 Good morning, everyone. I'm Isabelle Montañez, Chair of the Board of Earth Sciences and Resources and a Professor of Earth and Planetary Sciences at the University of California, Davis, where I'm also the Director of the UC Davis Institute of the Environment. Kathy Kling, who you can't see, but to my right, is Director of the Water Sciences and Technology Board and the Tisch University Professor of Environmental, Energy, and Resource Economics at Cornell University and the Faculty Director of the Atkinson Center for Sustainable Future, and she is the co-convener of the meeting. I'd like to thank all of you for attending today's meeting on the future of managed aquifer recharge in the US. So I'm going to start with just a brief overview of the mission of the National Academy of Sciences and the two boards who are sponsoring this meeting. So the investigative arm of the National Academy of Sciences aims to be the nation's preeminent source of expert evidence-based and objective advice on science, engineering, and health matters. And the NAS and its boards provide a neutral, convening body that supports the use of scientific research for evidence-based policymaking and to recruit scientific and technology specialists to participate in advisory work and confronting challenging issues for the benefit of society. Next slide. The Water and Science Technology Board is chaired by Kathy Kling, as I mentioned, of Cornell University and consists of a board of volunteers that span a broad diversity of expertise and backgrounds. And I invite you to look through the agenda booklet for the members' bios. This board is the National Academy's focal point for activities and issues related to water science and resources, including surface and groundwater, aquifers, and ecosystem restoration and management, water infrastructure systems, water reuse, waste water, weight water hazards and mitigation, and hazardous waste cleanup and water quality. Next slide, please. The Board of Earth Sciences and Resources, which I chair, is the National Academy's focal point for activities and issues relevant to solid earth sciences and resources. And again, I invite you to look through the agenda booklet for the members' bios. We cover a broad topical space, including a range of geologic hazards, energy and mineral resources and stewardship, geographic geologic and geospatial mapping and modeling, geological and geotechnical engineering, carbon sequestration and the energy transition, strategic directions for earth science research, the intersection of geology and health, and environmental justice and equity in earth science and education and workforce development. Dr. Deborah Glickson oversees as director both of these boards. Next slide, please. Okay. The funding sources for both boards are diverse and showcase the breadth of earth sciences. Core funding is currently supported by the Department of Energy, Chemical Sciences, Geosciences and Biosciences Division and the Basic Energy Sciences. NASA's Earth Surface and Interior Focus Area, NSF's Division of Earth Sciences in the Geosciences Directorate and the Chemical, Bioengineering, Environmental and Transport Systems and Engineering Directorate. United States Geological Survey, core science systems as one of our sponsors, energy and mineral resources and natural hazards. Next slide, please. So today we'll be discussing the current and emerging issues in managed aquifer recharge in the US, a topic of great relevance to the water science, resources and earth science communities. We'll be assessing how the national academies can help the utilities, municipalities and agricultural sectors and others in the efforts to adapt to climate change and its impacts. And we aim to better understand the role that managed and aquifer recharge can play in meeting water demands in the US over the next 30 to 50 years. And next slide, please. You'll find the agenda for the two-day meeting in the booklet. Today we'll start with two speakers who will address the status of US aquifers under climate change and an introduction to managed aquifer recharge, followed by a series of case study presentations. And the second part of the meeting, I can go ahead and give me the next slide, please, will be held tomorrow. We'll include two panel discussions on the technical and institutional considerations for the managed aquifer recharge. And for today, we may have time for a question or two following each of the first two speakers, but otherwise questions from the audience, the board and these responses will be addressed in the Q&A function of following the case study presentations. So please enter your questions into the Q&A function of the Zoom meeting. Note that the webinar is being recorded. So any questions you submit may be read aloud and it will be included in our recording and a link to the recording will be posted on our website. All right, so now I would like to introduce our first speaker, Bridget Scanlon, who is a senior research scientist at the Bureau of Economic Geology in the Jackson School of Geosciences at the University of Texas at Austin. Bridget is a member of the NAE and has conducted research on groundwater recharge across regional to global scales. I'm gonna turn the screen to you, Bridget. Thank you so much, Isabelle. I really appreciate the opportunity to talk a little bit about recharge at the beginning of this session. And I was asked to discuss the status of US aquifers under a changing climate. So I'm going to talk about work we did under the Power Research Group with the USGS that involved NASA and USGS and academic researchers and some of them listed here. Next slide. So I talk a little bit about the current status and provides some background on the US aquifers and depletion that has occurred to date. And then consider both the direct impacts of climate change and indirect impacts through changes in groundwater pumpage and other processes. And then how we might be able to move towards more sustainable management. Next. So Lenny Conoco did a fantastic work on compiling data from regional models and monitoring data of the aquifers throughout the US. And this represents the results of his analysis based on data from 90 modeling from 1900 to 2008. And he estimated total depletion of about 1,000 cubic kilometers. And this represents a large subsurface reservoir that we could use for storage for managed up for recharge. And that compares to current US dam capacity of about 736 cubic kilometers. So here you can see that Dr. Conoco identified large depletion in the central valley in California 105 and 45 cubic kilometers. Arizona alluvial base is 102 and the high plains region 340 and the Mississippi alluvial base in 180 cubic kilometers. Slide rises in storage in the Northwest, the Columbia and the Snake 40 cubic kilometers and slide depletions along the coast here. So this provides long-term data on water storage depletion in these aquifers. Mostly in the Southwest, South Central US. And next slide. So we've been looking at the gray satellite data for the first mission based on 15 years of data 2002 through 2017 and Ashraf Rata published this work in water resources research. So over this much shorter timeframe, then you can see depletion in the reds and yellows in the Southwest and South Central US about almost 30 cubic kilometers in the central valley, slide depletion in Arizona and for almost 40 cubic kilometers in the central and southern high plains. The yellow areas show very little change in storage within the uncertainty envelope for the gray state data in these, based in the upper Colorado and the Mississippi and then slide rise in storage in the Columbia and slide rises in storage in the human Eastern US, Pennsylvania and Florida aquifer systems. Next slide. So if we try to compare, we don't have data for the same time periods that the gray state are shown on the left and kind of cause results for a much shorter time period 2000 through 2008 are shown on the right. And most basins there, they generally correspond but the biggest discrepancy is in the Mississippi alluvial basin where the gray state suggests very little change in storage and the regional model suggests minus a 60 cubic kilometer decline over this time period. And so we were working with the USGS on this study and so they think that their regional model may not be accurate enough and may not allow capture of surface water storage. And so they're revising that model now. And so even though a lot of hydrologists are allergic to gray state because they think it's too coarse resolution, I think it's just another data source that we need to look at when we're evaluating these systems. We can't ignore any source of data. Next slide. So now looking at the direct and indirect impacts of climate and groundwater storage using the gray state next. So we looked at total water storage from grace and this example shows the Southern Central Valley San Joaquin Tulare and you can see and on the lower bottom part of the graph we showed the US drought monitor data. So a drought from 2007 through 2009 and then 2012 through 2017 or 2017. And the grace data corresponds to this. So we see declines in storage during the drought and large decline during the recent drought with a correlation coefficient between the total water storage and the drought monitor data 0.9 of one. So this may reflect a direct and indirect impacts of climate extremes on water storage. Next slide. So next slide. So I just talked about the Central Valley and the relationship with the US drought monitor in the Northern High Plains. We also see a strong relationship between total water storage and drought with increasing storage during the non drought periods and declines during the flash drought from 2011-12. But an overall increase in storage and this trend is not projected to continue because it just reflects large inter-annual variability. In contrast, the Central and Southern High Plains shows a decline in storage that's amplified during the drought but overall groundwater pumpage exceeds recharge all of the time. And so basically mining the groundwater in this system. Next slide. And in the Mississippi Inlayment Regional Office System then we see increases and decreases in response to drought but not very much. The drought is not very intense in this humid region in the US. And so storage, there's no long-term storage decline seen. Next slide. So in addition to the relationships between climate directly and water storage, we also need to consider the impacts of irrigation on the water storage. And so here you can see the major irrigated areas, the Central Valley and the High Plains and the Mississippi Inlayment and the Northwest. Next slide. So in the Central Valley we saw a strong correlation between total water storage change and drought but this partially reflects the fact that during 2010 which was a wet year, most of the irrigation was from surface water about 70% was from surface water and about 30% from groundwater. And in the middle of the drought then 2015 they switched from predominantly surface water to mostly 70% groundwater. So this change in human water use then for irrigation amplified the impacts of drought in the Central Valley and Claudia Font has been reporting this for many years based on her regional modeling analysis. Next slide. So many people, there's a lot of emphasis in the Central Valley and all the groundwater pumpage that occurs there particularly during drought but it was interesting to me to see that groundwater pumping in the Mississippi region aqua system actually exceeded that in the Central Valley and there wasn't really any intense droughts during this time period but in this human region then that groundwater pumpage is essentially capturing water from either surface water or a vapor transpiration. And so we're not seeing a large decline in storage and hopefully the new regional model would be able to confirm this. So it's a combination then of climate impacts and human water use. Next slide. So just one example then and I'm sure in the case studies they'll be talking much more detail about this. This is Arizona and the Central Arizona project shown in yellow bringing water from the Colorado River to these active management areas in Phoenix, Penal and Tucson. And next slide. And these show the spreading basins used for managed after recharge in these areas in these active management areas. Next slide. And these green basins don't have access to surface water and next I'll show the groundwater level hydrographs in these different basins. So next slide. So in the areas where we have the active management areas we see increases in groundwater levels over time or stable or rising slightly rising water levels over time that can be attributed to surface water irrigation which accounts for about half of it. And then those managed after recharge basins which accounts for the other half. Next slide. And in the basins they don't have any access to surface water or Central Arizona project water. We see continued declines in water storage in these basins. Next slide. So how can we move towards more sustainable water management? Next slide. So I think some of the analysis that we have been looking at show the importance of conjunctive use of surface water and groundwater. And I recall Claudia found mentioning many years ago that when we were irrigating with surface water maybe we could do it inefficiently as long as it doesn't impact the surface water resources. So we take into account the recharge aqua reaches that's occurring as a result of that. Whether it's managed after recharge and flood managed after recharge like Helen Duffy I'm sure would be talking about or it just happens and it's unintentional. A recent study in Northwest India shows a net increase in water storage from canal irrigation in the last century of about 350 cubic kilometers even though most of the studies recently have been talked about the depletion during the grace record. And then when we're irrigating with groundwater because we're pulling water directly from storage it's important that that is efficient in drip irrigation and those sorts of systems. And to manage up for recharge is a very important tool to increase resilience at the local scale. And in cases like the high plains where we don't have any surface water we just need very efficient groundwater and acknowledge that we're mining the groundwater. So next slide. So this work, a lot of this work was during a power research group meetings that we had meetings every summer and really appreciate all the inputs from the various contributors to that work. Thank you very much. Thank you very much for a very engaging talk. I think we have a couple of minutes for questions. Thank you for your talk, Brigitte. I have a quick question. What's the relationship between soil structure and some of these dynamics you see? Because for example, I wonder in Mississippi they're using a lot of groundwater. I'm wondering if it's like less evaporation, more recharge due to the soil structure versus some of the other areas that are depending on groundwater. And I also wonder in Arizona when you looked at groundwater level changes did you mention there might be because of irrigated agriculture? I'm wondering if you have tested that hypothesis or is it more, I wonder what percentage of that is mostly because of managed aquifer recharge instead of irrigated agriculture? So the first question about soil structure I think that's very important for the recharge. And I think we see this in the high plains. I mean, the northern high plains in Nebraska you've got the sand hills and you have very high recharge, natural recharge. And then you also have some surface water irrigation from the plant. In the central and southern high plains, I mean, in parts of Texas it's like cement and but you do have some plier recharge. So a structure is very important. And I think the USGS in their new regional model of Mississippi, they're going to be, they have been doing geophysics to see the linkage between the rivers and the subsurface and the aquifers, the shallow aquifers and trying to determine the linkages there and how they may be inducing recharge from different areas. And then your second question on Arizona, Don Poole was involved in that study we were looking at Arizona and they have regional models of the groundwater system and they were able to see a thing from the surface water recharge and also from the water counting that the central Arizona project, much of that water was also used for flood irrigation and part of it was used in the recharge basins. So the flood irrigation from surface water contributed quite a bit to the increased groundwater levels and we saw it in the models and the data and Don Poole had ground-based gravity data to show that also. And the marbasin, we were able to look at those impacts locally. So I hope that answered your questions. Thank you. Thank you. Thank you, Bridget. We are going to need to move on to the next speaker, but there will be time to answer questions for Bridget in the Q&A discussion towards the end of this open session. So I'd like to introduce Bill Alley, who is the science and technology director at the National Groundwater Association and was previously the chief of the Office of Groundwater at the US Geological Survey. He's published widely, including several general interest environmental science books. Bill. Okay, thank you. My pleasure to be here. And I guess my job is to give you an introduction to manage that for recharge. Here's a, this particular picture is of the Montabello forebay area above LA. These spreading basins shown here off that that's the LA's idea of a river there, that concrete channel. The spreading basins been operating since the 1930s where they were recharging stormwater. In the 1950s, they started in recharging, adding also imported water from the Colorado River. And 60 years ago, they started using recycled wastewater recharging that. So that's the oldest potable reuse project in the United States. In 2019, they actually took themselves off imported water from anywhere in California. They've had a program they called WIN, which is water independence now. And they've managed to take themselves off imported water, which is very important for this particular year if they can continue. And the Los Angeles plans to basically recycle all of its wastewater at some point in the future. Okay, let's see if I can advance this. So there's a couple of ways to, hopefully that'll disappear