boundaries. So there's been changes in what the actual subbasin is. The next thing is some of these stream updates. We've updated how we simulate stream flow in the Napa Valley. And then kind of the meat of this presentation is on land use. land use mapping and how we simulate evapotranspiration and irrigation. And then just briefly touch on some of the other things that we're working on too as part of the model update. So on the boundary updates, As we've been kind of investigating things during GSP implementation, noticed some discrepancies about where DWR had mapped the sub-basin boundary extent compared to where the actual or our best guess of where the edge of the alluvium is. And what it seemed to come down to was, in DWR's data, there's a projection issue where everything was shifted, and then not always the best representation of that edge of the alluvium. So over the last couple of years, DWR has done that update to the boundary. And we needed to reflect that in the model in order to account for water budgets and water use and stuff like that. So we changed basically the overall extent of the model. Boundary kind of moved to the north. to the northeast. And so we wanted to accommodate that. And then also the different changes to the alluvium. The only thing we did was made the model bigger. We didn't make it smaller anywhere. But we want to include basically the entire sub-basin and then where that sub-basin goes into the uplands. thousand feet 500 feet between that edge we want to incorporate to just some of that upland area because it does contribute to the water balance and we don't want like a sharp change in there and then also the model is broken up into these water balance sub-regions where you know you take all the land use in that that water balance sub-region you calculate the recharge importantly the different sources of irrigation and then what's left over is groundwater pumping And so then the groundwater pumping is basically distributed amongst the wells in that water balance sub region. And since we moved the basin boundary, we want to be able to account for those water budgets appropriately as well. So we changed the delineation of those water balance sub regions to basically align with this new administrative boundary. On the streams, So we had done an initial mapping of streams in 2020 and 2021 when we were working initially on the model. And we did our best to incorporate the larger streams based on stream order and then some of these other smaller reaches and sloughs and stuff that are important for habitat. More recently, the county has delineated what they call significant streams. And that ties into the water availability analysis and then also approvals for new wells and stuff needed to be considered, these significant streams. And so in our model, we wanted to align basically with what the county had also mapped. So on the figure, On the right-hand side there, the gray lines are our original streams, and the purple lines are the significant streams that we're now including. You know, for the most part, the bigger tributaries in the Napa River in itself, not many changes. It was mostly in some of these smaller sub-watersheds, sloughs and stuff. And I think what went into the county is delineation of these significant streams is... Stream order, how big of an area is contributing to it. Significant species that kind of ties into some of the work that Christian's been working on. And then other kind of administrative things that the county has tried to implement as well. So yeah, we basically relied on their model or their delineation of these significant streams and then made the appropriate adjustments to our watershed model that encompasses the whole watershed to make sure we're getting the appropriate tributary inflows into some of the smaller sub-watershed streams. And then another kind of key update was previously We had specified streams kind of in the southern portion of the Napa Valley. A lot of those are tidally influenced, and the way that the groundwater model handles those, it's good, but it's not capturing some of those hydraulics that you'd see in a tidally influenced zone. And we weren't really satisfied with how it was performing. So we just changed, you know, we removed those from the existing stream package and just used kind of more of a fixed, not a time varying, but it's just a head dependent, simpler head dependent boundary to be able to simulate how those behave over time. And those are informed by the stream gauging that the RCD does in that area. So we have a pretty good sense of what the water level in that Napa River down low and some of those tidal flats is. The other update we made to the streams, and I presented on this, I think, maybe 18 months ago or something. And so those figures on the right-hand side are from that presentation. But the original way we were modeling streams in the model was we were using a wide rectangular channel that we kind of defined based on LIDAR aerial imagery where we could see the stream had water in it. One of the limitations with that is that as the flow goes up, the stream is going to get wider. And then that also determines what the stage in the river might be. As it gets wider and you get more flow, you get less of an increase in stage. So we wanted to be able to, as best we could, incorporate the actual channel geometry. And the way that an option in the modeling software to deal with that is doing these 8-point um, channel cross sections. Um, so you can see in the lower right how that might be, uh, represented in the model. Um, and then the way we, we did that in, in terms of actual implementation is using the lidar data. Um, and we just did cross sections for each of, uh, we had ended up with 147, um, of these kind of stream segments, uh, that we broke up the stream system into. And so we did cross-sections across those, looked at the elevation profile, which on the lower left figure is going to be the black line, and then superimposed our eight-point channel cross-section on top of that. There's different LIDAR sources out there now. There's some from the USGS, additional products that the NAPA has derived from those data. And then there's the NCALM data that was done in 2003. as well as some other additional LiDAR that the RCD has as part of their stream restoration program. So we kind of looked at those different LiDAR data sets. In some cases, they didn't penetrate water, so you couldn't get a good representation of what the actual channel was. And so where that was happening, we'd switch to another data source. What ended up being the best, and I don't know if it's because they did it during low flow or they just had a better processing algorithm, was the ENCOM was able to be able to define the channel the best that way. Definitely discrepancies, I think, and issues with accuracy in the LiDAR. But for modeling purposes, I think we just tried to characterize as best we could what that channel geometry was to try and capture some of these dynamics that we think are important for groundwater surface water interaction. On to the land use, and this has been a challenge. Different parts of this have been a challenge. We've done a lot of exploring in ET data and different land use data sources to try and get the best representation that we can into the model. And so first I'm going to touch on just the land use mapping. The land use comes from a bunch of different sources. There's some from DWR county level surveys, varying quality in those. They go back to 1987 and up through 2011, 2012. That was taken over by Land IQ for DWR starting in 2014. So that's another data source. UC Davis did a pretty good job mapping out the native vegetation types. It's mostly in the upper watershed, but there are a lot of native lands too in the subbasin and in our model domain. And then Napa County has also their own mapping, mostly of the parcel data, obviously, but then differentiating different grape types and growing practices. So stitching all those together, especially really small parcels, really complex geometry in those parcels, was pretty challenging on our initial cut. It took a lot of manual intersecting different things to try and get the best representation. So we're pretty confident in what that land use looked like for the initial cut, but it's challenging to update, especially for annual reports, to go back and try and do that manual update to the land use. So that was our goal, to try and basically streamline that process and take a lot of the manual stuff we did and basically have a scripted workflow for that. And so that's what we spent quite a bit of time doing is trying to streamline that process so we can update the land use in the model more readily. Some other advantages of scripting is if you go a different assumption for some historic period is pretty easy to implement. So that's basically the goal with that. And then since we changed the model domain, we needed land use for that as well that we didn't have before. We just focused on our old model domain for the initial cut. So we went ahead and decided to just expand into the entire watershed in case we wanted to refine anything in the basin characterization model, basically be able to accommodate that more easily as well and just give us some flexibility in the future. um and then getting to the water use side of things um i think one thing that we had have recognized over since the original gsp was prepared um done a lot of work in looking at et one of the key things is that the et is pretty spatial spatially variable um on that figure on the right is a little bit dated but just gives you a sense of you know for vineyards uh how much the et can can vary I think this is just for one year, but over the valley, vineyard ET can vary quite a bit. For our modeling process, what we do typically is just break up all the land use in the categories. So you might have vineyards. In this case, we had white and black grapes. And then different native land use classes. In Napa Valley, there are some orchards and other rural crops and stuff. Very small percentage of overall what's going on. But we did include those. And then different native land use classes. So we'll take the land use data, break it up into different land use classes, and then assign crop coefficients and other parameters to that. And we multiply the crop coefficient for each land use times the reference ET, spatially and temporally distributed. And then that gets you the ET estimate. And then that ET, you take away the other sources of water, which might be irrigation from surface water, precipitation, direct groundwater uptake. And what you're left with is your irrigation demand for groundwater. And then again, in each water balance subregion, that's all going to be summed up. And then the model is going to kick all that pumping out to the wells that are in that water balance subregion. So in thinking about just say vineyards, that spatial variability in the ET is important to characterize because some areas they might have a higher water use and other areas a lower water use. And we wanted, to the extent possible, to try and incorporate that in our modeling. Over the last few years, we've looked at a bunch of different variables, spacing, variety, rootstock, elevation, slope aspect to try and kind of relate some of these physical concepts to what the ET might be. We definitely saw some relationships, but we're never able to really correlate some of these other factors to what the ET might actually be. And then the other question is there's a lot of native land and urban land in the valley. And so those predictors for vineyards might not work for some of these other land use types. So I guess the question is, how do we meaningfully capture this variability in a way that's simple enough to be able to incorporate into a model? And also with a model, you go back in time to where you don't have those data in the early 80s. And then you have to predict out 50 years in the future. And so what do you do there? So there's all these challenges where you have all this data. can make some sort of correlations and stuff. But it might not be all that useful for projected water balance and climate change and things like that. So what we did in this most recent effort, we've gone down various rabbit holes trying to explore things. In trying to put together this stuff for the model, we relied on different Open ET that we're mostly confident in. We used kind of a Sigma-specific version of Open ET that was, I think, a contract between open et folks and dwr to come up with a data set for sigma so he kind of like aligned with what dwr expects and again our model relies on crop coefficients rather than actual et because we account for that reference et and so we're like maybe we take away the don't look at et but look at the variability in crop coefficients and what we found uh two The two charts kind of in the middle are showing the ET by the map on the right is water balance regions, which is usually like two or three water balance subregions. And so we were looking at the differences in these different crop types in crop coefficient within those water balance regions. And the charts in the middle basically show the variability in the actual crop coefficient. within those water balance regions. There is quite a bit of spread in the ET field by field in those water balance regions that I'll get to in the next slide. But we kind of think back of what the model is doing is summing up all the irrigation demand for the water balance region and then kicking out the pumping to appropriate amount to meet the irrigation demand. So we kind of end up grouping everything back together in the model. And those differences in the field scale, they still matter, but they stop mattering as much. So yeah, you can see in the graphs in the center, there's not a huge spread. That's looking at the average Kc within each water balance region for each month for the period of record that we have. Not a huge spread in the averages there. But I'll kind of get to that. So it seems to take care of some of this variability and trends we were seeing in the ET data. So yeah, getting more into this grouping by the water balance region. I took a look at the crop coefficients and just took the mean of means. So we took just the growing season, looked at the average crop coefficient from March through September, and then just took the average of all those across years. And so those charts in the middle show basically the distribution of the average growing season crop coefficient. in each one of those water balance regions. And then the spread within them. And there's definitely, like I mentioned, some variability in field to field and the differences between the crop coefficient. But overall, there's kind of like some identifiable trends. And so our thought is maybe we can group and have individual crop coefficients, looking at a top graph, for black grapes. um by water balance region and some groupings there to keep it relatively simple so you know I can I can stay sane in the modeling side of things but then also uh kind of capture some of these sub-regional differences that might affect you know where you might be pumping more or pumping less you know for modeling purposes so that's kind of that The direction we're moving in, this is all pretty provisional. We're still working on it and kind of exploring other ways we might be able to group black grapes. Maybe it's not by water balance region. That seems to be the most promising at this point. But some other methods we might be able to group. And the key is to keep it simple enough that you're not ending up with hundreds of land use types, which is really challenging to model. And we actually looked at the actual physical computer memory to try and do that. And it was going to break the model. And then also keeping in mind that we have to do a huge 50-year projection and then going backwards. Again, we don't have this ET data in the 80s. So kind of like simplifying a simplified model of KC for the model is kind of the direction we were going in. And then also looking at some of these other land use classes, again, we don't have as many physical characteristics and growing practices and stuff for native vegetation that might affect the ET. But we can look at the crop coefficients again. And in this case, the actual spread in these crop coefficient for the growing season within these water balance region was a lot bigger than for the vineyards, just because you might have something that's called oak, and there's like five oak trees in a big field, versus another really dense oak forest. So there's going to be some variability there. But generally, yeah, we still see some areas where we can do some grouping to capture the highs and lows, basically. So I'm showing oak, or I guess I'm showing urban on the top graph. So that variability in the urban, and then the bottom one is the riparian woodlands. So trying to group those. With some of the native vegetation, there's also a density class. And for oaks and conifers, there seem to be a relationship between the density of the ochre conifer and the crop coefficient. So that's another avenue that we've been exploring too is maybe we can use the data from UC Davis to better constrain what the crop coefficients might be. So that's just to summarize all this, because it was a lot of information. But modeling ET on the field scale is probably going to be too complicated, just from a computing perspective, and then also the fact that we might not have that same information going 50 years in the future. So yeah, there's challenges in both incorporating that for the modeling side and then also just forgetting that information to correlate those different things. So in the past, we've been looking at ET. Using KC seems to be able to kind of take care of some of the variability that we're seeing in the actual ET. And that these groupings might be, whether you group it spatially or some other method, could be a meaningful way to try and capture some of that variability across the valley in water use and irrigation ultimately. Just some other considerations and next steps. Kind of go through this quickly, but we've been coordinating with the State Water Resources Control Board. They've been doing a watershed model to inform curtailments and stuff for surface water diversions. And part of that process was putting together a pretty robust database of the surface water diversion data. Our approach in our initial model was pretty similar, but there's some minor differences in what we thought was important. But for the sake of consistency, I think we're just going to go with what the water board did, mostly because the surface water diversion data only go back to, like, 2016, I think. So there's 10 years of data, and you've got to go back to 1984 and then forward again to 2077. But we're just going to try and be consistent with what they did. They've been pretty good to coordinate with, giving them information on our model as well. And on the supply wells, the county has done a pretty robust inventory of all the supply wells in the sub-basin and the county as a whole. And we're working on incorporating those data to get a better feel for the distribution of the wells and the construction, so we get a better sense of what parts of the aquifer are being pumped, different water uses, and stuff like that. On the soil moisture storage, which we did a presentation on also I think about 18 months ago or so, we've been coordinating with the USGS to get those refinements done. There's been some changes in the USGS recently. So we've had some challenges getting that accomplished. But we're definitely exploring maybe some simpler options for getting that incorporated into the model platform. sooner rather than later, I think. And then on climate change, there's been updates to these global circulation models. It's called the CMIP6 kind of ensemble of climate models. And the USGS emeritus people, they're kind of on their own. who run the BCM and do that downscaling and bias correction for those data, actually collaborated with Sonoma Water to put together these climate change data for a lot of the North Bay. I was fortunate. I ran into this person at a conference, and she's like, oh, we've done it. So we're working with Sonoma Water to get those downscaled and bias corrected climate change data in order to inform our climate change futures and hopefully be working with the most recent data set for those. So that's what I got. I appreciate your time. And just open to any questions or comments or clarifications.

