HomeMy WebLinkAboutSynTerra CAP Part 1 TOCCorrective Action Plan Part 1 November 2015
Asheville Steam Electric Plant SynTerra
TABLE OF CONTENTS
SECTION PAGE
ASHEVILLE STEAM ELECTRIC PLANT — CORRECTIVE ACTION PLAN
EXECUTIVE SUMMARY.................................................................................................... ES -1
ES -1.
Introduction..........................................................................................................
ES -2
ES -2.
Site Conceptual Model........................................................................................
ES -3
ES -3.
Extent of 2L and 2B Exceedances.......................................................................
ES -5
ES -4.
Receptor Survey...................................................................................................
ES -5
ES -4.1 Public Water Supply Wells.......................................................................
ES -6
ES -4.2 Private Water Supply Wells......................................................................
ES -6
ES -4.3 Human and Ecological Receptors............................................................
ES -6
ES -5.
Geochemical Modeling Results..........................................................................
ES -7
ES -6.
Groundwater Modeling Results........................................................................
ES -8
ES -7.
Corrective Actions to be Evaluated Based on Provisional Background
1.5
Site Description.......................................................................................................1-7
Concentrations......................................................................................................
ES -9
1.0 INTRODUCTION.........................................................................................................1-1
1.1
Site History and Overview....................................................................................1-1
1.2
Purpose of Corrective Action Plan.......................................................................1-2
1.3
Regulatory Background.........................................................................................1-3
1.3.1 15A NCAC 2L.0106 Requirements.............................................................1-3
1.3.2 Coal Ash Management Act Requirements
................................................1-4
1.3.3 Regulatory Standards for Site Media.........................................................1-5
1.3.4 NCDEQ Requirements.................................................................................1-6
1.3.5 NORR Requirements....................................................................................1-6
1.4
Summary of CSA Findings....................................................................................1-6
1.5
Site Description.......................................................................................................1-7
1.6
Site Geology.............................................................................................................1-8
1.7
Site Hydrogeology..................................................................................................1-8
1.8
Site Hydrology........................................................................................................1-9
1.9
Receptor Survey......................................................................................................1-9
1.9.1 Availability of Public Water Supply...........................................................1-9
1.9.2 Public Water Supply Wells..........................................................................1-9
1.9.3 Private Water Supply Wells.......................................................................1-10
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Corrective Action Plan Part 1 November 2015
Asheville Steam Electric Plant SynTerra
TABLE OF CONTENTS
SECTION PAGE
2.0
3.0
2.1
2.2
2.3
2.4
1.9.4 Potential Human Receptors.......................................................................1-10
1.9.5 Potential Ecological Receptors...................................................................1-11
3-1
BACKGROUND CONCENTRATIONS AND EXTENT OF EXCEEDANCES 2-1
Provisional Background Concentrations.............................................................2-1
3.1.3 Horizontal Hydraulic Gradients.................................................................
2.1.1 Provisional Background Soil Concentrations ............................................
2-2
2.1.2 Provisional Background Groundwater Concentrations ..........................
2-3
2.1.3 Duke Energy Private Background Well Sampling Summary.................2-9
3.3 Mineralogical Characteristics of Soils..................................................................
2.1.4 Provisional Background Surface Water Concentrations .........................
2-9
2.1.5 Provisional Background Sediment Concentrations ................................
2-12
Exceedances...........................................................................................................
2-12
Areas to be Considered for Corrective Action or Further Evaluation ..........
2-13
2.3.1 Soil.................................................................................................................2-13
2.3.2 Groundwater................................................................................................2-15
2.3.2.1 Surficial Groundwater........................................................................
2-15
2.3.2.2 Transition Zone Groundwater..........................................................
2-16
2.3.2.3 Bedrock Groundwater........................................................................
2-16
2.3.2.4 Receptor Wells.....................................................................................
2-17
2.3.3 Surface Water...............................................................................................
2-17
2.3.4 Sediment.......................................................................................................
2-18
Initial and Interim Response Actions.................................................................2-18
SITE CONCEPTUAL MODEL...................................................................................