on the screen there. There's a couple of ways that you can deal with groundwater overdrafts. One is to replenish the aquifer, which is the Mar idea, but they're also demand management and alternative supplies. So it's really working together with those three basic ways of trying to control the amount of water in an aquifer. Okay, so I think there's a delay here. So there's purposes. So we tend to think of storage as the purpose of bandage duct for recharge, but actually they're also used for environmental benefit, for halting land subsidence, for preserving wetlands and managing the reuse of treated wastewater, as well as providing possibly a local emergency water source for fire control or loss of water supply during storms. So there are a lot of different purposes of bandage duct for recharge. Now there's a very, okay, lots of names out there. So originally it was referred to as artificial recharge and that term carries on today. Most people involved in bandage duct for recharge prefer not to use that term. They wanna emphasize the management because the idea is the purposeful recharge of water either for later withdrawal or for environmental benefit. But there are a lot of other terms. Another one you hear a lot is aquifer storage and recovery, which I'll get into in a moment. And that actually is a specific type of bandage duct for recharge, but it's often used as a synonym for bandage duct for recharge. And then I'll skip down to the bottom to next to last there, managed underground storage of recoverable water. That was a term invented by the National Academy of Sciences in their last report, but it just tends not to be used. And one can also think of in lieu recharge as related to manage duct for recharge in the sense that you are not withdrawing using surface water supplies during letting your aquifers recharge during wet periods. So let's look at some different types, Maher. So there's water spreading. The top one in infiltration pond or spreading basin as I just showed you example on the introductory slide, but there are other types. In the Netherlands, they do do infiltration. One that's received a lot of interest is for a long time is taking wastewater and using essentially spreading basins to mostly purify the water from pathogens and to deal with nutrients is the main purpose there. This study probably all were Herman Bauer back in the 1960s in Arizona. So there are also recharge wells. Aquifers storage and recovery is actually where you use the same well or wells for recharge and recovery. And it's a little different because you can actually use brackish aquifers that way and build up a freshwater bubble, if you will. And so it's a very, it should be used as a specific term. So to distinguish that sometimes in texts you'll see the term aquifers storage transfer and recovery which is helpful to show the distinction but there's not a recharge project in the United States where somebody's recharging wells and they would say, I'm doing aquifers storage transfer and recovery. They would tell you they're doing well injection or what have you. So it's kind of not used much. And there's also dry wells and I'll actually get to an example of that later. And then finally there's stream bed channel modifications. These are typically done on ephemeral streams either where you build a dam and capture water behind it for the express purpose of recharging the aquifer and using it down. Now in gradient or if you have a low distance to an impermeable relatively impermeable unit you might build a dam underground dam to pond water or you might actually build up gradually a series of dams and make your own aquifer if you will. Because these are used a lot in for example, a place like India. And in fact, India recharges more water than anywhere else in the world. The United States is second but India is far out in number one slot on that. They also use more groundwater than anybody else. And another in terms of future use approximately 1% of the groundwater withdrawals today are recharged through managed aquifer recharge means. So there's a lot of potential out there. Oh, finally there's also bank filtration. This often uses a pre-treatment technique particularly in places like Berlin and Hungary but also in the US and I'll get to an example of that. We're using essentially put a well maybe a couple of hundred yards from a stream and you're pulling the water from the stream and it's naturally cleansing itself. And it's shown to be pretty effective in certain types of chemicals and that's so effective in others. So what are the advantages? Well, one is what most people think of immediately as a reduced evapotranspiration losses but there's also a smaller impact on land use and also avoids water quality problems such as algal blooms. A very important part of it is it can be scaled up over time and actually there's reasons for scaling them up over time which I'll get to later. Generally requires lower capital investment and it's adaptable to different situations as I've already discussed. So Bridget included this. I included this in case Bridget didn't show this figure so I'm gonna go ahead and skip it. Okay, so what are some of the issues and challenges? One is regulatory complexity. Well's, injection wells are regulated by the underground injection control part of the Safe Drinking Water Act amendments and there are state and local jurisdictions that deal with things like water rights and so forth. So it can be a difficult thing to get one of these projects going. For smaller users, there are financial and scientific challenges. The lack of certainty about water rights and recovery and I know you'll hear more about that tomorrow is a challenge. Data limitations, chemical reactions of recharge water would act for materials think arsenic but there are other issues. Variability of source water quality if you're using something like stormwater has a highly variable water quality characteristics to it as can surface water. And you need to improve groundwater governance and management really. And then basically you have to deal with well clogging. So almost for sure. And well clogging can occur in different time scales and different ways. This just shows a number of those whether they're gas bubbles or abundant or you may have bacterial growth that may depend on essentially the food supply for the bacteria or you just may have a gradually increasing suspended sediment clogging your well. So those all have to be dealt with in whatever and either well injection or in spreading basins. So let's take a simplified aqua storage recovery system here. Same well pumping and withdrawing or recharging and withdrawing some monitoring wells around it. And it has to think in terms of various operational phases. So with recharge you need a sufficiently permeable aqua that you have and without overpressuring it. For storage, that depends on the timeframe. So these may be seasonal long-term or short-term and so or maybe to optimize permitted water rights and surface water rights. So the aqua transmissivity and gradient should be such that the recharge water is gonna remain close enough to the point of recharge that you can recover it. So that's an issue with longer term issues. And then recovery water quality becomes a big issue on the water quality side of things. And typically these projects, as I mentioned, are staged. You start with a sort of a design. You might have a pilot and a demo project particularly with a recharge well. You've got permitting and stakeholder involvement that may come into play here. And so it's a gradual process and oftentimes so there have been projects where they've decided to just go full steam ahead right from the beginning and they've had problems. So what are some research questions? I'll list a number of them there. I'll point out the introduced micro contaminants. So PFAS is a big deal these days. But there are others, there's still the issues of pathogens, disinfection byproducts either forming or being injected into wells. What's gonna happen to them? Monitoring techniques, applications of geophysics and just to show you an example there. They can be applied to surface spreading for identifying storage zones and recovery well field locations. And I know that you've probably all heard about airborne electromagnetics at one time or another, you will probably by tomorrow which is being done in a big scale in California. With aqua storage and recovery, you can do it for, you need storage zones and potential for mixing. Again, there's a whole range of geophysical techniques and finally you can do thermal logging to monitor wells during recharge trials. So there's a lot of tools that are out there that can be applied to manage that for recharge in various ways. Okay, so I'm gonna end with focus on potable reuse projects. And I'm gonna, I can't stop myself from passing around a book that my wife and I just published a month ago. This is totally on this topic. This is a fascinating topic. This is an EPA map. It's actually a little out of date, 2017 but all those blue dots are indirect potable reuse. They're not all groundwater. Some of them are surface water such as Gwinnett County and the Acoquan, not far from here. But you can see there's a lot of them and there's a lot California and along the coast for good reason. So with National Research Council has actually looked into potable reuse back in actually a previous report but in 1998, there's a book about this stick that has a 12 page or so executive summary. Embedded in that summary somewhere are the words indirect potable reuse is an option of last resort. It shows up one other place in the report. There's nothing else in that report that ever really mattered. So that became a real red flag for a lot of people, unfortunately. And it was still a developing technology really at the point and they made it in the report which is a fine report made that point. In 2012, it was looked at again by another academy group. This time they compared the chemical and biological risks of potable reuse with what's in a de facto water reuse if you will, normal situation. And they basically concluded that the chemical risks are about the same maybe. And the microbial maybe even better, it might be even better to do the potable reuse. So it's come a long ways in a couple of decades. The book I'm not passing around, I'm gonna give you three examples from it. One is Monterey One Water, which is a classic case of the application of the One Water idea. Scottsdale, Arizona is, I'll mention that mainly from a dry well and Aurora, Colorado as an interior, very interesting study. So if this is the monitor, you see Monterey there, Monterey Peninsula and the orange area is shown as the Salinas Valley, otherwise known as the Salad Capital of the World. It also has had seawater intrusion from pumping for that leafy stuff back in the 1970s. It undertook an 11 year study of application of tertiary treated wastewater to food crops eaten raw. It was a classic study and eventually in 1998, they started irrigating, they built a regional wastewater treatment plant and started irrigating 12,000 acres with tertiary treated water. And so that was a setting for another problem that existed in Monterey, which is the people and businesses, there's not enough water. They're drawing water from the Carmel River, which you'll see south of there and from a seaside groundwater basin, a really small groundwater basin. And they've been told for years just to cease and desist on the Carmel River, at least reduce their flows because of the damage to environmental issues, salmon, et cetera. And so they started Monterey One Water, our pure water Monterey, just came online maybe a couple of years ago. This is a diagram of it. So they have four sources of water, wastewater, industrial processing water from Washington at Leafy Vegetables, crop drainage water and urban storm water runoff. And they're able to essentially either direct that to tertiary treatment for application at the top there to their seawater project with the 12,000 acres or they can put it through the advanced water purification process that they use typically in California for well injection, injected in wells where it has maybe a nine to 12 month residence time and then pull it out for use by businesses and residences. So it's a sort of a landmark case of the application of one of one water. Scottsdale Water Campus, interestingly enough, is actually a collaboration between 23 golf courses and the city of Scottsdale. And they use dry wells because they're about 500 feet of water. So they use the advanced treated wastewater for recharging those dry wells and they then use the water during the wet season. They can put it injected underground through those dry wells. And during when the irrigators need it, they can send the water up for irrigating crops. And the golf courses pay part of the cost of this whole operation. And it's worked very well over time. Finally, Aurora, Colorado, it's a very interesting case of most of the South Platte rivers downstream from Denver and certain times of the year is actually treated wastewater from the wastewater treatment plant. And they pick it up further downstream use the bank filtration process that I mentioned, pump it 26 and a couple of other things and pump it back to Aurora where they treat it advanced techniques and then provide it for drinking water. They've been doing that since about 2010, I think. And interestingly enough, there's a whole nother story where they're actually sharing this capability and their capacity with the South Metro areas which are all mostly dependent on the Denver basin aquifer. So it's been a very successful project. It doesn't get as much press as some of the other managed aquifer recharge projects do. Finally, a couple of things about, I've mentioned the US but there's a lot of managed aquifer recharge around the world. This is a recent report that was just by UNESCO looking at 28 managed aquifer recharge schemes around the world, including some in the United States. Very interesting report. And then finally, I'll end there with just a few references mentioned the first and the third on the list there. There's also under John Cherry's groundwater project and intended as an introduction to aquifer recharge has become much more and much more very heavy on the governance management and governance side. Probably will be coming out soon this year as a joint publication of IAH, UNESCO and the National Groundwater Association. And finally, we at NGWA are planning a special issue of groundwater, we're almost there. It's like herding cats. I think we've almost got all the authors and that's planned for 2022. Thank you very much, Bill. That was a really wonderful introduction to the topic today. We have plenty of time for questions. And so those in the room, raise your hand on Zoom and then we'll have questions in questions and answer. Bob or Robert? Yes, thanks, Bill for the presentation. You made a particular note of the comment, the line in the 1998 Academy study, indirect potable reuse is an option of last resort. If somebody said, Bill, would you rewrite that? What would you say? I would say that indirect potable reuse, first of all, let's separate the two correct is a fairly advanced technology and it's used in many places. There are many caution, you don't just jump into it. You need to make sure you've got like the sewer shed idea where you try to control the chemicals that people are injecting into the sewer system in the first place, there's operator training. So it's not something that it's easy to jump into but it's something that people should be planning for in a measured way, I'd say, in a small way. That's what I would say to them. Direct potable reuse is becoming very popular which is where you don't have the intervening aquifer or the surface water reservoir. Scottsdale, Arizona is the third place city in the United States that's received essentially to go ahead for doing direct potable reuse but they don't plan to do it because they like the aquifers for storing the water for when they need it. So that's one of the downsides of direct potable reuse. There's only one city in the United States, Big Spring, Texas that does that now but there's a lot of interest. There's been a lot of pilot studies around the country on that. Jonathan or John. I'll figure this out. Bill, thank you for this overview. Quite comprehensive and noting the title of one of the texts coming out in terms of governance and internationally. Can you identify anything without unless you just need to remain quiet until it's published but are there any aspects of governance that here in domestically there are some things we could learn from that other countries are doing that we just haven't brushed against yet? Yeah, so a couple of interesting things. First of all, the UNESCO document that was published they actually did an interesting thing. They came up with indicators of sustainability for the projects and they evaluated it with them. They actually based it on an EPA reporter methodology for that. So that's one, I think, people need to think about the long term there. The other part in the document that I mentioned the IAH UNESCO NGWA, there is a lot that's been done by Australia also in governance, Peter Dillon in particular, but others. And there they kind of divide up, they kind of look at it depending on where you are development-wise in terms of how you proceed forward with trying to manage the situation. But it's very case dependent, of course. But there are a lot of issues to think about in terms of what if you recharge an aquifer that's been dry for a while and all of a sudden you have springs just showing up in somebody's backyard that bought a house that was dry. So you have to think a lot about what's gonna happen to that water and how it might change the environment along the way. Thank you, Bridget, I know you have a question and then there's actually one that I'm gonna follow up for you. So Bridget. Thanks, fantastic presentation, Bill. One question in the Aurora case, you said the water table is about 500 feet deep. How deep are the dry wells? And is that to recharge actually reaching the aquifer? I know Claudia Fountain in California sometimes questions the spreading basins and if they're actually recharging the aquifer that's being pumped, you know, when the wells that are pumping are much deeper. So just maybe. So that was Scottsdale, Arizona actually. Oh, sorry. And so there's