Great. Thanks, Nick. Comments from the tag?

Yeah, so that was a lot. And it does sound like a lot of updates on many different items. And so I'm curious how you go about, as you work through the updates, what is your understanding of the effect that each of them have on the model and how you kind of keeping track of that, because I'm thinking eventually you're going to release this updated model with many, many different updates, and it's probably going to show results that, you know, some of them might be quite different from the original model, and kind of being able, I think, from a communication perspective to pinpoint to those were the major updates that impacted the results. And here in the presentation, I think it was not entirely clear. I'm assuming some of them, we need to do them, but they may not have a huge impact on the results, and some of them may have a very big impact. But how are you evaluating that, and what is your understanding of those changes now that you presented in terms of how they impact the model?

Yeah, so my approach is always to take things kind of stepwise. I don't want to completely discombobulate the model and then hope it works. So, you know, we've implemented the stream in the watershed stuff already. And then, you know, I try and evaluate, yeah, what are those differences in the model? What differences are we seeing and why do we see those differences? You know, for that stage and just kind of summarize it for myself. and then implement the next thing. Like did that, you know, say we updated supply wells and it doesn't make that much of a difference. You know, maybe that change wasn't necessary. Maybe, you know, we keep it or don't. Probably going to keep it since it's the best information. But yeah, I know. I think that's important, especially for teasing out when you get to the end, you know, you see that your water budgets might be different and you want to know like, oh, what stage in the game changed those results, um, and be able to explain them. And it helps for understanding what, you know, as a model or what I'm actually doing, um, you know, being able to track those differences over time and kind of be able to explain the results I'm seeing, um, rather than, uh, just kind of tearing everything apart, putting it back together and getting a different, different answer.

Yeah, so that's where it would be very useful as part of this information, like what is your current understanding of the changes that you presented that really mattered?

