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Brennon R. Orr

Publications and source records attributed to Brennon R. Orr.

10 recordsLinked to original sources
USGS2006

A conceptual model of ground-water flow in the eastern Snake River Plain aquifer at the Idaho National Laboratory and vicinity with implications for contaminant transport

Ground-water flow in the west-central part of the eastern Snake River Plain aquifer is described in a conceptual model that will be used in numerical simulations to evaluate contaminant transport at the Idaho National Laboratory (INL) and vicinity. The model encompasses an area of 1,940 square miles (mi2) and includes most of the 890 mi2 of the INL. A 50-year history of waste disposal associated with research activities at the INL has resulted in measurable concentrations of waste contaminants in the aquifer. A thorough understanding of the fate and movement of these contaminants in the subsurface is needed by the U.S. Department of Energy to minimize the effect that contaminated ground water may have on the region and to plan effectively for remediation. Three hydrogeologic units were used to represent the complex stratigraphy of the aquifer in the model area. Collectively, these hydrogeologic units include at least 65 basalt-flow groups, 5 andesite-flow groups, and 61 sedimentary interbeds. Three rhyolite domes in the model area extend deep enough to penetrate the aquifer. The rhyolite domes are represented in the conceptual model as low permeability, vertical pluglike masses, and are not included as part of the three primary hydrogeologic units. Broad differences in lithology and large variations in hydraulic properties allowed the heterogeneous, anisotropic basalt-flow groups, andesite-flow groups, and sedimentary interbeds to be grouped into three hydrogeologic units that are conceptually homogeneous and anisotropic. Younger rocks, primarily thin, densely fractured basalt, compose hydrogeologic unit 1; younger rocks, primarily of massive, less densely fractured basalt, compose hydrogeologic unit 2; and intermediate-age rocks, primarily of slightly-to-moderately altered, fractured basalt, compose hydrogeologic unit 3. Differences in hydraulic properties among adjacent hydrogeologic units result in much of the large-scale heterogeneity and anisotropy of the aquifer in the model area, and differences in horizontal and vertical hydraulic conductivity in individual hydrogeologic units result in much of the small-scale heterogeneity and anisotropy of the aquifer in the model area. The inferred three-dimensional geometry of the aquifer in the model area is very irregular. Its thickness generally increases from north to south and from west to east and is greatest south of the INL. The interpreted distribution of older rocks that underlie the aquifer indicates large changes in saturated thickness across the model area. The boundaries of the model include physical and artificial boundaries, and ground-water flows across the boundaries may be temporally constant or variable and spatially uniform or nonuniform. Physical boundaries include the water-table boundary, base of the aquifer, and northwest mountain-front boundary. Artificial boundaries include the northeast boundary, southeast-flowline boundary, and southwest boundary. Water flows into the model area as (1) underflow (1,225 cubic feet per second (ft3/s)) from the regional aquifer (northeast boundary-constant and nonuniform), (2) underflow (695 ft3/s) from the tributary valleys and mountain fronts (northwest boundary-constant and nonuniform), (3) precipitation recharge (70 ft3/s) (constant and uniform), streamflow-infiltration recharge (95 ft3/s) (variable and nonuniform), wastewater return flows (6 ft3/s) (variable and nonuniform), and irrigation-infiltration recharge (24 ft3/s) (variable and nonuniform) across the water table (water-table boundary-variable and nonuniform), and (4) upward flow across the base of the aquifer (44 ft3/s) (uniform and constant). The southeast-flowline boundary is represented as a no-flow boundary. Water flows out of the model area as underflow (2,037 ft3/s) to the regional aquifer (southwest boundary-variable and nonuniform) and as ground-water withdrawals (45 ft3/s) (water table boundary-variable and nonuniform). Ground-water flow i

Scientific Investigations Report↗
USGS2005

Review of the transport of selected radionuclides in the interim risk assessment for the Radioactive Waste Management Complex, Waste Area Group 7 Operable Unit 7-13/14, Idaho National Engineering and Environmental Laboratory, Idaho

