CCST BRIEFING: Remote Sensing Technologies and Water Resilience

Can we look to the sky to address California’s water challenges?  As California continues to grapple with frequent drought and overdrafted aquifers, satellite-based measurements offer a cost-effective way to generate high-resolution data on groundwater resources across a wide geographic area.  In conjunction with other ground-based monitoring, data from satellites can help inform sustainable groundwater management.

In December, the California Council on Science and Technology brought three experts together to discuss the role of remote sensing technologies to provide information to support water management decisions. 

But first, John Thompson, Senior Program Associate, briefly introduced the California Council on Science and Technology (CCST) and their Disaster Resilience initiative.  The CCST is a nonpartisan nonprofit organization established over 30 years ago at the request of the legislature to provide science and technology advice directly to policymakers from the wealth of outstanding academic and research institutions in the state.

We’re lucky to be home to such an incredible network of expertise, and our job at CCST is to help amplify and translate that expertise in this network into actionable advice for policymakers,” he said.  “We do this through a number of mechanisms, including briefings, workshops, peer-reviewed reports, and the CCST Science Fellows Program, where we place Ph.D. scientists and engineers for a year of government service and leadership training in the executive branch and state legislature.”

Among the CCST’s partner institutions are six federal labs and research centers located in California that occupy a unique position in the research ecosystem, leveraging their resources and expertise to conduct large team mission-based research to develop science and technology for the public good.

Earlier this year, the CCST released the report, 2021 Impact Report: California’s Federal Labs & Research Center, highlighting some of the research and economic impacts of California’s federal labs and research centers.  In addition to producing innovative technology that improves the state and the nation’s resilience to disasters, the labs employ world-class staff and support hundreds of California businesses through procurements and small business grants.

As part of their mission, the CCST recently launched a disaster resilience initiative to help the state better prepare for and respond to ongoing complex and intersecting disasters, such as climate change, extreme heat, power outages, and the COVID 19 pandemic, which are radically disrupting how Californians live and work.  While often destructive and painful, these disruptions can provide opportunities to redesign our systems to be more resilient and sustainable moving forward.  Through the CCST’s Disaster Resilience initiative, they work to deliver science and technology advice to reduce harm and improve the lives of all Californians.  This expert briefing focuses on how remote sensing technology can address water resilience challenges in the state and the nation.

Why remote sensing?

The moderator for the panel was Dr. Tara Moran, President and CEO of the California Water Data Consortium.  She began by noting that conversations like these are important because California’s water resources are under increasing threat.  Producing high-quality data that can be translated into actionable information to address these threats is only possible through collaborations that start from discussions such as these.

Significant droughts are becoming more frequent occurrences here in California and throughout the West, and the frequency and duration of droughts are expected to increase with climate change.  Currently, California is in the midst of a record-breaking 20-year dry spell punctuated by both periods of intense drought as well as flooding, Dr. Moran noted.

So as we think about resilience, we think about what are the mechanisms and the tools that we can use to improve resilience moving forward,” she said.

California’s groundwater, which accounts for anywhere between 40 to 60% of the state’s water supply in a given year, is critically overdrafted in many of the state’s groundwater basins.  So to mitigate the issues associated with this chronic groundwater overdraft in 2014, the California Legislature passed the Sustainable Groundwater Management Act, which requires local agencies to develop groundwater sustainability plans to achieve groundwater sustainability within 20 years of plan adoption.

However, achieving groundwater sustainability requires access to reliable data sources on groundwater levels, the Earth’s subsurface, and a lot of other information, but collecting and interpreting information about groundwater, which is unseen, difficult to measure directly, time-consuming, and extremely expensive.

So using satellites to make measurements about the Earth’s surface and subsurface, called remote sensing, offers a cost-effective method of generating groundwater data over large geographic regions that can be used to inform more resilient water management practices,” said Dr. Moran.

She then asked the panelists to introduce themselves and explain what projects they are working on.

Forrest Melton: Open ET

Forrest Melton is a senior research scientist with NASA Ames Research Center and California State University Monterey Bay and serves as the Program Scientist for the NASA Western Water Applications office and the project scientist for the Open ET project.  He works primarily on using remote sensing to understand the water cycle and develop satellite data applications for water resources management and agricultural production.  