So I've implemented the stream changes, and then I think the supply wells and the land use changes are kind of going to be the next big ones. The boundary modifications did not change very much at all because we're talking about a few cells here and there. But yeah, I'm in the process. I try and do the update and then kind of roughly calibrate. Again, I don't want to do a full blown thing until all the updates are there. But I'm still in the process of evaluating exactly what those changes to the watershed and the changes to the stream are. So I would have included it if I had it, but I don't quite yet. Still kind of looking at that at this point. I think it'd be maybe valuable to include, you know, we'll provide a technical memorandum describing the model changes and then maybe, you know, describe what we're seeing along those different steps. I think it would be helpful, you know, both for our understanding and then, you know, for your understanding and the public's understanding. You know, we want to know what our model is doing and why we're doing it. And I think we want to stay on top of that as much as possible.

In that technical memo, just to be able to see it a little clearer, would it be possible to do something like, this is what the model showed us, these are the changes we've made, then this is what the model showed us after the changes were made, to see what the actual effect of a specific change is?

Yeah, no, absolutely. I'm moving in a cumulative direction, but I think it'd be helpful. Here's the existing model. Here's the existing model with the changes to the stream. Maybe focus on what the changes to the flow and the groundwater exchange and stuff like that. But I think we can do something like that.

Yeah, I mean, I'm sure a lot, like you're saying, a lot of them are minimal, but they might be cumulative. But I'm sure every once in a while you come across something and you're like, holy smokes, that changed the model. So it'd be good to point that out to us and say, I think that'd be helpful.

yeah absolutely and we can you know kind of probably work with you guys a little bit you know when we present some of the model findings to to be able to summarize that effectively yeah even if it's by a category right like what you said you know you change the boundaries but if you look at that like even on the map i i'm looking at the map and i'm like it's probably inconsequential right yeah it's important to be accurate but is that really gonna have like the major right so we would like to know whether it was like something that we needed to do because yes we needed to be technically accurate right but it's not going to have that much of an impact on our you know irrigation demand estimates right whereas something else may have a much greater impact and so even if we can't see the like you know, because you implement multiple at once of like, we won't necessarily see the specific numbers of each change, but if understanding the magnitude of impact overall that that change has, I think is important.

Yeah. And I think another, um, another important thing is you make a change. Like, was it the right change to, um, you know, uh, Yeah, I mean, I think it's always in adding maybe too much complexity that doesn't give you anything better. Like I try and keep my models as simple as possible to kind of answer the question and characterize the physical processes. But I've seen other models where there's a lot of complexity and I kind of ask myself why, you know, makes it more challenging to understand. And then you're not really getting much benefit from it. Um, but I think, yeah, being able to, to account for what the changes are doing and if we're, we're, we're implementing those changes appropriately, um, is important to do too. And kind of taking it stepwise, I think is a good way of doing that as well.

right like for example the stream bed geometry may have a greater impact on the model than you know changing the boundaries slightly right or accurately being able to characterize the vegetation may have more of an impact on the model than changing the boundaries or you know so i i just think some even if it's qualitative i think that would still be useful communication wise for us to see it also like allows to your point for you to say like okay is it sort of worth going down a certain pathway on a model or is it not and should we just focus on some of these other areas where qualitatively we have greater impact of improving the model but we can't say that based on you know just hearing about what the changes are right

the the data that the county is going to be collecting in an effort to collect fees correctly related to dry farming and fallowed land and things like that is that information going to flow into the model

I think at some point, I mean, I do think we want to try and find out, and this might be more qualitative, too, on the dry farming and stuff like that.

I'm thinking about, like, other water use sources, surface water. Like, I know you guys have collected that information, but this is kind of like the ground truth thing, and... To me, that would be really interesting to see that incorporated and kind of see a comparison. That seems to me like something that could be quite impactful to the model.

Yeah, I think we want to stay on top of that. I don't know if we'll have those data in a way that we can use them for this round. But, I mean, we're continually refining and updating. And I think we try and get, if there's useful data, we try and incorporate it to the extent possible.

minor point but the uh state water board diversion data that you're incorporating are those really data on diversions or are they drawn from water rights records it's it's what the permit holders are reporting as diversions to the water board

I think there's always a question of how accurate those are. And consistent, too. There be years where a water user might not report for whatever reason. And I don't know how good the enforcement is on that. So there's limitations as well. And there's a lot of assumptions that you might need to make to recreate those data sets and have them complete. know to the extent possible trying to be consistent with what the water board has done um just so we're you know they're going to come up with some results and some recommendations based on some assumptions and i think we want to make sure we're operating under similar assumptions to kind of fill those data gaps and and you know both extrapolate the data and interpolate the data too so

Yep, Monica.

Yeah, just when you are talking about what the state water board has done, that's in relation to their modeling effort for the Napa River.

So I have a question that I'm still grappling with. So the point of the model is to be able to consistently model irrigation demand like through time, right? Interannually and then seasonally. It's assuming that you get to a certain number, right, of demand for applied water. But what it's not doing is then incorporating the human factor around like what proportion of the demand is then being pumped and applied. Am I correct? Because you're assuming that irrigation is at 100% of ET or at what percent of ET are we assuming?

Yeah, for

So there's two things, right? So we're trying to look at sort of overall sort of water uses, demand, whatever, within the basin. But then also, we're trying to look specifically at applied water that is pumped from the ground. And so I'm still confused about how the model is either integrating or like differentiating those pieces.

Or what does the model assume is happening?

Assume is happening related to behaviors around irrigation in relation to plant water demand.

Yeah, that's a really good question. Most of the models kind of operate under similar constraints. So most of the integrated models have a similar approach for dealing with this. So they're going to say that you have a crop coefficient. Say we're talking about one field. You have a crop coefficient, and you have a reference ET, right? Multiply those together, you get the ET. And then... This model in particular is going to say, okay, in this month we had this much precipitation. So whatever amount of precipitation that fell is going to meet a portion of that or all of that ET, or there'll be an excess and then you'll have runoff and deep percolation. So that's the first. It's kind of tiered in how it deals with it. And then the second... thing is we have a precipitation we still have some unmet et it's going to look at groundwater uptake so if if the capillary fringe is intersecting the roots um it's going to use that available water next um and so that might meet all the demand if that doesn't meet or meet all the et if that doesn't meet the et then they're going to look at surface water um surface water is measured right usually uh so it's gonna say okay now we're gonna whatever that residual demand is and then we jump out of the field scale and you sum up what the residual water required to meet that et is sum it all up take the surface water that's being delivered to that water balance sub region and subtract that out um That might meet all the ET requirement for that, or irrigation demand requirement for that water balance region. And if it doesn't, then it's going to say, okay, we need to pump groundwater so that the modeled ET is the same as the actual ET that is derived from the crop coefficient and the reference ET. So it's kind of stair-step. It's still modeled, yeah. What's that?

Which is still modeled.

Yes, exactly. And how good are those ETS limits?

Yeah, exactly. So I still, like... I still feel like being able to see that and like what the model is saying for what proportion of applied water as a proportion of ET, the model is assuming that any acre of land has applied to it. I'd like to see that. So that just what you just talked about is like, okay, so here's my, you know, demand. So I'm going to say that 70% of it is met by, you know, the groundwater and then 30% is met by, you know, the applied water. I actually like to see what that output is from the model on a month by month basis throughout the, well, Year. And for each sub-watershed.

Yeah, I mean, that level of transparency would be awesome. Just to be able to understand the model.

Because otherwise, it's like, you know, you can tell us, you can talk to us all day about what parameters you're feeding into the model, but until we, like, see some non-aggregated outputs of it, I think it's like, it's... it's difficult to understand and then also make sure it's sort of aligning with the acts that we are doing, which is to reduce groundwater pumping. But what is our assumption that groundwater pumping is and is it actually accurate for that time of year and that point in the growing season and that crop and like that?

Well, is it also so you can apply your own individual kind of more than anecdotal knowledge about what's going on in each of those subregions to, you know, kind of apply a little bit? I think this is a little more than we would have expected here or less or maybe right on.

Yeah, exactly.

Okay.

