WSRC-STI-2007-00184, Rev. 2
Total Page:16
File Type:pdf, Size:1020Kb
WSRC-STI-2007-00184, REVISION 2 Key Words: F-Area Tank Farm Closure Cap Infiltration Performance Assessment Retention: Permanent FTF CLOSURE CAP CONCEPT AND INFILTRATION ESTIMATES M. A. Phifer W. E. Jones E. A. Nelson M. E. Denham M. R. Lewis E. P. Shine OCTOBER 2007 Savannah River National Laboratory Washington Savannah River Company Savannah River Site Aiken, SC 29808 Prepared for the U.S. Department of Energy Under Contract Number DE-AC09-96SR18500 WSRC-STI-2007-00184, REVISION 2 DISCLAIMER This report was prepared for the United States Department of Energy under Contract No. DE-AC09-96SR18500 and is an account of work performed under that contract. Neither the United States Department of Energy, nor WSRC, nor any of their employees makes any warranty, expressed or implied, or assumes any legal liability or responsibility for accuracy, completeness, or usefulness, of any information, apparatus, or product or process disclosed herein or represents that its use will not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, name, manufacturer or otherwise does not necessarily constitute or imply endorsement, recommendation, or favoring of same by Washington Savannah River Company or by the United States Government or any agency thereof. The views and opinions of the authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Printed in the United States of America Prepared For U.S. Department of Energy WSRC-STI-2007-00184, REVISION 2 Key Words: F-Area Tank Farm Closure Cap Infiltration Performance Assessment Retention: Permanent FTF CLOSURE CAP CONCEPT AND INFILTRATION ESTIMATES M. A. Phifer W. E. Jones E. A. Nelson M. E. Denham M. R. Lewis E. P. Shine OCTOBER 2007 Savannah River National Laboratory Washington Savannah River Company Savannah River Site Aiken, SC 29808 Prepared for the U.S. Department of Energy Under Contract Number DE-AC09-96SR18500 WSRC-STI-2007-00184, REVISION 2 REVIEWS AND APPROVALS - ii - WSRC-STI-2007-00184, REVISION 2 LIST OF MAJOR REVISIONS Notes to the list of major revisions: 1. Revision bars are not utilized within the text for revisions that consist of the addition of an entire section, appendix, etc., or the essential complete rewrite of an entire section, appendix, etc. Such revisions are shaded in yellow in this table. 2. Revision bars are utilized within the text for revisions within an existing section, appendix, etc. Such revisions may or may not be noted in this table. 3. Only major revisions are noted; minor revisions (e.g., changes in Section, Table, and Figure numbers; typographical error corrections; spelling corrections; minor word changes for clarification) are denoted with revision bars within the text only. Revision Date Sections Comment Number 0 4/16/07 All Initial Issue 1 6/4/07 1.0 Added configuration #1a and the closure cap degradation mechanism evaluation 4.3 Added clarification concerning the design of the erosion barrier as a barrier to burrowing animals 4.4.9 Added information on stone QA/QC, the use of weathering analogs, and the future evaluation to determine the material that will be used to infill the stone voids 5.0 Added configuration #1a 5.3.3 Added HELP model input for erosion barrier with sandy soil infill (configuration #1a) 5.3.4 Added table containing literature values of the saturated hydraulic conductivity of sand 5.5 Added HELP model results for the initial conditions of configuration #1a 6.0 Added configuration #1a 7.0 Inserted entirely new section to address potential FTF Closure Cap degradation mechanisms 8.0 1) Reference section became Section 8.0 rather than Section 7.0 as in revision 0 of the document; 2) Added additional references Appendix F Inserted entirely new appendix to provide calculations for the HELP model input for an erosion barrier with sandy soil infill (configuration #1a) Appendix G Inserted entirely new appendix to provide HELP model input for an erosion barrier with sandy soil infill (configuration #1a) Appendix H Inserted entirely new appendix to provide HELP model annual water balance data for an erosion barrier with sandy soil infill (configuration #1a) - iii - WSRC-STI-2007-00184, REVISION 2 Revision Date Sections Comment Number 2 10/12/07 1.0 Updated Executive Summary with additional information provided in revision 2 3.0 Divided the background section into the following two subsections: 3.1 FTF Background; and 3.2 Background Water Balance and Infiltration Studies 3.2 Inserted entirely new section to address background water balance and infiltration studies 4.3 1) Divided the foundation layer into an upper and lower layer; 2) Eliminated the elevation difference between the top rip rap and the vegetative soil cover in Figure 12 4.4 Added an additional FTF Closure