In California and across the West, thousands of folks make decisions about managing water every day.  One of the key pieces of information needed is how much water is consumed by crops and other vegetation as they grow.  So over the last four or five years now, a consortium of partners, scientists, software developers, water managers, and agricultural producers have been working together to develop a system called Open ET, or Open Evapotranspiration.

Open ET was publicly launched in October of 2021 and is now providing satellite data of evapotranspiration at a resolution of about a quarter of an acre, or 30 meters by 30 meters.  Information is currently available at a monthly time step; they are working on adding daily data.  The data is available through a web-based data explorer so that anyone with a web browser can access this information and retrieve it for any location in the Western US. 

Next year, an additional suite of open data services will be released to allow Open ET data to be integrated with local, state, and federal water information systems, irrigation scheduling tools, farm and ranch management software, and a range of other applications for water management.

Dr. Melton noted that the information is not just available for agricultural fields for water management; it is available for every quarter acre across the West.  Open ET data can be used for applications related to assessing the hydrologic impacts of wildfires, looking at pre-fire indicators of wildfire risk, and analyzing how forest management practices affect hydrology and potentially reduce wildfire risk across the West.

The Open ET system provides field-scale information on evapotranspiration computed using six well-established satellite-driven models.  Currently, data can be retrieved from 2016 to the present day.  However, the satellite records go back to 1985, so the information can be extended back for decades.  Information can also be easily retrieved and downloaded as annual summaries or monthly data; daily data will be available next year.  This will allow changes in evapotranspiration to be tracked, especially as we implement different approaches to conserve water across the West and in California.

So what is evapotranspiration?  And why does it matter for this discussion?

Evapotranspiration is the combination of evaporation from the land surface and transpiration from plants,” said Dr. Melton.  “You can think of it as the reverse of precipitation.  It’s the process by which water returns from the land surface to the atmosphere that’s happening all around us all the time.  But, because it’s invisible, it’s difficult to measure on the ground.  It requires specialized expensive equipment and expertise.  And we can measure it with satellite data, so we’ve been working for about the last two and a half decades to develop techniques to map evapotranspiration with satellite data accurately.”

In contrast to ET, water applied to agricultural fields can either percolate down and recharge underlying groundwater resources, or it can run off and return to a local canal or river; that water can be reused in many cases by other users in a watershed or from within a water supply.  

The evapotranspiration is the part that’s transferred from the land surface to the atmosphere, and it’s consumed through that process and no longer available for other uses within a watershed,” explained Dr. Melton.  “So the reason we need an accurate measurement of evapotranspiration, especially in the context of addressing longstanding issues with groundwater resource management. is that ET has been this key piece of the water budget that’s been difficult to quantify consistently across the western US, especially at field scales.  So measuring ET allows us to improve the water budgets central to initiatives like the Sustainable Groundwater Management Act or SGMA.  It also allows us to develop incentive-driven conservation programs and programs to drive innovation and on-farm water management.”

Because measuring ET makes it possible to provide proper credit for reductions in use, those reductions in use ensure that agricultural producers and others making efforts towards conservation are getting credit for those efforts, he pointed out.  ET data can also help reduce transaction costs for water trading programs, which many GSAs are considering as a key component of their groundwater sustainability plans; accurate information on evapotranspiration can ensure that those markets function efficiently.  Finally, he noted that the UC Cooperative Extension has done a lot of work demonstrating how ET data can increase on-farm water use efficiencies.

Use cases have driven the work in Open ET; over 100 experts organized into multiple working groups have provided input to the design and development of Open ET. 

He then gave two examples of how Open ET advances operational use to address California’s longstanding water management problems.

Alternative plan of compliance in the Delta for SB-88

In the Sacramento San Joaquin Delta, they are working with the Central and South Delta Water Agencies and the Delta Watermaster to look at how to use information from Open ET to support the alternative plan of compliance for the measurement of diversions in SB-88. 

(Maven note:  SB-88 required all water right holders who divert more than ten acre-feet per year to measure and report the amount of water diverted.  However, measuring consumptive water use in the Delta is particularly challenging: in this post, the Delta Watermaster explains just how thorny it is.)

So they are working to implement a system next year by which growers can access the information from Open ET, evaluate it, and then decide whether or not they would like to use that in the place of water meters to report their water use in the Delta.

This represents a use case where we are using remotely sensed information to reduce the regulatory compliance cost for growers in the Delta,” said Dr. Melton.  “This has been a fantastic use case and a nice demonstration of the power of making information available, both to water resource managers and agricultural producers at the same time.”