Because there, you know, there's been other ways of sort of looking at. you know, quantifying the amount of irrigation in a vineyard over time compared to, you know, eddy covariance measurements, right? And so I'd like to see how well that those data are matching up with these data that we're using in order to model water demand, which is then being

communicated as like this is the amount that was pumped yeah so like you know generally for a presentation i'll summarize those data by water year um just so we're not looking at a ton of graphs in the The model report, those are in appendices. So those results are typically in there. I think maybe for the sake of time, for next time, so we're not looking through every water balance region, every month, everything, maybe take a few representative areas and you know if this would be helpful to be like okay you know down in carneros we're looking at this sub area and here's what we're seeing as far as you know water that's met by precipitation groundwater uptake uh surface water diversions you know here's our et so kind of be able to disaggregate kind of what we've previously aggregated just for the sake of of time and looking at the big picture.

Yeah, I think specific examples for the public presentation, this is where they came from and this is where you can...

Yeah. I don't necessarily want to see all data. But you're asking, as a technical group here, you're asking us to provide input on parameters, stuff that's going into the model. But we're really not getting the level of detail of the output in order to be able to, like Jameson said, lend our expertise, compare this to other efforts that have gone on around water use specific to either vineyards or non-profit.

planned right yeah absolutely and i'd love to get get feedback on that too i mean i think you know you're obviously the experts and i'm just doing that the best i can i will say usually people don't ask for that so well yeah but we're the yeah exactly yeah this is what we're supposed to be doing yeah no i appreciate that it would also be useful you know your model stepwise you know um goes to the surface diversions and then it goes to the groundwater pumping

where we have actual rates and data for some of these, it would be really interesting to see that. So for a given region, you know, maybe only two farmers are reporting this, but still, let's see that. Does it line up with what you would expect from the model?

Right now, we don't. We don't have a comparison between actual measurements and the model to know what error we might have in the model and where.

There's this, what do you call it, unmeasured residuals in modeling. So where you measure all this other stuff and then this number you calculate by subtracting and say, okay, well, this term must be this because all these other things are quantified. That's what you have is your balance. But that term then also incorporates all the error and everything else which you don't see. So, you know, in this case, the term we're really interested in here, how much is pumping, it's like a residual term.

Subject to every error in all your different inputs, right?

Right. And it's the term that we're focused on, you know, trying to reduce.

Yeah, absolutely. And we can work on, for when we're presenting model results, we can work on summarizing those in a way that's not too voluminous, but informative too.

Okay. Thanks, Nick. Don't go away because we have time for public comment.

Chris Malin. So the Division of Water Rights is getting pretty good at enforcement of water rights. And they are issuing fines for statement of information not being filed and for people not turning in their metering information. They've really amped that up. It's getting a lot better. And, of course, anybody can look up any water diversion under CalWaters, C-A-W-A-T-R-S. And that's a whole new database that they started just a few months ago from ERIMS. So I am wondering if you could attribute the maps. I would like to see which of the watersheds you are actually focusing in on. I also wonder about saltwater intrusion. We don't hear much from any of the reports on what it was historically and what it is now, and that those streams are being taken out of the model at a certain point where there's tidal influence. I don't understand how that all works in the model. It was there, now it isn't. And I'm not sure about the very last slide where you say you're going to Sonoma Water to acquire downscaled CMIP6. I don't know what that is for future projections. I've been asking almost every time I come if the model incorporates metrics for climate change, and this is the closest I've seen about maybe something. It says acquire. I don't know. The public never really gets an answer on the hydrologic modeling of how climate change factors into reduced groundwater pumping and then meeting our target date based on climate change metrics going on. That seems like a big black hole. So the other thing was that, yeah, the groundwater aquifer really does start at the headwaters, starts at the ridgetops. And the groundwater makes its way all the way to the ocean. So I still don't understand why the model does not look at the loss of recharge in the watershed, starting at the ridgetops. I know that the county has approved new vineyards in the watershed. And over 5,000 trees are going to be taken out over a period about a year and a half. That changes the groundwater percolation. So those trees that are coming out, those people who are doing that land use should be playing a part in recharging the aquifer or paying for part of the fees in running the GSA. Thank you.

Hi, I'm Michelle Benvenuto, wine gurus of Napa County. Thanks, you guys, for having a great discussion today, jumping into this. And quick question, I might have missed this, but does the crop coefficient for black and white grapes incorporate all grape data, like table grapes? Or is it specifically for wine grapes? Because if it does have table grape data, it could significantly overestimate the water demand for wine grapes. Thanks.

I can respond to that just really quickly. We derive local crop coefficients based on remote sensing data and are still working with those remote sensing data to get the best, as I presented in the presentation, to get the best crop coefficient that we can. So it's just one? Yeah, just one. Yes, correct.

We have one caller. Okay. Two callers, actually. David, you were first. You'll have three minutes.

Hi, David Graves. Thanks for taking my call. I am very cognizant of the intricacy of the BCM rewrites, having tried to understand a little bit of it from the USGS website. But one thing that's... very curious to me is that the whole, if you look at the water budget of the watershed as a whole, both for the uplands and the subbasin, the amount of evapotranspiration by the non-crop, I'll call it wildlands, of the whole watershed is several times the amount of water that's applied. And it strikes me that things like the fires of 2017 and 2020 really changed the amount of leaf area index and therefore evapotranspiration of thousands of acres in a way that's much larger than the amount of water that's applied by irrigation in the subbasin. So I just am hoping that you can focus on that at some point to explain how that's treated in the model for the entire watershed. Thank you.

Dawn, you will have three minutes.

Thank you, Don Monk, Napa County Farm Bureau. Monica, thank you for trying to flesh out the applied water in the model. I've been asking this question several times over the last couple of years and we haven't got an answer. And let's just assume, I mean, it's in the summer a vine can use up to 20 gallons of water per week. And if the natural system is providing 10 gallons of that water, most likely no irrigation is going to happen in that particular week because most growers are deficit irrigating. And if the model does not have a deficit irrigation value figured into it, it is overestimating the amount of water being pumped from the aquifer. So thank you for trying to flesh that out. And I think seeing how the model puts the pieces together like you were talking about would be great for the public. Uh, my other question is, uh, you mentioned that the model has made the aquifer bigger, not significantly bigger, but it's bigger. Do we know how many acres that is? How many additional vineyard acres, uh, got added to the model? And in turn, maybe this is a question for Jameson. is that additional irrigated land that's going to have fees for the GSA tied to it? Thank you.

We have no other callers. Nick, do you want to answer that first part?

On the model boundaries? Yeah, so it's not changing. For the most part, the subbasin just shifted because of a projection issue. So the subbasin isn't necessarily getting bigger. It's just moving over a couple hundred feet. And it doesn't change anything about the aquifer. It's just trying to accommodate that change in the subbasin location in the model domain. So I think it gets back to the question of kind of quantifying. We made this change to the model. How did it affect the water budget? And we can take steps to be able to accurately quantify that to the extent possible.

Yeah, and I can answer the second part that, yes, we did incorporate the change in the watershed or in the sub-basin boundary in the determination of which parcels were affected by the fee.

Okay, well, very good presentations and discussion. I think we can take our 10-minute break now. Thank you very much, everyone. So we'll resume at 3.26. Oh, yeah. Here we are. Are we ready? We're ready. We'll resume. So we have next, Christian Broderick from Stillwater Science will provide us an update on the interconnected surface water and groundwater-dependent ecosystem work plan implementation and the CEF assessment, California Environmental Flows.

