Hydrogeologic Investigation and Groundwater Modeling Report

All documents presented in Adobe Acrobat PDF Format.

• Slides from Presentation at March 16, 2011, Community Meeting

Complete Report Documents

• Hydrogeologic Investigation and Groundwater Modeling Report (227 kb, 58 pages)
• Reference Documents (45.8 mb, 602 pages)

For ease of use, the above documents have been broken into smaller sections.

Contents

Section 1 Introduction (67 kb, 4 pages)

• 1.1 Site Location 1-2
• 1.2 Environmental Setting 1-2
• 1.2.1 Climate 1-2
• 1.2.2 Topography and Drainage 1-2
• 1.2.3 Hydrogeology 1-3
• 1.3 Project Scope 1-4

Section 2 Hydrogeologic Investigation (62 kb, 2 pages)

• 2.1 Fly Ash Sampling 2-1
• 2.2 Groundwater and Surface Water Analyses 2-1
• 2.3 Aquifer Performance Test 2-1
• 2.4 Investigation Derived Waste 2-2
• 2.5 Additional Data Sources 2-2

Section 3 Hydrogeologic Investigation Results (64 kb, 8 pages)

• 3.1 Site-Specific Geology 3-1
• 3.2 Groundwater Flow 3-2
• 3.3 Groundwater and Surface Water Quality 3-2
• 3.3.1 Initial Data Screening 3-3
• 3.3.2 Detailed Constituent Analysis 3-4
• 3.4 Groundwater and Surface Water Conclusions 3-5
• 3.4.1 Constituent Concentrations 3-5
• 3.4.2 Constituent Spatial Distributions 3-8

Section 4 Groundwater Model Data Review (54 kb, 4 pages)

• 4.1 Modeling Review and Previous Reports 4-1
• 4.2 Hydrogeologic Data Review 4-2
• 4.2.1 Aquifer Performance Test Analysis 4-2

Section 5 Hydrologic Analysis (54 kb, 4 pages)

• 5.1 Recharge, Drainage and Ponds 5-1
• 5.2 Leachate Production Rates (HELP Model) 5-3

Section 6 Groundwater Flow Model (72 kb, 10 pages)

• 6.1 Model Code 6-1
• 6.2 Model Domain and Computational Grid 6-2
• 6.3 Hydrogeologic Layers and Properties 6-2
• 6.4 Boundary Conditions 6-4
• 6.4.1 Model Perimeter 6-4
• 6.4.2 Rivers and Streams 6-4
• 6.4.3 Agricultural Drainage 6-5
• 6.4.4 Onsite/Golf Course Ponds 6-5
• 6.4.5 Recharge and Evapotranspiration 6-6
• 6.4.6 Groundwater Withdrawals 6-7
• 6.5 Flow Model Calibration and Sensitivity 6-7
• 6.5.1 Aquifer Performance Test Transient Calibration 6-7
• 6.5.2 Steady State Calibration 6-8
• 6.5.3 Model Sensitivity 6-9
• 6.6 Simulated Groundwater Flow Field and Water Budget 6-10

Section 7 Transport Model (75 kb, 10 pages)

• 7.1 Model Code 7-2
• 7.2 Input Parameters 7-2
• 7.2.1 Source Representation 7-2
• 7.2.2 Transport Parameters 7-7
• 7.3 Transport Simulations 7-8
• 7.4 Sensitivity Analysis 7-10

Section 8 Conclusions (69 kb, 8 pages)

• 8.1 Current Water Quality Conditions 8-1
• 8.2 Groundwater Flow 8-1
• 8.3 Future Water Quality Conditions 8-3
• 8.3.1 HELP Model Infiltration Rates 8-5
• 8.3.2 Arsenic Migration 8-6
• 8.3.3 Nitrate Migration 8-6
• 8.4 Future Land Use Considerations 8-7

Section 9 References (73 kb, 3 pages)

Figures (18.7 mb, 60 pages)

