Estimation of natural ground water recharge for the performance assessment of a low-level waste disposal facility at the Hanford Site

Rockhold, Mark; Fayer, M.J.; Kincaid, C.T.; Gee, Glendon W.

doi:10.2172/46664

Cited by 44 publications

(48 citation statements)

References 65 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In contrast, an 8-year record (1985)(1986)(1987)(1988)(1989)(1990)(1991)(1992)(1993) of drainage data for a bare (unvegetated), 7.6-m deep, sand-filled lysimeter in the 300-N Area (~1.8 km west-northwest of the 300 Area) yielded an average annual recharge rate of ~55 mm/yr (Rockhold et al 1995). The average annual precipitation rate at the Hanford Site has increased since the period when the lysimeter data were collected, so a value of ~60 mm/yr is considered to be more representative of the average annual recharge rate through unvegetated sand for recent climatic conditions .…”

Section: B21 Group 1 Wellsmentioning

confidence: 97%

Three-Dimensional Groundwater Models of the 300 Area at the Hanford Site, Washington State

Williams¹,

Rockhold²,

Thorne³

et al. 2008

View full text Add to dashboard Cite

iii Executive SummaryThe purpose of this research is to develop and maintain numerical groundwater flow and transport models that can be used to refine the conceptual site model for groundwater beneath the 300 Area, and to assist in evaluating alternative remediation technologies focused on the 300 Area uranium plume. Groundwater flow rates and directions in the 300 Area are very dynamic because of the high hydraulic conductivities, along with the large daily, weekly, and seasonal fluctuations in the Columbia River stage. Quantifying the dynamics of groundwater flow and transport in the 300 Area aquifer will help understand the significant seasonal variability of uranium plume concentrations seen in biannual groundwater monitoring, and will help evaluate remediation options. Groundwater flow rates are very high in the upper portion of the 300 Area unconfined aquifer (within the Hanford formation), with velocities up to 10 to 15 m/d (35 to 50 ft/d) based on a tracer test and limited plume-migration data. Variability in the groundwater-flow directions is apparent from analysis of hourly and subhourly automated water-level measurements from monitoring networks established in the 300 Area. Generalized flow directions in the area between the north and south process ponds are toward the east to south, with the directions changing toward the south and west during periods of increases in the river stage (daily and seasonal).High-resolution water level and river stage data were required to simulate the dynamics of the 300 Area aquifer. Two scales of groundwater flow and transport models were developed based on the availability of high-resolution water-level monitoring data. A larger-domain model was developed that includes the 300 Area and extends north and south using data from the early 1990s water-level monitoring network. A smaller domain model was developed for a portion of the large scale model domain in the north of the 300 Area that used water-level data from another smaller monitoring well network that was established in 2004. These models focus on the highly permeable upper portion of the unconfined aquifer within the Hanford formation that has hydraulic conductivity values 2 to 3 orders of magnitude higher than the underlying Ringold Formation aquifers. These models simulate saturated and unsaturated groundwater flow and transport with the STOMP code, which was developed at Pacific Northwest National Laboratory. 1The hydrostratigraphy, topography, and bathymetry for the three-dimensional models used a consistent framework using EarthVision  software.The model domains include the lower portion of the vadose zone to encompass the range of river stage and water- The hydrostratigraphic units were determined from previously published interpretations of the 300 Area, along with data from additional wells installed since those studies. A reanalysis of some of the older geologic unit picks from well logs in the area, along with using geophysical logs, was conducted based on the detailed knowledge gained from the 300 ...

show abstract

Section: B21 Group 1 Wellsmentioning

confidence: 97%

Three-Dimensional Groundwater Models of the 300 Area at the Hanford Site, Washington State

Williams¹,

Rockhold²,

Thorne³

et al. 2008

View full text Add to dashboard Cite

show abstract

“…The upper boundary condition beneath land areas was set to a natural recharge rate of 1 cm/yr (Rockhold et al 1995). The eastern boundary condition for the nodes directly under the river (at approximate mid-channel) was set as no-flow because of the symmetry in flow from each side of the river.…”