Rosedale-Rio Bravo Water Storage District groundwater trading

They have been working with the Rosedale Rio Bravo WSD to incorporate open ET into their water accounting and trading platforms developed as part of their groundwater sustainability plan.

A key aspect of what Open ET does is ensure that both the grower and the program administrator or the water resource manager has access to the same information at the same time,” he said.  “Having launched in October, we are already hearing back from growers, especially in the Kern basin, with questions, thoughts, and evaluation of open ET over that region.”

He closed by emphasizing that Open ET has been a partnership-driven effort involving three federal agencies, seven universities, dozens of water users in California, water management agencies, agricultural producers, and agricultural and commodity organizations.  The Open ET project was led by the Environmental Defense Fund, which provided overall project management and collaboration with the private sector, most notably Google Earth Engine and Habitat Seven.

Peter Nico: Satellite measurement of groundwater recharge

Dr. Peter Nico is a scientist at Lawrence Berkeley National Lab in Earth and Environmental Sciences, where he leads the Resilient Energy, Water, and Infrastructure Program.  He recently led a team of scientists on satellite-based groundwater accounting approaches,  including measuring components of groundwater movement, verification of local recharge activities, and satellite-based groundwater accounting approaches.

An orbiting satellite sends a coherent radar signal to the surface and measures the backscattered radiation. The phase difference (position in the wave cycle) between the signals returning at two different times (time 1 in black and time 2 in red) can be used to estimate ground movement caused by a range of mechanisms.  Source.

Dr. Nico has been working on using the InSAR satellites to measure ground surface change and translate that to changes in water volume underneath those areas.

We often hear about subsidence and how when we over pump groundwater, the surface of the Earth goes down because the water is being taken out,” explained Dr. Nico.  “But in fact, that surface is very dynamic; it goes down at different rates, depending on how fast water is withdrawn.  And it goes back up again as water recharges into the system.  So these small variations in the surface can then be used to calculate the changes of the groundwater underneath.”

Satellites can accurately measure variations in the surface, from kilometers down to centimeters and millimeters at field and project scale.   With that information and knowledge of the structure of the ground underneath it, determining how much the water has changed to lead to that surface change is capable through the three-dimensional modeling capabilities available at Berkeley Lab.  What this produces are the differences in groundwater resources at a high resolution.  This is important for SGMA implementation as the GSAs need to measure the groundwater in their basin.

He credited Don Vasco as the lead scientist on the effort and the collaborators at JPL who are assisting the project.   

Something like InSAR base surface deformation modeling that can provide groundwater data at all these different scales would be very useful for GSAs communicating with each other for water trading, for verification, and for understanding the big picture as well as the small picture of what’s going on in groundwater resources.”

JT Reager: Turning data into information to understanding

JT Reager is an Earth Scientist at the NASA Jet Propulsion Laboratory specializing in freshwater.  He described his work as ‘doctors’ for the planet; they send satellites up to space to look back at Earth, which is then used to assess the health of the Earth, how the Earth is changing in time, and, at the same time to improve our understanding of how the planet functions.

Credit: NASA

In terms of NASA workflow, he described himself as ‘a bit upstream’ of Dr. Forrest Melton; whereas Dr. Melton is working to make the decision process easier by supplying information and helping with the applied science, Dr. Reager’s work involves data discovery, new observations, and using technology to try to get a handle on new variables in the system.

Dr. Reager said at JPL, there are three ways to think about data:

  • The raw information or data from the satellites
  • Next, an algorithm is applied to the raw data that turn it into information
  • Then that information has to be put into context to turn it into understanding.

So what is the story or the setting that this information fits into,” he said.  “It’s that transition from data to information to understanding is really what we try to do to NASA.

A lot of people think about remote sensing as cameras up in the sky looking down, but remote sensing has evolved in the last 30 to 40 years where there are several techniques, such as radar and radiometry, altimetry, interferometric SAR, and even gravity, which can all be used to help better understand water. 

Water is the life force of our planet,” said Dr. Reager.  “The first thing that scientists look for when they look for life on other planets is the presence of water.  So water is fundamental to life as we know it.  And, with increasing demand for water in places like California and around the world, we think of California as a microcosm for what’s happening in many places.  There’s a finite supply, and that supply is changing in time with changing climate.  And the demand is usually increasing; it usually only goes up.  So that’s the problems we try to wrap our heads around at JPL.

