Geology Reports⌕ Search

Geology topics

B.A. Robinson

Publications and source records attributed to B.A. Robinson.

At least 19 recordsLinked to original sources
USGS2003

The saturated zone at Yucca Mountain: An overview of the characterization and assessment of the saturated zone as a barrier to potential radionuclide migration

The US Department of Energy is pursuing Yucca Mountain, Nevada, for the development of a geologic repository for the disposal of spent nuclear fuel and high-level radioactive waste, if the repository is able to meet applicable radiation protection standards established by the US Nuclear Regulatory Commission and the US Environmental Protection Agency (EPA). Effective performance of such a repository would rely on a number of natural and engineered barriers to isolate radioactive waste from the accessible environment. Groundwater beneath Yucca Mountain is the primary medium through which most radionuclides might move away from the potential repository. The saturated zone (SZ) system is expected to act as a natural barrier to this possible movement of radionuclides both by delaying their transport and by reducing their concentration before they reach the accessible environment. Information obtained from Yucca Mountain Site Characterization Project activities is used to estimate groundwater flow rates through the site-scale SZ flow and transport model area and to constrain general conceptual models of groundwater flow in the site-scale area. The site-scale conceptual model is a synthesis of what is known about flow and transport processes at the scale required for total system performance assessment of the site. This knowledge builds on and is consistent with knowledge that has accumulated at the regional scale but is more detailed because more data are available at the site-scale level. The mathematical basis of the site-scale model and the associated numerical approaches are designed to assist in quantifying the uncertainty in the permeability of rocks in the geologic framework model and to represent accurately the flow and transport processes included in the site-scale conceptual model. Confidence in the results of the mathematical model was obtained by comparing calculated to observed hydraulic heads, estimated to measured permeabilities, and lateral flow rates calculated by the site-scale model to those calculated by the regional-scale flow model. In addition, it was confirmed that the flow paths leaving the region of the potential repository are consistent with those inferred from gradients of measured head and those independently inferred from water-chemistry data. The general approach of the site-scale SZ flow and transport model analysis is to calculate unit breakthrough curves for radionuclides at the interface between the SZ and the biosphere using the three-dimensional site-scale SZ flow and transport model. Uncertainties are explicitly incorporated into the site-scale SZ flow and transport abstractions through key parameters and conceptual models. ?? 2002 Elsevier Science B.V. All rights reserved.

Journal of Contaminant Hydrology↗
USGS2003

The site-scale saturated zone flow model for Yucca Mountain: Calibration of different conceptual models and their impact on flow paths

This paper presents several different conceptual models of the Large Hydraulic Gradient (LHG) region north of Yucca Mountain and describes the impact of those models on groundwater flow near the potential high-level repository site. The results are based on a numerical model of site-scale saturated zone beneath Yucca Mountain. This model is used for performance assessment predictions of radionuclide transport and to guide future data collection and modeling activities. The numerical model is calibrated by matching available water level measurements using parameter estimation techniques, along with more informal comparisons of the model to hydrologic and geochemical information. The model software (hydrologic simulation code FEHM and parameter estimation software PEST) and model setup allows for efficient calibration of multiple conceptual models. Until now, the Large Hydraulic Gradient has been simulated using a low-permeability, east–west oriented feature, even though direct evidence for this feature is lacking. In addition to this model, we investigate and calibrate three additional conceptual models of the Large Hydraulic Gradient, all of which are based on a presumed zone of hydrothermal chemical alteration north of Yucca Mountain. After examining the heads and permeabilities obtained from the calibrated models, we present particle pathways from the potential repository that record differences in the predicted groundwater flow regime. The results show that Large Hydraulic Gradient can be represented with the alternate conceptual models that include the hydrothermally altered zone. The predicted pathways are mildly sensitive to the choice of the conceptual model and more sensitive to the quality of calibration in the vicinity on the repository. These differences are most likely due to different degrees of fit of model to data, and do not represent important differences in hydrologic conditions for the different conceptual models.