3-1
3.1 Site Hydrogeological Conditions..........................................................................3-1
3.1.1 Hydrostratigraphic Units.............................................................................
3-1
3.1.2 Potentiometric Surfaces................................................................................
3-2
3.1.3 Horizontal Hydraulic Gradients.................................................................
3-2
3.1.4 Vertical Hydraulic Gradients.......................................................................
3-2
3.2 Geochemical Site Conceptual Model...................................................................
3-3
3.3 Mineralogical Characteristics of Soils..................................................................
3-3
3.3.1 Constituent Transport and Distribution in Groundwater .......................
3-4
3.3.1.1 Major Anions and Cations...................................................................
3-4
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Corrective Action Plan Part 1 November 2015
Asheville Steam Electric Plant SynTerra
TABLE OF CONTENTS
SECTION PAGE
3.3.1.2 Oxidation and pH Conditions............................................................. 3-5
3.3.1.3 Solute Speciation...................................................................................
3-5
3.3.1.4 Facilitated (Colloidal) Transport.........................................................
3-6
3.3.2 Correlation of Hydrogeologic and Geochemical Conditions to
Constituent Distribution...............................................................................
3-7
4.0 MODELING...................................................................................................................4-1
4.1 Determination of Distribution Coefficient..........................................................
4-1
4.2 Geochemical Modeling..........................................................................................
4-3
4.3 Numerical Fate and Transport Model.................................................................
4-5
4.3.1 Flow and Transport Models.........................................................................
4-6
4.3.2 Model Scenarios.............................................................................................4-S
4.3.2.1 Existing Conditions..............................................................................
4-9
4.3.2.2 Capping Ash Basins..............................................................................
4-9
4.3.2.3 Removal of Ash...................................................................................
4-10
4.4 Groundwater and Surface Water Interactions..................................................4-12
4.4.1 Flow Considerations...................................................................................
4-12
4.4.2 Concentration of a Constituent.................................................................
4-14
4.4.3 Results...........................................................................................................
4-15
4.4.4 Sensitivity Analysis.....................................................................................
4-15
5.0 CORRECTIVE ACTION PLAN PART 2..................................................................5-1
6.0 REFERENCES................................................................................................................ 6-1
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Corrective Action Plan Part 1
Asheville Steam Electric Plant
LIST OF FIGURES
Executive Summary
Figure ES -1 Plan View Conceptual Site Model
Figure ES -2 Cross -Section View Conceptual Site Model
Figure ES -3 Cross Section View Post Excavation
Section 1 Introduction
Figure 1-1 Site Location Map
Figure 1-2 Site Layout Map
Figure 1-3 Drinking Water Well and Receptor Survey
November 2015
SynTerra
Section 2
Extent of 21, and 2B Exceedances
Figure 2-1
Areas of Protection of Groundwater Standard and Provisional
Water Level Map- Surficial- June 29,2015
Background Exceedance in Soils
Figure 2-2
Areas of 2L and Provisional Background Exceedances in Surficial
Potential Gradient Between Hydrostratigraphic Units
Groundwater
Figure 2-3
Areas of 2L and Provisional Background Exceedances in Transition
Figure 3-5
Zone Groundwater
Figure 2-4
Areas of 2L and Provisional Background Exceedances in Bedrock
Isoconcentration Maps -
Groundwater
Section 3
Site Conceptual Model
Figure 3-1
Water Level Map- Surficial- June 29,2015
Figure 3-2
Water Level Map- Bedrock- June 29,2015
Figure 3-3
Potential Gradient Between Hydrostratigraphic Units
Figure 3-4
Isoconcentration Maps -
Eh in Ash Pore Water
Figure 3-5
Isoconcentration Maps -
Eh in Surficial Groundwater
