Best, Heather R. (ORCID: 0000-0003-0764-3060) 20230320 tabular digital data Anchorage, Alaska U.S. Geological Survey, Alaska Science Center Suggested Citation: Best, H.R., 2023, Water surface elevation data derived from submersible pressure transducers deployed in the Susitna, Yukon, and Nushagak Rivers, Alaska, summers 2020-2021: U.S. Geological Survey data release, https://doi.org/10.5066/P9TDI0A6 https://doi.org/10.5066/P9TDI0A6 This dataset includes locations and water surface elevation measurements from submersible pressure transducers deployed in channels of three rivers in Alaska: Susitna and Yukon Rivers (July-October 2020), and Nushagak River (May to September 2021). Submersible pressure transducers were deployed and surveyed to compute water surface elevations for comparison to remotely sensed measurements of water surface elevation and reach slope from satellite platforms. 20200702 20210928 observed Complete None planned -157.1837 -149.2866 65.8854 59.4915 USGS Metadata Identifier USGS:ASC521 ISO 19115 Topic Category InlandWaters NASA GCMD Earth Science Keyword Thesaurus Flood plain River USGS Thesaurus Hydrographic datasets Hydrology Floods None Pressure transducer USGS Geographic Names Information System (GNIS) Alaska Nushagak River Susitna River Yukon River No access constraints. No use constraints. These data are marked with a Creative Common CC0 1.0 Universal License and are in the public domain. It is requested that this USGS data release be cited for any subsequent publications that reference or utilize these data. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. U.S. Geological Survey, Alaska Science Center Mailing and Physical

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Anchorage Alaska 99508 USA 907-786-7000 gs-ak_asc_datamanagers@usgs.gov HOBOware Pro v 3.7.25, Winsitu v. 5.7.8.0 Bjerklie, D.M. Durand, M. Lenoir, J.M. Dudley, R.W. Birkett, C.M. Jones, J.W. Harlan, M.E. 2023 journal article Journal of Applied Remote Sensing 17(1):014520 online SPIE Digital Library Bjerklie, D.M., Durand, M, Lenoir, J.M., Dudley, R.W., Birkett, C.M., Jones, J.W., Harlan, M.E., 2023. Satellite remote sensing of river discharge: a framework for assessing the accuracy of discharge estimates made from satellite remote sensing observations. Journal of Applied Remote Sensing 17(1):014520. https://doi.org/10.1117/1.JRS.17.014520 https://doi.org/10.1117/1.JRS.17.014520 Data quality assessment for the Yukon and Susitna records was done by comparison to a USGS streamgage that has been QA/QCed by standard methods; the trends for the transducers were plotted side-by-side with the USGS gage height record to check for stability. At all sites the Online Positioning User Service (OPUS) solutions provide +/- precision values for the reported NAVD88 elevations computed for the base location and thus precision values for the computed water surface records. At all sites, the water surface elevation plots were checked for appropriate downstream order (high elevation to lower elevation) and appropriate spacing between each assuming continuous stream gradient. The vertical precision of each transducer is provided in the table "waterSurfaceElev_PTsurvey_nushagakSusitnaYukon_best.csv" included with this data package. Attribute values fall within expected ranges. Water surface elevation data (WSE) was excluded during period when the pressure transducers (PTs) were above water surface. This occurred for some amount of time for each of the PTs. The dataset as presented includes all data for period of PT submergence. Blank cells are described for each attribute. Horizontal coordinates are accurate within about 10 feet, consistent with the 5-minute average location accuracy of a recreational grade GPS. Four unvented submersible pressure transducers (PTs; Onset HOBO water level data loggers; Onset, Bourne, Massachusetts) were deployed into the channel of the Yukon River in a reach above and below the Yukon River at Stevens Village, Alaska (15453500) streamgage (July - October 2020). A 5th PT was left in the gage house to correct for barometric pressure fluctuations. At the time of retrieval in October, each of the PTs was above the current river level and each PT position as well as water surface adjacent to it were surveyed with Global Navigation Satellite System (GNSS) equipment. A base station was set up for over 30 minutes at each PT location while the rover was used to survey the PT and water surface. A single base could not be set up to survey each location because the distance between locations exceeded radio range for the base and rovers. An OPUS-RS https://geodesy.noaa.gov/OPUS/ position solution was obtained for the base location at each PT, then this elevation in NAVD88 was used to correct the