Journal of Contaminant Hydrology↗
USGS2003

Yellow jackets may be an underestimated component of an ant-seed mutualism

Yellow jackets (Hymenoptera: Vespidae) are attracted to the typically ant-dispersed seeds of trilliums and will take seeds from ants in the genus Aphaenogaster . To determine if yellow jacket, Vespula maculifrons (Buysson), presence interferes with seed foraging by ants, we presented seeds of Trillium discolor Wray to three species ( A. texana carolinensis Wheeler, Formica schaufussi Mayr, and Solenopsis invicta Buren) of seed-carrying ants in areas where vespids were present or excluded. We found that interspecific aggression between yellow jackets and ants is species specific. Vespid presence decreased average foraging time and increased foraging efficiency of two of the three ant species studied, a situation that might reflect competition for a limited food source. We also found that yellow jackets removed more seeds than ants, suggestive that vespids are important, albeit underestimated, components of ant-seed mutualisms.

Southeastern Naturalist↗
USGS2001

Use of borehole and surface geophysics to investigate ground-water quality near a road-deicing salt-storage facility, Valparaiso, Indiana

Borehole and surface geophysics were used to investigate ground-water quality affected by a road-deicing salt-storage facility located near a public water-supply well field. From 1994 through 1998, borehole geophysical logs were made in an existing network of monitoring wells completed near the bottom of a thick sand aquifer. Logs of natural gamma activity indicated a uniform and negligible contribution of clay to the electromagnetic conductivity of the aquifer so that the logs of electromagnetic conductivity primarily measured the amount of dissolved solids in the ground water near the wells. Electromagnetic-conductivity data indicated the presence of a saltwater plume near the bottom of the aquifer. Increases in electromagnetic conductivity, observed from sequential logging of wells, indicated the saltwater plume had moved north about 60 to 100 feet per year between 1994 and 1998. These rates were consistent with estimates of horizontal ground-water flow based on velocity calculations made with hydrologic data from the study area. Ratios of chloride to bromide concentrations in water samples were used to distinguish sources of chloride in the ground water?whether from road-deicing salt, domestic wastewater, or natural occurrences. Water samples identified with the chloride/bromide ratios as being affected by road-deicing salt had concentrations of dissolved solids, chloride, and sodium many times the background levels for the study area. The largest concentrations were in water from wells near the salt-storage facility?12,400 to 12,800 milligrams per liter (mg/L) dissolved solids, 6,730 to 7,230 mg/L chloride, and 3,690 to 4,400 mg/L sodium. A conceptual, multi-layer model was developed to describe the vertical extent of the saltwater plume in the vicinity of the monitoring wells. A relation was derived between average borehole electromagnetic conductivity in the screened interval of the wells in the saltwater plume and concentrations of dissolved solids in water samples from those wells. This relation was used in the model to show borehole electromagnetic conductivity in transects of wells as a zone of saline water overlain by zones of brackish water and freshwater. The thickness and altitude of the zones of saline and brackish water decreased with increased distance from the salt-storage facility. Two surface surveys of terrain electromagnetic conductivity were used to map the horizontal extent of the saltwater plume in areas without monitoring wells. Background values of terrain conductivity were measured in an area where water-quality and borehole geophysical data did not indicate saline or brackish water. Based on a guideline from previous case studies, the boundaries of the saltwater plume were mapped where terrain conductivity was 1.5 times background. The extent of the saltwater plume, based on terrain conductivity, generally was consistent with the available water-quality and borehole electromagnetic-conductivity data and with directions of ground-water flow determined from water-level altitudes.

Indiana↗
USGS1997

Modified level II streambed-scour analysis for structure I-65-85-5527 crossing Sugar Creek in Johnson County, Indiana

Level II scour evaluations follow a process in which hydrologic, hydraulic, and sediment transport data are evaluated to calculate the depth of scour that may result when a given discharge is routed through a bridge opening. The results of the modified Level II analysis for structure 1-65-85-5527 on Interstate 65 crossing Sugar Creek in Johnson County, Indiana, are presented. The site is near the town of Amity in the southeastern part of Johnson County. Scour depths were computed with the Water Surface PROfile model, version V050196, which incorporates the scour-calculation procedures outlined in Hydraulic Engineering Circular No. 18. Total scour depths at the piers were approximately 26.8 feet for the modeled discharge of 26,000 cubic feet per second and approximately 30.8 feet for the modeled discharge of 34,100 cubic feet per second

Indiana↗
USGS1997

Modified level II streambed-scour analysis for structure I-70-104-5128 crossing Brandywine Creek in Hancock County, Indiana

Level II scour evaluations follow a process in which hydrologic, hydraulic, and sedient-transport data are evaluated to calculate the depth of scour that may result when given discharge is routed through a bridge opening. the results of the modified Levell II analysis for structure I-70-104-5128 on Interstate 70 crossing Brandywine Creek in Hancock County, Indiana, are presented. The site is near the town of Greenfield in the central part of Hancock County. Scour depths were computed with the Water Surface PROfile model, version V050196, which incorporates the scour-calculation procedures outlined in Hydraulic Engineering Circular No. 18. Total scour depths at the piers were approximately 6.5 feet for the modeled discharge of 6,900 cubic feet per second and approximately 8.0 feet for the modeled discharge of 9,140 cubic feet per second.