QUESTION (directed to Dr. Nico): You talked a little bit about some of the remote sensing work that you’re doing on groundwater recharge.  Can you talk more about the data gaps and challenges that these technologies are attempting to address and how those are complemented by ground-based measurements?

Dr. Nico said they are working to address the gaps between different areas and different GSAs adjacent to each other that are using different accounting and verification ideas.  “Having a single way to look across scales; the problem is that people need to then buy into a single way for things to be looked at.  But there’s a real advantage in that because, like with the Open ET, if you can agree on a set of facts, then you can work together a lot better on this process of managing the groundwater.”

As for data gaps, our models are only as good as our understanding of the subsurface –which is pretty good.  But, the better it is, the better the outputs of the models.  “For the InSAR work with the surface deformation, we need the data from the satellites that are going over.  This is generally available, but we need those to continue …  And if we’re going to use this for management, we need to take it out of the expert domain and into the practical management domain.”

James Briggs, California Department of Water Resources environmental scientist, performs routine maintenance on the California Irrigation Management Information System (CIMIS) station located at the UC Davis campus in California, January 26, 2017. California Irrigation Management Information System (CIMIS) stations are weather stations placed throughout California to assist irrigators in managing their water resources more efficiently. Florence Low / DWR

Dr. Melton noted that for Open ET, in particular, information from the California Irrigation Management Information System (CIMIS), which the California Department of Water Resources operates, is one of the key inputs into the Open ET information system.  It’s very difficult and expensive to measure evapotranspiration in an agricultural field; the stations cost about $50,000 and require expertise to operate the instruments and collect the data.

The agricultural weather station networks give us a theoretical measurement of reference evapotranspiration; it’s the ET that would occur from a reference crop if there was no water limitation,” said Dr. Melton.  “You can think about it as .. how much water would be used by your front lawn in a wet year.  That network is a really important input and allows us to do the time integration to interpolate between the days when we have a satellite overpass.  It’s a key anchoring data set for us.”

Dr. Melton acknowledged that roughly half of the uncertainty in the Open ET data is coming from the agricultural weather station network.  “So as we work towards further improving the accuracy in the future, continuing to invest in and expand upon the spatial CIMIS network will be a key activity and a key way that we can work with the state even further to reduce errors and uncertainty in the satellite-based ET.”

Dr. Reager said that he often jokes that hydrology is pretty much the dumbest science out there as there’s not a lot of complex physics involved.  The classic line is water flows downhill; that’s all you need to know.

But the problem with hydrology is it’s so hard to make observations,” he said.  “If you think about sticking a stream gauge in a river, you might get some of that river flow.  But if you’re not far enough downstream, or just upstream, there could be a tributary or something missing – it’s hard to capture it all.  ET is essentially impossible to measure directly, so we have proxy method methods.”

To measure ET directly, you’d have to dig a big ditch in a farm, put in instrumentation and a scale under that big ditch, refill it with soil, and then weigh it before and after some evaporation happens; he pointed out that’s very hard to do.  And since groundwater is essentially invisible to the naked eye, you drill some wells here and there, but they probably underrepresent what’s happening spatially.  Or you might use a satellite technique, which is also a proxy that gives some information at different resolutions and scales.

The best-case scenario is you have a few orthogonal pieces of information that all give you a piece of a puzzle, but none of them really gives you the whole picture, and you put them all together,” continued Mr. Reager.  “One great way to tie that all together with a framework or a skeleton for the data is with a model and numerical simulations.  If you can try to simulate what’s happening in a computer and then have these orthogonal pieces of information coming in from observations, you can sometimes tie that all together to get something that’s continuous and make sense that can be used for prediction and might tell you something about what’s going to happen in the future.”

QUESTION: What’s the accuracy of using ET data to measure water usage relative to water meters?  

Dr. Melton said that the accuracy of Open ET data has been assessed at different time scales over a growing season.  Open ET uses six well-established approaches to identify outliers and take advantage of the different strengths of the individual satellite-based techniques to produce an ensemble value.  He said the uncertainty is plus or minus 13% over the growing season and a little over plus or minus 16% of the monthly timestamp.

