Source: ALPINE HYDROMET submitted to
SNOW WATER CONTENT SENSOR - APPLICATION RESEARCH OF COSMIC RAY ATTENUATION PRINCIPAL FOR SNOW WATER CONTENT
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
Reporting Frequency
Annual
Accession No.
1019481
Grant No.
2019-33610-29765
Cumulative Award Amt.
$99,740.00
Proposal No.
2019-00586
Multistate No.
(N/A)
Project Start Date
Jul 1, 2019
Project End Date
Feb 29, 2020
Grant Year
2019
Program Code
[8.4]- Air, Water and Soils
Project Director
Heggli, A.
Recipient Organization
ALPINE HYDROMET
456 CRESTFIELD CIRCLE
ROSEVILLE,CA 956785980
Performing Department
(N/A)
Non Technical Summary
Alpine Hydromet sets out to research and further develop the applicationof cosmic ray detection technology for hydrological monitoring. This project will developa next generation snow water equivalent sensor, the Cosmic Ray Detector (CRD). The CRD measures passive secondary incoming cosmic radiation which attenuates through water. The attenuation of the signal can be used to quantify the amount of water in the snowpack and will measure through liquid water and ice without issue. Snow water equivalent and snow depth are measured in existing hydrometeorological networks to calculate the density of snow. The density of the snow is used to forecast when the seasonal snowmelt runoff will begin. Snow water equivalentis also used to quantify the amount of water which is fed into streamflow forecast models. These models are derived from regression analysis of snow course data, precipitation, soil moisture, and observed streamflow in basins. Improved data gives State and Federal agencies more reliable and timely forecasts vital for farmers, business owners, and communities.Monlau and Warnick (1982) explain, "Irrigation, power production, recreation and fisheries are only a few of the many uses to which this water can be put but wise use of this vast resource requires a knowledge of its variability, both in time and space. This requires proper instrumentation and a knowledge of snow characteristics and hydrology." This isamplified in larger state economies such as California which to leads the nation in agricultural production with $47 billion in cash receipts(California Department of Food & Agriculture, 2016). US Department of Agriculture (USDA) Natural Resource Conservation Service (NRCS) analyzed the importance of snow water equivalent for agriculture, recreation, flood management, and power generation and their findings revealed that 50-80% of water supply in the western United States comes from the snowpack (USDA NRCS).The cosmic ray detection principal that the CRD is based on has been proven to be an accurate sensor for measuring snow water content. Initial testing of the principal for snowpack monitoring was done in during the winters of 1996, 1997 and through February 24, 1998, had a correlation (r2 = 0.97) between the detectors and the manual core samples for 105 data points that was very promising.(Osterhuber, Gehrke, & Condreva, 1998) Further research is needed for basic-scale operation, integration of data, and application in remote forest with solar panel operation and a feasible installation. The passive cosmic rays that the sensor detects varies over space and time though there is little understood about how this varies on a basin-wide scale, especially during storms which can create noise in the data. The current configuration uses a reference detector installed above the snowpack on a tower to correct for the noise but the added sensor that must be installed always above the max height of the snowpack is less practicalfor this application where snow heights can regularly reach above 10 feet and even above 20 feet. Research in the cosmic radiation variation and variability is needed to either reduce the size of the reference detector, use a regional reference that can compensate all sensors for an entire basin, remove the reference detector altogether using meteorological parameters or a combination of a regional reference and local meteorological conditions. Power consumption is also high and Alpine Hydromet will be conducting research on ways that the power supply can be reduced by switching the sensor on and off or removing non-critical intermediate electronics. Included in the objectives in our data collection is to verify the minimum measurement duration to achieve an accurate reading which will standardize the minimum measurement duration requirements.The realistic development opportunity of the CRD will allow United States' Federal and State operations to phase out the use of chemical-based fluid snow pillows which have been an environmental concern for some time. Once the data proves to have a high correlation to the historical data sets, the phasing out of fluid pillows will begin. As existing fluid pillows fail, become damaged, or continuously report inaccurate data, the fluidless sensor will begin to replace the over 50-year-old technology. When budgets permit, agencies can be proactive in the replacement of fluid pillows to alleviate the demands from landowners to remove the snow pillow fluid. This also will end the cycle of fluid pillows and offer a long-term solution that should work without maintenance for a minimum of 10 years. This is a direct cost saving for Federal and State budgets. The main objective in developing a sensor to replace the legacy instrumentation is to assure that the sensor will not affect the climate data record; significant research and studying needs to be conducted to assure this. The State of California, in particular, is facing