Cap plot plan and cross-sections 4.4.1 Divided the foundation layer into an upper and lower layer 4.4.3 Added wrinkle control to the HDPE geomembrane QA/QC requirements 4.4.9 1) Added additional stone QA/QC; 2) Divided analogs to be considered into above and below grade analogs; 3) Added additional analogs for consideration 4.4.13 Added additional stone QA/QC 4.4.14 Added additional stone QA/QC 5.0 Descriptions of the seven configurations evaluated were revised for clarity 5.1 Added new Section 5.1 which provides the following: 1) Additional description of the HELP model and its use; 2) Detail concerning the appropriateness of its use; 3) A commitment to evaluate other models as a replacement to the HELP model 5.2 Section 5.2 was previously Section 5.1. Added information on 1) Evaporative zone depth; 2) Maximum leaf index; 3) Methodology used by the HELP model to estimate evapotranspiration; 4) Precipitation data set statistical detail 5.3 Section 5.3 was previously Section 5.2. 5.4 Section 5.4 and all its subsections were previously Section 5.3. - iv - WSRC-STI-2007-00184, REVISION 2 Revision Date Sections Comment Number 2 (cont.) 5.4.5 1) Added wrinkle control to the HDPE geomembrane QA/QC requirements; 2) Revised HELP model geomembrane placement quality designation to be consistent with HELP model guidance provided by Schroeder et al. 1994a and 1994b 5.4.7 Divided the foundation layer into an upper and lower layer 5.4.8 Divided the foundation layer into an upper and lower layer 5.5 Section 5.5 was previously Section 5.4. 5.6 Section 5.6 was previously Section 5.5. This section was essentially entirely rewritten as follows: 1) Added additional detail concerning the initial water balance for all seven configurations considered; 2) Divided the foundation layer into an upper and lower layer; 3) Revised HELP model geomembrane placement quality designation to be consistent with HELP model guidance provided by Schroeder et al. 1994a and 1994b; 4) Provided a comparison of the configuration #6 HELP model water balance to the water balance from background studies 7.0 Added information addressing the potential for mineral precipitation and microbial growth in the lateral drainage layer 7.2 1) Reworded sentence on death of pine trees for clarity; 2) Provided additional detail on pine tree succession assumptions 7.4.1 Added additional detail concerning granite weathering for both above and below grade stone 7.4.2 Added information concerning uprooted wind-thrown trees as a potential erosion barrier degradation mechanism 7.5.1 Added information concerning the potential for clogging of the filter fabric overlying the lateral drainage layer as a degradation mechanism 7.8 Added the following open design issues: 1) sufficiency of 50-foot extension of the closure cap beyond the sides of the tanks; 2) Interface of the Lateral drainage layer with the side-slope rip rap; 3) Practicality and benefit of conducting an electrical leak detection survey of the HDPE geomembrane - v - WSRC-STI-2007-00184, REVISION 2 Revision Date Sections Comment Number 2 (cont.) 8.0 Inserted entirely new section to address FTF Closure Cap degradation and infiltration modeling over 10,000 years 9.0 1) Reference section became Section 9.0 rather than Section 8.0 as in revision 1 of the document; 2) Added additional references Appendix G All the tables in Appendix G were revised as follows: 1) Divided the foundation layer into an upper and lower layer; 2) Revised HELP model geomembrane placement quality designation to be consistent with HELP model guidance provided by Schroeder et al. 1994a and 1994b; 3) Descriptions of the seven configurations evaluated were revised for clarity Appendix H The tables in Appendix H were essentially entirely rewritten as follows: 1) Divided the foundation layer into an upper and lower layer; 2) Revised HELP model geomembrane placement quality designation to be consistent with HELP model guidance provided by Schroeder et al. 1994a and 1994b; 3) Descriptions of the seven configurations evaluated were revised for clarity; 4) Added detailed water balance data tables for all seven configurations considered Appendix I Inserted entirely new appendix to provide FTF Closure Cap degraded property value calculations Appendix J Inserted entirely new appendix to provide HELP model input for FTF Closure Cap configuration #1a over 10,000 years Appendix K Inserted entirely new appendix to provide the configuration #1a detailed HELP model annual water balance data over time Appendix L Inserted entirely new appendix to provide a detailed probability based root penetration model - vi - WSRC-STI-2007-00184, REVISION 2 TABLE OF CONTENTS LIST OF MAJOR REVISIONS ...........................................................................................iii