The U.S. Department of Energy (DOE) requested that the U.S. Geological Survey conduct an independent technical review of the Interim Risk Assessment (IRA) and Contaminant Screening for the Waste Area Group 7 (WAG-7) Remedial Investigation, the draft Addendum to the Work Plan for Operable Unit 7-13/14 WAG-7 comprehensive Remedial Investigation and Feasibility Study (RI/FS), and supporting documents that were prepared by Lockheed Martin Idaho Technologies, Inc. The purpose of the technical review was to assess the data and geotechnical approaches that were used to estimate future risks associated with the release of the actinides americium, uranium, neptunium, and plutonium to the Snake River Plain aquifer from wastes buried in pits and trenches at the Subsurface Disposal Area (SDA). The SDA is located at the Radioactive Waste Management Complex in southeastern Idaho within the boundaries of the Idaho National Engineering and Environmental Laboratory. Radionuclides have been buried in pits and trenches at the SDA since 1957 and 1952, respectively. Burial of transuranic wastes was discontinued in 1982. The five specific tasks associated with this review were defined in a ?Proposed Scope of Work? prepared by the DOE, and a follow-up workshop held in June 1998. The specific tasks were (1) to review the radionuclide sampling data to determine how reliable and significant are the reported radionuclide detections and how reliable is the ongoing sampling program, (2) to assess the physical and chemical processes that logically can be invoked to explain true detections, (3) to determine if distribution coefficients that were used in the IRA are reliable and if they have been applied properly, (4) to determine if transport model predictions are technically sound, and (5) to identify issues needing resolution to determine technical adequacy of the risk assessment analysis, and what additional work is required to resolve those issues.

Idaho↗
USGS2002

Kilometer-scale rapid transport of naphthalene sulfonate tracer in the unsaturated zone at the Idaho National Engineering and Environmental Laboratory

To investigate possible long-range flow paths through the interbedded basalts and sediments of a 200-m-thick unsaturated zone, we applied a chemical tracer to seasonally filled infiltration ponds on the Snake River Plain in Idaho. This site is near the Subsurface Disposal Area for radioactive and other hazardous waste at the Idaho National Engineering and Environmental Laboratory. Within 4 mo, we detected tracer in one of 13 sampled aquifer wells, and in eight of 11 sampled perched-water wells as far as 1.3 km away. These detections show that (i) low-permeability layers in the unsaturated zone divert some flow horizontally, but do not prevent rapid transport to the aquifer; (ii) horizontal convective transport rates within the unsaturated zone may exceed 14 m d −1 , perhaps through essentially saturated basalt fractures, tension cracks, lava tubes, or rubble zones; and (iii) some perched water beneath the Subsurface Disposal Area derives from episodic surface water more than 1 km away. Such rapid and far-reaching flow may be common throughout the Snake River Plain, and possibly occurs in other locations that have a geologically complex unsaturated zone and comparable sources of infiltrating water.

Idaho↗
USGS1987

Water resources of the Zuni tribal lands, McKinley and Cibola Counties, New Mexico

An evaluation of the water resources of the Zuni tribal lands in west-central New Mexico was made to determine the yield, variability, and quality of water available to the Pueblo of Zuni. This study is needed to aid in orderly development of these resources. Rocks of Permian to Quaternary age supply stock, irrigation, and domestic water to the Zuni Indians. The Glorieta Sandstone and San Andres Limestone (Glorieta-San Andres aquifer) of Permian age and sandstones in the Chinle Formation of Triassic age provide most of this water supply. Water in the Glorieta-San Andres aquifer is confined by minimal-permeability shales and is transmitted through the aquifer along interconnected solution channels and fractures. Water-level and water-quality information indicate greater hydraulic conductivities along the southern boundaries of Zuni tribal lands. Well yields from the Glorieta-San Andres aquifer are as much as 150 gallons per minute, and aquifer transmissivity ranges from 30 to 1,400 feet squared per day. Longterm, water-level declines of as much as 29 feet have been measured near pumping centers at Black Rock. Multiple-well aquifer tests are needed to further define aquifer properties (storage, transmissivity, and leakage from confining units) and the effects of well design on well yields. Dissolved-solids concentrations in water from the aquifer range from 331 to 1,068 milligrams per liter. Calcium and sulfate are the predominant ions. Water in sandstones of the Chinle Formation is confined by adjacent shales and is transmitted along interconnected fractures. Well yields range from 5 to 125 gallons per minute, and aquifer transmissivity ranges from 40 to 1,400 feet squared per day. Water-level declines of as much as 27 feet have been measured near Zuni Village. Dissolved-solids concentrations in water from the aquifer range from 215 to 1,980 milligrams per liter. Sodium and bicarbonate are the predominant ions. Other sources of ground water are used primarily for livestock watering by means of windmills, with the exception of buried alluvial channel deposits along the Rio Pescado. These deposits provide domestic and irrigation water through springs and wells to Pescado and Black Rock. The Bidahochi Formation of Miocene and Pliocene age could potentially provide an additional supply of water chemically suitable for most uses. Seismic-reflection techniques are being used to locate buried channels eroded in the rocks underlying the Bidahochi Formation. These buried channels may contain thicker sections of saturated sands and gravels that could be developed for stock and domestic use.