pressure from local landowners to remove fluid systems and are in need ofalternative instrumentation.There are also several issues with a weighing principle to measure the snowpack. Complex snow structures can inhibit accurate measurements which are projected to become more frequent in a changing climate as snow levels rise and more rain-on-snow events are experienced (Musselman,et al., 2018). The proposed sensor will provide more robust and reliable data which is used in forecast models for everything from recreation, hydropower generation, water supply planning for agricultural uses, urban water deliveries, forecast informed reservoir operations, andflood forecasting. Water from the snowpack touches every aspect of life in the United States, improving monitoring practices will benefit the economy and the citizensfacingwater demand challenges as they become increasingly complicated. Alpine Hydrometanticipates placingthe United States as a leader in snow monitoring practices with this promising technology.California Department of Food & Agriculture. (2016). California Agricultural Statistical Review, 2015-2016. California Department of Food & Agriculture. Retrieved from https://www.cdfa.ca.gov/statistics/PDFs/2016Report.pdfMolnau, M., & Warnick, C. (1982). A History of Snow Research at the University of Idaho. Western Snow Conference, (pp. 212-214). Reno.Musselman, Keith N., Lehner, Flavio, Ikeda, Kyoko, Clark, Martyn P., Prein, Andreas F., Liu, Changhai, . . . Rasmussen, Roy. (2018). Projected increases and shifts in rain-on-snow flood risk over western North America. Nature Climate Change, 808-812.Osterhuber, R., Gehrke, F., & Condreva, K. (1998). Snowpack Snow Water Equivalent Measurement Using the Attenuation of Cosmic Radiation. Western Snow Conference, (pp. 19-25). Snowbird.USDA NRCS. (n.d.). Snow & Tell. Retrieved from Natural Resource Conservation Service: https://www.nrcs.usda.gov/Internet/FSE_MEDIA/stelprdb1246671.jp
Animal Health Component
50%
Research Effort Categories
Basic
40%
Applied
50%
Developmental
10%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1120210205030%
1120499201040%
1120210201020%
1120499207010%
Goals / Objectives
The project objective is to research, design and test the cosmic ray detector which eliminates all major known issues with current snow water equivalent remote, continuous monitoring. Initial proof of concept has been tested through further research is required to refine the measurement for basin-scale hydrological application. Additional research will be conducted for the sensor that will additionally reduce the costs, improve electronics and signal processing aiding in reducing power consumption, and understand temporal variation. The project will be reviewed by leading operational snow hydrologists who work with current networks for water supply and flood forecasting. This will aid in providing a peer-reviewed design to keep the cost of installation and reoccurring maintenance of the sensors low. The participating snow hydrologists will also participate in data analysis prior to entering Phase II for product commercialization. Alpine Hydromet anticipates having a configuration for one to two prototype designs for side by side comparison with the legacy technology to enter Phase II.The research of the CRD will lead to the development and commercialization of a new age snow water content sensor, allowing for the phase-out of fluid-based sensors. This will directly alleviate environmental impacts, improve data reliability, and minimize reoccurring costs for the operators which are funded by taxpayers. The major goals are divided into two main aspects.GOAL 1:The first goal is tobetter understand thevariation over space and time of secondary cosmic radiation in thehigh energy band beingmeasuringon abasin-wide and state-wide scale. This has been outlined with three questions that this project will answer.Objective 1: What averaging time of raw data will achieve the necessary precision?Objective 2: Can a smaller scintillator be used as a reference detector without affecting accuracy?Objective 3: Does each station need a reference detector, or could one reference detector be applied to a region?A portable station has been designed to collect data over the first four months. The data will be used tounderstand the variation of secondary cosmic radiation on smalltime-scales and over smaller regions across elevation gradients from 5,000 feet to 9,000 feet. The analysis of this data will allowAlpine Hydromet toknow ifthereference detector can be reduced in size fora lower cost solution but also for an easier installation process for the state and federal hydro-meteorological network operators. We anticipate being able toknowif thesensor can workin any of the followingfour ways: with the original reference detector size only, with a reducedsized reference detector, through a multi-reference network, or through meteorological compensation and remove the reference detector altogether.Alpine Hydromet will set all stations with enough power to operate continuously. The high-resolution raw data will then be post-processed by applying averages ranging from 10-minutes up to 24-hours for each data collection location. The data from each location will be used to examine the most appropriate averaging time necessary to achieve accuracy that is acceptable to the users. Data from varying averaging times will be compared and it is known that shorter averaging times can be applied for higher elevations, though it is unknown where these breakpoints will occur.GOAL 2:The second goal is to prove that the principal measure reliably and accurately in the most extreme snowpacks with varying percentages of ice, liquid water and in the deepest snowpacks. This has been outlined with one questions that the project will answer.Objective 4: What is the relationship between the attenuation of cosmic rays and water content?A study will also be conducted where the sensor will be submerged at varying depths of water up to 10 feet of water to validate the capacity of the detector to measure water accurately and reliably on often harsh mountain snow environment. 