He noted that by comparing the models for some locations and basins, they found that some models have higher accuracies and perform more consistently for some locations, so the focus of the Open ET science team over the next year is updating the ensemble value to further take advantage of the strengths of these different approaches.

Dr. Melton pointed out that meters can be tricky; it depends on how old the meter is and how carefully it is maintained.  “It’s difficult to do a direct comparison,” he said.  “Typically, we would expect something on the order of plus or minus 3%, plus or minus 5%, for a new, well-maintained meter.  But we’ve certainly seen examples where meters are not well maintained, where at least the satellite data may be more accurate.  So it depends on the maintenance history on those meters.”

QUESTION: Is Open ET planning to provide data at the APN level or the assessor’s parcel number level?

Currently, the publicly available field boundaries and the data are at the original satellite resolution of 30 meters by 30 meters.  However, Dr. Melton said that next year, they will be releasing a programming interface that will let users use any spatial dataset to compute summaries for any location of interest, such as APN boundaries, a ranch map, water district boundaries, or watershed boundaries.

QUESTION: Regarding remote sensing of the change in groundwater resources, to what extent can we measure each of those components with enough accuracy to ensure that we’re estimating the difference accurately?  Is InSAR good enough to directly measure the difference?

Dr. Nico said that you have a lot of ins and outs, and if you know what all of them are, it’s simple math.  “The problem is that it’s very hard to know all of those; it’s hard to make sure you’re getting all of the ins and outs.  So we think the InSAR work is very useful on that scale because you’re aggregating, but then you’re getting an aggregated impact, so you see the impact of all of the ins and outs.  And whether it’s good enough depends on what level of detail you want to understand your measurements.”

Total subsidence in the San Joaquin Valley from May 2014 to January 2015. Credit: Canadian Space Agency/NASA/JPL-Caltech

We’re getting values that have resolutions on the scale of acre-feet of groundwater changes, so it’s a high enough resolution to make a meaningful difference in big picture groundwater accounting and budgets, but maybe not precise for charging somebody based like a meter.  But it is giving you the resolution to think of these sustainability budgets that we’re interested in from a SGMA implementation point of view.”

Dr. Reager added that to measure the changes in two fluxes that are similar or only a small difference, you just wait a long time, so hopefully, if there’s some separation there, it continues.  As the record gets longer, the separation becomes more clear.  He noted that parts of the valley during the last drought were subsiding at a rate of a foot per year or 45 centimeters per year – a huge signal.  But in a typical year, it’s slow and kind of monotonous. 

Groundwater depletion is like an insidious process; it just ticks down year after year,” said Dr. Reager.  “So long records for satellite data are very important.  We need to maintain these records year after year, mission after mission sometimes, to really make them actionable for decision making.”

Dr. Nico agreed that records are very important for the long-term.  And all models and measurements need to be calibrated against something, so we need to work on calibrating multiples of measurements against each other to make sure that they all agree.

He recalled talking to an irrigation district manager from a basin in which they had done InSAR work.  “We told them our calculation, and he said, ‘You want to know ours?’  It was about a few 1000 acre-feet different on a budget of about 150,000 acre-feet.  So that at least shows that we’re very much in the same ballpark of the accuracy of how things are being measured now.”

QUESTION: Can you elaborate on remote sensing and water trading?

The focus with Open ET within the Rosedale-Rio Bravo Water Storage District, which relies almost entirely upon groundwater, is to provide flexibility for the agricultural producers in the district.  So as part of the groundwater sustainability plan, producers and growers would receive an allocation in the district that they can track and monitor.  Then, if they need more water, there would be a market through which they could purchase it from other producers.

For example, if someone had just taken out an orchard and was fallowing the land for a year before replanting, they would have that water available to trade on the market to another water user in that water storage district,” said Dr. Melton.  “So in a year like this one, it’s really important to have that flexibility so that local communities can develop solutions to groundwater management challenges that make sense for them.  And that it’s based on information that is transparent and accessible to the individual agricultural producers and the water resource manager or policymakers.  So I would advocate that, as we think about advancing various types of remote sensing data for use in water resources management, we’re always keeping that focus on transparency and equal access to information.”

So when we want to think about making as much progress on groundwater management as quickly as we can, we want to ensure that we’re all working from the same starting point, the same understanding of what’s the state of the water resource?  How is it changing?  Where is water being used?  And we want to be sure of the growing agreement on that as we start to work on solutions.”