rover surveyed elevations for the PT and WS elevation. The PTs were programmed to record a depth measurement every 15 minutes during the deployment period. The depth record produced by the transducer was corrected to NAVD88 water surface elevations using the surveyed PT elevation in October as the elevation for zero depth of the transducer record. The record collected by the transducers were plotted alongside each other and the corrected gage height record from the streamgage to determine stability of each deployment. All transducers showed similar trends to the streamgage record and therefore were assumed to not have been disturbed during deployment. Based on this assumption, the records were able to be converted to NAVD88 for the entire period without survey information from the deployment in July. Unknown Five unvented submersible pressure transducers (PTs; Onset HOBO water level data loggers; Onset, Bourne, Massachusetts) were deployed on the Susitna River in a reach up and downstream of the Susitna River at Sunshine, Alaska (15292780) streamgage (July - October 2020). Only 3 PTs were recovered. The PTs were programmed to record a depth measurement every 15 minutes during the deployment period. Instead of an independent PT for recording barometric pressure fluctuations, the records from the in-stream PTs were corrected using the barometric pressure record from the Talkeetna airport (PATK) during the period of deployment. Water surface elevations were surveyed using GNSS during the October recovery of the PTs and records were corrected to NAVD88 datum by determining the difference between depth and true elevation, then using that value as an offset to correct the entire period of depth record from the transducer. Again, comparison of PT records against one another and the corrected gage height record from the streamgage indicated that the PTs were stable during the period of deployment. On the Susitna, a single base set up was used to survey the water surface elevations at the location of the 3 recovered PTs, thus only a single OPUS solution from https://geodesy.noaa.gov/OPUS/ was obtained to correct the data into NAVD88 elevations. Unknown Four unvented submersible pressure transducers (PTs; Onset HOBO water level data loggers; Onset, Bourne, Massachusetts) were deployed on the Nushagak River in a reach between the communities of Koliganek and New Stuyahok (May - September 2021). One PT was placed on shore near the location of submerged PT2 to collect a barometric pressure record to correct for atmospheric variability. At the time of deployment and again when the PTs were recovered, the water surface was surveyed with Global Navigation Satellite System (GNSS) equipment. A base station was set up for a minimum of 30 minutes at each PT location while the rover was used to survey the water surface. During the September recovery the water surface and an arbitrary control point were surveyed twice at each location to verify the quality of shots. A single base set up could not be used to survey all locations because the distance between locations exceeded radio range between the base and rover. An OPUS-RS position solution was obtained for the base location at each PT via the Trimble Access GNSS Processor (https://gnss-processor.trimbleaccess.com/gnssprocessor), which extends the CORS network by including National Park Service operated ground stations. Due to the remote location along the Nushagak River, a warning was generated noting that the survey locations were outside of polygons created by the reference CORS stations, thus solutions required extrapolation and should be used with caution. The maximum distance outside of the polygon was 17.5 km for the PT3 site. The OPUS-RS solutions were used as computed and the base elevation in NAVD88 was used to correct the raw water surface elevations surveyed on both days. Unknown Nushagak PTs were programmed to record a depth measurement every 30 minutes during the deployment period. The depth record produced by each PT was converted to NAVD88 water surface (WS) elevations using the NAVD88 surveyed water surface from May as the zero depth of the water level record. The September surveyed NAVD8 WS elevation were used as a check for PT movement during deployment. The records collected by the PTs were plotted alongside each other and notes were made on the condition of the PT and anchor set-up when the PTs were retrieved. All evidence indicates stability at each PT deployment with records showing almost identical water level trends and the surveyed starting and ending water surface elevations within the reported precision of the OPUS-RS solutions. Upon download it was noticed that PT3's record had the same time and date for each data point. When a time increment