10 feet of water has been selected because that is the maximum snow water content measured at existing stations and liquid water is the densest form of water. It is an important step to prove accuracy and durability with this quantity of water to assure network operators that the device is capable of measurements in all anticipated snowpack but measuring in water allows for accurate testing and known water levels.GOAL 3:The final goal is to reduce the overall cost to the state and federal agencies in equipment purchase cost, transportation costs and time costs incurred during installing and maintaining the sensor. This includes reducing the power required to allow operators to monitor with 12-volt DC battery and solar panel configurations. The less power the sensor will require, then the smaller the solar panels and battery banks will need to be. This objective was simplified into the question below.Objective 5: How can electronics be simplified to work with off the shelf data loggersThis question will be answered by spending more time with the electronics and existing data loggers that are utilized by network operators to measure the existing current draw, isolate the areas of the detection array that require the most amount of power to analyze the feasibility of reducing the power draw. This will also be analyzed with the 4 months of data collection by verifying the minimum measurement time required for an accurate measurement. With this data Alpine Hydromet can configure the system to power on and off to obtain measurements rather than running continuously and in return reduce power requirements.
Project Methods
The problem has been identified and validated by State and Federal agencies who monitor the network. The initial research for the project has already been conducted with evidence that the measurement principle will work for all existing snowpack conditions across the entire United States which experience some of the deepest and wettest snow across the globe due to the maritime conditions on the west coast. The research questions have been formulated and outlined with appropriate experiments to make observations and collect data that will allow Alpine Hydromet to conduct an analysis that will guide the next steps in the development of the CRD. The data collection process will have a control station where baseline data will be collected continuously. A portable station will data collected at each location along the American, Yuba and Bear River Basins at varying elevations from 5,500-9,000-foot elevations. An additional location at a similar elevation in a southern basin will also be made to evaluate the deviation from the control station. The data collection will be made conjunction with local network operators at existing stations which will aid in Phase II development and testing to provide more repeatable data in the process and to assure the basic research is being done simultaneously in an applied manner. Meteorological parameters are measured at many of the stations and will be collected to analyze the effect of passing pressure systems and varying temperatures on the measurement. This will allow decisions to be made on the feasibility of reducing or removing the reference detector that is understood to be required for clean data.The findings will provide science-based knowledge and be presented through a research poster to the scientific and network operation community. This presentation of findings will also be used as part of the evaluation by receiving direct feedback from the network operators and users of snowpack data for decision making and research. However, Alpine Hydromet has also decided to build the evaluation into the project by establishing an informal steering committee who will aid in the selection of the locations for our data collection and be a part of the discussion of application, measurement frequency requirements and power supply requirements for a functional integration into existing networks.There will be three main evaluation points: 1. the validation of reliable data collection up to 10 feet of water, 2. the data collection and analysis of reference detector size and application in the data compensation process, 3. signal processing and power supply requirements for station integration. The project will be successful if Alpine Hydromet has a clear outline for the development of 1 or 2 prototype sensors to be developed for a full winter of comparative data collection with an existing station. The key milestone of success for the project will be the award of Phase II and interest from DWR and NRCS to co-locate the prototype sensors with their stations for continued testing to prove data correlation with existing datasets. Alpine Hydromet anticipates when the prototype is completed and full comparison of data is conducted delivering reliable and accurate data, the agencies will beginto place orders to co-locate the CRD at more stations and begin to phase out the use of snow pillows.

