Ward Valley -- Copyright -- Contents -- Executive Summary -- INTRODUCTION -- MAJOR CONCLUSIONS REGARDING THE SEVEN ISSUES -- Discussion of Issue 1 -- Issue 1 Subissues -- Basis For General Conclusions -- Limitations of Field Data at the Ward Valley Site -- Recommendations for Issue 1 -- General Recommendations -- Specific Recommendations -- Discussion of Issue 2 -- Basis for Committee Conclusions -- Recommendation For Issue 2 -- Discussion of Issue 3 -- Basis For Conclusions -- Discussion of Issue 4 -- Compliance and Performance Monitoring -- Integrated Approach -- Conclusions on Saturated Zone Monitoring -- Recommendations For Issue 4 -- Unsaturated Zone Monitoring -- Saturated Zone (Ground-Water) Monitoring -- Discussion of Issue 5 -- Flood Protection Berm -- Breakup Berms -- Recommendations For Issue 5 -- Discussion of Issue 6 -- Plan to Remediate Potential Impacts -- Habitat Loss -- Compensation For Habitat Loss and Fragmentation -- Recommendations For Issue 6 -- Discussion of Issue 7 -- The Revegetation Plan -- Consequences of Elevated Trench Cover -- Recommendations For Issue 7 -- 1 INTRODUCTION -- Department of Interior Involvement -- FEDERAL LOW-LEVEL RADIOACTIVE WASTE POLICY ACT -- Regional Compacts -- Regulations Governing Low-Level Radioactive Waste -- Classification of Wastes -- Composition of Low-Level Radioactive Wastes -- Siting Considerations -- Multiple Barriers -- Ground-Water Travel Time As an Barrier -- THE WARD VALLEY CONTROVERSY -- Issues Raised By the Wilshire Group -- The DHS/U.S. Ecology Response -- The Second Report -- The NAS/NRC Committee's Review -- Limits of NAS/NRC Review -- Source of Documents and Data -- Time Constraints -- The Open Meetings -- The Beatty, Nevada, Site as Analog -- The Plutonium-239 Issue -- Organization of the Report -- COMMITTEE DECLARATION -- REFERENCES -- 2 SETTING OF THE WARD VALLEY SITE.

LOCATION -- GENERAL FACILITY DESCRIPTION -- REGIONAL GEOLOGIC SETTING -- PRE-MIOCENE GEOLOGIC HISTORY -- Proterozoic Era -- Paleozoic Era -- Mesozoic Era -- Cenozoic Era -- Miocene Extension and Magmatism -- Block Faulting -- Detachment Faulting -- Post-Extension Geologic Evolution and Landscape Development -- Late Faults -- Basin Fill -- GEOMORPHOLOGY -- SUBSURFACE GEOPHYSICAL DATA -- Climate -- SURFACE-WATER HYDROLOGY -- Hydrologic Soil Group Classification -- HYDROGEOLOGY -- Features -- Recharge -- Water Table -- ECOLOGY -- Vegetation -- Desert Fauna -- Critical Habitat -- REFERENCES -- 3 RECHARGE THROUGH THE UNSATURATED ZONE -- THE WILSHIRE GROUP POSITION -- THE DHS/U.S. ECOLOGY POSITION -- THE COMMITTEE'S APPROACH -- THE NATURE OF WATER MOVEMENT IN THE UNSATURATED ZONE -- Water Content -- Potential Energy of Soil Water -- Hydraulic Conductivity -- Potential Energy of Soil Water -- Nature of Water Movement: Piston Flow And Preferential Flow -- THE NATURE, DIRECTION, AND MAGNITUDE OF WATER FLUX BENEATH THE WARDVALLEY SITE -- Soil Physics Methods Applied To Ward Valley -- Water-Content Data -- Conclusions Regarding Water-Content Data From The Ward Valley Site -- Monitoring of Water Potential at Ward Valley -- Direction of Water Flow -- Heat Dissipation Probe Measurements of Matric Potential -- Conclusions Regarding Water Content and Water-Potential Data at The Ward Valley Site -- ENVIRONMENTAL TRACERS AS INDICATORS OF SOIL-WATER MOVEMENT -- Chloride as a Soil-Water Tracer -- Chloride Accumulation Rate -- Non-Piston Water Movement -- Chloride Data From Ward Valley -- Conclusions Regarding Chloride Data From The Ward Valley Site -- Tritium as a Soil-Water Tracer -- Limitations of Tritium as a Tracer -- Tritium Distribution in the Unsaturated Zone -- Tritium Measurements at Ward Valley -- Procedural Blank and Uncertainty in The Blank.

Conclusions Regarding Tritium Found M The Unsaturated Zone -- Conditions at Homer Wash -- Summary of Subissue Conclusions -- EVIDENCE FOR RECHARGE TO THE GROUND WATER BENEATH THE SITE -- Observational Methods -- Tritium in the Ground Water -- Conclusions Regarding The Observation of Tritium In The Ground Water -- Carbon-14 Age of the Ground Water -- Stable Isotopic Composition of Ground Water As An Indicator Of Its Age -- Ward Valley Stable Isotope Data -- Estimates of Paleotemperatures Using The Claussen Approach -- Conclusions Regarding The Stable Isotopic Signature of Ground Waters -- Water Chemistry Changes -- Chemical Variations In Ward Valley Ground Water -- Variations In Specific Conductivity -- Conclusions Regarding The Fluctuations In Water Chemistry -- Water-Level Fluctuations -- Water-Level Measurements At The Ward Valley Site -- Conclusions Regarding Water-Level Fluctuations -- Ground-Water Gradients -- Conclusions Regarding The Observed Vertical Gradient -- SUMMARY OF CONCLUSIONS OF SUBISSUES 3, 4, AND 5 -- ADEQUACY OF THE PERFORMANCE-ASSESSMENT MODELING -- Adequacy of The Database For Performance Modeling -- Conclusions Regarding The Data For Modeling -- Modeling of The Complex System -- Scenario 1: Undisturbed Unsaturated Zone Under Normal Climatic Conditions -- Scenario 2: Undisturbed Unsaturated Zone Without Vegetation -- Scenario 7 And 7a: Complete Failure of The B/C Trench Cover -- Conclusions Regarding The Adequacy of Modeling To Incorporate The Complexities of The System -- Summary of Modeling Subissue -- SUMMARY OF CONCLUSIONS -- Major Conclusion -- Basis For Committee Judgements and Conclusions -- Limitations of Field Data -- Effects of Low Water Fluxes -- Effects of Instrument Limitations -- Quantity and Quality of Data -- Subissue Conclusions -- RECOMMENDATIONS -- General Recommendation -- Specific Recommendations.