Figure 3-6
Isoconcentration Maps -
Eh in Transition Zone Groundwater
Figure 3-7
Isoconcentration Maps -
Eh in Bedrock Groundwater
Figure 3-8
Isoconcentration Maps -
Eh in Seeps and Surface Water
Figure 3-9
Isoconcentration Maps -
pH in Ash Pore Water
Figure 3-10
Isoconcentration Maps -
pH in Surficial Groundwater
Figure 3-11
Isoconcentration Maps -
pH in Transition Zone Groundwater
Figure 3-12
Isoconcentration Maps -
pH in Bedrock Groundwater
Figure 3-13
Isoconcentration Maps -
pH in Seeps and Surface Water
Figure 3-14
Isoconcentration Maps -
DO in Ash Pore Water
Figure 3-15
Isoconcentration Maps -
DO in Surficial Groundwater
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P: \Duke Energy Progress. 1026 \ 102. Asheville Ash Basin GW Assessment Plan\ 16.Corrective Action Plan\Text\ Final Asheville
CAP.docx
Corrective Action Plan Part 1
November 2015
Asheville Steam Electric Plant
SynTerra
Figure 3-16
Isoconcentration Maps
- DO in Transition Zone Groundwater
Figure 3-17
Isoconcentration Maps
- DO in Bedrock Groundwater
Figure 3-18
Isoconcentration Maps
- DO in Seeps and Surface Water
Figure 3-19
Isoconcentration Maps
- Specific Conductance in Ash Pore Water
Figure 3-20
Isoconcentration Maps
- Specific Conductance in Surficial
Isoconcentration Maps - Strontium in Bedrock Groundwater
Groundwater
Isoconcentration Maps - Strontium in Seeps and Surface Water
Figure 3-21
Isoconcentration Maps
- Specific Conductance in Transition Zone
Section 4 Modeling
Figure 4-1 Computed vs Observed Values
Figure 4-2 Map of preliminary basin closure for the CAP2 scenario
Figure 4-3 Simulated hydraulic heads
Figure 4-4 Conceptual figure of groundwater discharge to the French Broad
River
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Groundwater
Figure 3-22
Isoconcentration Maps - Specific Conductance in Bedrock
Groundwater
Figure 3-23
Isoconcentration Maps - Specific Conductance in Seeps and Surface
Water
Figure 3-24
Isoconcentration Maps - Strontium in Ash Pore Water
Figure 3-25
Isoconcentration Maps - Strontium in Surficial Groundwater
Figure 3-26
Isoconcentration Maps - Strontium in Transition Zone
Groundwater
Figure 3-27
Isoconcentration Maps - Strontium in Bedrock Groundwater
Figure 3-28
Isoconcentration Maps - Strontium in Seeps and Surface Water
Figure 3-29
Boron, Sulfate, TDS, and Strontium in Ash Pore Water
Figure 3-30
Boron, Sulfate, TDS, and Strontium in Surficial Groundwater
Figure 3-31
Boron, Sulfate, TDS, and Strontium in Transition Zone
Groundwater
Figure 3-32
Boron, Sulfate, TDS, and Strontium in Bedrock Groundwater
Figure 3-33
Boron, Sulfate, TDS, and Strontium in Surface Water and Seeps
Figure 3-34
Time vs. Boron Concentration Graphs
Section 4 Modeling
Figure 4-1 Computed vs Observed Values
Figure 4-2 Map of preliminary basin closure for the CAP2 scenario
Figure 4-3 Simulated hydraulic heads
Figure 4-4 Conceptual figure of groundwater discharge to the French Broad
River
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CAP.docx
Corrective Action Plan Part 1
Asheville Steam Electric Plant
LIST OF TABLES
November 2015
SynTerra
Section 2
Extent of 2L and 2B Exceedances
Table 2-1
Soil Provisional Background Concentration Summary
Table 2-2
Background Well Analytical Results
Table 2-3
SSI Analyte Summary
Table 2-4
Surficial Groundwater Provisional Background Concentration
Table 2-12
Summary
Table 2-5
Transition Zone Provisional Background Concentration Summary
Table 2-6
Bedrock Provisional Background Concentration Summary
Table 2-7
Duke Energy Private Background Well Summary
Table 2-8
Surface Water Provisional Background Concentration Summary
Table 2-9
Sediment Provisional Background Concentration Summary
Table 2-10
Hexavalent Chromium Analytical Results
Table 2-11
Soil Exceedances
Table 2-12
Alluvial Groundwater Exceedances
Table 2-13
Saprolite Groundwater Exceedances
Table 2-14
Transition Zone Groundwater Exceedances
Table 2-15
Bedrock Groundwater Exceedances
Table 2-16
Surface Water Exceedances
Table 2-17
Sediment Exceedances
Section 3 Site Conceptual Model
Table 3-1 Local Groundwater Gradients and Flow Velocities
Table 3-2 Potential Vertical Gradients Between Hydrostratigraphic Units
Table 3-3 0.1 Micron Analytical Data Summary
Section 4 Modeling
Table 4-1 Summary of Kd Values from Batch and Column Studies
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CAP.docx
Corrective Action Plan Part 1
Asheville Steam Electric Plant
LIST OF APPENDICES
November 2015
Appendix A Site Specific Soil Remediation Goal Development (Graphs)
Appendix B Soil Sorption Evaluation
Appendix C Geochemical Modeling Report
Appendix D Groundwater Modeling Report
Appendix E Analytical Data Laboratory Reports
SynTerra
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