Progress 07/01/19 to 02/29/20

Outputs
Target Audience:The main target audience is the US Department of Agriculture (USDA) Natural Resource Conservation Service (NRCS) National Water and Climate Center and Snow Surveys Program as well as the California Department of Water Resources (DWR) who conduct their own snow survey program for water supply planning. The secondary audience is the users of the data. The NRCS and California DWR own and operate the two largest snow monitoring networks and publish their data for water managers, reservoir operators, political decisions regarding water rights and infrastructure and researchers including but not limited to; forecast informed reservoir operations, to risk management, flood forecasting, agriculture water uses and water availability, groundwater recharge solutions, ecosystems restoration, species protection programs, and climate change monitoring. Though this data is highly valuable and supports economic planning for many industriesin the western United States, the general public is not aware of the location of their water supply. Alpine Hydromet focuses on the network operators, cooperators, and decisionmakers who understand the technical nature of reliable snowpack data for hydrological forecast models and conduct the water deliveries. Alpine Hydromet will present the findings to the State, Federal and private agencies at two conferences in 2020where the audience is most appropriate. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?The data that has been collected is being processed. We have collected the data necessary to answer each objective completely. Each objective helps to narrow the decisions for bringing the product to market in Phase II.

Impacts
What was accomplished under these goals? During the entirety of the research period, we were collecting and processing data. The objectives will be updated in the final report with the full data analysis.

Publications


    Progress 07/01/19 to 02/29/20

    Outputs
    Target Audience:The main target audience is the US Department of Agriculture (USDA) Natural Resource Conservation Service (NRCS) National Water and Climate Center and Snow Surveys Program as well as the California Department of Water Resources (DWR) who conduct their own snow survey program for water supply planning. The secondary audience is the users of the data. The NRCS and California DWR own and operate the two largest snow monitoring networks and publish their data for water managers, reservoir operators, political decisions regarding water rights and infrastructure and researchers including but not limited to; forecast informed reservoir operations, to risk management, flood forecasting, agriculture water uses and water availability, groundwater recharge solutions, ecosystems restoration, species protection programs, and climate change monitoring. Though this data is highly valuable and supports economic planning for many industriesin the western United States, the general public is not aware of the location of their water supply. Alpine Hydromet focuses on the network operators, cooperators, and decisionmakers who understand the technical nature of reliable snowpack data for hydrological forecast models and conduct the water deliveries. Alpine Hydromet will present the findings to the State, Federal and private agencies at two conferences in 2020where the audience is most appropriate. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?Alpine Hydromet attends the Western Snow Conference and the California Cooperators Snow Survey Program Conference every year. We have a booth and that is our opportunity to discuss the research we have been doing with updates on our progress in technology development. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

    Impacts
    What was accomplished under these goals? 1.Objective:How can electronics be simplified to work with off the shelf data loggers 2.Objective:What is the relationship between the attenuation of cosmic rays and water content? 3. Objective:What averaging time of raw data will achieve the necessary accuracy? 4.Objective:Can a smaller scintillator be used as a reference detector without affecting accuracy? 5. Objective: Does each station need a reference detector, or could one reference detector be applied to a region? 1.Objective:How can electronics be simplified to work with off the shelf data loggers The CRD consist of three major electronic components with multiple subcomponents; Detector, Controller, Breakout board/terminal block. Each major component was tested for power draw using a digital control dc power supply. The controller is by far the most power-intensive of the components. Detector size does not change the power draw of the detector due to the detector electronic components being identical on larger and smaller detectors. Tests were also done on the minimum voltage to see what the minimum operational voltage is. By minimizing the voltage, the current draw of each component increases. The DM board of two detectors were monitored to see if the voltages on the same power supply differed by detector. The dc power supply was then tuned down to identify the lowest voltage where the system remained operational. The main obstacles faced with bringing the existing instrumentation to market is the power draw and limited signal output options. Here are items that need to be further pursued to bring a viable product to the market. With the controller contributing to the highest current draw, removal or replacement will drastically help the detector become more ideal in a remote application where low power draw iscritical. There are a couple of options for replacing the current Controller that should be further evaluated. One option would be to identify a more robust data