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<br /> <br /> <br />5-8 <br />DRAFT for review purposes only. Use of contents on this sheet is subject to the limitations specified at the end of this docu ment. <br />Section 5 <br />Presentation of Results <br />This section presents the baseline field measurements, laboratory analyses, and QC measurements. <br />Hydrographs for each groundwater well are provided in Appendix F. Laboratory reports and data <br />validation summaries are provided in Appendix E. <br />5.1 Groundwater and Surface Water Quality Field Measurements <br />The depth to groundwater was measured to 0.01 feet from top of casing (TOC) using an electrical <br />water level sounder before sampling the well. Water quality parameters were measured during <br />groundwater sampling activities. Water quality field parameters were also measured at surface water <br />sampling locations. Field parameter measurements are summarized in Appendix H. <br />The first quarterly sampling event used low-flow purging methods to collect groundwater samples. <br />Water quality parameters (pH, oxygen reduction potential, dissolved oxygen, temperature, and <br />specific conductance) were measured using a flow-through cell and water quality multi-meter. The <br />remaining quarterly sampling events used bailing purge methods. Grab samples were taken from the <br />bailer to measure water quality parameters. <br />5.2 Groundwater Level Assessment <br />Pressure transducers were used to monitor groundwater levels beginning in December 2021 shortly <br />after the wells were installed. Transducers record the total pressure (centimeters of water [cmH2O]) <br />on the sensor, the net pressure from both water and air acting on the transducer. To calculate the <br />portion of the pressure reading due only to water, barometric pressures must be measured <br />separately and subtracted from the total pressure reading. A separate data set of barometric <br />pressure is needed to compensate for fluctuations in atmospheric pressure. Data from the Fremont <br />County airport (approximately 13 miles northwest of the Site) were downloaded from the K1V6 <br />weather station on the MesoWest website developed by the University of Utah <br />(www.mesowest.utah.edu). Barometric pressures from the Fremont County airport were used to <br />calculate the pressure of water above the transducer from the transducer total pressure readings. <br />Barometric pressure readings from the Fremont County airport were converted from inches of <br />mercury to cmH2O prior to compensation of the Site transducer data. <br />Water level data collected from the transducers were used to develop hydrographs showing changes <br />in water levels with time (Appendix F). Hydrographs were generated by subtracting the depth to water <br />data from the transducers from the surveyed elevation of the top of casing for each well. Water level <br />elevations were plotted with the estimated elevation of the contact between the Fort Hays Limestone <br />and Codell Sandstone observed during the well drilling operations. Groundwater elevations <br />calculated from the manual water level measurements collected both before and after purging of the <br />wells during the sampling events are also plotted on the hydrographs. <br />Groundwater elevations above the limestone-sandstone contact indicate the groundwater in the <br />Codell Sandstone has a positive vertical hydraulic gradient (upward gradient). Well 3 and Well 4 to <br />the southeast of Red Creek have groundwater elevations above the limestone-sandstone contact for <br />the entire duration of monitoring (Appendix F). Groundwater elevations in Well 1 show a steady <br />decrease from the time the well was installed until approximately May 2023 when the groundwater