REFERENCES -- 4 INFILTRATION AND LATERAL FLOW -- THE WILSHIRE GROUP POSITION -- THE DHS/U.S. ECOLOGY POSITION -- THE COMMITTEE'S APPROACH -- LATERAL FLOW UNDER NATURAL AND ENHANCED RAINFALL CONDITIONS AT ARIDSITES -- LATERAL FLOW UNDER PONDED CONDITIONS AT ARID SITES -- LATERAL FLOW IN ENGINEERED SYSTEMS AT ARID SITES -- CONCLUSIONS -- REFERENCES -- 5 GROUND-WATER PATHWAYS TO THE COLORADO RIVER -- THE WILSHIRE GROUP POSITION -- Details of Pathways -- THE DHS/U.S. ECOLOGY POSITION -- THE COMMITTEE'S APPROACH -- The Geological Framework for the Ground-Water Pathways -- Subsurface Bedrock Topography -- Fracture Permeability -- A Hydrologic Evaluation of the Proposed Ground-Water Pathways -- Water-Level Data -- Hydraulic Conductivity -- REVIEW OF PATHWAYS -- THE MAGNITUDE OF POTENTIAL IMPACTS OF LONG-LIVED RADIONUCLIDE MIGRATION FROM THE SITE TO THE COLORAD RIVER -- Assumptions for Bounding Estimates -- Path Length -- Travel Time -- Potential Impacts on the Colorado River -- Potential Radioactive Contamination by Ground Water -- Factors Affecting Radionuclide Transport -- Conclusion Concerning Contamination of the Colorado River -- Potential Radioactive Contamination by Airborne Dust -- SUMMARY OF CONCLUSIONS -- REFERENCES -- 6 SUBSURFACE MONITORING PROGRAM -- THE WILSHIRE GROUP POSITION -- THE DHS/U.S. ECOLOGY POSITION -- THE COMMITTEE'S APPROACH -- THE PERFORMANCE MONITORING PLAN FOR THE UNSATURATED ZONE -- Scope and Purpose of a Monitoring Plan -- Scope of Ward Valley Proposed Monitoring Plan -- PERFORMANCE MONITORING OF THE UNSATURATED ZONE -- Monitoring the Trench Cover -- Monitoring Beneath the Trenches -- Monitoring Adjacent to the Trenches -- Trench-Cap Demonstration Unit -- Committee Observations on Proposed Performance Monitoring of the Unsaturated Zone -- Unsaturated-Zone Monitoring Investigation and Action Levels.

Integration of Monitoring and Performance Assessment -- Extension of Site Characterization Database During Operational Monitoring and Integration with Performance Assessment -- Oversight Advisory Panel -- Other Issues and Recommendations -- Long-Term Monitoring -- Technology Development -- Soil Air Pressure Monitoring -- Monitoring Ambient Conditions -- Integration of Facility Design and Subsurface Monitoring -- Trench-Cap Demonstration Unit -- SUMMARY AND CONCLUSIONS -- Monitoring in the Unsaturated Zone -- THE COMPLIANCE MONITORING PLAN FOR THE SATURATED ZONE -- The Wilshire Group Position -- The DHS/U.S. Ecology Position -- The Committee's Approach -- Investigation and Action Levels -- Ground-Water Monitoring -- Committee Observations and Recommendations on Ground-Water Monitoring -- Investigation and Action Level Response Plan -- Oversight Advisory -- Placement of Monitoring Wells -- Well Construction -- Drilling Methodology -- REFERENCES -- 7 FLOOD CONTROL AND ENGINEERING CONSIDERATIONS -- THE WILSHIRE GROUP POSITION -- THE DHS/U.S. ECOLOGY POSITION -- THE COMMITTEE'S APPROACH -- DESCRIPTION OF PROPOSED FACILITIES -- Radiological Control Area Facilities -- General Trench Area Design -- Flood Protection Berm -- Breakup Berms -- HYDROLOGICAL SETTING -- Homer Wash Watershed -- Local Site Surface Hydrology -- DESIGN CRITERIA -- Permanent Flood Protection Berm -- Scour Depth -- Rip-Rap Construction -- Temporary Breakup Berms -- The PMF Design -- Historical Flood Experience -- GEOMORPHIC EVIDENCE OF EROSIONAL STABILITY -- Drainage Incision and Alluvial Surfaces -- Evidence For Fan Deposition -- Homer Wash Erosion Potential -- Conclusions From Geomorphic Evidence -- CONCLUSIONS: ADEQUACY OF PROPOSED FLOOD PROTECTION SYSTEM DESIGN -- Recommendations -- REFERENCES -- 8 THE DESERT TORTOISE -- THE WILSHIRE GROUP POSITION -- THE DHS/U.S. ECOLOGY POSITION.

THE COMMITTEE'S APPROACH.