Water Supply Paper↗
USGS1983

Water resources of the Zuni Tribal Lands, McKinley and Cibola counties, New Mexico

An evaluation of the water resources of the Zuni Tribal lands in west-central New Mexico was made to determine the yield, variability, and quality of water available to the Pueblo of Zuni. This study is needed to aid in orderly development of these resources. Rocks of Permian to Quaternary age supply stock, irrigation, and domestic water to the Zuni Indians. The Glorieta Sandstone and San Andres Limestone (Glorieta-San Andres aquifer) of Permian age and sandstones in the Chinle Formation of Triassic age provide most of this water supply. Water in the Glorieta-San Andres aquifer is confined by minimal-permeability shales and is transmitted through the aquifer along interconnected solution channels and fractures. Water-level and water-quality information indicate greater hydraulic conductivities along the southern boundaries of Zuni Tribal lands. Well yields from the Glorieta-San Andres aquifer are as much as 150 gallons per minute and aquifer transmissivity ranges from 30 to 1,400 feet squared per day. Long-term, water-level declines of as much as 29 feet have been measured near pumping centers at Black Rock. Multiple-well aquifer tests are needed to further define aquifer properties (storage, transmissivity, and leakage from confining units) and the effects of well design on well yields. Dissolved-solids concentrations in water from the aquifer ranged from 331 to 1,068 milligrams per liter. Calcium and sulfate are the predominant ions. Water in sandstones of the Chinle Formation is confined by adjacent shales and is transmitted along interconnected fractures. Well yields range from 5 to 125 gallons per minute and aquifer transmissivity ranges from 40 to 1,400 feet squared per day. Water-level declines of as much as 27 feet have been measured near Zuni Village. Dissolved-solids concentrations in water from the aquifer ranged from 215 to 1,980 milligrams per liter. Sodium and bicarbonate are the predominant ions. Other sources of ground water are used primarily for livestock watering by means of windmills, with the exception of buried alluvial channel deposits along the Rio Pescado. These deposits provide domestic and irrigation water through springs and wells to Pescado and Black Rock. The Bidahochi Formation of Miocene and Pliocene age could potentially provide an additional supply of water chemically suitable for most uses. Seismic-reflection techniques are being used to locate buried channels eroded in the rocks underlying the Bidahochi Formation. These buried channels may contain thicker sections of saturated sands and gravels that could be developed for stock and domestic use.