Thanks, Matt. Thanks, Matt. All right. Yeah, so today I'm mostly going to be talking about the progress we've been making on the California Environmental Flows Framework Assessment that we're doing for the Napa Subbasin. I'll just let it go by for a second. okay great all right so um uh i'll just uh move along so now the california environmental flows framework assessment for the rest of the talk i will call seph um with the soft c um Just as a reminder of why we're doing this, we're trying to understand linkages between groundwater levels and the amount of habitat that's available for different species of interest. And there are basically three different states of groundwater and surface water interaction that happen from our perspective. One is when your groundwater is relatively high, you have flowing conditions. image on the left. As the groundwater level drops, some parts of the river channel, the riffles, the higher elevation areas, become dry and only the pools are left. And those are called isolated pools. And that condition can persist for months in some places. And then if the groundwater continually goes down, you get dry stream beds. and so part of what the work plan implementation has been trying to understand is where do these transitions occur when do they occur and how does that align with the requirements for target species um And this is my reminder I give every time that the Napa watershed and the Napa subbasin are different, that a lot of the habitat for fish and other aquatic and terrestrial organisms occurs upstream of the subbasin boundary. So we're doing our work focusing on the subbasin, but a lot of the habitat occurs outside of the subbasin. The tributaries outside of the subbasin tend to be perennial streams. In their lower reaches, they tend to have better water that's cooler. I guess that's what makes it better. Whereas within the Napa Valley, you have both a combination of intermittent and perennial streams. But there's been extensive incision throughout the valley floor. And that's in combination with some other things has led to warmer water and less favorable conditions for fish. Our fisheries biologist made me modify this slide to show the other place besides the uplands that fish go, and that's the Napa Sonoma marsh system, which has extensive rearing habitat. And so fish can go down there and use that habitat. I think Jacob Katz talked a lot about that setting in his talk, which was, I think, gosh, a year ago. So he talked about that back then. So now jumping to CEF, CEF is a systematic framework to look at functional flows, use a functional flows approach to develop scientifically defensible environmental flow recommendations throughout California. The functional flows is basically looking at the different parts of the hydrograph. You have dry season low flows, which we'll mostly be focusing on today, spring recession flows, wet season base flows, peak flows, and fall pulse flows. The focus for most of our self-assessment is on the spring recession flow and the dry season low flow. CEF consists of three different sections, each with different steps. The first is section A, which is looking at different locations of interest, trying to identify what the natural range of flows would be in the absence of human alteration. and then using those to identify the corresponding flow criteria. There are people that do SEF assessments that just do Section A and then skip to Section C in places where there hasn't been a lot of alteration. The Napa Valley and the sub-basin, the channels have been very altered, mostly through incision and other things. And so we are going to do Section B, which then says, well, considering that the... The environment has changed a lot since this pristine condition that Section A looks at. are you still able to meet the ecological requirements at each location of interest? And so we'll do section A for dry season base flow and spring recession flow. Section C is when you put everything together and you think about the ecological flow requirements, and then you think about other water users in the basin and try and find a happy medium that satisfies everybody. So the process and timing, this timeline should probably go back further to talk about the groundwater modeling and groundwater monitoring has been going on. for quite some time now, at least since 2015. But once we implemented the GDEs and ISW work plan, we started doing biological modeling as well. And Nick talked about modeling updates that are ongoing. We're using that data and the model results to work on sections A and B of CEF, which are the scientific parts, with the goal of including that in the GSP periodic evaluation due in January 2027. And then after that, we would then embark on CEF section C. As you know, and with your help, we identified these six intensive monitoring sites with four sites on the main stem going from Calistoga down to Oak Knoll and two tributaries, Sulphur Creek and Bale Slough. This is where we've been doing a lot of the monitoring in combination with Napa County and the RCD. Today, I'm just going to talk about three of them. And I'm just going to talk about dry season base flows so that we don't have to sit here to make it not go on forever. But the report will address all six sites. And just to remind you, dry season base flows are flows that typically occur June through October is what we'll be talking about today. So we have a lot of hydrologic tools. We have the Napa Valley integrated hydrologic model. I'll be showing you some results from that today, but that's not the updated model that Nick was just talking about. We're going to be using the previous model. That's a physically based model. It gives you monthly outputs, and you can model flow with and without pumping, which is what we're going to be talking about today. We'll also be using the TNC Natural Flows Database, which we're going to call CNFD. And that's a statistical model of unmanaged flow. And they did a lot of work to identify USGS gauge data in situations before there was a lot of alteration to flow from dams and limited groundwater use, and also what they called pristine conditions. And that's based on daily flow data. Then we'll show results from USGS gauges at St. Helena and Okinawa. There are new gauges being added at Calistoga and four tributary sites that are getting installed this year. Just to jump in a little bit on the natural flows database, it predicts a range of functional flows from percentile to the 90th percentile for each functional flow metric. It's based on work by Ted Grantham. And it's a statewide model. So you can go to any, click on any stream reach in the state and it will give you a range of flows. It's, again, a statistical model and it's has some drawbacks because of that. But we like all the information we get, so we're using this in addition to the groundwater model to sort of try and understand what's happening. And this data is available on the web. I did forget to talk about the right-hand side of this figure. I'm going to show a few figures that show these box plots. The upper whisker is the 90th percentile flow. The top of the box is the 75th percentile. And then the middle of the box is median and so on. So we'll be looking at those in a sec right now. So we'll just work our way. We'll start at the Napa River at St. Helena site. And the blue here is the natural flows database. The yellowish, like dark mustard color, I guess it is, depending on your color schemes, is the USGS gauge data. The NV IHM with pumping scenarios, so that's the existing conditions. is in green, and then the no pumping scenario is shown in orange. And you can see, in general, the NVIHM says that pumping has an effect of about 5 CFS. It changes a little bit depending on the water year type, but at this site, groundwater pumping, and that's basin-wide groundwater pumping, not just local pumping, has an effect of 5 CFS. The natural flows database prediction of flow is somewhere between the existing pumping model and the no pumping model. And All three of them are, everything else is a little higher than what's at the USGS gauge, and that's mostly because of the monthly time step. Because the USGS gauge, we can actually define when the summer base flow starts. But the models are calibrated to that, so they actually agree pretty well. If we go downstream to Oak Knoll, we see the same trends, but the magnitudes are bigger. So the flows are larger in the summer. It tends to be flowing more often. And the effect of pumping is about 10 CFS instead of about 5 CFS. And again, the NVIHM is intermediate between those two. And then if we make a plot of Sulphur Creek, it's really boring. And that's because the Natural Flows database makes a prediction for Sulphur Creek. And it's not taking into account things like that it's on an alluvial fan. And its prediction is even the 90th percentile flow here is 1.2 CFS, which is not a lot of water. and you wouldn't put a lot of stock in that kind of value in the model. So I don't really see these models as all that different. And the effect of pumping is zero because both the – The existing model predicts zero flow in the base flow period, as does the no pumping model. And that agrees with what we see in the field, which is that the groundwater level, even in the winter, is below the elevation of the bottom of the channel bed at our site. As you went downstream on Sulphur Creek and got closer to the main stem, the effect of groundwater pumping may be higher.

And it may be connected to groundwater further down.