logger than can take simultaneous differential analog outputs. The pursuit of a more powerful datalogger would bridge the gap and inefficiencies of the existing controller but would limit the end user's ability to select their own data logger as the system would come with its own. 2.Objective: What is the relationship between the attenuation of cosmic rays and water content? A preliminary pool study was done at six depths up to 168.5 cm deep to verify the relationship between the attenuation of cosmic rays and water content and establish an equation. One detector was left outside of the water to act as the reference detector to correct for natural fluctuations in cosmic rays and variation in atmospheric water vapor. The second detector was placed in the pool to act as the ground detector that would be under the snow. The cosmic rays attenuate in water and the attenuation of the cosmic rays can build a relationship to the amount of water present. Based on the results, the maximum water content experienced in the deepest annual snowpack, about 300 cm, can be measured using this technology. A relationship between the attenuation factor and water content has been established and proven accurate from the findings. This validates the initial study done by Osterhuber et al. (1998). The upper limitation of water content that can be measured has not yet been found. 3. Objective:What averaging time of raw data will achieve the necessary accuracy? Four detectors were tested in Roseville, California at an elevation of 50 meters in a pool 3.9-meter-deep pool. Gamma rays are weaker at lower elevations. Testing in Roseville allowed us to test the minimum required averaging time since as most snow monitoring locations are at higher elevations in the mountains and will require less averaging time. In the field study, we validated that both small detectors, one being half in length and the other half the length of the larger detector, have the same surface area and can be used interchangeably. The short sensor was left on the pool deck to act as a reference detector while sensor 99 and the narrow sensor were lowered into the water to 2.6 m, 1.5 m and 0.5 m depths. The objective was to see if the smaller detector required more time to collect sufficient counts of gamma photons and would, therefore, require a longer averaging time. The study also allowed for the comparison of the effects averaging time on sensor accuracy. This study illustrated the advantage that the larger scintillator has at deeper depths and calculated the improvement of accuracy with longer averaging times. Based on the equations developed, a minimum of 8-hour averaging is required to obtain accuracies of +/- 1 cm water content. 4.Objective: Can a smaller scintillator be used as a reference detector without affecting accuracy? The study at Meadow Lake was used as it had the most complete data set and longest measurement time at the station. The portable station was comprised of four detectors that were three different sizes. Two detectors were the same size (457cm2) and the short sensor was half the length and the narrow sensor was half the width. The detectors were placed on the soil surface and measured the total counts of cosmic rays every 15 minutes. This data was then processed to hourly averages from hour 1 through 12. Each combination of sensor pairing was calculated to compensate the other detector to measure the total water content present. In these no snow studies the water content should always be 0 cm. This study demonstrated accuracy increases with averaging time but not with reference detector size The reference detector is always above the snowpack and will not be affected by attenuation of the signal in the snowpack so these findings prove that a smaller detector can be used as a reference detector without reducing accuracy. This will allow the price of the sensor to be reduced along with the installation costs and installation difficulty which means less time installing and therefore less labor cost incurred by the potential operators of the system. ?5. Objective:Does each station need a reference detector, or could one reference detector be applied to a region? The regional study utilized two stations. One was used as the control at Sagehen Creek Field Station which remained installed collecting data continuously throughout the entire study. The second station was a portable station that was moved to varying locations spanning small changes in latitude and significant elevation. The station at Sagehen Creek was used to test if a regional reference detector could be used to compensate anentire region and if so, the area could it cover. The data collected and calibrated locally at Meadow Lake resulted in all combinations of sensors reading within +/- 0.8 cm of 0 water content. To see if a regional reference would be feasible, the station at Sagehen Creek was used to compensate the detectors 23 kilometers away at Meadow Lake. All options were calculated to see if there was a preference in sensor combination over the other. The data from Meadow Lake compensated with the data from Sagehen had an accuracy of +/- 1.7 cm. This study answered the question and demonstrated that each station will require a reference detector installed locally above the maximum height of the snowpack to cancel the natural variation in gamma radiation and water vapor content in the atmosphere. A regional reference is not only not as accurate and introduces unknown error, but it is also not practical for operations and will not be pursued further based on these findings. The sensor development will continue with a local reference compensation to assure the most accurate water content and eliminate the need to post-process data to create an easy to use product.

    Publications