Waterborne Gradient Self-potential, Temperature, and Conductivity Logging of the Upper part of the Delaware River between Hancock and Port Jervis, New York, June–July 2021

This data release contains waterborne gradient self-potential (SP), surface-water temperature, surface-water conductivity and specific conductance, and surface-water nitrate concentration data measured continuously in the upper part of the Delaware River along approximately 123 kilometers (km) between Hancock and Port Jervis, New York. All of the data were measured from a kayak between June 27 and July 2, 2021. Gradient self-potential data were measured along five survey segments that varied in length between 13.1 and 31.6 km. The first segment began at Hancock, N.Y. on the east branch of the Delaware River, progressed into the main stem, and ended about 13.1 river-km downstream in Lordville, N.Y. at U.S. Geological Survey (USGS) streamgage 01427207. The second segment began in Lordville, at USGS streamgage 01427207 and ended about 28.6 river-km downstream in Callicoon, N.Y. The third segment began in Callicoon, and ended about 31.5 river-km downstream in Narrowsburg, N.Y. The fourth segment began in Narrowsburg, and ended 15.3 river-km downstream in Barryville, N.Y., and the fifth segment began in Barryville, and ended 31.6 river-km downstream in Port Jervis, N.Y. Gradient SP voltage data contained in this data release were continuously logged at a period of 1 second per measurement along each of the five survey segments using an Agilent U1252B data-logging multimeter and a 0.55-meter long electric dipole comprised of two freshwater-submersible, non-polarizing copper-sulfate electrodes. Eleven separate electrode drift tests were performed to make electrode-drift corrections during data processing. At least one electrode-drift test was performed along each survey segment by leaving the kayak and the electrodes stationary in an eddy along the riverbank for 15 to 30 minutes while gradient SP voltages were continuously logged. Surface-water temperature and conductivity and specific conductance data were continuously logged along each survey segment with a YSI Pro DSS and In-Situ Aqua TROLL 500 multi-parameter water-quality sondes at a period of 5 seconds per sample. Surface-water nitrate concentration data were measured with the Aqua TROLL sonde only and are limited to the first four segments of the gradient SP survey covering a river distance of approximately 80 km. This data release includes more than 79,000 measurements of voltage from gradient SP logging in the river, 4,779 measurements of voltage logged during the electrode drift tests, 35,304 measurements each of surface-water temperature and conductivity, 20,543 measurements of surface-water nitrate concentration, and the geospatial coordinates of each measurement. Time-series of streamflow in cubic feet per second are included for five U.S. Geological Survey streamgages that are on survey reach. USGS streamflow data cover the time period between 12:00 AM eastern time on June 21, 2021 and 11:45 PM eastern time on July 3, 2021.