Jumping to CEF Section B, thinking about non-flow factors, this plot I show here is courtesy of Nick Featherston. And it's overlaying the two different temperature gauges we put out at Oak Knoll in summer 2025. Things in the green are optimal for juvenile steelhead rearing. Based on the literature, yellow is but, you know, survivable. And you start, as you go from orange into the reds, you have increasing stress on juveniles, and you get reduced survival above about 22 degrees, which is the top of the yellow there. So 22 degrees is a good thing to keep in mind. So that's the flow. And I'm going to just skip to the third bullet to start. What we've found from the temperature monitoring we've been doing over the last two years and data going back to 2001 that Stillwater did as part of their limiting factors analysis for steelhead and the data that has been obtained at surface flow locations since the shallow water wells were put in in 2015, all tell the same story, which is that the stream temperatures are awfully high and are above 22 degrees often during the summer. Dissolved oxygen levels are often stressful. And a lot of the reason for that is because of this widespread incision. There's not a lot of shading in the channel. The trees that would normally be in the riparian zone are 15 feet above the channel. So aren't helping to keep the temperatures cool. And so you get a lot of direct solar radiation. The incision also causes limited habitat for juvenile steelhead and foothill yellow-legged frogs, which we're going to mostly be talking about today. And that is because there's not a lot of bar and pool formations or morphology because of the limited width. So next I'm going to talk a little bit about flow ecology relationships and these two species, the steelhead and foothilly elegant frogs, which are very cute. The... We'll start with steelhead. And just to remind you that steelhead have a pretty complex life history. They're born in the river. They come out as they're laid in a nest in the gravel of eggs. The juveniles emerge from that nest, and they typically stay in the watershed for one to two years. So that means that they have to make it through the summer. They then outmigrate back out to the ocean. And when they get the ocean, they just get big, big, big, big, big. And then they come back and spawn again. Steelhead are different from Chinook salmon in that after they spawn, they don't die. They can sometimes just go right back to the ocean and repeat the cycle again. You can see that the dry season base flow is a critical time for steelhead often. That's because they are sensitive to stream temperatures and flows. And also, Kelts can sometimes be migrating out of the basin during that period as well. Kelts are the adults that spawn and then go back to the ocean again. So the dry season basefall is a critical time. And that's not unique to the Napa system. That's true basically everywhere in California. It's often a bottleneck for steelhead recovery. We put together this plot looking at just sort of very simple limiting factors for steelhead under current conditions at the three sites. The black circles say it's for likely limiting. The black and white circles are limiting in some water years, typically dry water years. And the white circles indicate not limiting. And if we look at St. Helena, first of all, The limiting factors include that the channel goes dry at the Napa River at Santa Helena. Or in other places, it can be reduced to isolated pools. There is limited connectivity or access to refuge habitat, that is, places with better stream temperatures. There are stressful stream temperatures and dissolved oxygen levels and poor physical habitat. So St. Helena has it all. Oak knoll tends to be flowing most years, although it can go dry in drier years. And during those years, it can also have limited connectivity. But the stream temperatures, I'll show you some data in a second, are often high. And the physical habitat is also poor. In contrast, Sulphur Creek, which also goes dry, and goes dry pretty early in the season, on its upstream end has pretty good connectivity to the reach upstream. So the fish that are at our particular study site can get up upstream. They just have to go up a little bit, and they can get into the uplands outside of the basin. And the stream temperatures can become stressful in places because there's not a lot of cover there. But the physical habitat is actually rather good there. And if we compare these limiting factors to what we've seen in our fish surveys, we've seen small numbers of fish at the St. Helena site, juvenile steelhead. We haven't seen any juveniles at Oak Knoll. We've only had one year of surveys there. The second year of surveys is happening right around now. And all we saw there were two of these adults swimming out. But at Sulphur Creek, we've seen a lot of fish. We saw almost 40 the first year of our surveys, and the second year we saw over 770. So there's a lot of interannual variability happening here that is outside of the basin's control as well, which is always a problem with fish. But Sulphur Creek has been a much more successful place for fish to be so far. And just a reminder that although Sulphur Creek's the most successful, it's independent of groundwater because that groundwater level is it's pretty high up on the alluvial fan, and so the groundwater level is further from the surface. So I wanted to take a closer look at two limiting factors. The first was a question of, would increasing groundwater levels and associated flows reduce stream temperature? And we're going to take a simple way of doing that, that is just using data when flows were higher to see if the temperatures were better. And then also asking, at what point does flow connectivity become limiting? Um, so these two plots, uh, show our, the data are colored by month with five being May and 10 being October. Um, they show stream temperature versus the daily discharge measured at the Napa River at St. Helena USGS gauge and the Napa River at Oak Knoll. And again, there's our, um, the dash line going across is our 22 degrees C reduced juvenile salmonids line. Um, and, um, You can see we didn't get a big range of flows on the left at St. Helena from about six CFS down to zero. But you can see that if you were to increase the flows by five CFS, you still could be in a potentially high range. temperature situation there. And that's in part because the groundwater isn't all that cool. The groundwater in the Napa sub-basin is relatively warm in places. The deeper groundwater is more like 21 degrees C, which is frighteningly warm and nice if you want to own a hot spring. And then at Oak Knoll where the flows, we got a much larger range of flows up to 30 CFS. Even at something like 25 or 30 CFS, you're still very close to that sketchy temperature zone for fish. And with the caveat that in May, there's less solar radiation coming onto the channel than there is later in the season. And then just going back to this to remind you of the three flows. We're going to switch now to connectivity and to remind you of the three flow states of flowing, isolated pools, and dry. So StreamWatch, we've talked a lot about that, and it's a really useful way to think about that. And Nick Featherston did a really noble thing and got the RCD to identify the length of the stream reach that would be represented by the point where they're doing StreamWatch data, and so we can make a map. And so we've done that here. And here the green are flowing, blue is isolated pools, and red is dry. And we've got three different periods over 2025, which was a relatively wet year, particularly in the upstream part of the basin. And you can see if you come out in June, Bear Creek, which is a tributary to Vail Slough, has gone to isolated pools. And Selby Creek up in the north have gone dry. But basically, everything else is connected under Streamwatch in May. As we move forward to June, a lot of other things start turning off and becoming dry. Sulphur Creek goes dry in its lower parts in June. Soda Creek and Garnet Creek all start to go dry. If you were a fish in In Sulphur Creek, you would be stuck either upstream or down in St. Helena. And then as you move forward to September, the disconnection just grows, with maybe the exception of some channels that I think maybe probably get some urban water support through the city of Napa. So that's fish. And now I'm going to quickly do the same thing for frogs. Frogs have a much different life cycle than fish. They lay their eggs in the stream. Foothill-legged frogs lay their eggs in the stream. They then rear as tadpoles in the stream. And then once they become adults, they metamorphose into adults. They can start hopping around and go find other sources of water. So these first two life stages really depend on stream flow. And we've also got some timing data from the literature and our observations from the Napa. The light blue is observations in the literature for egg incubation timing and hatching, and then for tadpole rearing time. For foothilly-legged frogs, the incubation and rearing time is all, their growth and time to metamorphosis is very stream temperature dependent. So the warmer it is, the faster that occurs. So they're sort of the opposite of fish in their needs for warm water. So looking at the limiting factors in the same way for foothill-yelligid frogs, one of the things that might be a problem is the channel going dry before they can metamorphose, like you get a bunch of stranded poor tadpoles. There might be no habitat for the frogs to deposit their eggs in or the tadpoles to rear. They need slow water for that. There could also be predation that could be a pressure. Those are bullfrog tadpoles, and bullfrog tadpoles are giant and ugly and eat everything. The pictures of them terrify me. But the thing about bullfrogs is that they need – bullfrog tadpoles stay in the water for over a year or so. In channels that are dry, they're not as much of a problem. Another problem could be competition from other frogs, and we're basing that based on what we observed in the field. At St. Helena, the channel may go dry before tadpole metamorphosis in some years. It's wet for long enough based on what we've observed in Sulphur Creek. The habitat's pretty poor, though, outside of the confluence with Sulphur Creek. There may be bullfrogs in some years, and competition from other frogs may also be a problem. And we did see foothill yelling at frogs there, an egg mass in 2024, but did not see any frogs in 2025. Oak Knoll doesn't go dry early enough to be a worry for the tadpoles. But it does have very poor habitat. It may have bullfrogs in some years. And there are other frogs there. We didn't observe any frogs there in 2025 or 2026. The frogs we observed at Oak Knoll We did get a positive eDNA result there, and it ended up being from the tributary that's just upstream at Dry Creek, where we did observe juveniles. And then at Sulphur Creek, there's a worry in some years that the channel may go dry too early for those tadpoles to mature. But in general, the habitat's good. There's no bullfrogs and few other frogs. so based on this, we're going to, these observations, we're going to, we're going to make some preliminary flow recommendations. And the, The timing is a little squishy right now. This is just a first crack at this, and we've got a little more data to look at. But I'm just going to roll with it. But keep in mind, this is preliminary. We're still working on drafting this. So for the St. Helena site, it's important to maintain wet conditions long enough to allow foothill-legged frogs to metamorphose. Based on what we saw in 2024 at Sulphur Creek, that probably occurs in late June to maybe mid-July if there's a difference between the sites. We don't really know if the amount of wetted area is... is sufficient to support tadpoles there. And we only saw an egg mass there. We haven't seen tadpoles. So there's some questions about the site and frogs. And continued monitoring could help to answer some of those. And we don't really understand very well the effects of annual variability at the St. Helena site. Another thing you'd want to do is support steelhead movement to more suitable habitats. We know the temperatures aren't good for steelhead rearing here. And we want to do that while tributaries are flowing so there's a place for them to go. Stream watch indicates that nearby tributaries transition to isolated pools in June or July. And there's some uncertainties about that, too. There's a difference between a channel can be flowing, but it can be such low flow that the fish can't get up it. And we haven't really taken that into account here. We don't know how long juvenile steelhead are occupying main stem habitat, but we're doing some later fish. The RCD is doing some later fish surveys this year to try and better understand that. And then, again, the effects of interannual variability. So mostly because of the poor water quality and habitat conditions that limit steelhead rearing at the site, our preliminary recommendation is to maintain wetted conditions through the June, mid-July period to support frog rearing and steelhead movement. And our general approach is thinking about providing enough water so that the fish can go elsewhere. We know if a juvenile fish is in this site in July when it goes to isolated pools, they're going to die. So that's our preliminary recommendation at St. Helena. Going downstream to Oak Knoll, where we don't see any foothill yellow-legged frogs or haven't to date. We've not observed juvenile steelhead despite flowing conditions for a much longer period. But it does support steelhead movement to more suitable habitats while the tributaries are flowing. We recommend maintaining the current flow conditions here. I mean, our simple look at stream temperature doesn't seem to indicate that increasing flows is going to increase temperature very much. Increasing groundwater levels and increasing flows is not going to make more suitable temperatures. So we recommend maintaining current flow conditions at this site. Moving to Sulphur Creek. And you can see why Sulphur Creek water can sometimes get pretty warm. It's shallow, and there's rocks, and it's Whenever you visit Seltafer Creek, you want to make sure it's in the morning and not the afternoon when it gets really hot. What we know so far suggests that the flows in the summer are not dependent on groundwater at this site. And the groundwater dependence likely increases downstream. And here the flows are very dependent on what is coming into the basin. The Sulphur Creek is mostly a place for groundwater recharge. And so our recommendation here is not to do anything that would change the current flow conditions. So limiting any in-stream flow diversions in Sulphur Creek that might might reduce flows in this critical period of the at the beginning of the dry season so what are we going to do next we're continuing to collect data at intensive sites this year we're doing two fish surveys per site continuing continuing to measure water quality through temperature and dissolved oxygen and The RCD is doing monthly wet-dry mapping at each of the six sites, and we're continuing to monitor groundwater and surface water elevation. For the other biological surveys, those are scheduled to happen again either during a drought year, a flood year, or five years from the first survey. um the net will then final while also finalizing the draft sef report for section a and b as part of the periodic evaluation due in january at the end of january 2027 and later we'll develop sef section c so in summary uh the nvihm results indicate that basin-wide groundwater pumping reduces dry season base flow by about five cfs at saint helena and about 10 cfs at oak knoll High stream temperatures limit rearing for juvenile steelhead and connectivity to better habitats. That's a weird sentence. Also is limiting at St. Helena and Okinawa. We got a lot of Foothill Jagged Frogs happening in Sulphur Creek, and we started seeing adults in June, and there were no more tadpoles by July. And we recommend maintaining flowing conditions to support Foothill Jagged Frog metamorphosis and intra-basin steelhead migration through at least June or maybe mid-July. at the Oak Knoll in St. Helena and limit changes to surface water inputs to this subbasin on Sulphur Creek. And that is the end. Thanks very much.