Indiana↗
USGS1997

Modified level II streambed-scour analysis for structure I-65-120-6016 crossing Little Eagle Creek and I-65 in Marion County, Indiana

Level II scour evaluations follow a process in which hydrologic, hydraulic, and sedient-transport data are evaluated to calculate the depth of scour that may result when given discharge is routed through a bridge opening. the results of the modified Levell II analysis for structure I-65-120-6016 on Georgetown Road crossing Little Eagle Creek and 1-65 in Marion County, Indiana, are presented. The site is in the city of Indianapolis in the northwestern part of Marion County. Scour depths were computed with the Water Surface PROfile model, version V050196, which incorporates the scour-calculation procedures outlined in Hydraulic Engineering Circular No. 18. Total scour depths at the piers were approximately 5.2 feet for the modeled discharge of 3,450 cubic feet per second and approximately 5.6 feet for the modeled discharge of 5,210 cubic feet per second.

Indiana↗
USGS1997

Modified level II streambed-scour analysis for structure I-69-87-4781 crossing Wabash River in Huntington County, Indiana

Level II scour evaluations follow a process in which hydrologic, hydraulic, and sediment transport data are evaluated to calculate the depth of scour that may result when a given discharge is routed through a bridge opening. The results of the modified Level II analysis for structure 1-69-87-4781 on Interstate 69 crossing Wabash River in Huntington County, Indiana, are presented. The site is near the town of Markle in the eastern part of Huntington County. Scour depths were computed with the Water Surface PROfile model, version V050196, which incorporates the scour-calculation procedures outlined in Hydraulic Engineering Circular No. 18. Total scour depths at the piers were approximately 13.1 feet for the modeled discharge of 10,600 cubic feet per second and approximately 14.6 feet for the modeled discharge of 17,000 cubic feet per second.

Indiana↗
USGS1997

Modified level II streambed-scour analysis for structure I-74-70-4437 crossing Eagle Creek in Marion County, Indiana

Level II scour evaluations follow a process in which hydrologic, hydraulic, and sedimenttransport data are evaluated to calculate the depth of scour that may result when a given discharge is routed through a bridge opening. The results of the modified Level II analysis for structure 1-74-70-4437 on Interstate 74 crossing Eagle Creek in Marion County, Indiana, are presented. The site is near the town of Clermont in the northwestern part of Marion County. Scour depths were computed with the Water Surface PROfile model, version V050196, which incorporates the scour-calculation procedures outlined in Hydraulic Engineering Circular No. 18. Total scour depths at the piers were approximately 16.0 feet for the modeled discharge of 22,700 cubic feet per second and approximately 31.7 feet for the modeled discharge of 31,600 cubic feet per second.

Indiana↗
USGS1997

Modified level II streambed-scour analysis for structure I-70-141-4972 crossing Greens Fork in Wayne County, Indiana

Level II scour evaluations follow a process in which hydrologic, hydraulic, and sediment transport data are evaluated to calculate the depth of scour that may result when a given discharge is routed through a bridge opening. The results of the modified Level II analysis for structure 1-70-141-4972 on Interstate 70 crossing Greens Fork in Wayne County, Indiana, are presented. The site is near the town of Jacksonburg in the west-central part of Wayne County. Scour depths were computed with the Water Surface PROfile model, version V050196, which incorporates the scour-calculation procedures outlined in Hydraulic Engineering Circular No. 18. Total scour depths at the piers were approximately 23.0 feet for the modeled discharge of 8,900 cubic feet per second and approximately 28.1 feet for the modeled discharge of 11,500 cubic feet per second.

