Scientific Investigations Report 2010–5253
During 2007 and 2008, the U.S. Geological Survey, in cooperation with the U.S. Department of Energy, collected quarterly depth-discrete measurements of fluid pressure and temperature in six boreholes located in the eastern Snake River Plain aquifer of Idaho. Each borehole was instrumented with a multilevel monitoring system consisting of a series of valved measurement ports, packer bladders, casing segments, and couplers. Hydraulic heads (head) and water temperatures in boreholes were monitored at 86 hydraulically-isolated depth intervals located 448.0 to 1,377.6 feet below land surface. The calculation of head is most sensitive to fluid pressure and the altitude of the pressure transducer at each port coupling; it is least sensitive to barometric pressure and water temperature. An analysis of errors associated with the head calculation determined the accuracy of an individual head measurement at ±2.3 feet. Many of the sources of measurement error are diminished when considering the differences between two closely-spaced readings of head; therefore, a ±0.1 foot measurement accuracy was assumed for vertical head differences (and gradients) calculated between adjacent monitoring zones.
Vertical head and temperature profiles were unique to each borehole, and were characteristic of the heterogeneity and anisotropy of the eastern Snake River Plain aquifer. The vertical hydraulic gradients in each borehole remained relatively constant over time with minimum Pearson correlation coefficients between head profiles ranging from 0.72 at borehole USGS 103 to 1.00 at boreholes USGS 133 and MIDDLE 2051. Major inflections in the head profiles almost always coincided with low permeability sediment layers. The presence of a sediment layer, however, was insufficient for identifying the location of a major head change in a borehole. The vertical hydraulic gradients were defined for the major inflections in the head profiles and were as much as 2.2 feet per foot. Head gradients generally were downward in boreholes USGS 133, 134, and MIDDLE 2050A, zero in boreholes USGS 103 and 132, and exhibited a reversal in direction in borehole MIDDLE 2051. Water temperatures in all boreholes ranged from 10.2 to 16.3 degrees Celsius. Boreholes USGS 103 and 132 are in an area of concentrated volcanic vents and fissures, and measurements show water temperature decreasing with depth. All other measurements in boreholes show water temperature increasing with depth. A comparison among boreholes of the normalized mean head over time indicates a moderately positive correlation.
First posted January 20, 2011
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Fisher, J.C., and Twining, B.V., 2011, Multilevel groundwater monitoring of hydraulic head and temperature in the eastern Snake River Plain aquifer, Idaho National Laboratory, Idaho, 2007–08: U.S. Geological Survey Scientific Investigations Report 2010-5253, 62 p.
Hydraulic Head and Temperature Measurements
Appendix A. Data Used to Calculate Pressure Probe Transducer Depths at Measurement Port Couplings, Boreholes USGS 103, USGS 132, USGS 133, USGS 134, MIDDLE 2050A, and MIDDLE 2051, Idaho National Laboratory, Idaho, 2007–08
Appendix B. Field Sheet Used for Data Collection at Multilevel Monitoring Boreholes, Idaho National Laboratory, Idaho
Appendix C. Port Measurement Data Pre- and Post-Inflation of Packer Bladders at Borehole USGS 133, Idaho National Laboratory, Idaho
Appendix D. Calibration Results for Fluid Pressure Sensor, a Component of the Sampling Probe Used in Boreholes USGS 103, USGS 132, USGS 133, USGS 134, MIDDLE 2050A, and MIDDLE 2051, Idaho National Laboratory, Idaho, 2006–09
Appendix E. Barometric Pressure, Water Temperature, Fluid Pressure, and Hydraulic Head Data from Port Measurements for Boreholes USGS 103, USGS 132, USGS 133, USGS 134, MIDDLE 2050A, and MIDDLE 2051, Idaho National Laboratory, Idaho, 2007–08
Appendix F. Lithology Logs for Multilevel Groundwater Monitoring Boreholes USGS 103, USGS 132, USGS 133, USGS 134, MIDDLE 2050A, and MIDDLE 2051, Idaho National Laboratory, Idaho, 2007–08
Appendix G. Vertical Hydraulic Head Gradient Data Between Adjacent Monitoring Zones for Boreholes USGS 103, USGS 132, USGS 133, USGS 134, MIDDLE 2050A, and MIDDLE 2051, Idaho National Laboratory, Idaho, June 2008
Appendix H. Quarterly Mean and Normalized Mean Hydraulic Head Values for Boreholes USGS 103, USGS 132, USGS 133, USGS 134, MIDDLE 2050A, and MIDDLE 2051, Idaho National Laboratory, Idaho, 2007–08