Thanks, Christian. Comments from Tag? Well, I'm curious. You have the relationship between basin-wide pumping and these flow differences at the two sites. We have wells right there, right? Near St. Helena, yeah. Couldn't we try to drill down and be a little more precise, a little more specific about the groundwater conditions there?

You mean about the effects of local pumping? Yeah. That's probably not a question for me so much as it is for the people in the first row who think about this more than I do.

MS. So that has been looked at as part of the city – sorry, Vicki Kreutzinger-Graeber. For the city of St. Helena, it's in a draft technical memorandum. It's part of water supply strategies that the city of St. Helena has been looking at, including relocating or adding different sites for groundwater development to shuffle some of their groundwater pumping away from directly adjacent to the Napa River, and also recycled water use. And Napa County staff, we've set up a meeting I think in July. We're working to have a meeting with the city To receive more information on where the city is with their overall Plan for those strategies because we were just looking at a focus piece Because of the development of the Napa Valley integrated hydrologic model So that should become available later this year And we have presented some of that information previously. What it shows is that there's a small amount of influence by the local pumping, but the larger effect is actually the broader pumping occurring within the St. Helena region.

Just going in the same direction. Kind of towards the same, in the same direction, but here we have some recommendation for what the flow, I mean, weighted condition that should remain through June and mid-July. Are we attempting, or is that next step to link that to what the groundwater condition, just in terms of water level elevation, we should be targeting at some of those sites that are used for the GSP to look at?

undesirable results and and then after that back calculate to what it means for pumping yes it's so it would be tied to it we can tie it to a groundwater elevation we haven't done that yet they're gonna be part of sections and the report yes that's our plan yeah and and the important thing is is often you'll see a minimum threshold will be set that is a minimum, like the lowest you want to go to the summer. And our focus, at least for these sites, we haven't really fleshed out the Calistoga site yet, which may be different. But for these sites, we're really focusing on a timing and maintaining a certain condition through when the The different species are likely to use the site. It'll be different at Calistoga because there's freshwater shrimp there. And they need isolated pools maintained for them to survive. So there, I think we'd have closer to a minimum elevation without the timing part. But down lower in the basin, we've been focusing more on the timing. I think we got into a loop of trying to figure out when that timing was. How long do you really need to keep those conditions? There are other reasons to maintain flowing conditions, but if you're thinking specifically about steelhead, if the temperature is way too hot for them to be there, having more hot water is not going to be a good thing necessarily.

Yeah.

Speaking of hot water, that 21 degrees groundwater, is that attributable to the geothermal?

I think so. There was some variability. This was from data I saw in the GSP, and that was the deeper groundwater. There was some variability in it from year to year. And at St. Helena, the shallow surface water is is basically a two-month delay on the shallow groundwater is a two-month delay on the shallow surface water. So you can see that the shallow surface water is going in and influencing that shallow groundwater layer. But the deeper groundwater is much warmer. And I think it probably is related to some geothermal action.

So I realize at this point we're very invested in these particular sites, but as I look at the ones on the mainstream of the Napa River, none of them or maybe only the Yonville site is within areas of the river that have undergone the restoration because most of that was done like the oldest part of the restoration is in that sort of rutherford to oakville reach and then oakville to sort of oak knoll and so i'm a little bit wondering going forward if we can't have some at least maybe one site within that particular reach. Uh, because I mean, I don't know the dates on when the Rutherford restoration was, but it's, you know, old, you know, it's been, it's been a while and it feels to me like a bit of a, data gap for us and then like we're in Calistoga which is like there I mean the incision there you know or not it wasn't the Calistoga site we I was at last year right it's like that and then you know there's houses right on you know yeah exactly whereas if you go to parts of the river and Rutherford like it's a completely different experience Um.

Yeah, I mean, I feel like one of the things we talked about in the work plan is that we would revisit the sites.

Yeah, I realize that's not part of the conversation right now.

No, but I think this is a good conversation to have because there's always the tradeoff. Do we just get more data? Like, do you just stay at one site and get a more complete data set to sort of have a better idea of how you get at that interannual variability? Or do you try and get more spatial patterns? And this is like a debate – you know, that keeps us all up at night every day. I do think that for most of the rest, for a lot of the restoration, a lot of it was sort of targeted at Fish Passage and providing some, you know, there's, so there was some, one of the restoration sites is right downstream of the Yonville Cross Bridge. And that was, the restoration there was mostly targeted towards like higher flows, right? And creating a little bit of floodplains And at other sites in that restoration program, we're focused on creating little benches, places for fish to rest as they're going upstream. And I think the reason for that was this stream temperature problem, right? That it was recognized that the stream temperature was like you putting a lot of money and effort into trying to have better rearing habitat was going to just be defeated by stream temperature. So the idea was to get fish up as far as possible. I'm probably over speaking for the people who designed that restoration who weren't me. They may say something different, but that's the way I've looked at the restoration project that they've done. That's not to say that I don't think it's a good idea to move some of the sites. I think there are some sites we've probably learned a lot about so far. It is nice to have sites where we can say something about that linkage with groundwater and local effects. So having a nearby shallow well is really useful. But I think it's definitely something that we should start, like before we do that, like once this five year, I think it's good to have a few years of data. And we've done our two years of baseline data collection at all the sites. And one of the things we talked about here three years ago and i think it was you who who brought this up was that we should really revisit some of these these tributary sites um and maybe we should think about other places and you know i think given the lack of depend like we didn't know going into sulfur creek that the groundwater level was below the level of the stream bed that was something we learned when because that well got installed when we started the monitoring

Right. Whereas Bale Slough is an area where work has been done, right? Yeah, recent work. And when I hear you say, well, the trees are so far above. Well, in parts of the Rutherford region, the Oakville region, it's not like that anymore. And I hear you around, yes, generating long-term data sets. But if your site selection is not robustly really representing different aspects of the river, then it might be time to revisit that.