about 500 feet of water. The dry wells are about 180 feet down. So you've got another 300 feet. What's interesting there, water levels have gone up and actually as you may know, I know you know, Bridget, but others here may know the Arizona has set a safe yield what they define as safe yield where in other words you don't pump any more than you recharge. And Scottsdale was the first city in Arizona to actually achieve that goal, which is a goal set for 2025, but they said it some years ago. So I'm guessing it's fairly effective, Bridget. Thanks. Okay, and before I go to your question, Bridget, I did want to comment that Sharon Megdal said that she'll be providing a link to the UNESCO book that was just referred to in her presentation tomorrow. So Bridget, is there a model like the USGS based in characterization model for California available for other states? Well, USGS originally had the RASA program and Bill could probably speak to this more directly, but now they have regional models in many areas and they continually update them. So yes, there are models in many regions. Texas has its own modeling program, the groundwater availability modeling, and they have models for most of the aquas in Texas, including the Oculol or Hype Veins aquas. So Bill, do you want to add to that? The only thing I'd add is you'd be amazed how many groundwater models there are out there. They don't always agree with one another. Thank you. So I have a question that I think from the audience that I think both of you could probably address. What are the spatial scale and temporal lead times which recharge technologies are considered successful water management operations? So either of you want to take that? I'll start. Actually, the person you want to talk to is Sharon McDowell tomorrow since you have her on the line there. She can help you a lot also with your governance questions for sure. Some of it depends on the time scale of the use. So in Florida, you may be injecting water underground for use the next season. And so your time scale is that particular season. If you're in Charleston, South Carolina, you may actually be putting it underground because you've had an earthquake and floods there and you want to have an emergency source of water. So it's going to be there for a very long time. The Arizona situation is interesting because they have been, as shown by Bridges' work, they've been recharging a lot of water. And now, as you well know, it looks like they're going to need it. But the question is, where's that water now and how do you extract it? Maybe just add a little bit. I mean, Arvin Edison, one of the basins that has been doing it since the 1960s, they tried to store enough water for the multi-year droughts that they have. So they're putting it in continually when it's a wet period. And then all of the wells are pumping during the drought, 24, 7, 365. So until they can't, I guess. Neil, yeah. I think you had a question. I'm going to ask for a quick time. I'm having a hard time using the mic and looking at the speaker both at the same time. But I can hear you. So I think in the Southwestern US, one of the implications of climate change over the next 50 years is that we will expect more extreme precipitation events. And I think in, for example, in New Mexico, we know roughly what part of the state is likely to get more extreme precipitation, but we don't know exactly obviously where that's going to happen. Do you have any comments about how, how methods for capturing water associated with extreme precipitation events in an ASR context? So I know tomorrow you have Helen Dahlke on the schedule. And I'm sure she's going to talk about a very large effort in California called Floodmar. That's trying to, and actually learning how to operate reservoirs better to make, take maximum advantage of them for recharging the water while you have it. You know, in New Mexico, you know, you've got major water issues, especially data El Paso. And El Paso, by the way, is the first city in the United States to have actually used wells for injection of pot while we're used back in 1885. And they have, they're continuing to expand their program. They're one city that's actually going to be the largest city in the US that has a sizable direct pot over use program, probably within the next 10 years. So it's a big deal. Okay, thank you. We are right on time. There are some additional questions and I'm gonna encourage people to bring those up in the Q&A discussion in a little while. So thank you to both of our speakers. And now I'm going to, you're gonna hear from a series of case studies, presentations moderated by John Arthur, the ex-director for the American Geosciences, executive director for the American Geosciences Institute. You didn't know that. And the previous, getting punchy already, previous state geologist of Florida and director of the Florida Geological Survey. And he's a member of the Water Science and Technology Board, John. Thank you. And thanks for reinstating me so quickly. So in this next session, Managed Act for Recharge Case Studies, there are abundant applications as we just heard for MAR. And today we're going to hear from six geoscientists and engineers with experience in these various systems from across the country. Through their unique lens, we will hear case studies, successes, caveats, lessons learned, and not only in relation to system design, but also operation management as well as scientific and engineering considerations that are shaped by local hydrogeology and regulatory requirements. And with that, we'll start with our first of our 15-minute presentations with Dr. Charles Bott, who is the director of Water Technology and Research at Hampton Road Sanitation District. He manages technology innovation and research and development at the district's 16 wastewater treatment plants. And he is also adjunct professor at the Department of... Departments of Civil Engineering and Environmental Engineering at Virginia Tech and Old Dominion University. So Charles, please tell us about Virginia and the Eastern Shore. Okay, thank you. Can you hear me okay? Yes. Good. Well, I think that the slate of speakers for these case studies is an alphabetical order. I feel a little nervous about speaking ahead of Orange County Water District and the groundwater replenishment system, which is of course very well-known and many, many years, light years ahead of what we're doing at HRSD. So anyway, this is our SWP research-centered demonstration facility for indirect quotable reuse and managed aquifer recharge. And I'm gonna tell you a little more about our study here, our work here. This has been going on now for about five years. We're into the SWP program, but first a bit about HRSD. We serve about 1.8 million people in Southeast Virginia and operate about eight medium to large plants and eight or so smaller plants with a combined capacity of 225 MGD. The status of water in Hampton Roads is that approximately 20% is supplied by groundwater. About 80% of the population is supplied by surface water as we move west in our service area, there's much more reliant on groundwater than surface water and more reliant on surface water in the East. We treat wastewater to now really high standards because we discharge mostly into the Chesapeake Bay watershed. So we've been upgrading treatment plants over the last 20 years for much more substantial nitrogen and phosphorus removal. So as we contemplated our future, one of the considerations was we treat to really high standards and we effectively take this resource and we discharged into saltwater and sort of throw that resource away and it was bothering us. And five or six years ago, we really started to think about this and over the course of a few years of study and piloting and careful work, we developed the SWP program which involves adding advanced treatment and managed aquifer recharge. And there are a number of benefits for that. First of all, the Hampton Roads area is second only to New Orleans in terms of population and infrastructure at risk of sea level rise and about half of our observed sea level rise is due to land subsidence. So perhaps managed aquifer recharge has the opportunity to reduce the rate of land subsidence. Perhaps provides us some regulatory stability by taking our water quality sort of to an end point in terms of drinking water quality. It further reduces our nutrient loads into the Chesapeake Bay. It protects the area and the Potomac aquifer from saltwater intrusion and provides a sustainable supply of groundwater. So the Potomac aquifer is under pressure of extraction and has been for many years. On the left shows critical surface violations of the Potomac aquifer over a 50 year simulation. The green dots are our treatment plants and this shows a look after 50 years of recharge of these plants of substantial rebound in pressure. So in this case, I'll just make clear that the travel times in the aquifer are thought to be quite long from these treatment plants. You know, it's more than a hundred years for a mile of transport through the aquifer. So Swift is really about repressurizing the aquifer and ensuring that the pressures in the aquifer remain sustainable along with the other drivers I just talked about. So the Swift goal, for first of all, on the left is our larger treatment plants treating about 150 million gallons per day. The Swift goal is a hundred million gallons per day by 2032, several large capital projects I'll talk about at the end of the presentation. This star Chesapeake Elizabeth treatment plant has already been shut down, shifting flow to Atlantic treatment plant. The Atlantic treatment plant is our one ocean discharge plant. It's too far east in the Potomac aquifer to really be useful and it will never be a Swift plant by our current planting. In fact, also not a nutrient removal plant which is a big leap in order to get to Swift for our facilities. So we started as I mentioned about five years ago with some pilot testing. We've scaled up now to our demonstration facility, our research center and we're now starting the build out. When we started this, we took some time to consider the advanced treatment approaches and broadly and I think probably there will be more discussion on this. There are two general approaches and the way I like to describe it is the top approach is basically a tricked out drinking water plant that might be treating water from a relatively contaminated surface water supply. And the bottom approach is what has been typically used in California involving ultra filtration reverse osmosis and UV advanced oxidation. So we set out about some pilot testing to determine which of these approaches made sense for us and we worked for quite a while and summarizing a lot of work in one slide to convince ourselves that ozone bio filtration GAC was equally protective in terms of emerging contaminants and pathogens and we could routinely and easily meet primary maximum contaminant levels. But of course there's no TDS removal. It turns out that the status of the atomic aquifer in the region where we're injecting is already quite salty and so to be sustainable in terms of injection and being compatible with the geochemistry of the aquifer we really need this TDS for sustainable recharge into the aquifer. Recharging water that is in the 50 to 100 milligram per liter TDS range is just not sustainable in this aquifer at these locations. And that pilot work was done by a combination of HSD staff and quite a few universities. I'm not naming all of them but the major work by Virginia Tech, who are you and University of Michigan. The other thing that's going on in parallel and I'm not gonna spend much time talking about today is gaining really public and regulatory support in the region for SWIFT and within the state and EPA in Virginia. Virginia did not take delegated authority of underground injection control. So our permitting authority is really EPA region three through the underground injection control program. Three years ago, we started up our SWIFT demonstration facility that we call our SWIFT research center. This is a 1MGD advanced treatment facility. We also have recharge wells and monitoring wells which I'll talk about but it's also a public outreach location and public education facility. Even at the 1MGD scale, we're capable of making changes and modifying things in order to test new approaches. And we located this at a wastewater plant that's already a quite sophisticated wastewater plant consistent with the best nutrient removal plants in the Chesapeake Bay watershed. So a five stage bartender plant already doing really good nitrogen and phosphorus removal. The SWIFT research center process flow diagram is that ozone bioculturation approach. So coagulation with aluminum chlorohydrate, polymer addition, flocculation, sedimentation, ozonation, and then bio filtration. And the purpose of ozonation here is both emerging contaminant, oxidation pathogen disinfection as well as oxidation of bulk organic carbon to make that organic carbon more biodegradable in the bio filter. The bio filters operated like a drinking water filter with very stringent turbidity requirements. And then GAC, granular activated carbon adsorption for polishing of emerging contaminants like PFAS, for example, that aren't well removed upstream. UV disinfection, chlorine addition, and pH adjustment prior to recharge. So at the SWIFT research center, we have a couple of interesting features. One is a recharge well in a very closely located well to look at a store locker of treatment, monitoring wells, which I'll talk about in a second. We partnered with USGS to install an extensometer to really measure land subsidence and contraction, I'm sorry, land subsidence and rebound as a result of just this one million gallon per day well. We partnered with Virginia Tech to put in a network of seismophones to look at seismic activity as a result of recharge over the future years. And so in cross section, this demonstration facility includes a recharge well located 50 feet away and three days travel time and screamed in exactly the same locations is a monitoring well with a flute sampling system that allows us to take discrete samples from the system. We see already a lot of soil aquifer treatment with three days of travel time and some interesting trends as a result of both organic and inorganic contaminant transformation and removal through the aquifer. And then some months away is wells, a nest of wells located in the upper middle and lower Potomac. The upper Potomac, the swift water has reached the upper Potomac aquifer. It has also reached the middle Potomac but not has it seemingly passed by completely but it has not reached the lower Potomac. So there is some very significant differences in preferential flow through the aquifer with the more transmissible zones sort of transporting more water. From a regulatory standpoint, this is what the Swift Research Center is required to do and also our first full scale facility meeting all primary MCLs. It turns out that's pretty easy. We do that at the secondary effluent of the wastewater plant. Total nitrogen five monthly eight max day not challenging for our wastewater plants but a critical control point effluent TIN, secondary effluent TIN less than five based on ammonia and NOx measurements that are online. So online measurement of TIN, that's really challenging because it's effectively a 15 minute level of performance. Terminity requirements consistent with drinking water, TOC of four maximum month, six maximum or any sample. Total caliform and E. coli requirements consistent with the groundwater standards in Virginia but treatment goals of 12, 10, 10 consistent with the California requirements. No requirement for TDS so that we remain compatible with the aquifer and unregulated constituents are being handled very similar to other potable reuse applications with two lists, one short list of contaminants that tell us something about the performance of the advanced treatment facilities or advanced treatment processes and another list that are the compounds of concern and potable reuse. Things that we know are concerning in these types of treatment systems like PFAS and one portoxane and NDMA and so on. So I mentioned the nitrogen removal required. This is something that HRSD we're quite proud of and maybe in the end is more substantial and meaningful than Swift. We are really excited that we've been able to deploy mainstream anamox through the partial denitrification pathway. We're doing this at our York River treatment plant. We're in construction right now at our James River treatment plant and the benefits are just tremendous in terms of making nitrogen removal stable and reliable and doing it in smaller and smaller and more intensified wastewater treatment plants. And this is really a requirement if we don't pursue reverse osmosis-based potable reuse. So a little bit about some advanced treatment topics that we've been working on. So our current ozonation process uses preform monochloramine to control bromate formation and high bromide secondary effluent. And that works quite well. We rely on ozone as I mentioned for both disinfection and oxidation and ozone and wastewater really acts like an advanced oxidant because it very quickly decomposes into hydroxyl radical. The way preform chloramine works is by partly shielding. It works in several ways, but one of the mechanisms is by partly shielding and serving as a sink for hydroxyl radicals. And so while preform chloramine does a nice job of minimizing bromate formation, it also hurts us to some degree from the standpoint of oxidizing emerging contaminants. Hey, Charles, we've got about a minute. Another possibility is hydrogen peroxide. Hydrogen peroxide enhances the removal of emerging contaminants, but it hurts us because we don't get CT credit for disinfection while we know we actually do get disinfection with peroxide. I'll just say quickly that from a biofiltration standpoint, we've learned a lot. We're doing some work on adding propane to the biofilters to enhance one portoxane removal. We've learned a lot about how these biofilters remove effectively in DMA, bully nitrify a little bit of ammonia. This is a picture of those modifications to the full-scale filters. From a GAC standpoint, one of the questions that we get all the time is PFAS, and we've done a lot of work to look at both high molecular weight and low molecular weight PFAS. Getting ourselves really comfortable