New Mexico↗
USGS1981

Water resources of the Rincon and Mesilla Valleys and adjacent areas, New Mexico

The Rincon and Mesilla Valleys of New Mexico extend from Caballo Reservoir to El Paso del Norte, west of El Paso, Texas. Water supplies for this area are obtained from the Rio Grande and from the saturated sediments filling the intermontane basins of south-central New Mexico. The two major aquifers are the Santa Fe Group of Miocene to middle Pleistocene age and the flood-plain alluvium of late Pleistocene and Holocene age. The Santa Fe Group is composed of thick deposits of interbedded clay, silt, sand, and gravel. The flood-plain alluvium, generally less than 80 feet thick, is composed of a basal gravel layer overlain by interbedded sand, silt, and clay. In the Rincon Valley, the flood-plain alluvium is the principal source of ground water because the underlying Santa Fe is composed predominantly of lacustrine clay deposits. In the Mesilla Valley, thick deposits of fluvial sands and gravels in the Santa Fe Group are hydraulically connected with the flood-plain alluvium. Water-table conditions occur in the flood-plain alluvium, which is recharged primarily by infiltration of surface water from the Rio Grande, irrigation canals, and irrigated fields. Recharge to the Santa Fe Group occurs primarily from downward infiltration of water from the flood-plain alluvium and secondarily from runoff infiltrating upland sediments and mountain-front fan deposits. In the short term, the Santa Fe Group responds as a leaky confined aquifer due to the presence of interbedded clays that reduce vertical permeability. Aquifer tests were conducted on 58 wells and test holes, most of which were completed in the Santa Fe Group. Transmissivities range from 1.3 to 21,100 feet squared per day. Average well yields range from about 1,050 gallons per minute in the Rincon Valley to about 1,500 gallons per minute in the Mesilla Valley. Yields in the Jornada del Muerto generally are much smaller. Movement of ground water is generally southward in the Rincon and Mesilla Valleys and toward the valleys in the adjacent upland areas. Ground water moves southeastward beneath the West Mesa area, converging with ground-water flow in the southern end of the Mesilla Valley. Good hydraulic connection exists between sediments of the West Mesa and Mesilla Valley areas. Ground water in the southern end of the Jornada del Muerto moves generally to the northwest, converges with south-flowing ground water near Point of Rocks, and moves westward into Rincon Valley sediments near Rincon. A small amount of ground water flows westward from the southern end of the Jornada del Muerto across a subsurface igneous body into the Mesilla Valley. Ground-water discharge occurs throughout the Rincon and Mesilla Valleys as drain flow to the river and evapotranspiration. Dissolved-solids concentrations in the water in the flood-plain alluvium of the Rincon and Mesilla Valleys are generally greater than 1,000 milligrams per liter. A freshwater zone, with dissolved-solids concentrations less than 1,000 milligrams per liter, underlies this thin, slightly saline zone beneath much of the Mesilla Valley. This freshwater zone, occurring in the Santa Fe Group, is surrounded by saline water. Within the study area, major dissolved ions in ground water include sodium, calcium, bicarbonate, and sulfate. The Rio Grande is a gainlng stream in the northern parts of the Rincon and Mesilla Valleys and a losing stream in the southern part of the Mesilla Valley. Gains and losses result from a close interconnection with ground-water flow systems. Large surface-water irrigation allotments increase ground-water recharge. Increased recharge raises ground-water levels and improves shallow ground-water quality adjacent to these recharge areas. Shallow ground-water discharges to drains, which flow into the Rio Grande. Dissolved-solids concentrations in the Rio Grande increase by as much as 60 percent between Caballo Reservoir and the southern end of the study area.

New Mexico↗
USGS1977

Review and analysis of hydrogeologic conditions near the site of a potential nuclear-waste repository, Eddy and Lea counties, New Mexico

This interim report reviews and summarizes the hydrogeology of rocks associated with the Permian salt beds (Castile and Salado Formations) of Los Medanos area in southeastern New Mexico. The information will be considered, together with other factors, in the preparation of an analysis of the impact of a potential nuclear-waste repository on the environment. Most of the geologic units in and adjacent to the Permian salt deposits are characterized by low permeabilities and highly mineralized water. Sandstone of the Delaware Mountain Group, which underlies the salt, has an average hydraulic conductivity of 0.16 ft/d and an average porosity of 15.65 percent. Flow is north-northeastward toward the margin of the Capitan Limestone, at velocities ranging from 0.0005 to 0.0008 ft/d. The Capitan Limestone, a relatively high yielding limestone-reef aquifer adjacent to the study area, has transmissivity values ranging from 500 sq ft/d to 10,000 sq ft/d and an average hydraulic conductivity of about 5 ft/d. Water movement west of the Pecos River is northeastward in the reef, with discharge at Carlsbad Springs. East of the Pecos River, water moves at very low rates and the direction of movement is uncertain. The Castile and Salado Formations, which might be used to contain the nuclear waste, have a few isolated pockets of brine and gas, but generally transmit little or no ground water. (Woodard-USGS)

Open-File Report↗