This is something we've been talking about internally with the technical team as well, is the need to try and represent more restoration sites. We do have the Bale Slough as one of our sites. It turns out to have not... I mean, it's a really kind of anomalous reach because it's pretty low slope. The water's really slow and murky, and it tends... So far, it hasn't been super fishy or great for foothilly-alleged frogs. It's great for the tree frogs. And it does go dry pretty soon. But, you know, that's a site that we're, you know, there's trees, you know, a lot of the trees that are... up outside of the channel, but are in the riparian zone. They're starting to come up, but there are places where they planted them when they did the, as they've been doing the restoration. It's pretty recent. So I think an older site would be an interesting one.

Whereas I've been in the vineyard in Rutherford, and there are river otter in there, right? I mean, I can hear them frolicking. So I think we maybe could revisit some of that.

Yeah, I mean, I think that that's something that as part of the period, you know, I've been talking about the SEF part of the periodic evaluation, but there's also a part that's like sort of a here's what we've seen in the ISW and GDE work plan as well. And I think that's a, and so that's, you know, that's coming, that's the train coming down the track heading for us that we need to plan for. So I think that that's a good thing to consider.

Well, I think a very good point on different sites. And I think in conjunction or also independent of that is starting to think about how we're going to apply. I mean, even if we have many more sites, how are we going to apply what we learned at some localized sites to the entire basin and other area in terms of setting up some

recommendation for the flow because I mean I think we have to be realistic we are not going to be monitoring everywhere but eventually we need to put some recommendations that covers the entire basin yeah I think that I think that's a we've been sort of thinking about them setting them up as at different points tied to the shallow groundwater monitoring network and but but expanding I mean there are other shallow wells along the main stem and expanding to include them and different tributaries. We got very intrigued by Dry Creek when we found the foothill elegant frogs there. So that, I think, is sort of one other thing we've been thinking about is thinking about different tributaries as well. MS.

When do you think we might revisit that conversation? Oh. Organizationally, you know, if you want something, then you've got to put it on a future agenda, right?

When do I come back here next? Is it September? Yeah.

Maybe between now and then, having conversations with the flood control district around, you know, the potential site selection.

Yeah, I'd like to bring the RCD in, too. I think, you know, Paul has walked... Paul Blank and Martine have walked so much of the channel that I'd be really interested in where they think would be good sites too. And they have a pretty good sense. They've been doing a lot of the monitoring associated with the restoration too, and so they have a good sense of where that could be. They're like the encyclopedia of the Napa River for me. I really love talking to them.

Yeah, it's tough. Every stream is unique. Every reach is unique. And you don't necessarily know the stories. I mean, Sulphur Creek's a great example because we've learned so much from Sulphur Creek from the well. And then just observing how the fish adapt when it's starting to dry out and they swim upstream. You know, it's got a surprisingly good ecosystem there, given how quickly it dries out. And it's just the way the biota have adapted to that situation.

Yeah, I think the way, to answer Julie's question, we're sort of developing conceptual models. We're using Sulphur Creek as the basis for a conceptual model of of tributaries on alluvial fans that go dry. And especially thinking about it in terms of frogs, we really think that those places are really good for foothill yellow-legged frogs if there's habitat there. They tend to be a little less incised. Going dry over the summer helps keep out the bullfrogs and other things that eat them. And, you know, but those are like conceptual models that need to be tested, right, and gather more data to sort of see if they're true.

But it's also complicated by the fact that if the wells locally are drawing the water table down and drying out the stream early near its confluence with the river, I mean, that could have implications.

For sure, yeah. Yeah. just about access and species getting in and out and things like that, yeah.

Yeah, and so I think when you want to think about additional sites, that's where it would be useful to see where you are in terms of being able to use the existing sites to project a conceptual model in the different area, and some of them where we would have obvious gap because the conditions are not represented by any of the sites. And I think one of the examples is at least the one you mentioned, but there might be more.

Yeah, we haven't really tested, like, you know, the conceptual model I have in my brain is like a low-slope tributary versus high-slope tributary or, you know, more confined reach of the main stem and the less confined reach of the main stem. But there could be spatial differences. You know, it could be a lot different in the northern part of the valley than it is in the southern part of the valley on tributaries or eastern, you know, ones that drain out of the east or west and... And, you know, we can work with our partners at the RCD to sort of think about where are the big data gaps and how to stratify these things and say, where do we look next? And it might be as simple as, you know, just... taking some eDNA samples at a bunch of tributaries and seeing what you see in there and also looking at leveraging the stream watch and the sort of fine scale monthly wet dry mapping that the RCD has been doing at the sites is really, I found really insightful to think about how the sites dry up. I mean, the St. Helena site just kind of goes dry really fast and all at once, whereas some of the other ones, especially Calistoga, tends to go dry slowly, leaving isolated pools, and some of those pools sometimes dry up and others don't. So there's definitely a lot of dynamics that vary spatially. Okay.

Yeah, and it seems like, you know, this is our opportunity to do that, so we should be thoughtful about it.

Yeah, right. You can't study everywhere, but maybe there's a different mix that would yield.

Yeah, make sure we could learn some additional things that could then be applied, you know, various times.

No, I think that's a really good reminder to include that in this periodic evaluation.

Any other tag comments? Do we have any comments from the public?

We have one caller. David, you will have three minutes.

Thank you. When I was learning to fish with Potski's balls of fire salmon eggs and was a catch release, I learned the saying that of it's a truism that seems trivial, but it is not, that one should fish where the fish are. And I'm puzzled as to why we're spending, if we're looking at steelhead production in the Napa River watershed, many studies, most importantly, I think the Leidy survey of 2005, shows that they're all over the watershed, but they're not near the main stem most of the time in most years. So to me, this is, with all due respect, Christian, it's not where the fish are. It's not where we need to be concerned about making sure that they have cool, oxygenated water where they can thrive. And the second observation I would make is that probably a really good idea to control bullfrogs because the results I've seen in the work that I cited in notes to the GTag would suggest that bullfrog control releases foothill yellow-legged frogs unlike any other factor. including, I would argue, water supply. So unless you look at that, you're kind of missing the point, seems to me. Thank you.

Okay.

Chris. The button.

Hello. Let's not forget that these species are hanging on by a thread. When you add in climate change, we can lose these animals very quickly if we have years of drought on top of the continuous groundwater pumping. These animals were abundant throughout the Napa River watershed. I'm talking steelhead. Chinook still migrate up the Napa River. And in the day, we had coho, okay? So... Water quality, warming of the Napa River, loss of canopy, these things, and definitely loss of habitat from severe incision to the Napa River, which we don't talk about enough here. And DWR made a big deal about that when we were doing our GSP to address river incision, which is a clear indication that there's groundwater problems, groundwater recharge problems, and the river not in contact with the floodplain. It's really important that we do reach our goal of 10% groundwater pumping reduction, because what we're trying to do is to put more water back in the Napa River so the fish can go back there. Right now, they're having to go high in the watershed. At my nonprofit, we've been doing snorkel surveys for 24 years. We know where the fish are. they go where there's water they go where there's cool temperatures and plenty of habitat and what's left in the watershed is high in the watershed definitely above 50 feet elevation definitely probably more like a hundred um And steelhead are resilient, so they will push to the high part of the watershed. They will drive up into there to survive, but the Chinook don't. They are on the valley floor. They are more low gradient. So pretty much all that habitat on the valley floor, because it's so warm and dry, The Chinook just are hardly making it. They still will come up here. I know they call them strays from the Central Valley, but nonetheless, they are trying to be here. And, you know, the question is whether they are the actual genetic material of what was the Chinook run in the Napa River is always under debate. But we can recover. We can bring it back if we reduce the groundwater pumping, put more cool water in the system, and continue restoration. There's hope that the Napa River can recover and be a more robust environment for these incredible species. And we can't lose sight of that and just think, oh, you know, just, you know, get them up there and they'll make it up there in the high part of the watershed. But that's not the goal. The goal is to improve groundwater supplies and to make them sustainable. And we have to reduce pumping and that'll connect the pools in the Napa River and create more habitat. Thank you.

We have no other callers.

Okay. Great. Well, thanks, Christian, for the very interesting presentation. And I think that brings us to wrap up. Was there any final comments from tag members? Good. Okay. Well, I'll get to use the gavel here and adjourn the meeting.