that four milligram per liter TOC is really protective of low molecular weight PFAS compared with the most stringent regulations from around the world. And of course, we'd like to minimize GAC utilization. GAC is a big cost for the SWIFT program and really maximizing biological removal of TOC in the GAC contactors is a real benefit, particularly in the summertime. So the build out looks like this. So the SWIFT facilities are shown here. The James River plant is our first full-scale SWIFT facility. It will be, we're in design for this facility right now or at the 60% design for this facility. It says a project is between $400 and $500 million capital project. So a huge project for us. And the James River project is proceeding ahead with the EPA Region 3, hopefully very soon, hopefully within the next week or two, issuing our full-scale UIC permit for public review, the draft permit for public review. And that's it. Thank you, Charles, for an excellent talk and sounds like you've got a lot of balls to juggle there. Thank you. And we'll move on to our next speaker, Adam Hutchinson. And so we'll flip over to the West Coast. Adam Hutchinson is the recharge planning manager for the Orange County Water District in Southern California. He's responsible for testing and evaluating new methods to increase the capacity of existing recharge system and planning for future expansion of that recharge system and assisting recharge operations in developing optimization strategies. Adam. Yes, hello, everybody. Great to be with you. Can we go ahead and click the slide presentation up? So we're gonna talk about Orange County Water District and our managed recovery recharge system and what we can learn from that next. So just to get everybody oriented in terms of where we are, we are in Southern California, not Orange County, Florida, but Orange County, California. We are in the Santa Ana River watershed which is covered over 2,500 square mile. Fortunately, we're at the bottom of the watershed which has some good characteristics in terms of stormwater capture and receiving water from the Santa Ana River. Next slide. So why was the Orange County Water District formed? Well, back in the early 1900s, there was an explosion of agriculture in the area, hence the name Orange County. A lot of Orange growing and other crops being grown and other results, not surprising them. We had a lot of groundwater overdraft. We had sea water intrusion. So the local in Orange County at the time went to the state and said we need to create an agency to manage the groundwater supply as well as protect the rights to the Santa Ana River which were being diverted upstream of Orange County. So the Orange County Water District now provides water to 19 different cities and special water districts and there's two and a half million people that rely on the groundwater supply in North and Central Orange County. Next slide, please. So in Orange County, where did we get our water? So 75% of the water supplies of those 19 different agencies is met with groundwater and the cost of groundwater is $500 an acre foot and we charge that fee for every acre foot of water pumped out of the basin. And the alternative, the supplemental source of water is imported water and the cost of that water is more than double, so we're $1,000 an acre foot. And that water comes from the Metropolitan Water District of Southern California which gets imported water from Northern California and the Colorado River. So we have a strong financial incentive to obviously maximize the amount of groundwater available. Not only benefit the region, but it benefits our producers directly from an economic standpoint. So next slide. So we have 200 wells that pump water out of the basin and all these wells have been metered since the 1950s. So we have a very good handle on our groundwater budget, what's being pumped, what's being recharged. And so that's a very important element in terms of allowing us to manage the basin properly. Next slide. So this is the cross section of the groundwater basin at the typical Bolivial system, sedimentary basin of three different aquifer systems like a layer cake, a shallow principle and deep aquifer. The aquifers merge as you go inland toward the canyon area. And that's where our surface water recharge facility is located, where the water can easily percolate down through into these three different aquifers. If you try and do surface recharge as you move to the southwest, it won't work because of the subdividing layers or clay layers that start to create these three aquifer systems. Next slide. So you can drop in. So the basin itself contains the massive amount of water, 66 million aquifers of water, but obviously you can't withdraw all that water without causing a lot of problems. So our operating storage range, that we actually try and keep the basin within is only 500,000 acre feet, which is still a substantial amount of water, but everyone only represents, you know, less than 1% of the total storage in the basin. And so that's the operating range and we stay within it and it works really well for us. So next slide please. So why do we do Manitoc for recharge? Well, going back to the 1930s when we were formed, the district really had a supply side approach. Really, let's see what we can do and maximize what we have available to us. So in the early stages, it was really about the caps and recharge of river water, the base flow as well as storm flow that were coming down to us. And then later as the imported water became available, we started recharging imported water and buying it. And then in the 70s, with seawater intrusion, we built a barrier to protect the basin from seawater intrusion and replenish the basin as well. And then more recently, recycling water is been a really key element of our water supply. The other reason to do Manitoc for recharge is to store water in the basin to get through drought periods and take that water during the wet periods and bank it and get prepared for droughts. That's currently what we're in right now in a dry period and so basin storage is gonna go down, but that's what that storage is for. And as I said earlier, it makes financial sense. Imported water is very expensive alternatives. We have a very strong economic signal to maximize our recharge program as much as possible. Next slide. So the mention since we've been formed, we've been developing our Manitoc for recharge program. This map here shows the surface water basins that we have. We have 1,500 acres of land purchased starting in 1936 all the way to the present. Our little back toy on the right there is our first purchase of land in 1936 with $27 an acre. Our last purchase in 2013 was $1.6 million an acre. So tremendous increase in land values in the area. We were to try and build the system today. We could not afford to do it. So unfortunately we started a long time ago and really lucky to have all that property under our belt. One thing I wanna highlight too in this map is if you look on the upper right, you see Prado Dam. That is the Army Corps of Engineers facility built in 1941. And we actually have a program with them to temporarily store stormwater behind that dam and let that stormwater out slowly so we can recapture that water, not leave it to the ocean. So next slide. So what I'm gonna show you here are a couple of a picture and a figure. So number one and see that the arrow, that's gonna be a photograph looking to the northeast at the Santa Ana River from the aerial view. And then number two is the figure I'm gonna show you the annual U-Chart done in 2021, schematically a three-dimensional cartoon showing the amount of water that all these different facilities you see on the map were able to recharge in one calendar year. Next slide. So here is a aerial photograph of the Santa Ana River channel on the right. On the left you call the offer of the system. So you're looking to the north towards the canyon, towards Prado Dam. So this is a very urbanized area and the river is really one of our best recharge facilities because it was very long and wide and it doesn't clog like the recharge basins do. So it's really the backbone of our recharge system. The next slide here, I'll show you the actual recharge that was conducted in 2021. So you can see the river showed up with a long skinny line there, but it did the most recharge of any facility in that particular year. And then the recharge basins show up at the different columns popping up there. And in the foreground, the tallest one you see popping up there is our La Palma recharge basin that's only recharging recycled water. So it's a relatively small footprint, but the water is so clean and so pure that our recharge rates are far and exceed any other facility we have in our system. So really glad to have that source of water for us. So next slide. So we do a lot of research and development to maximize the amount of recharge we can get. Clogging of our recharge basins is a key constraint. That's true of any man and doctor recharge system that they all clog, just a matter of how quickly. For our recharge basin, the clogging layer is really the heavy equipment. The technology there hasn't changed too much, but we are doing research to try and optimize that process. We did a lot of research in what we call basin cleaning vehicles, almost like a glorified pool cleaner that would go on the bottom of the basin and sweep up that clogging layer, which is just a really fine silty clay type sediment that builds up in the bottom. That process did work. However, the ability to do it on a scale that made economic sense for us did not work. We did a massive sediment removal testing project. We looked at all the different treatment technologies to remove suspended sediment from the river water. We found that adding any chemicals did not work. That would actually cause clogging on the back end, even if the turbidity levels were low. One of the systems that came out of this testing process was what we call riverbed filtration, where we used the riverbed to filter out the suspended sediment. So like what Bill talked about earlier with riverbank filtration, this is riverbed filtration where we're actually building a collection gallery of pipes about three feet under the riverbed, collecting that filtered water and conveying it to a recharge basin and let the sediment remain in the river where it gets washed downstream. So that's something we're seeing very good success with and we may expand that through a full scale here in the future. Next slide, please. Sorry, that meant to me build a seawater duty barrier in the 1970s to protect the basin from seawater. We built over 30 injection wells. And what's really good about this is that not only protect the basin from seawater intrusion, but 95% of that water flows into the basin itself and become part of the water supply. So it's a really multi-identical type of problem. Looks like it. So over the years, we've developed a really diverse water portfolio using different sources of water that we can charge into the basin and the percentages on average. And some of these are more affected by weather, such as stormwater, for example, that's going to be highly variable depending on local weather condition. Imported water is less affected by local weather, but can be affected by regional weather conditions such as we have today. It's extreme drought condition to be full of water supplies and much lower. The Shannon and a river base flow and recycled water are very reliable sources of water. They're very resilient. They're not as affected by climate change and other impact. So we're really fortunate to have a diverse portfolio that can get it through drought periods to sustain our groundwater basin. So the next slide, please. So I'm sure many of you've heard about our groundwater replenishment system project that went online in 2008. This is a typical California approach from microfiltration reverse osmosis advanced oxidation process. 70 MGD plant was put online in 2008. We are currently underway in building the final expansion where we'll go up to 130 MGD next year. That will basically be the final because there's no more recyclable water to be had in our area. So we'll basically be recycling everything possible and all that water will either go into the area or up to our Anaheim spreading ground. Next slide. Adam, can we have about a minute? Thank you. Yeah, I'm almost done. So effort to create new supplies. We're looking at increasing the amount of strong water with the capture by importer dam using forecast informed reservoir operation. We're operating the dam using forecast information rather than the old approach of water on the ground. Metropolitan looking at their own recycle water projects and we might participate in that. And then finally, PFAS treatment at the final bullet there. I wanted to quickly cover that next slide. Just a little out of order here. So we talked about the diverse portfolio also diverse water quality sources. So base flow of the river 700 TBS all the way down to GWS water with under a hundred millimeter liter TBS. But what's really interesting about our groundwater basin is because we have so much recycled water that's a pure quality. We are actually reversing the salinity balance in our basin. We're going to actually be freshening the basin over time rather than more salinity level going up. So we'll be putting a paper together and publishing that result probably in a year or so. Next slide. So I'm going to wrap up with the PFAS. We've had a lot of PFAS impact through our basin. 60 of our 200 well, we'll take it offline. This is in the treated wastewater that we're receiving from upstream. PFAS levels are in that water. And so it's caused us to have to do a math of well head treatment program. It's been cost over a billion dollars long-term. And so we are paying for this. We're going to go in and pay for the treatment system and then the utility to be on the hook for some of the O and M long-term. So final slide next. I want to wrap up with, you know, Manitaka Recharge is central to our leading to manage our groundwater basin. This program has more than doubled or tripled the yield of the groundwater basin. The natural yield is 100,000 a feet per year. The OSCEWD won't do anything. But the current yield is over 350,000 a feet per year. We'll continue to look for opportunities to increase supply with furrow, recycled water and just protecting groundwater quality is going to be a continual challenge for our project because PFAS wasn't on our radar several years ago and now it's a huge issue that we're having to address. And so as our technology detection approach will get better, we're going to continue to find more challenges in the future. So that's just keep us busy. That concludes my presentation. I'll forward the questions later on. Thank you. Thank you, Adam, very much. And we'll move on to Dr. June Marecki. And June comes to us with a story from Florida. She's senior hydrogeologist with the US Army Corps of Engineer and a licensed professional geologist in Florida. She's a hydrogeochemist and then some and serves as technical lead for the ASR projects or has served as technical lead for, you can correct me, June, the ASR pilot projects and the ASR regional study related to the comprehensive Everglades restoration projects to increase water storage in Southern Florida and June. All yours. Thank you very much, John. I apologize, I cannot get the camera to work on my federal laptop. So the wheel just keeps going round and round. So unfortunately you can't see me. Today I'd like to present a decided or a comparatively low-tech approach to managed aquifer recharge, specifically for ecosystem restoration. And then this project at the Pickie Uneshtrand Ecological Restoration Project is part of the comprehensive Everglades restoration plan. Next slide, please. Just one slide about the Comprehensive Everglades restoration plan or SERP. This suite of projects, 68 projects in total is designed or was compiled and integrated to replum Southern Florida, both from a surface water sheet flow and surface water groundwater interaction standpoint. The entire attempt is to allow a more natural but controlled for flood control purposes, movement and conveyance of surface and groundwater from the headwaters of the Kissimmee River Basin up north near Orlando, southward through the Kissimmee River Basin and Lake Okeechobee and then into the areas south of Lake Okeechobee including the Everglades National Park. The SERP is the acronym and it is a compilation of 68 projects of which the project I will discuss today is one of the first to come online. When all of these projects are implemented it will improve the volumes of water in storage. Some of the projects will provide nutrient reduction by water treatment. It will provide a more natural rate of water conveyance from north to south and will enable and continue water supply for ecosystem restoration purposes. Next slide, please. Now, the Picky Unstrain Restoration Project was one of the first ecosystem restoration projects to come online and SERP in the mid 2000s. The importance of the Picky Unstrain Restoration Project it's located in Western Collier County and toward the city of Naples. It is a keystone to ecosystem restoration in this area. As we'll see in a moment, it was proposed suburban development the figure on the upper right shows that dark green area called the Southern Golden Glades Estates. But notice that that proposed suburban development is surrounded by natural wilderness areas, state preserves, national preserves, national wildlife refuges. So this footprint is actually a keystone to ecosystem restoration of this entire area. In addition, it's the location of some of the big important endangered species in South Florida. And that includes the Florida panther, the endangered woodstorks, and there's even a feature for manatee restoration also in this area. The other important feature about the Picky Unstrain Restoration Project is that it is the largest wetlands restoration project in all of SERP. It's 55,000 acres of rehabilitated wetlands. The objectives for this project include, of course, wetland restoration and habitat improvement, improved hydro period of these wetlands more mimic the natural wet, dry season cycles. And finally, what we're all interested in is aquifer recharge. Next slide, please. Now the pre-project condition of the Southern Golden Glades or the Southern Golden Gate Estates. This was a