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Title: Hydrologic Data and Evaluation for Model Validation Wells, MV-1, MV-2, and MV-3 near the Project Shoal Area

Abstract

In 2006, a drilling campaign was conducted at the Project Shoal Area (PSA) to provide information for model validation, emplace long-term monitoring wells, and develop baseline geochemistry for long term hydrologic monitoring. Water levels were monitored in the vicinity of the drilling, in the existing wells HC-1 and HC-6, as well as in the newly drilled wells, MV-1, MV-2 and MV-3 and their associated piezometers. Periodic water level measurements were also made in existing wells HC-2, HC-3, HC-4, HC-5 and HC-7. A lithium bromide chemical tracer was added to drilling fluids during the installation of the monitoring and validation (MV) wells and piezometers. The zones of interest were the fractured, jointed and faulted horizons within a granitic body. These horizons generally have moderate hydraulic conductivities. As a result, the wells and their shallower piezometers required strenuous purging and development to remove introduced drilling fluids as evidenced by bromide concentrations. After airlift and surging well development procedures, the wells were pumped continuously until the bromide concentration was less then 1 milligram per liter (mg/L). Water quality samples were collected after the well development was completed. Tritium scans were preformed before other analyses to ensure the absence of high levels of radioactivity.more » Tritium levels were less than 2,000 pico-curies per liter. Samples were also analyzed for carbon-14 and iodine-129, stable isotopes of oxygen and hydrogen, as well as major cations and anions. Aquifer tests were performed in each MV well after the bromide concentration fell below acceptable levels. Water level data from the aquifer tests were used to compute aquifer hydraulic conductivity and transmissivity« less

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Desert Research Institute, Nevada System of Higher Education, Reno,NV
Sponsoring Org.:
USDOE
OSTI Identifier:
921628
Report Number(s):
DOE/NV/13609-50; 45220
TRN: US200806%%121
DOE Contract Number:
AC52-00NV13609
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
08 HYDROGEN; ANIONS; AQUIFERS; BROMIDES; CARBON 14; CATIONS; DRILLING; DRILLING FLUIDS; GEOCHEMISTRY; HYDRAULIC CONDUCTIVITY; HYDRAULICS; HYDROGEN; IODINE 129; LITHIUM BROMIDES; OXYGEN; RADIOACTIVITY; STABLE ISOTOPES; TRITIUM; VALIDATION; WATER QUALITY

Citation Formats

B. Lyles, P. Oberlander, D. Gillespie, D. Donithan, J. Chapman, and J. Healey. Hydrologic Data and Evaluation for Model Validation Wells, MV-1, MV-2, and MV-3 near the Project Shoal Area. United States: N. p., 2007. Web. doi:10.2172/921628.
B. Lyles, P. Oberlander, D. Gillespie, D. Donithan, J. Chapman, & J. Healey. Hydrologic Data and Evaluation for Model Validation Wells, MV-1, MV-2, and MV-3 near the Project Shoal Area. United States. doi:10.2172/921628.
B. Lyles, P. Oberlander, D. Gillespie, D. Donithan, J. Chapman, and J. Healey. Wed . "Hydrologic Data and Evaluation for Model Validation Wells, MV-1, MV-2, and MV-3 near the Project Shoal Area". United States. doi:10.2172/921628. https://www.osti.gov/servlets/purl/921628.
@article{osti_921628,
title = {Hydrologic Data and Evaluation for Model Validation Wells, MV-1, MV-2, and MV-3 near the Project Shoal Area},
author = {B. Lyles and P. Oberlander and D. Gillespie and D. Donithan and J. Chapman and J. Healey},
abstractNote = {In 2006, a drilling campaign was conducted at the Project Shoal Area (PSA) to provide information for model validation, emplace long-term monitoring wells, and develop baseline geochemistry for long term hydrologic monitoring. Water levels were monitored in the vicinity of the drilling, in the existing wells HC-1 and HC-6, as well as in the newly drilled wells, MV-1, MV-2 and MV-3 and their associated piezometers. Periodic water level measurements were also made in existing wells HC-2, HC-3, HC-4, HC-5 and HC-7. A lithium bromide chemical tracer was added to drilling fluids during the installation of the monitoring and validation (MV) wells and piezometers. The zones of interest were the fractured, jointed and faulted horizons within a granitic body. These horizons generally have moderate hydraulic conductivities. As a result, the wells and their shallower piezometers required strenuous purging and development to remove introduced drilling fluids as evidenced by bromide concentrations. After airlift and surging well development procedures, the wells were pumped continuously until the bromide concentration was less then 1 milligram per liter (mg/L). Water quality samples were collected after the well development was completed. Tritium scans were preformed before other analyses to ensure the absence of high levels of radioactivity. Tritium levels were less than 2,000 pico-curies per liter. Samples were also analyzed for carbon-14 and iodine-129, stable isotopes of oxygen and hydrogen, as well as major cations and anions. Aquifer tests were performed in each MV well after the bromide concentration fell below acceptable levels. Water level data from the aquifer tests were used to compute aquifer hydraulic conductivity and transmissivity},
doi = {10.2172/921628},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Feb 14 00:00:00 EST 2007},
month = {Wed Feb 14 00:00:00 EST 2007}
}