QUESTION:  With GSAs moving towards sustainability by potentially augmenting groundwater with surface water, how can remote sensing technology model surface water and groundwater interactions?

NASA has been supporting work to try to measure multiple components of the hydrologic cycle to give the ability to start to pin down some of the components of groundwater use and surface water use, so we can support increases in the accuracy of various models that are used to try to untangle that,” said Dr. Melton.

So with Open ET right now, we’re looking at measuring total evapotranspiration from our water sources,” he continued.  “So it’s the ET from rainfall, ET from groundwater pumping, ET from applied water, ET from access to shallow groundwater.  The next step for us is to work on calculating the effective precipitation, which is the amount of precipitation that falls and stays on that part of the land to be available to the plants in the root zone.  Once we can do that, we can start to focus on what the ET of applied water is.  And that’s a key component if you want to start to look at groundwater-surface water interactions.”

ET can also be really important for riparian systems, for looking at total withdrawals from riparian systems, and ensuring that, as we see changes in water management, we are not also impacting water supplies for natural ecosystems.  And we can look for changes in those systems as an indicator of modifications to groundwater and surface water interactions.”

Dr. Reager noted that glaciers covered North America 20,000 years ago, and as those glaciers melted in the Sierra melted, it created the groundwater resources in California.  “That’s what we call a fossil aquifer.  That is historically carbon-dated old water in California’s aquifers.  We will never get GSAs into sustainability from groundwater recharge, at least the critical GSAs.  There will have to be reductions in use; there has to be reductions in consumption.  But yes, a lot of GSAs, a lot of regions, a lot of counties are developing these water banks, and more and more so over the past 20 years, where when there’s an excess of surface water, they can recharge a bit to groundwater and try to bring it back up.  The problem is when it’s dry – we just tend to hit the groundwater hard during dry years.”

So doing a better job of managing surface water is part of the water portfolio in California,” he continued.  “We have upcoming missions like NASA’s SWOT mission and NISAR mission, which both do surface water monitoring and measuring changes in lakes and reservoirs and rivers.  And yet, there’s probably some science that needs to be done to understand how we can measure changes in surface water, groundwater recharge and augment long-term groundwater storage using recharge.  I think it’s a bit of an open question.”

Groundwater naturally recharges from rivers, lakes, reservoirs, and the ground when it rains.  And it does that more quickly and more slowly in different locations,” said Dr. Nico.  “So there’s definitely a modeling and sensing aspect that can tell you where, if you want to recharge groundwater, you’re likely to be able to do it the most quickly and most effectively, assuming you have that surface water to recharge.  Of the vast lands of California, probably a very small section of it is really going to be the most effective for getting water underground quickly because we have surface water in a very short window.  We have big storms occasionally, so when we have a lot of water, we want to get underground quickly.  So I think that’s definitely one place where these types of sensing can show us where that’s likely to be most effective.”

Also, closing the budget and making sure we’re doing what we think we’re doing in terms of putting water underground or surface water to groundwater budgets to make sure our numbers all add up so that we’re not fooling ourselves on sustainability, I think is another important part of what these measurements can do,” said Dr. Reager.

QUESTION:  When you talked about the subsurface, were you also referring to airborne electromagnetic remote sensing technologies and their applications to understand subsurface?  Can you talk a little bit about how that works and how that fits together?

Airborne Electromagnetic Survey (AEM); Photo taken November 16, 2021 by Andrew Innerarity, DWR

Airborne electromagnetic sensing involves flying a helicopter over the surface with a wire coil that emits a magnetic field, and how that magnetic field goes up and down indicates information about the structure of the Earth underneath it, Dr. Nico said.  The state has been working to have much of the groundwater basins surveyed to improve understanding of the subsurface.

First, we have to know what’s underneath there; that can tell you something right away: sand, gravel, clay, things like that, and you can learn something directly from that,” said Dr. Nico.  “The next step is to take that information and move it into models used for predicting processes … So that airborne electromagnetics is a static snapshot; it is what it is.  You can use that structure, like the layers in a cake, to then go into these other more dynamic models to understand how water movement is changing and producing these other things like surface deformation or other processes that you’re interested in.”

QUESTION: Can each of you talk briefly about some of the biggest barriers to using these technologies to produce data that can then inform best management practices that ultimately result in actionable implementation or policy?