proposed suburban development and one of the largest at the time suburban developments of all of the United States. And the developers proudly declared that this would be the giant machinery is creating a dream city of new out of virgin territory. And they were quite proud of that. Well, the proposed development was again the 55,000 acre area, 19, almost 20,000 planted parcels, roadways, drainage canals, culverts and bridges and weirs for water flow conveyance. And what this resulted in was over draining of this sensitive wetland area. And it's probably the basis of that statement. If you wanna buy some, I have some Swampland in Florida to sell you because one of the failures of this proposed development was the fact that during wet season flows, all of this area was under feet of water and the development was just, even with all the drainage activities they could not develop it further. Next slide, please. Okay, so how will we restore this area, prevent the over drainage of the wetlands, promote wetland restoration and managed aquifer recharge? The components of the Pick-Yoon Strain Restoration Project and again, these are low tech compared to the talks that you've just seen include the construction of three varying size pump stations and you can see those along the top, the Merritt pump station, the Focke Union pump station and the Miller pump station. Now these are not just pump stations to convey water down canals. They are positioned near the existing canals but these pump stations will work in conjunction with associated spreader features and canal plugs. And the three of these components, the pump station, spreader and canal plugs will slow the flow, allow for the development of sheet flow over the surface and allow for a more natural hydro period for these wetlands. In addition to those pump stations, spreader canal plug systems, the project also includes 227 miles of road removal and also some flood protection levees. These are actually small berms around private lands and agricultural lands to this out. There's also a manatee mitigation feature that allows controlled water levels so that manatees can access the area and the canals in the very southern part of the project area. So we have all these, the important thing here is the integration of pump stations, spreaders and canal plugs. Next slide please. And here we can see how these features work in conjunction. The first pump station to come online is the Merritt pump station. And that came online in 2015 and started conveying water in earnest in 2016. If we look at that figure on the left side, you can see from north to south, you can see the existing Merritt canal and on the southern lower part of that photograph, the Google Earth photograph. You can see where the canal plugs are starting to infill the former Merritt canal to the south. The pump station is situated within a berm at the dog leg of that Merritt canal. So water is brought into the pump station through the dog leg canal and the flow is controlled by conveying that pump station down gradient through a stilling well over spreading canal or spreader feature and then into a recharge basin. So if we go kind of counterclockwise in these three photographs, we have all of the features are shown here, the canal and pump station for intake and the spreader basin for discharge. That spreader basin has a levy around it to contain the basin, but also armored gaps that allow overflow once the tailwater pool depth is reached. So the second upper right photo shows the directions of water flow conveyance and that bottom photo shows what the recharge basin looks like as it operates. About a minute. Oh, already? Oh, I'm sorry. Okay, next slide please. Here are the canal plugs before and after we show the canal plugs in construction then in restoration to the left or to the right, I'm sorry. And also the waiting bird populations that develop. Next slide please. Now just for groundwater surface water interactions to discuss how water gets into the upper aquifer, we have a Holocene peat underlain by fractured limestone and underneath that is marine sands and silts ultimately underlain by karst of the Tamiami formation. Next slide please. Okay, this is the excavation of not the Marath pump station but the larger Faki Union pump station foundation and we can see the hydrogeologic setting is consists of undifferentiated quaternary marine sands and shells overlain by a Tamiami formation which here is rusty colored and it's because we're dewatering the pump station foundation and surface water with a lot of iron is coming through. What's important here is that you can see just rivulets coming out of that foundation and which causes issues with dewatering but it also indicates the transmissivity of this particular aquifer in this area. Next slide please. Now, restoration success takes a while to develop and basically we don't have a water budget with a water budget for recharge versus evapotranspiration in this rainfall-driven system. There are two monitoring wells down gradient from the Marath pump station. The hydrograph on the left or in the right from one of the closest monitoring wells shows a typical wet season, dry season sawtooth curve and one of the indications that we are getting recharge is that the dry season potentiometric surface of the Tamiami formation is increasing over time. You see those low values are show a higher and higher elevation. So it's a qualitative evaluation but it seems like we are starting to recharge the aquifer. Next slide please. And this slide shows the same tendency. This is a little farther away from the pump station. We see increased dry season water levels over time. Okay, final slide. The restoration status, nearly all of these features are in place. We just have to finish construction of the flood control levies around the agricultural and private lands on the western side of the Pikiun strand. Two of three pump stations are now operational. Early data from the Marath pump station and spreader system suggests that ground water levels are increasing during the dry season and the studies to evaluate restoration success are in progress. And that's my final slide showing before and after. Thank you. Thank you so much, June. What a wonderful restoration story related to MIR. Our next speaker is Dr. Peter Mock who is the principal scientist at Peter Mock Ground Water Consulting Inc. and a registered geologist who conducts studies in hydrology, geology and environmental science. He worked extensively on several remediation investigations related to superfund sites across the West and I'll turn it over to you, Peter. Good morning, can everyone hear me? Yes. Very good. So thank you for having me here to give you a presentation on the Hilo River Ending Community's Manchock for Rechart. So I start by saying I'm not a community member but I've been a consultant to the community for about 20 years. So if you could give me the next slide. The Hilo River Ending Community is in the middle of Arizona. You saw some of those pictures before of the blue outlined active management areas in Arizona or how the Department of Water Resources in the state manages groundwater at least in the more urbanized areas. So on the lower left, you can see there's the Phoenix AMA and the Penal AMA and the Hilo River Ending Community sits right on their border with quite a bit of a jagged line going through it which makes it interesting in a regulatory process. On the right, we see briefly that the cities of the Phoenix metropolitan area, Phoenix, Chandler, Gilbert, Queen Creek, et cetera are right up against the Hilo River Ending Community's boundaries on the north and then on the south of the growing communities of the Penal AMA, Maricopa, Casa Grande, Coolidge. But more importantly for now, I'd like to see the ODUSF that's the Old River BAM Underground Storage Facility which is the largest and first of the community's MAR projects. It's in the middle of the community roughly and the Sacotone is where the governance center is for the Hilo River community. And you can see it's right there in the middle. Next slide. So I give you a little bit bigger picture that here's the community, the black outline and the blue line going through the middle is the Hilo River. And of course the reservation was drawn to incorporate the people who lived along the Hilo River here in Central Arizona. Hilo River starts in the mountains in New Mexico, high altitude forests and then flows west through here where you see it. It joins the Salt River near the top of the picture. And then the fragments of the Santa Cruz River as it goes across the flats to the south of the Hilo River shown. And again, I'm showing where the Old River BAM Underground Storage Facility is. Next slide. So I give you a little bit of background and I'm not gonna do justice to this at all. There's an entire book called Stealing the Hilo by David DeYoung who was going to speak to you but was unavailable. He is the Director of the Pima Maricopa Irrigation Project. But briefly the Hilo River in the community is a combination of the Akama O'odham and the Pipash Peoples. Akama O'odham are better known as Pima and the Pipash Peoples are better known as Maricopas. But these are river peoples and they irrigated tens of thousands of acres with Hilo River divergence prior to the arrival of the Spanish. So they've been here a very long time and they had a very thriving agriculture economy. Since that time the Hilo River flows were diverted upstream and completely cut off and groundwater levels were pumped down on both sides of the community. So whereas the river was in tight connection with the groundwater system before, the water table is approximately 120 feet below land surface on the far east side and it's at land surface or it's in the stream bed at the far east. So there's a wedge of available opportunity for storage. Next slide. So the goals of the Mar program at Hilo River are to store water underground but to also partially restore Hilo River flows that can be seen at the surface and also to partially restore riparian corridor along the Hilo River to, this is so important to the river people but they understand they cannot completely restore the Hilo River flows or completely restore their riparian corridor. They're just looking for some sections of it to help restore their culture. Next slide. So we conducted a recharge feasibility assessment in 2010 when I was at CH Stone Hill, I worked on the Tucson recharge feasibility assessment as a young hydrologist and I brought that same approach to this. Many departments and people including elders participated in that process. We took our time and everyone and talked throughout the options. We identified the Hilo River bed as a primary location for recharge and I knew this was looking good because the US Geological Survey had looked at some floods during five months of 1983 and 1984 when a hurricane stalled out over the watershed and 250,000 acre feet recharged beneath the community during that time. And using that same process that the USGS did, I estimated over a million acre feet went in in 1993 through 1998 along with 83 floods. That's up 1.5 million acre feet infiltrated naturally. Again, we had some tremendous atmospheric rivers that came in in 1993. And so that was a great test. I couldn't ask for a bigger test for recharge facility. So I identified just over a dozen locations where water could be delivered to this to the Hilo River channel bed. These are called MAR sites. We numbered them and we talk about them in that vein like MAR 1B or MAR 5. And these MAR sites have been used and the recharge feasibility assessments have been used since to select each succeeding project. Next slide, please. So typical Greek MAR system is just to put the water into the natural lofo channels of the river, Hilo River. And these are called managed recharge projects in Arizona as opposed to constructed. The community has an intergovernmental agreement by which this recharge is permitted under the state of Arizona system. And that system considers as managed recharge where you don't do anything to the channel as opposed to putting in basins. Water is currently from the Colorado River. This is called Central Arizona Project for CAP water. They showed you a picture of the CAP coming through Central Arizona previously. The delivered water infiltrates into the modern Hilo River deposits, which are the youngest of five policy included units. We have extensive surficial geologic mapping through the area. And this one, these are 500 years or old or less. So this entire system is built by the Pima Maricopa Irrigation Project. It's operated by the Hilo River Indian Irrigation and Drainage District. And it's monitored by the Hilo River Indian Communities Department of Environmental Quality. Next slide. So just to give you a feel for the cross section, these are vertically exaggerated, but the Hilo River does its work by cutting and partially refilling. And where we are doing our recharge is where you see T0 there. It's the youngest unit in the latest incision and refilling. And these are not big clips. These are only about that inner cut that you see is only about two or three weeks to four feet high. But beneath it are the Pleistocene River sediments of the Hilo River. And beneath that is more typical sedimentary basin. Next slide, please. Here's the Oberdam Underground Storage Facility. It's about six miles long and the river flows from the lower right to the upper left. And the deliveries are to the point says delivery area. We have six monitoring wells to track water levels and to take water quality samples. There's a blow up here in the top corner expanded view of the delivery area where an agricultural canal is used to obtain the water. Two Rubicon slip meters are used. We'll talk about that in a little more detail to a delivery point. And you can see just to really quickly under the word delivery area that multiple channels are receiving the water just the natural low flow channels at the river. And then it extends for about three miles before sinking in all the way. Next slide, please. So two Rubicon slip meters, 50 CFS are used to both divert and measure quite precisely. It's an impressive piece of machinery. We have totalizers for each day for USF or underground storage facility reporting under permits and as well as instantaneous readings that the staff takes every day just for operations knows about what the flows are. They explicitly keep the flow within the USF. This is a permit condition. So we define arbitrarily defined that lower boundary and just keep the flows all within them. And we temporarily stop operations when there are flood events on the Healer River which have occurred a few times. We haven't had any large ones since we started recharging. And we started dividing the delivery to three directions as you saw before back in 2017. We found most infiltration happens close to the delivery point as you'd expect with such a system that can infiltrate water so well. And so we recently added a second delivery downstream underneath the permit and that's been operating for much of 2021. Next slide please. But it works. Long-term average infiltration rate is approximately one foot per day. Mounding is modest. It's 10 to 28 feet or so. The pre-recharge depth of water was 90 to 100 feet and in general in the area it's come up a few tens of feet. Maintenance consists of just flushing with much higher flows. So if they run at 20 or 30 CFS I'll blast it at 100 CFS for a day or two to scour the channels naturally. And what was interesting although we're comparing notes with other operators to similar systems found similar results. The total of the free surface water, surface evaporation and the riparian water use is approximately 2% of the delivered water long-term. Next slide please. So here's the outlet structure. There's some rip wraps there to control erosion. And then you see an area where the low flow channel causes a bit of extended pine and then off it goes. Next slide. Two-minute warning. You bet. Here's the total volumes that have been recharged from 2015 to recently and you see we've been running at about 20,000 acre feet per year and you see the proportions of the water that's stored actually recharged versus transpiration evaporation. Next slide. So monitoring happens both at the ground level for riparian growth. You can see the riparian growth that's now come in in certain areas. And on the right is one of many raptors and wonderful bird populations that are moved into the area. Next slide. The next slide please. Thank you. We started with vegetation surveys by biologists before and after deliveries. We track it with GPS and stakes. It's just been amazing renewal. Next slide. Now we've gone to using drones of the drainage district staff and fly the drones and we have an on-bed procedure for using that and we estimate riparian use with a fairly sophisticated process. Next step. And that's what the drone photos look like of the reestablishing riparian areas. Next slide please. On the left, you see what it looks like when the first dribbles of water came across and now you see what it looks like in some of these trees near the wedded area. Next slide. A really big part of this that's different from what you may have seen before is that this really has helped cultural restoration for these peoples. They, I can't go into the details of what it means to them to have the reestablished river in riparian natural riparian growth. And by the way, the riparian growth was not seeded. That can build those tri-channels when the water was added that just sprung up. Next slide. The water quality, just briefly. Let's just skip down to the bottom here. The total dissolved ions dropped from the native water about 13, 1400 down to about 800 milligrams per liter and sulfate drops from 300 to 200. There are similar drops in the other major ions and some minor ions. But we have noticed that we had some problems with turbidity and total coliform. They really weren't serving as indicators of the arrival of pollutants. These are biofilms that build up the stagnant wells. And this is a downside of Loaf Sanford. Although it's an industry standard, it does cause some problems for the water just sitting there. With that, I'm done. Thank you. Peter, thank you. We'll move on to our next speaker, Andrew O'Reilly with the USDA Agricultural Research Service where he is a research hydrologist. And he also works at the National Sedimentation Laboratory