• 1-1 Site Location Map
• 1-2 Site Vicinity Map
• 1-3 Climate Data
• 1-4 Generalized Hydrogeologic Section
• 1-5 Data Collection Locations
• 3-1 Boring Log Summary
• 3-2 Surficial Aquifer Sand Zone Structure Contour Map
• 3-3 Yorktown Confining Zone Structure Contour Map
• 3-4 Yorktown Aquifer Structure Contour Map
• 3-5 Surficial Aquifer Potentiometric Surface Map
• 3-6 Yorktown Aquifer Potentiometric Surface Map
• 3-7 Constituent Distributions in Groundwater
• 3-8 Constituent Distribution in Groundwater
• 4-1 Aquifer Performance Test Well Locations
• 4-2 MW-3A/MW-3B Observed Water Levels
• 4-3 PZ-1/PZ-2 Observed Water Levels
• 4-4 MW-3C Observed Water Levels
• 4-5 MW-5A/MW-5C Observed Water Levels
• 4-6 Aquifer System Cross Section
• 5-1 USGS Stream Flow Gauge Average Stream Flow Values
• 6-1 Model Domain and Computational Grid
• 6-2 On-site Model Computational Grid
• 6-3 Cross-Section AA East-West
• 6-4 Cross-Section BB North-South
• 6-5 Land Surface Elevations
• 6-6 Surficial Aquifer Base Elevation Map
• 6-7 Yorktown Confining Zone Base Elevation Map
• 6-8 Yorktown Aquifer Base Elevation Map
• 6-9 Land Use
• 6-10 Drainage Ditches
• 6-11 Golf Course Ponds and Staff Gauge Locations
• 6-12 Yorktown-Eastover Aquifer Pumping Location
• 6-13 Aquifer Performance Test Well Locations
• 6-14 Aquifer Performance Test Simulated and Observed Drawdowns
• 6-15 Aquifer Performance Drawdown
• 6-16 Upper Surficial Aquifer – A Wells – APT Model
• 6-17 Lower Surficial Aquifer – B Wells – APT Model
• 6-18 Upper Yorktown-Eastover Aquifer – C Wells – APT Model
• 6-19 Upper Surficial Aquifer – A Wells – High Flow Model
• 6-20 Lower Surficial Aquifer – B Wells – High Flow Model
• 6-21 Upper Yorktown-Eastover Aquifer – C Wells – High Flow Model
• 6-22 Upper Surficial Aquifer Flow Vectors - High Flow Model
• 6-23 Simulated Head Contours – East-West Cross Section
• 6-24 Simulated Head Contours – North-South Cross Section
• 7-1 Ash Fill Emplacement Area
• 7-2 through 7-9 Simulated Arsenic in Upper Columbia Aquifer
• 7-10 through 7-13 Simulated Nitrate in Upper Columbia Aquifer
• 7-14 Time History of Simulated Constituent Concentrations – Surficial Aquifer
• 8-1 Conceptual Hydrogeologic Model

Tables (629 kb, 25 pages)

• 1-1 Data Collection Locations
• 2-1 Fly Ash Data Summary
• 2-2 Surface Water Data Summary
• 2-3 Groundwater Data Summary
• 2-4 Duplicate Sample Data Summary
• 2-5 General Water Quality Parameters
• 3-1 Water Level Data
• 3-2 Water Quality Data Summary Statistics
• 3-3 Water Quality Data Analysis
• 4-1 APT Well Construction
• 4-2 AQTESOLV Results
• 5-1 Summary of HELP Model Simulations and Calculated Leachate Production Rates
• 6-1 Groundwater Model Layers
• 6-2 Assigned Model Hydraulic Properties
• 6-3 Steady State Model Calibration Results: Aquifer Performance Test Model
• 6-4 Steady State Model Calibration Results: High Flow Model
• 6-5 Water Budget for Steady State Calibration: APT and High Flow Model
• 7-1 Transport Analysis Constituents
• 7-2 Summary of Initial Source Loading Rates and Source Decay Parameters
• 7-3 Transport Parameters

Appendices

• Appendix A – Fly Ash Laboratory Report (7.2 mb, 73 pages)
• Appendix B – Groundwater and Surface Water Laboratory Reports (1.45 mb, 293 pages)
• Appendix C – Aquifer Performance Test Hydrographs (4.26 mb, 3 pages)
• Appendix D – Comprehensive Water Quality Data Base (344 kb, 117 pages)
• Appendix E – Water Quality Quantile Plots (895 kb, 31 pages)