Section: Boundary Conditionsmentioning

confidence: 99%

Zone of Interaction Between Hanford Site Groundwater and Adjacent Columbia River

Peterson¹

2001

View full text Add to dashboard Cite

SummaryThis report describes results for activities conducted under the Groundwater/River Interface task, which is part of the Science and Technology effort associated with the Groundwater/Vadose Zone Integration Project at the Hanford Site. The goal for the Groundwater/River Interface task is to improve the conceptual model for the zone of interaction and its interfaces with the river. The groundwater flow system beneath the Hanford Site represents a primary pathway for contaminants to migrate away from source areas and, for some contaminants, to ultimately discharge into the Columbia River. Near the river, groundwater flow is strongly influenced by the river stage. The rise and fall of the river stage create a dynamic zone of interaction between the two flow systems, thus influencing flow patterns and transport rates. Also, chemical and biological processes at the various interfaces between the aquifer and river channel may alter the characteristics of contaminants potentially moving with groundwater.The need for an improved understanding of the Hanford Site's groundwater/river interface is acknowledged in the Integration Project's Science and Technology roadmap (DOE/RL 2000, Appendix B, pp. B-51 to B-67). Technical information gaps identified in the roadmap are an outgrowth of workshops conducted in May 1999 during which several National Laboratories and site contractors collaborated to help define science and technology information needs. Information Need RL-SS37 has been addressed under the Groundwater/River Interface Task. This need is described in the roadmap as follows:• "Provide methodology to relate information derived from sitewide-scale groundwater flow modeling to the various scales associated with assessing impacts in the river environment."The roadmap also describes several aspects of research appropriate to address the information need. Two focus areas addressed in this report are:• "Develop the modeling capabilities to characterize the flow path of water within the zone of interaction, which is strongly influenced by river stage fluctuations."• "Develop the modeling capabilities to quantify the changes in groundwater characteristics that take place in the zone of interaction between the aquifer and the river." Water Movement Simulation (Flow Path Modeling Capabilities)Flow patterns in the zone of groundwater/river interaction (ZOI) are highly variable because of daily and seasonal fluctuations in river stage. Intermingling of groundwater and river water in the zone, along with the locations of groundwater discharge into the river channel, are key issues. The computer code Subsurface Transport of Multiple Phases (White and Oostrom 1996) was used to simulate movement in two dimensions along a cross section oriented perpendicular to the river at the 100-H Area. The simulation covers the entire year of 1998 in hourly increments and includes the transient hydraulic conditions created by the fluctuating river stage. The velocity field was animated using the graphical iv display capabilities of TecPlot...

show abstract

“…Lysimeters can be simply designed with little or no peripheral instrumentation, or they can be designed with extensive monitoring features, including devices for monitoring temperature, water content and matric potential and devices for extracting samples of water for chemical analysis. Lysimeters have been built and used at the Hanford Site for a variety of reasons, including the assessment of recharge rates, biointrusion studies, radionuclide transport studies, evapotranspiration studies, and field-scale waste-form performance tests (Gee and Jones 1985;Rockhold et al 1995).…”

Section: Field Testingmentioning

confidence: 99%

A Strategy to Conduct an Analysis of the Long-Term Performance of Low-Activity Waste Glass in a Shallow Subsurface Disposal System at Hanford

McGrail¹,

Ebert²,

Bacon³

et al. 1998

View full text Add to dashboard Cite

Estimation of natural ground water recharge for the performance assessment of a low-level waste disposal facility at the Hanford Site

Abstract: Example Time Periods and Analysis Considerations 4.3 Cline et al. (1980) noted that most of the disturbed areas at the Hanford Site have developed irregular stands of cheatgrass, tumbleweed, and rabbitbrush. All three of these plants have been

Cited by 44 publications

References 65 publications

Three-Dimensional Groundwater Models of the 300 Area at the Hanford Site, Washington State

Three-Dimensional Groundwater Models of the 300 Area at the Hanford Site, Washington State

Zone of Interaction Between Hanford Site Groundwater and Adjacent Columbia River

A Strategy to Conduct an Analysis of the Long-Term Performance of Low-Activity Waste Glass in a Shallow Subsurface Disposal System at Hanford

Contact Info

Product

Resources

About