in Oxford, Mississippi. Andrew conducts research on groundwater sustainability and agro-ecosystems focusing on beta-zone and groundwater hydrology, green infrastructure and much more. Andrew. All right, thank you for that introduction, John. Appreciate that opportunity to speak with you all today. And I want to talk to you about a pilot project involves utilizing riverbank filtration, combine that with the ground or transfer an injection to, with the objective of obtaining a sustainable agro-ecosystem and the project areas in the Mississippi Delta. Like to recognize my collaborators, Daniel Wren, Martin Locke with USDA and June Borecki with the Corps of Engineers. Next slide. Also like to acknowledge a wide variety of partnerships in particular, the USDA ARS and the Army Corps of Engineers, Vicksburg District have been working closely to design, build, perform the research and operate and maintain the system. And without the two agencies working together, it wouldn't be happening. Also, there's a wide variety of other stakeholders at the local, state and federal level that have been instrumental in getting the project going and keeping it going. Next slide, please. I'll first start off with sort of the obvious question. And I think, well, we all kind of know the answer here, but you know, why we don't be concerned about sustainability managing an aquifer? And I kind of summarize it as sustainable groundwater as a prerequisite for sustainable development. As you may know, the United Nations has developed 17 sustainable development goals. And you see this little graphic here to the right that 14 of those 17 goals have a groundwater-related target. So in order to meet that goal, there's targets that have to be met that are related to groundwater. So groundwater can't be underestimated. And of course, managed aquifer recharge, which is one technology that can support this. Next slide, please. Taking a one-slang diversion to a little bit about history of the Mississippi Delta. If you've never been there, it's a very unique region. It's generally considered to be the birthplace of the blues and other American and mutual genres, but it also has a long history of racism, slavery, toward African-Americans and Native Americans, the murder of Emmett Till and his body was found in the Talhatch River. It was largely considered a seminal event in getting the civil rights movement rolling. So there have been a lot of difficulties in the Delta. The Delta is a major agricultural region, but many communities in the Delta still suffer from pervasive, a long-term economic depression. So ultimately, the objectives, the overarching objectives of this project or a follow-up expansion of the project will be to increase water security in order to provide a sustainable agro-ecosystem and sustainable economy in the region. This essentially nutshell the Mississippi Delta is a groundwater-irrigated agro-ecosystem under stress. There's been a seven-fold increase in the number of irrigation wells in Mississippi from the 1980s to today. And the little diagram of the state of Mississippi, you can see the vast majority of those are located in the northwestern portion of the state, which is the Delta. And estimates of over 3 million acres per feet of groundwater have been lost within the central part of the Delta, within a cone of depression from the mid-80s to late 2000s. And this has been a well-known problem. It's been going on for decades. A number of studies have been done and an aquifer injection storage has identified one more technology that might potentially reverse this trend of groundwater pollution. Next slide, please. This slide pretty much subs up the entire project in the nutshell. You can look at it as four components. First, we extract groundwater from an extraction well that's adjacent to the Tallahassee River. So this is a river-rate filtration scheme. So by pumping that well, we induce leakage of water from the river and improvement of the water quality in the process. We take that water, we pump it about two miles to the west and inject it into two injection wells. And fourth, one of the key attractions of the scheme is that of course the water is stored in the aquifer and then it can be withdrawn as needed using the existing irrigation infrastructure in the region. So the farmers don't need to develop the vast majority of the farm line is irrigated with groundwater already so they don't have to develop any new irrigation infrastructure with the schemes such as this. Next slide, please. The project objectives, it's a pilot project. So we're assessing feasibility. We want to identify sustainable injection rates in appropriate operation and maintenance requirements. The photograph here to the right is the aerial view of the injection well site as soybeans and corn were planted at the time. This is typical view of the Delta. You can see pretty much everywhere you see it is cultivated. And ultimately, we want to determine is this technology a viable path forward towards sustainability in the region? Next slide, please. A little overview of the layout of the system. On the right hand image, the extraction site, as I mentioned earlier, there's one well adjacent to the Italian River. You can see there's a bend to the Italian River and the pipeline shown in blue and then the two injection model located at the injection site. And the large yellow boxed regions are areas that have about six to eight monitor wells to monitor the impact of the system. And we'll look within the injection well, back flushes is part of the necessary operation and maintenance practices. So we just charge a backwash water to Lake Henry, which is just south of the injection wells. And you can go to the next slide. A little bit more about the system characteristics is about nearly $2 million construction cost. We can adjust the flow rate on the extraction well as needed. Each injection wells per minute for capacity is 750 gallons per minute. All the wells are 16-inch diameter. They're all essentially identical. The extraction well is a bit shallower than the injection well, but there's still all the range around 220 feet deep. And each of the two submersible, I'm sorry, each of the two injection wells have a submersible pump for backwashing at about 1,200 gallons per minute. All right, next slide, please. So we've conducted two operational tests so far. The first was an initial three month test from mid-April to mid-July last year. We injected a total of about 558 feet of water. The average injection rate was about 750 gallons per minute per well. And it ended with the unhappy, a major clogged event required a rehab operation. And I'll get a bit more into that in the following slide. We have started a second operational test that started in early February of this year. So far, we've injected about 365 acre feet. We've reduced the injection rate to around 570 GPM per well. And also we've increased the backpush frequency and both of these are to minimize well-clogging issues. Next slide, please. So some challenges. There's been many of them for the project, but just hitting some of the highlights. The groundwater in the region has naturally high iron concentrations. So that results in fouling of water quality sensors, fouling in the injection wells. I'll get to that in the next slide. Also, we discharged our backpush water to Lake Henry and the one milligram per liter is the typical iron limit for aquatic ecosystems. We're not able to meet that, certainly because the groundwater naturally actually already has iron concentrations of about 10 milligrams per liter on average. The clogging event resulted in a sand boas of leakage of the injected border at land surface. Something you definitely don't want to happen. And we've also had a sinkhole develop at the extraction well, the switch shown on the photographs, upper right-hand side. That's been filled with some wash river rock for the time. I relate to that sinkhole. I think it's related to it. We've had a drop in specific capacity at the extraction well. And so that's been a bit of a challenge as well. Next slide, please. Okay, so here's our unhappy clogging event. In mid-July, we got a phone call from a local farmer saying there's water flooding out around your wells. Is this what's supposed to happen? So we shut them off, we went out there the next day. And as you see on the right-hand photograph, there were several holes around each injection well where there was essentially sand, boils, muddy water coming out, injected water. In a nutshell, basically we exceeded the buoyant weight of the river, which in hindsight seems pretty apparent, but at the time it wasn't clear. The Corps of Engineers conducted an oxalic acid rehab treatment of the wells. You can see here on the lower left-hand is a video log that the Corps ran. So the left-hand one is quite a mid-bio mass iron reducing bacteria adhered inside the well screen. After the oxalic acid treatment, we had a significant improvement, as you can see by the right-hand photograph. And the specific capacity was returned about 90% of the value it was in May near the beginning of that first injection period. So we were really pleased that it all, we were just able to be rehabbed successfully. Next slide, please. Okay, so the last few slides, I want to just touch upon more of the positive aspects or some of the projects that we speak without, rather than the problems. We have an extensive monitoring network. The map to write, as I mentioned earlier, we've got monitor wells around the extraction well site and monitor wells around the injection well site, 17 in total. All the wells are monitored continuously at least this hourly for groundwater level. Six of those 17 wells are monitored twice a per month for field of water quality parameters, temperature and conductance, pH and dissolved oxygen. Now, while this isn't operating, we sampled all the wells monthly and those are analyzed by the Carve Engineers, Erdick Lab in Vicksburg, Mississippi. And in addition to sampling monitor wells, we also sampled the Townsend River in the injection well back flush water, as well as Ling Henry itself in order to assess the impact to the back flush water on the lake. Next slide, please. Okay, so here's some of the data from our groundwater monitoring. To sort of walk you through it, the upper graph are monitor wells near the extraction well site, lower our monitor wells near the injection well site. We started collecting data as early of January of 2020, so we have over a year of background data and we see some clear trends. There's not been much continuous water level monitoring in the alluvial aquifer region. But you clearly see rising water levels during the winter and early spring. These drops in water levels in the spring, summer, those are drawdowns due to irrigation pumping. Then you have some recovery after that. Our first injection period shown by the first blue shaded region was mid-April, so mid-July of last year. At the extraction well site, of course we had drawdowns of water levels near the extraction well. At the injection well though, we had a rise of the water level at the monitor wells as much as about six to seven feet. And of course the rise was less, the further distance you were from the injection wells. The section injection period is shown here as well. We've had similar responses then. They're just of lesser magnitude because we have a lower injection rate this time around. Many slides, Andy. Okay, thanks. So this will be a last slide of results. A little bit of comparison of groundwater quality before and toward the end of the first injection period. The graph shown to the right, these are the various analytes we're sampling for. But shown, and I'm showing the medium, max and min values for the groundwater observation wells. The black data is for March, which is prior to injection. And then the blue are the concentrations in June toward the end of that first injection period. So a few highlights I want to point out. The river water itself, of course, is toxic. The groundwater is suboxic. We have a deal of six or so milligrams per liter on average in the river in the extraction well, about 0.3 milligrams per liter. And in some of the observation wells, it's essentially zero dissolved oxygen. We have high iron concentrations shown by the red arrow. The median iron concentration is about 10 milligrams per liter. As high as 30 milligrams per liter. And all iron concentrations exceed one milligram clear. So that's certainly cause some headaches, as I mentioned earlier. We have low arsenic or at least arsenic concentration shown by the dark blue arrow that are below the US EPA drinking water limit. And there's been no significant change in those. And also, we have some geochemical, we have some concentrations that I think are reflective of biogeochemical activity. Some changes in organic carbon concentrations in nitrate and sulfate. And next slide. And just in conclusion, kind of where we headed with this, we want to complete the second injection period. It's been running for about three months. We want to hopefully run it up for a total of six months. We want to determine the best ONM practices so far at the lower injection rate and the back flush. We're now backfushing twice per week. That has been able to maintain a stable injection well operation. So there's been no indication of clogging whatsoever in the injection wells the second time around. Ultimately, this is a pilot project. So we'll be making some estimates on projections of an expanded version of this technology. The USGS and others are going to be involved in some modeling work with that. And next slide, please. And that's it. I appreciate the opportunity to speak at all today. Thank you very much, Andy. We'll now turn over to our full speaker for the. Sorry. That was me. It said unmute yourself. So I did. And that was a mistake. Oh, let's see. Well, Tim, you can help me pronounce your last name before we move along. It's Tom, your Tom, your thank you, Timothy, Tom, your Tim. Tim is the interim assistant city manager for the city of Tucson overseeing the public works functions of the city. And he has served on multiple, multiple committees related to reuse, drought contingency, water management, and so on. And since we're a little behind schedule, Tim, I'll just turn it over to you. OK, thank you very much. And thank you for inviting me out today. I'll tell a story about groundwater recharge in Tucson. And actually, the upper left part of the cover slide shows our iconic Sonoran desert with the Saguaro's. And in the background, you can see some of our recharge basins in the Abra Valley, which is a big part of our water story. We are located in South Central Arizona. So we are the second brightest light in Arizona behind the Phoenix Valley. We have about 730,000 customers through a main potable system, nine rural systems, and a reclaimed water system. We do provide local and regional service in a 400 square mile area. And we're in a semi-arid climate of the Sonoran desert where rainfall is less than 12 inches per year. And when it does come, it almost always comes all at once in our monsoon season. So we have adapted to our desert environment and managed aqua for recharge is a big part of that story. This is a slide that shows sort of the hydrogeology of the Tucson area. This is a cross section running generally west to east across the slide. And on the right hand part of the slide is where urban Tucson is in the Tucson Valley. It's a broad alluvial valley between mountain ranges on three sides, sand and gravel and clay deposits interfingered much like what you saw with Orange County. But a very productive aquifer over, we have productivity down below 1,000 feet and it could actually go much deeper than that. The Santa Cruz River flows through that valley from south to north, but flow is a relative term because it does not flow very often in modern times, although it used to be a perennial river pre-development. To the west of the Tucson mountains is what we call the Avra Valley, which is an area where it was historically used for farming, a lot of cotton grow out in that area. But in the 1960s to 70s Tucson bought a lot of those farmlands, retired them for production to preserve the water for the future. And that's actually both been preserving of groundwater, but also the location where much of our groundwater recharge and recovery efforts undergo. So since the 2000s, we've been doing significant recharge and recovery, although it began in the 80s for Tucson on the recycled water side. Our water supplies are diverse. We have our groundwater, which is our largest supply, but it's also our supply of last resort because we've overused it, we've abused it in the past. Our goal is reserve it and enhance it for the future. Our largest renewable supply is the Colorado River delivered through the Central Arizona project. And that water comes into our customers taps through our aquifer. We do recharge and recovery of that water. So we recharge it through constructed spreading victims. I'll talk more about that in a moment. And then we recover it through deep wells where it blends the native groundwater and the Colorado River water that's been recharged. And that's the product that we deliver to our customers. If you want to read about the attempt we made at direct delivery through a surface water treatment plant, there's a book out about how not to do that well. We also have generally pristine aquifers, relatively uncontaminated, but we do have a large superfund site associated with military operations in the area. So we do remediate some groundwater through an advanced oxidation plant. We do have recycled water. You often hear whether Tucson was first or Scottsdale was first, we disagree it was a tie. We've been doing recycled water since the early 1980s. We do some direct through a purple pipe system for non-potable use. And then we do use the aquifer for storage for the future. And then we've begun to further exploit local rain and stormwater. We don't get much of it, but what we do get is a significant amount that if captured could both reduce the demand for our other water supplies, but also be used as part of our climate resiliency strategies in the form of augmenting tree canopy in Tucson. So we have a lot of efforts into the rain and stormwater area. For Tucson, some of the biggest benefits for recharge and recovery, being our first recharge activities were with recycled water or municipal