Hydrogeologic Evaluation of a Ground-Source Cooling System at the BSF/CSF on the Battelle Campus: Final Report

Abstract

SummaryThis report documents both the field characterization activities and the numerical modeling effort at the Biological Sciences Facility (BSF) and the Computational Sciences Facility (BSF/CSF) site to determine the viability of an open-loop ground source heat pump (GSHP). The primary purpose of the integrated field and modeling study was to determine far-field impacts related to a non-consumptive use water right for the well field containing four extraction and four injection wells.In the field, boreholes were logged and used to develop the geologic conceptual model. Hydraulic testing was performed to identify hydraulic properties and determine sustainable pumping rates. Estimates of the Ringold hydraulic conductivity (60 to 150 m/d) at the BSF/CSF site were consistent with the local and regional hydrogeology as well as estimates previously published by other investigators. Sustainable pumping rates at the extraction wells were variable (100 to 700 gpm) and confirmed field observations of aquifer heterogeneity.Field data were used to develop a numerical model of the site. Simulations assessed the potential of the well field to impact nearby contaminant plumes, neighboring water rights, and the thermal regime of nearby surface water bodies. Using steady-state flow scenarios in conjunction with particle tracking, a radius of influence of 400 to 600 m was identified around the well field. This distance was considerably shorter than the distance to the closest contaminant plume (~0.8 km northwest to the Department of Energy Horn Rapids Landfill) and the nearest water right holder (~1.2 km southeast to the City of Richland Well Field). Results demonstrated that current trajectories for nearby contaminant plumes will not be impacted by the operation of the GSHP well field.The objective of the energy transport analysis was to identify potential thermal impacts to the Columbia River under likely operational scenarios for the BSF/CSF well field. Estimated pumping rates and injection temperatures were used to simulate heat transport for a range of hydraulic conductivity estimates for the Ringold Formation. The long-term operational scenario was simulated using conservative assumptions that assumed that river water did not intrude in the near shore groundwater. This operational scenario simulated continuous heat rejection, a condition anticipated once the BSF/CSF is fully loaded with laboratory and computer equipment. When hourly peak conditions were simulated as one month long peak to account for two 12-hour peak periods, the maximum change in groundwater temperature at a point along the shoreline was +0.9ºC from ambient. This change is less than 20% of the natural diurnal variability in groundwater temperatures at the shoreline. These findings are based on highly conservative assumptions for the GSHP system's operations, assumptions to which the model simulation results are highly sensitive. Other attributes of the model (such as aquifer hydraulic parameters and boundary conditions) were selected in a careful and co...

Pacific Northwest National Laboratory Annual Site Environmental Report for Calendar Year 2014

“…A generalized suprabasalt stratigraphic column showing what underlies the PNNL Campus is shown in Figure 1.5. The stratigraphic column for the upper Ringold Formation and the Hanford formation is based on information obtained from the drilling of 11 boreholes within the footprint of a construction site adjacent to the PNNL Campus (Freedman et al 2010). Additional stratigraphic information was obtained from previously existing geologic logs for nearby irrigation wells, water supply wells, monitoring wells, and characterization borings associated with environmental remediation activities.…”

Pacific Northwest National Laboratory Site Environmental Report for Calendar Year 2011

“…A generalized suprabasalt stratigraphic column showing what underlies the PNNL campus is shown in Figure 1.3. The stratigraphic column for the upper Ringold Formation and the Hanford formation is based on information obtained from the drilling of 11 boreholes within the footprint of a construction site adjacent to the PNNL campus (Freedman et al 2010). Additional stratigraphic information was obtained from previously existing geologic logs for nearby irrigation wells, water supply wells, monitoring wells, and characterization borings associated with environmental remediation activities.…”