was forced onto the data record, the plot looked like that from PT1 and PT2, thus the data was time corrected and considered valid. Only half the number of data points were collected by PT3 indicating it recorded data on an hourly interval rather than 30 minutes. Unknown Point 0.0001 0.0001 Decimal degrees World Geodetic System of 1984 (WGS84) World Geodetic System of 1984 (WGS84) 6378137 298.257223563 North American Vertical Datum of 1988 (NAVD88) 0.01 meters Attribute values waterSurfaceElev_PTcoordinates_nushagakSusitnaYukon_best.csv Table containing the geographic location and serial number of each pressure transducer deployed. Presented in a Comma Separated Value (CSV) formatted table. Author defined PT_Name Name given to each pressure transducer deployed. A concatenation of the river name and a sequential number. Corresponds to the 'PT_Name' field in all tables included with this data package. Author defined Name of each pressure transducer. Latitude_DD The latitude of the transducer location in decimal degrees. Author defined 59.4915 65.8854 Decimal degrees (WGS84) Longitude_DD The longitude of the pressure transducer location in decimal degrees. Author defined -157.1837 -149.2866 Decimal degrees (WGS84) PT_SN Serial number of the them submersible pressure transducers (Onset HOBO water level data loggers); a unique identifier assigned by the manufacturer. Author defined Serial number of the them submersible pressure transducers. waterSurfaceElev_PTsurvey_nushagakSusitnaYukon_best.csv Table providing Real-Time Kinematic (RTK) water surface elevation measurements at each pressure transducer location. Presented in a Comma Separated Value (CSV) formatted table. Author defined PT_Name Name given to each pressure transducer deployed. A concatenation of the river name and a sequential number. Corresponds to the 'PT_Name' field in all tables included with this data package. Author defined Name of each pressure transducer. DateTime_local The date and local time of the transducer measurement. Local time = Alaska Daylight Time (AKDT) Coordinated Universal Time (UTC) minus 8 hours). Author defined 2020-10-07 09:45 2021-09-28 16:24 YYYY-MM-DD hh:mm (UTC-8; 24-hr) elev_PT_NAVD88_meters Surveyed elevation of pressure transducer. Blank cells indicate that data were not collected. Author defined 82.128 86.387 Meters elev_WS_NAVD88_meters Surveyed water surface elevation. Author defined 33.803 85.620 Meters vert_precision_meters Vertical precision of surveyed water surface elevation. Author defined 0.144 0.197 Meters survey_type Survey method used to measure water surface elevation. Author defined RTK Real-Time Kinematic survey Author defined waterSurfaceElev_[PT_Name]_[river]_[year].csv Three ZIP folders (one for each river) each containing tables with pressure transducer measurements, water temperature, and derived water surface elevation. Presented in Comma Separated Value (CSV) formatted tables. Filename convention [PT_Name] = transducer name; [river] = river; [year] = year of deployment Author defined PT_Name Name given to each pressure transducer deployed. A concatenation of the river name and a sequential number. Corresponds to the 'PT_Name' field in all tables included with this data package. Author defined Name of each pressure transducer. DateTime_local The date and local time of the transducer measurement. Local time = Alaska Daylight Time (AKDT; Coordinated Universal Time (UTC) minus 8 hours). Author defined YYYY-MM-DD hh:mm (UTC-8; 24-hr) baro_corr_Sensor_depth_m Barometric pressure compensated depth measurement. Author defined Barometric pressure compensated depth measurement, in meters (m) WSE_NAVD88_m Computed NAVD-88 water surface elevation for each transducer. Author defined Computed NAVD-88 water surface elevation for each transducer, in meters (m) U.S. Geological Survey USGS ScienceBase Team Mailing and Physical

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Denver Colorado 80225 USA 1-888-275-8747 sciencebase@usgs.gov The U.S. Geological Survey, Alaska Science Center is the authoritative source of these data, distributed by ScienceBase (a USGS Trusted Digital Repository). Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data for other purposes or on all computer systems, nor shall the act of distribution constitute any such warranty. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. CSV Tabular data in CSV format; FGDC metadata in XML and HTML formats. https://doi.org/10.5066/P9TDI0A6 None 20250507 U.S. Geological Survey, Alaska Science Center Mailing and Physical

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Anchorage Alaska 99508 USA 907-786-7000 gs-ak_asc_datamanagers@usgs.gov FGDC Content Standard for Digital Geospatial Metadata (CSDGM) FGDC-STD-001.1-1999