effluent. We found that at the time, the regional wastewater provider was providing kind of a secondary quality of treatment. This is in the 70s, 80s. And it had high suspended cell, high TOC. And we found that through doing soil aquifer treatment through recharge basins, through using spreading basins and short recharge cycles, one or three days of recharge before we let it dry out and repeat the cycle. We found that soil aquifer treatment was effective at removing pathogens, suspended solids and organics and actually made it so that when we recovered that recycled water, it could go directly into the reclaimed water system. We find that both for the, we also find those benefits on the Colorado Riverside. The aquifer treatment we do there, and you can see the picture sort of in the middle is some of our large basins in Avera Valley from a different angle. We see the TOC removal. We see other stabilization of the water as it infiltrates through the aquifer and the veto zone. And we find that we can recover that water and actually deliver it directly into our system as recovered water. We don't have to do any further treatment of that water, no additional filtration. All we do is disinfect and distribute. And that water quality, whether it's on the reclaimed water side or the potable side using our Colorado River water, it's very consistent coming from those wells. So unlike a surface water treatment plant that can have, when you're treating a river water, you can have upsets in both how the plant performs or failures of the plant when you have like an algal bloom or something come through the system, recharge buffers us from all of that. So we find that consistent water quality to be a major benefit. We use it for both short and long-term storage. So we recharge it all and recover some of it on an annual basis to meet our annual needs, but then we have a net gain in water in the aquifer year over year with both water supplies by recharging everything that we have a right to or the ability to acquire and then only using what we need on an annual basis. So we're net banking about a half a years of water supply every year at recent times. We do know that the Colorado River is undergoing multi-decade old drought, significant impacts from climate change and entered its first shortage in 2022. That is not yet affected Tucson because of our priority within the system, but we do know that we're banking water for a drier day. The use of Mac managed aquifer recharge also gives us resiliency against outages in our delivery canal versus a surface water treatment plant. If you're using a surface water treatment plant, you have to have water in the canal every day to extract, treat and deliver in order to have water for your customers. When you have the aquifer between that source water and that production, you can go months if not years of interruption on the delivery system and still meet the needs of your customers on a daily basis. And then we've also emerged into recognizing that recharge facilities can be multi-benefit facilities. The lower right is a picture from our sweetwater wetlands at our sweetwater recharge facilities. When we first got into recharge, we were fence everything off, make it square, make it boring. It's all about water into the ground. We've evolved into a more modern perspective on that where embracing the multiple benefits of recharge is where we are now and into the future. So this is a quick snapshot of all of our facilities. We have a lot of them. We've been at it for a long time. We use both recycled water and Colorado River water in our recharge facilities. In our case, everything is through either a constructed basin or the river itself. And as Peter Mock indicated earlier when he was telling the Arizona story, when you use a native river channel, you can because our native river channels are usually dry but can introduce water into those channels and through the permitting mechanisms get credit for the recharge that occurs. So we've actually been trailblazers on that and also expanded that to be multi-benefit facilities and moving that from more of the rural areas into the urban Tucson. So I'll highlight the Santa Cruz River Heritage Project in a moment. But that's where we brought this multi-benefit in river recharge concept right into downtown Tucson. And also let a charge to change state law in order to get full credit for that recharge that we were creating. Some of our facilities are crowded, they're large, some of them quite small, but through recharge all of our annual demands are met fully. And in fact, we, as I mentioned, we start about half a year of new supply every year for the future. And currently our current savings account in the aquifer on top of all of the ground that exists which is quite a bit and renewable or annual recharge of natural groundwater. We have 550,000 acre feet of renewable water stored which is about five and a half years of our supply. Another part of our story is we store for others. This isn't just for Tucson's put and take and storage. We store significant volumes of water here in Tucson for the city of Phoenix, for Southern Nevada Water Authority, for the Pasqualeaki tribe, Arizona Water Banking Authority, town of Oro Valley and many others where we actually are a savings account for several folks regionally because of our approach to it, our plentiful aquifers and our excess over time in managing aquifer recharge. So just a moment on the Santa Cruz River Heritage Project and how we've evolved, you saw that air photos, the rectangular basins in the middle of the desert with concertina wire around it. We now have evolved to making it a part of the community and embracing water, not just for what it means to us on paper or what it means to us for economic development or ability to meet customer demand, but what does it mean for the heart, soul and culture of Tucson? The Tucson began right in downtown at the base of what we call Aime Mountain and that area has been continuously cultivated for over 4,000 years with tribal communities, native communities and then the Spanish conquistadores and now Western European settlements. It's been continuously a story about water, but we had dried up that river since about the 1920s. The river no longer flowed only during large rain events did it flow. Well, we using our reclaimed water system and our management of recharge, we introduced an outfall to the river right upstream of downtown and you can see the ribbon picture is sort of a depiction of what our vision of what that area would look like in the future. And the lower left is a picture of how it looked. This was only after about two to three months of charge has been continuous for now going on three years, June will be three years. We have the benefits of flowing water in downtown Tucson. We've been storing native vegetation and riparian habitat in an important area for wildlife to move throughout the community. We've embraced and protected flood protection. We've seen economic stimulus from having this flowing stretch of the river. And of course we've seen the impacts of groundwater recharge. So I'll conclude with my Tucson's water story in one schematic, all within asterisk of our water resources flow through the aquifer. This is a stock and flow diagram of our water supply. And you can see the, in the light blue, the groundwater in the middle, that's our largest stock of water supply. And you can see that most arrows flow into it. Our Colorado river water coming through the central Arizona project, a bit is lost to evaporation either on its way to us or in the recharge basins or after the fact of my life's about to go out. But the majority of it, 98% or better of it goes into the groundwater and joins that stock for use for potable water and our customers. And that's where the vast majority of their water comes from. You can see that rainwater joins the groundwater through natural and mountain front recharge. Although we do have thumb that we're harvesting directly before it reaches the aquifer and using. And then we do have a small amount that flows out of the community. For the most part Tucson's a closed basin where what happens in Tucson stays in Tucson. But during very large rain events we will have a pulse of water that flows out toward the Gila River. And then on the right, you can see that after groundwater becomes potable water regardless of how it became groundwater. We introduce it, it becomes potable water. We have a wastewater return flow to our groundwater or to our users at the customer side. So while natural recharge can physically support a portion of Tucson supply our legal access to natural recharge is very limited. Whereas managed aquifer recharge is our primary water resource management tool in Tucson. With that I thank you for your time. And I think we're ready to move into a question and answer session. Thank you. Tim thank you very much. Fascinating story with and I truly appreciated a yet another example of geo heritage being woven into presentations as well. We have now we're moving into our Q&A which we will wrap up at two o'clock. Is that correct? Yes. So at this point the floor is open for questions for any of our speakers. Nusia. If you know I'm going to ask you a question. Thank you so much everyone. This was fantastic. I have three questions. One is for Charles. I'm wondering what happens to the brine after what you do and how does that impact your outflows to the Chesapeake Bay? And if you covered that and I missed it, I apologize. And then I guess the second question is for Tim. And I wonder how do you differentiate between natural and managed aquifer water? And is that through your accounting system or do you have a different way since you touched on the legal rights? And yeah, I actually go with those two and then if there's time I'll ask. This is Charles, I'll go first. So with the advanced treatment approach we've taken there is no brine return back to the wastewater plant or anywhere there, right? So the ozone biofiltration GAC approach produces some filter backwash waste that can go back to the wastewater plant. But since there's no reverse osmosis there is no brine which is a nice benefit. Is that why you chose that approach? I mean, that's one of the reasons. Like I said, the big reason is that the TDS and the aquifer is already quite high and there's the presence of swelling clays and we have local experience with recharge wells with low TDS water that failed immediately. So right now the impression is that we can't recharge into that aquifer with real low TDS water sustainably. So we need that salinity for the aquifer. Of course the treatment approach that I identified is also less expensive both on a capital and an operational basis. It recovers nearly 100% of the water that's applied because there is no brine return. But it's really important of course then to get comfortable with a non-membrane based advanced treatment approach. And that's an active topic of a lot of interest around the US and around the world right now. Thank you. Okay, we'll look over to Nelia Dunbar. Yeah, I have a question for Tim. Tim, you mentioned that as part of your more modern approach to ASR in the Tucson area, that this helped you lead a charge to change state law. And I'm curious to hear a little bit more about that process. Thank you for the question. So in Arizona, we use the term managed aquifer recharge a little bit differently than we are in this room. When you're using a natural stream bed without modification, we call that managed recharge and the institutional framework first created in the 1980s and carrying forward through some revisions only allowed you to gain 50% credit for that water you would recharge. So you can physically show your recharging 98 or 95% of that water after you account for evapotranspiration but you would only get credit for 50% of the recharge and the other 50% is what they call a cut to the aquifer. And so that was a disincentive from using a river to do recharge when you could take that same supply and construct a basin outside of the river basin off channel and you could get 95 or 100% credit. So we actually got that changed in 2019. It's one of those stories when we had, we finally achieved the drought contingency plan which is a Colorado river thing needed to be passed needed to have a broad coalition of stakeholders and long story short, in order to satisfy some of the concerns of agricultural users in Central Arizona, Tucson was willing to commit to doing some things over a short period to shore up water supply for Central Arizona agriculture if we got three or four changes to the code that they made since in 1980 but they didn't make sense in 2019. So we got through that drought contingency plan legislation we got the cut to the aquifer reduced for managed recharge what we call managed recharge river bed recharge. Thank you. Great. Okay, we have a question from Rabia and then we'll go to David Sedlock. Hi everybody. This is Rabia Chaudhry. I'm from the EPA and I just want to caveat non-regulatory part of EPA. So please don't get scared when I ask this question. So I have two questions, one for Charles and one for Tim. Charles, really curious, you know, Hampton Roads Swift project is really revolutionary in the way you've managed your specific challenges around, you know, outfall to the Chesapeake and this very strict TMDL requirements in that bay. I'm just wondering, have you had any conversations with other your peers, you know other wastewater treatment facilities up and down the Chesapeake and how they're managing their discharges and whether they're thinking about approaches like yours and using MAR, because they're probably dealing with very similar challenges that kind of drove you to do the approaches you've taken at Swift. Yeah, absolutely. So we've had been a lot of conversation with Anne Rundell County in Maryland that's interested in a very similar approach right now. It's actually a little different, but similar technologies, similar aquifer system not exactly the same. So yeah, I think there are some others interested on the East Coast and yeah, I can answer absolutely yeah. Thank you so much. And mostly I was asking this because we heard about a number of different drivers today for MAR, for water reuse. And this is a really interesting regulatory driver that is pushing water reuse and MAR in a direction that we hadn't expected. And the other question I have is for Tim, could you tell a little bit just for information what regulatory approaches are? You've mentioned credits in Arizona and we know there's, of course there's no water reuse regulations at the federal level and as far as kind of in our understanding there's nothing really at the, like in law necessarily at the Arizona state level. So could you help us understand a little bit about what levers and permitting systems you're using that kind of interface with your project? Thank you. Thank you for the question. So water is regulated in Arizona through two main agencies, the Arizona Department of Water Resources which really focuses more on quantity and the Arizona Department of Environmental Quality which focuses on quality and the environment. And there are, there is water code. There are things in Arizona's administrative code but much of it, and some things that becomes very difficult to change because now you have to have a legislative act change it but much of it flows through the regulatory programs. So for any of our recharge projects there's a number of permits we have. If it's a recycled water side of the equation we have to have what we call an aquifer protection permit which is more focused on the water quality side of protecting the groundwater. And then we have a facility permit which has all the regulations about how you operate the facility then we have storage permits and recovery permits. But all of that is kind of interwoven underneath the 1980 Groundwater Management Act which really was the seminal point where Arizona broadly moved from unsustainable to sustainable groundwater use. It's still on our pathway to coming out of that. Well, we had significant water level declines. Action needed to happen in order to change that trajectory. So born out of the Groundwater Management Act we have assured water supply program where all new development in the urban areas has to show a hundred year assured water supply aquifer recharge is one mechanism by which we do that. But so it's really a close relationship with the state and their regulatory authority that leads to what Tucson does and others do with aquifer recharge. Hopefully that answered your question if there's anything specific, let me know. No, that was great. Thank you. And to David. Yeah, so thank you everyone for some great presentations this morning. I couldn't be there in person to engage with you. I'm kind of, I have a more general question to everyone except for people like Charles who are on the coast and discharged in the ocean. This groundwater centric view of managed aquifer recharge feels a little like a free lunch. That is these flows that you're putting into the ground would have otherwise been base flow in a downstream section and we charged another section of aquifer they might have been environmental flows with the hydrology needed to maintain habitat for certain kinds of species and they might have been someone else's water. So I'm kind of curious if there are examples from the presentations this morning about when the use of managed aquifer recharge is restricted because those flows are not going directly to the ocean and are needed somewhere downstream for either ecological purposes or for water supply. I'm happy to dive in a little bit. Good to see you, David. So in at least in Arizona, there's not in at least historic time not a connective river system that moves water from basin to basin. We do have sub flow or flow underground flow from water basin to groundwater basin but where managed aquifer recharge comes in it's almost always, if not always, a supply that you're either importing. So it's only there because you brought it there Colorado River water supplies. So it's not, you could argue downstream in the Colorado River, you're taking it out of that system and bringing it to Arizona but that's all part of that allocation scheme. On the wastewater side, we do have a complex ownership of that wastewater once it's been created and typically whoever treats the wastewater owns the wastewater in Tucson. It's complicated by some IGAs