I’ll answer backward,” said Dr.  Nico.  “There’s an XKCD webcomic that starts with someone saying, there are six ways to measure this, and everybody does it differently.  And what we need is one that everybody agrees with, and then they go off, and they do it.  And then the end of the comic is now there are seven ways to measure this.”

So about InSAR, it’s getting people to buy into an agreed set of measurements.  So I think that’s a really important part for the scientists who are developing things to interact with the stakeholders so that we build things that people will use at the end.  There’s a lot out there like we’ve talked about.  But we need to start early so that we end up with things that people will want to use in the end.”

If you asked me that four years ago, I would have said access to consistent information,” said Dr. Melton.  “So what we’ve spent the last four years trying to address and solve is to ensure that there is equal access to this information by all types of water users, water resource managers, policymakers, and regulators.

What I will say is that that is not an easy process,” he continued.  “It takes time.  It requires in-depth engagement with users of the system in advance to be sure that we understand their requirements, how they want to access the information, how they need to retrieve it, and what types of information systems they need to pull it into.  So making sure that we are investing both upfront and understanding these requirements and providing support to build open data systems built on open data services is important.”

Dr. Melton said that NASA is thinking about long-term operational sustainability, both in terms of the satellite missions and the data capabilities themselves.  A few years back, NASA created the NASA Western Water Applications Office to serve as a program office tasked with solving these problems.

If there are additional data gaps, information products that seem useful, that need refinements or improvement to make them useful for water resources, management, please don’t hesitate to reach out to me; we’d love to hear about that,” he said.  “If there are gaps that you’re looking towards in the future, we have a number of missions, upcoming satellite missions, such as SWOT and  NISAR; we see really critical water resource management applications for those, but we know we need to understand the operational requirements for those data products for the water resources management community and the agricultural communities.  So we’re interested in the feedback and input.”

There are three words to make NASA data more usable: access, access, access,” said Dr. Reager.  “We scientists, we love being dorks and dorking around with data … That’s what we do all day.  And we publish our papers.  The only other people that read them are scientists, and we’re preaching to the choir.  So at the end of the day, we need to build that bridge to management, to decision making, to policy.”

Open ET is a great example of how to do that,” he continued.  “You take information that is hard to understand, hard to decipher, hard to aggregate, and hard to reach for the average person, and you make it accessible.  So access, access, access.  I think that’s the future.   We need to keep funding the science, the discovery, new missions, and new technologies.  But to actually make it relevant and put it from data to information to understanding, we have to wrap it in a pretty package, make it accessible, and make it so people can understand what they’re looking at.  I think Open ET is a great example of how to do that.

Moderator Dr. Moran asked each panelist to end with a parting thought.  “How do you see these techniques providing California with sort of insights on these other emerging pieces around like flooding, wildfire, and other threats moving forward?

California has got a wealth of resources, with the national labs located in the state and the exciting work that’s happening here and several research centers – there is some real brainpower in California,” said Dr. Reager.  “We also have a lot of issues in California that need to be managed; we have a growing population, and we have limited water resources.  And so putting these all in a pie together and baking it up is the future.  I think programs like this are a great way to tackle that, to try to make these connections between decision-makers, scientists, and science applications people and trying to get everyone more comfortable with each other so that we can build those connections.  We can collaborate together in the future.  And we can make sure that we’re doing the kind of science that actually matters to society.  And I think that that’s a great way to go.”

I’ll just close by saying how much we appreciate the partnerships with the state of California, with the State Water Resources Control Board, and the Department of Water Resources, and the Cooperative Extension agencies,” said Dr. Melton.  “Their input into Open ET has been essential to the success along with all of the growers and agricultural organizations that took the time to go through that.  So as we’re thinking about building open data systems, there’s so much work to be done.  It’s sometimes tempting to skip over those early conversations and get right to building something.  And I think if we’re going to invest the time, resources, and funding to do this, we want to make sure we’re doing it right.  So we want to make sure we’re having those conversations at the outset of the projects with the end-users to make sure we understand how best to apply data to turn it into information, and then use that to support effective planning and decision making.”

I’ll just echo what I said before with thanking collaborators, the state, and CCST,” said Dr. Nico.  “Then ending with the old trope that what gets measured gets better.  So we have real issues with water management and such, but there are real solutions and possibilities too.  So the more we can understand our problem, the better we can implement what is, in the end, a wide variety of potential adaptation solutions that can really help address those problems.”

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