Technical Report:

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  • The U.S. Department of Energy, Nevada Operations Office (DOE/NV) has initiated the Off-Site Project to characterize the hazards posed to human health and the environment as a result of underground nuclear testing activities at facilities other than the Nevada Test Site (NTS). The Project Shoal Area (PSA) is one of the Off-Sites Project areas located off the NTS, but within the state of Nevada. The PSA is located approximately 48 kilometers (30 miles) southeast of Fallon, Nevada. Four wells were drilled at the PSA in 1996 as part of the site investigation administered through the Federal Facility Agreement and Consentmore » Order (FFACO) (1996). The hydrogeologic data gathered from these wells was used to support the groundwater flow and contaminant transport modeling of the PSA. However, the subsequent evaluation of the groundwater model concluded that further delineation of the subsurface was required to reduce uncertainties in the model. In accordance with the FFACO, an addendum to the Corrective Action Investigation Plan (CAIP) for the proposed PSA subsurface investigation, Corrective Action Unit 447, was developed. The addendum proposed the drilling and construction of four additional wells and the conduct of hydrologic testing at the PSA. This Fluid Management Plan (FMP) provides guidance for the management of fluids generated from the well construction and testing activities at the PSA.« less
  • The groundwater flow and radionuclide transport model characterizing the Shoal underground nuclear test has been accepted by the State of Nevada Division of Environmental Protection. According to the Federal Facility Agreement and Consent Order (FFACO) between DOE and the State of Nevada, the next steps in the closure process for the site are then model validation (or postaudit), the proof-of-concept, and the long-term monitoring stage. This report addresses the development of the validation strategy for the Shoal model, needed for preparing the subsurface Corrective Action Decision Document-Corrective Action Plan and the development of the proof-of-concept tools needed during the five-yearmore » monitoring/validation period. The approach builds on a previous model, but is adapted and modified to the site-specific conditions and challenges of the Shoal site.« less
  • Stoller has examined newly collected water level data in multiple wells at the Shoal site. On the basis of these data and information presented in the report, we are currently unable to confirm that the model is successfully validated. Most of our concerns regarding the model stem from two findings: (1) measured water level data do not provide clear evidence of a prevailing lateral flow direction; and (2) the groundwater flow system has been and continues to be in a transient state, which contrasts with assumed steady-state conditions in the model. The results of DRI's model validation efforts and observationsmore » made regarding water level behavior are discussed in the following sections. A summary of our conclusions and recommendations for a path forward are also provided in this letter report.« less
  • Stoller has examined newly collected water level data in multiple wells at the Shoal site. On the basis of these data and information presented in the report, we are currently unable to confirm that the model is successfully validated. Most of our concerns regarding the model stem from two findings: (1) measured water level data do not provide clear evidence of a prevailing lateral flow direction; and (2) the groundwater flow system has been and continues to be in a transient state, which contrasts with assumed steady-state conditions in the model. The results of DRI's model validation efforts and observationsmore » made regarding water level behavior are discussed in the following sections. A summary of our conclusions and recommendations for a path forward are also provided in this letter report.« less
  • Test wells UE-29a No. 1 and UE-29a No. 2 were drilled in Fortymile Canyon, Nevada Test Site, as part of the US Department of Energy`s program to study the feasibility of constructing a high-level nuclear-waste repository beneath Yucca Mountain. The wells were designed to obtain data pertinent to characterizing the regional ground-water flow system near Yucca Mountain. Drilling of test well UE-29a No. 1 began September 25, 1981, and reached a total depth of 65.5 meters before being abandoned because of an irretrievable drill bit and collar down the hole. A second well, UE-29a No. 2, was drilled 8.9 metersmore » from the first and reached a depth of 421.5 meters before caving problems stopped the drilling. Hydrologic testing of UE-29a No. 1 consisted of three short-term pumping tests, with pumping rates ranging from 0.61 to 1.64 liters per second. These tests were stopped when the water level inside the test well declined to the pump intake. A water sample was collected in a separate episode of pumping; that water had a carbon-14 content of 75.3% of modern. Test well UE-29a No. 2 was tested in two episodes of pumping. Temperature and tracejector logs were obtained during pumping. Water samples collected during the first episode had a carbon-14 content of 62.3% of modern. The second episode of testing involved pumping the upper part of the hole and obtaining temperature and tracejector logs. The second episode of pumping was complicated by generator failure and clogging of the pump intake by debris from the perforating charges. The water sample had a carbon-14 content of 60.0% of modern. Predominant ions in all samples were sodium, calcium, and bicarbonate. 10 figs., 7 tabs.« less