we have because actually we retain the ownership. But in our case, we have some flow for environmental flows in certain segments of the river where it's been historically flowing as an outflow of a wastewater treatment plant. So we've reestablished our appearing habitat and that change to state law was vital to remove that disincentive from us from taking it out of the river because otherwise your incentive was take it out of the river because I can use it or store it. But if I left it in the river, I lost it. Now we've changed that. So now you can preserve that. And the other is that effluent becomes an appropriable surface water if you lose control of it once it ends the river system. So we actually in our managed recharge facilities when there's downstream appropriators, we actually account for that in our crediting and our use of that stretch of the river. So very valid points in Arizona. We don't have a lot that actually flows all the way to a receiving water but we've had to navigate those very issues to make sure that people are made whole on their use prior uses of that water. David, this is Bridgette's scandal. And I'd like to add a little bit to that. I know California, Helen Darkie and some of our students evaluate how much third flows they could capture. We did similar work in Texas and greater than the 95th percentile and we could capture maybe in the state. And it didn't impact other water rights and then where there were detailed in-stream flows studies done, we would have to reduce the what we could capture by about 30% and allow pulses through and meet different requirements for environmental flows. But it still suggested that there was a lot of water but you can't take it. I mean, it was there for several days and storing it and then getting it into and out for takes time. So there are a lot of logistics that need to be managed to make it happen. But we did look at some of those aspects and I think possibly Helen did also with her students when she did that analysis. Yeah, I can add, we looked into diverting flood flows above the 90th percentile and looking into the outflows, into the San Joaquin Sacramento Delta and at every point when we had high magnitude flows, the Delta was in so-called excess condition, meaning it met all the biological opinion criteria. And the 90th percentile is a criteria that is often also used to ensure that whatever surface water rights we have in downstream regions or met floodwaters are the only source we've left in California. So most normal surface water is already allocated. Yeah, I wonder if this issue is getting, it's certainly getting attention in California, but in the South Plack River, for example, or the Mississippi River, it seems like if it's not something historically people have been thinking about quite as much and it would be nice for us to discuss or at least have an opinion about it. Yeah, I'll make a couple of comments about Mississippi. I think that's, of course, we're still just in the pilot phase, but any larger implementation of this, I think that's, you have to have some concern about impacting flows of the river. I mean, the current pilot project at 1500 gallons per minute, that's about half a percent of the daily minimum flow, daily minimum made flow in the river. But we might not need two injection wells, we might need 50 or 100 for a bigger scale implementation. Another thing that's sort of interesting is the greatest drawdowns are in the central part of the Delta, Mississippi, and the talented river is kind of on the east side of that. So it's not really located in the area of greatest drawdown, but rivers that do flow through that area of greatest drawdown have had major impacts on low flow. So if the idea of transferring that water and injecting it in the areas of greatest depletion would help mitigate that to some degree by raising the water levels and it might actually improve low flows in those rivers. All right, great response. Andy, while we've got your attention, I noticed I was quite impressed by the number of monitor wells you have in your pilot. Could you tell us a bit more about that? Yeah, there's, well, first of all, if I'm a relative newcomer to the project, I wasn't involved with the design and built you in the system, but it certainly has been helpful to have a large number of monitor wells. Of course, it has challenges of maintaining that data. But I'm not that thinking it was. Number one, part of the reason for the large number is there really isn't a lot of ground and monitoring done in the Delta, Mississippi. It has been for decades, a twice a year potential metric map done in the Delta. That's just been a fall and spring. As far as monitoring continuous water levels, there's very, very few of those of that data. In fact, we probably have most of it now and just for this project. All right, thanks. I'm scanning the screen for other hands up. Did you, Nush? Okay. Oh, Bill Alley is next and then Bridget. Speak, okay, thank you. Back to David Sidlach's question. So the example I gave in Aurora, well, first of all, the map I showed for probable reuse, you probably noticed that all those, most of the sites were on the coast, so particularly in the West. The one in Aurora is interesting in the sense that Aurora, like many communities along the front range, actually gets some of its water from the Colorado River Basin and from the Arkansas River Basin. And so that's transported over to the South Platte River Basin. And so they actually can use that water to extinction because it's lost its connection to those particular basins, but the water in the South Platte is already over allocated. And so they have to let that water, they're not treating that water. They're treating not molecule or molecule, but they're tracking very carefully the water that they get from inner basin transfer and that's what they're using for probable reuse. And Bridget, did you have a question? Yeah, I was just wondering if any of the people developing these projects has looked at the energy implications of different management scenarios and if they quantify greenhouse gas emissions or other things that was, if anybody has tracked that or evaluated it or... Yeah, I mentioned something Orange County done. So they mentioned imported water is a big part of our supply, 25%. But that requires a lot of energy to move that water to Southern California. So we've done calculations to show that our stormwater capture efforts locally present a huge savings in energy and greenhouse gas emissions. So another driver, in addition to water supply resiliency, just another benefit of trying to maximize local capture of stormwater from an energy standpoint. Thanks, that's very interesting. Just before I ask my question, one comment on your question, Bridget, sorry. Is that these are not wholesome answers just because even though maybe Orange County is not getting that water from metropolitan, that uses a lot of energy, that water does get transferred to Southern California and sold to others. So as a whole, we are not really gaining, but Orange County is obviously as a service area is trying to reduce its greenhouse gas emissions. One question I have, which is sort of the follow-up to what David said, like asked is, the regulatory requirement for the utilities or wastewater utilities that are on the coast is very specific. So when you start reusing and recycling water, then you have less water that needs to be put back to the environment, but also the quality of that is lower. So I wonder how does that, those regulatory requirements impacting some of you that are in the coastal region. So basically trying to meet the EPA requirements on your outflows. Well, I can answer that question very definitely. We've done a lot of work in this regard. So to give some perspective, we have right now seven or actually six treatment plants bubbled together with a mass load allocation for total nitrogen phosphorus. And we can choose how we divvy that up, but that mass load allocation is headed steady down and has been for a long time. And but we have flexibility to treat nitrogen and phosphorus, for example, at plants where it's least expensive to treat it and we take advantage of that. Soon we won't be able to take advantage of that basically because the limit will be so low. But what we have done is that that allocation is will eventually in the future be based on our treated flow. So the flow that comes in the front door of the wastewater plant will be the basis of the allocation. So we can take advantage of the recharge that goes in the ground. So one limit will be based on the flow that comes into the plant and we can benefit then from managed aquifer recharge. But we still have concentration based limits to deal with. So annual average concentration based limits still exist and afford nitrogen and phosphorus that is. And we still have, of course, beauty and TSS limits and ammonia limits and pH requirements and disinfection requirements and bacterial requirements. So we have all the same permit requirements. And yes, this is something that exactly we've talked about that if most of our discharge is during periods of wet weather when the wastewater treatment plant isn't performing as well, that's a risk. And that's a concern that we have to manage really carefully. And yeah, and we have a lot of, I mean, a large portion of the capital upgrades for these plants is figuring out how to integrate well the wastewater plant and the advanced treatment facility to ensure we always have appropriate water quality at the outfall in addition to the much harder actually is the water quality at the recharge wells. So it's a great question. And it's one that practically, I would say we've spent probably more time dealing with those questions than we have around the design of this with advanced treatment facilities because we know what they need to be. We know what those facilities need to be. It's the integration between the two that's really challenging. Great question. Nelia, did you have another? No. Okay. Okay. Well, I have a question for those working with ecosystem restoration that have that aspect to their projects. What is the greatest success and also the greatest challenge you have in terms of water compatibility issues putting water back into the natural system? I can start when in our environment it's pretty a simple recipe. If you put water into the desert, things happen. And so when we did our Santa Cruz River Heritage Project there were some concerns about emerging contaminants or PFAS chemicals or things of that nature. Luckily or unluckily, some of the groundwater shallow groundwater under our major river courses has already been impacted by things of that nature. And the recycled water that we're discharging is very low in those constituents of very high quality. So it actually is a net benefit to the aquifer from both the quantity and a quality perspective. When it comes to the riparian habitat itself we saw literally overnight impact from opening up that outfall. There's a local researcher, Michael Bogan who's a biologist who immediately came out and started the first thing he noticed was dragonflies. So we're going from a dry river channel literally standing gravel. He started noticing dragonflies and dozens of species of dragonflies. I learned more about dragonflies in the first month than I ever thought it was to know. But within several months we were able to actually work with Fish and Wildlife under a safe harbor agreement to reintroduce the endangered Gila topmino fish to that stretch of the river for the first time in 70 years. So it literally was an overnight transformation of that area from a dry barren dry river channel to a thriving riparian environment. And now we have to take good care of it. We have to manage it. You have to keep the flows continuous but water quality was not an impediment to any of those activities including the environment. Thanks, Tim. Great story. Yes, David Weger. Thanks. First off I want to thank all of our speakers today. You've done a great job in kind of laying out the issues. My question is kind of broad ranging and I don't know if there's any one of you who can approach it but I want to throw it out there anyway. We in some of our areas like Adam you've clearly have a long history in using aquifer management grounds water management, et cetera. And also we've heard there are some new pilot studies that are just kind of gathering the data as it is. I guess my question is where are the areas of research that are needed to help move this along even further? Is it water quality related? Would that help? Is it the cost part of this in terms of gathering and reinjection? Is there technologies that could be enhanced there? Or is it regulatory? And I want to get a sense of where can we help this initiative move along in the process? Do you see holes or gaps where you find that we might be able to help out? At the risk of jumping in first again I would say that's a very profound question and I think we should take advantage of it. So I'll lead to direct potable reuse which managed aquifer recharge is and potable reuse has a spectrum from indirect or de facto to direct. I'm not going to split hairs over how direct is direct but in cases where recharge is a part of a potable reuse scheme especially in inland areas. An area for research is in a coastal area there seems to be not always so more on the west coast a reliance on reverse osmosis brine creating a brine that's part of your stream that sometimes recapture but there's still ultimately this waste product you have to deal with whereas in non-arrow treatment schemes often you can avoid that brine and that loss of water but it's a newer approach to things and not as well studied as the full advanced treatment with reverse osmosis so I would say from an inland perspective the role of recharge in that overall approach to potable reuse and how from a regulatory and from a water quality perspective what are the acceptable treatment trains for potable reuse that we can have a high degree of confidence in and not say Adam's train is better than Charles's train or anything of that nature because every geography, every situation is a little bit different different opportunities, different challenges and research into how to do that all well and not have a value between different approaches I think would be helpful that's my perspective. Yeah, I'll jump in. I think all of us are doing such different good work I mean this panel alone I learned a lot about what people are doing all over the country that I wasn't aware of hopefully you learn something from Wunch County so I think one of the values you're going to this can provide it's just connecting people and getting people talking because there's a lot of expertise a lot of knowledge out there but if we don't know it exists it's not available to us so I think really doing what you're doing here is very valuable to connecting all these people and getting the research and practitioners connected with Wunch County very helpful This is Charles I guess I'll give one opinion that in the scheme of indirect potable reuse the topic of pathogens rarely comes up it seems anymore I know that's different in direct potable reuse and the topic of pathogen removal is still bright and shiny but in indirect potable reuse and managed aquifer recharge really the emphasis is all on emerging contaminants by stakeholders and that then brings the question is of course what's appropriate what's not and then goes to TOC which is really measuring bulk organics and not emerging contaminants and the range of requirements for TOC is tremendous out there in cases where reverse osmosis is not being employed so what for given circumstances is appropriate or not appropriate in terms of bulk organics and what's appropriate not appropriate in terms of emerging contaminants is really a hard one to deal with for lots of utilities because of the uncertainty and of course some of the problem and non-targeted analysis kind of makes things even more complicated I think but this issue of where things are going to go what's not appropriate and for there to be some point of resolution on that because those are the questions that come up that's really where the questions and concerns are from stakeholders right now I don't know how to phrase that more succinctly or get at what the problem is because I understand the nuance is tremendous and there's always things to talk about in this regard but it seems like there's always uncertainty and it's hard to get projects to move in the face of sort of unrelenting uncertainty Great observation, over to Kathy that conversation was really interesting and made me want to ask each of you what public opinion issues do you face and how do you manage those communications is that a struggle no problem just be interested in your comments I guess I'll jump in as far as the Mississippi project we're still in the pilot phase of course but and it's to serve the agricultural community so it's really the producer end there's from the producer point of view there's been a wide range of support or skepticism as the case may be of the project and I think that goes toward a little bit toward the previous discussion I think what Adam mentioned too just communication of information I'm pretty sure this is the first and only managed agricultural recharge project in the Mississippi so there's a lot to be learned from others and I think that would go a lot toward stakeholders educating them and getting them plugged into discussion Orange County as you know a lot of projects like ours got shot down with a toilet tap headline that appeared everywhere so at Orange County we were extremely aggressive in our PR efforts to educate the community and that's the reason that our project was able to succeed PR efforts probably would have been torpedoed other projects in the region and still have trouble getting going so I can't stress enough how that education component with the public is critical well everyone at this point I have to give myself a 10 second warning that we need to wrap up at 2 p.m. and thank you again to all the speakers for excellent presentations and for fielding the questions as well as to invite you same time tomorrow 11 a.m. Eastern same link to join us for continued presentations and discussions regarding technical and institutional aspects of managed act for recharge thank you very much for your attendance your questions, your attention and see you tomorrow