Indiana↗
USGS1997

Modified level II streambed-scour analysis for structure I-70-35-5245 crossing Big Walnut Creek in Putnam County, Indiana

Level II scour evaluations follow a process in which hydrologic, hydraulic, and sedimenttransport data are evaluated to calculate the depth of scour that may result when a given discharge is routed through a bridge opening. The results of the modified Level II analysis for structure 1-70-35-5245 on Interstate 70 crossing Big Walnut Creek in Pumam.County, Indiana, are presented. The site is near the town of Manhattan in the southwestern part of Putnam County. Scour depths were computed with the Water Surface PROfile model, version V050196, which incorporates the scour-calculation procedures outlined in Hydraulic Engineering Circular No. 18. Total scour depths at the piers were approximately 17.0 feet for the modeled discharge of 29,200 cubic feet per second and approximately 30.9 feet for the modeled discharge of 49,600 cubic feet per second.

Indiana↗
USGS1997

Modified level II streambed-scour analysis for structure I-69-16-5324 crossing Fosters Branch in Madison County, Indiana

Level II scour evaluations follow a process in which hydrologic, hydraulic, and sediment transport data are evaluated to calculate the depth of scour that may result when a given discharge is routed through a bridge opening. The results of the modified Level II analysis for structure 1-69-16-5324 on Interstate 69 crossing Fosters Branch in Madison County, Indiana, are presented. The site is near the town of Ingalls in the southwestern part of Madison County. Scour depths were computed with the Water Surface PROfile model, version V050196, which incorporates the scour-calculation procedures outlined in Hydraulic Engineering Circular No. 18. Total scour depths at the piers were approximately 8.0 feet for the modeled discharge of 1,600 cubic feet per second and approximately 12.8 feet for the modeled discharge of 2,720 cubic feet per second.

Indianapolis↗
USGS1997

Modified level II streambed-scour analysis for structure I-70-148-4528 crossing West Fork of East Fork Whitewater River in Wayne County, Indiana

Level II scour evaluations follow a process in which hydrologic, hydraulic, and sedient-transport data are evaluated to calculate the depth of scour that may result when given discharge is routed through a bridge opening. the results of the modified Levell II analysis for structure I-70-148-4528 on Interstate 70 crossing West Fork of East Fork Whitewater River in Wayne County, Indiana, are presented. The site is near the city of Richmond in the eastern part of Wayne County. Scour depths were computed with the Water Surface PROfile model, version V050196, which incorporates the scour-calculation procedures outlined in Hydraulic Engineering Circular No. 18. Total scour depths at the piers were approximately 19.8 feet for the modeled discharge of 6,000 cubic feet per second and approximately 26.5 feet for the modeled discharge of 7,900 cubic feet per second.

Indiana↗
USGS1997

Modified level II streambed-scour analysis for structure I-64-83-5678 crossing Stinking Fork in Crawford County, Indiana

Level II scour evaluations follow a process in which hydrologic, hydraulic, and sediment transport data are evaluated to calculate the depth of scour that may result when a given discharge is routed through a bridge opening. The results of the modified Level II analysis for structure 1-64-83-5678 on Interstate 64 crossing Stinking Fork in Crawford County, Indiana, are presented. The site is at the town of West Fork in the southwestern part of Crawford County. Scour depths were computed with the Water Surface PROfile model, version V050196, which incorporates the scour-calculation procedures outlined in Hydraulic Engineering Circular No. 18. Total scour depths at the piers were approximately 9.1 feet for the modeled discharge of 9,070 cubic feet per second and approximately 10.8 feet for the modeled discharge of 10,950 cubic feet per second.

Indianda↗
USGS1997

Modified level II streambed-scour analysis for structure I-65-118-4838 crossing Crooked Creek in Marion County, Indiana

Level II scour evaluations follow a process in which hydrologic, hydraulic, and sedimenttransport data are evaluated to calculate the depth of scour that may result when a given discharge is routed through a bridge opening. The results of the modified Level II analysis for structure 1-65-118-4838 on Interstate 65 crossing Crooked Creek in Marion County, Indiana, are presented. The site is in the city of Indianapolis in the central part of Marion County. Scour depths were computed with the Water Surface PROfile model, version V050196, which incorporates the scour-calculation procedures outlined in Hydraulic Engineering Circular No. 18. Total scour depths at the piers were approximately 8.3 feet for the modeled discharge of 7,000 cubic feet per second and approximately 9.2 feet for the modeled discharge of 9,870 cubic feet per second.

Indiana↗