CCR Monofill Location Restriction Demonstration. MidAmerican Energy Company, Louisa Generating Station

Transcription

1 CCR Monofill Location Restriction Demonstration MidAmerican Energy Company, Louisa Generating Station Final October 17, 2018

2 CCR Monofill Location Restriction Demonstration Prepared for MidAmerican Energy Company, Louisa Generating Station Muscatine, Iowa Final October 17, 2018 Prepared by Burns & McDonnell Engineering Company, Inc. Kansas City, Missouri COPYRIGHT 2018 BURNS & McDONNELL ENGINEERING COMPANY, INC.

3 INDEX AND CERTIFICATION MidAmerican Energy Company, Louisa Generating Station CCR Monofill Location Restriction Demonstration Report Index Chapter Number Number Chapter Title of Pages 1.0 Summary of Objectives Review of Available Information Unstable Area Demonstration Report Limitations 1 Appendix A Excerpt from CCR Rule 3 Appendix B Site Plan 1 Certification I hereby certify, as a Professional Engineer in the State of Iowa, that the information in this document was assembled under my direct supervisory control. This report is not intended or represented to be suitable for reuse by the MidAmerican Energy Company, Louisa Generating Station or others without specific verification or adaptation by the Engineer. a'1111 <ii, P-IT-I# Nathan Textor License Number My license renewal date is December 31, 2018 Pages or sheets covered by this seal: As noted above.

4 LGS Monofill Location Restrictions Demonstration Table of Contents TABLE OF CONTENTS Page No. 1.0 INTRODUCTION REVIEW OF AVAILABLE INFORMATION Geologic Information Geotechnical Investigations Design Drawings Monofill Inspections UNSTABLE AREAS DEMONSTRATION REPORT LIMITATIONS APPENDIX A EXCERPT FROM CCR RULE APPENDIX B SITE PLAN MidAmerican Energy Company TOC-1 Burns & McDonnell

5 LGS Monofill Location Restrictions Demonstration List of Abbreviations LIST OF ABBREVIATIONS Abbreviation BMcD CCR CFR EPA LGS MEC MWH RCRA U.S.C. Term/Phrase/Name Burns & McDonnell Coal Combustion Residual Code of Federal Regulations Environmental Protection Agency Louisa Generating Station MidAmerican Energy Company MWH Americas, Inc. Resource Conservation and Recovery Act United States Code MidAmerican Energy Company i Burns & McDonnell

6 LGS Monofill Location Restrictions Demonstration Introduction 1.0 INTRODUCTION On April 17, 2015, the Environmental Protection Agency (EPA) issued the final version of the federal Coal Combustion Residual Rule (CCR Rule) to regulate the disposal of coal combustion residual (CCR) materials generated at coal-fired units. The rule is administered as part of the Resource Conservation and Recovery Act (RCRA, 42 United States Code [U.S.C.] 6901 et seq.), using the Subtitle D approach. MidAmerican Energy Company (MEC) is subject to the CCR Rule. Per the requirements of 40 Code of Federal Regulations (CFR) , it must be demonstrated that existing CCR Landfills are not located in an unstable area. A qualified professional engineer must determine that the CCR Landfill meets the requirements of Per site nomenclature, the CCR Landfill will be referred to as a CCR Monofill in this document. On behalf of MEC, Burns & McDonnell (BMcD) has completed the Location Restriction Demonstration of the Louisa Generating Station CCR Monofill. An excerpt from the CCR Rule describing the requirements that are addressed in this report are included in Appendix A. This report contains a description of the information available to support the location restriction demonstration and the assessment of the required location restriction demonstration. The seal on this document certifies that the CCR Monofill meets the requirements of 40 CFR Section MidAmerican Energy Company 1-1 Burns & McDonnell

7 LGS Monofill Location Restriction Demonstration Review of Available Information 2.0 REVIEW OF AVAILABLE INFORMATION Louisa Generating Station (LGS) is a coal-fired power plant located in Muscatine, Iowa that is owned and operated by MEC. The LGS CCR Monofill (Monofill) is a special waste landfill permitted by the Iowa Department of Natural Resources (IDNR) Permit No. 70-SDP-16-04P. The Monofill was designed by Black and Veatch but a permit was not required when it began receiving CCR in In 2004, MWH Americas, Inc. (MWH) submitted a permit application for the existing Monofill. The following subsections provide information associated with the Monofill including geologic/hydrogeological information, design drawings, and inspections. This information was reviewed to provide an understanding of the subsurface conditions at the site relating to unstable areas and current conditions of the Monofill. Its application to the requirements of the CCR Rule are discussed further in Section 3.0. A general site plan of the area is included in Appendix B. 2.1 Geologic Information Based on a review of the Iowa Geological Survey s Map of the Surface Deposits of Louisa County, Iowa, (1900) and Maps of Surface Deposits of Muscatine County, Iowa (1899), the site is underlain by the alluvium from the Mississippi River. Borings at the Monofill indicate the alluvium is fine to coarse sand. Nearby borings encountered bedrock between elevations of feet and feet. No karst activity has been noted in these counties per the Iowa Geological Survey s Geologic Hazards webpage ( No underground mines are mapped in this area per the Iowa Geological Survey s Iowa Coal Mines online map. 2.2 Hydrogeological Investigations A hydrogeological investigation for the entire site was performed by MWH in This investigation included borings with visual classifications and standard penetration test blow counts. These borings were located along the east and south perimeter of the Monofill. General subsurface conditions are fine to coarse sands with varying amounts of silt. The sands were generally loose to medium dense. MidAmerican Energy Company 2-1 Burns & McDonnell

8 LGS Monofill Location Restriction Demonstration Review of Available Information 2.3 Design Drawings A Black and Veatch drawing showing a plan view of earthwork required to construct perimeter berms was reviewed. It indicated perimeter berm heights to be approximately 30 feet tall with 3.5H:1V slopes. There is no construction quality assurance information for the Monofill. 2.4 Monofill Inspections As part of the CCR Rule, inspections are required for the following: On a 7-day basis, a qualified individual inspects for any appearances of actual or potential structural weakness and other conditions that could disrupt the operation of the Monofill. On an annual basis, a qualified and certified engineer in the state of Iowa ensures that design, construction, operation, and maintenance of the Monofill is consistent with recognized and generally accepted good engineering practices. Weekly inspections performed by MEC during 2018 were reviewed by BMcD. No appearances of actual or potential structural weaknesses were observed by MEC during these inspections. The 2017 annual inspection was performed by HGM Associates, Inc. on October 4, 2017 and documented in a report dated January 12, Based on BMcD s review, no appearances of actual or potential structural weaknesses were observed by HGM Associates, Inc. at the time of their inspection. If future inspections find the appearance of actual or potential structural weakness caused by unstable conditions, generally accepted good engineering practices should be incorporated, at that time, to mitigate the unstable condition. MidAmerican Energy Company 2-2 Burns & McDonnell

9 LGS Monofill Location Restriction Demonstration Unstable Areas Demonstration 3.0 UNSTABLE AREAS DEMONSTRATION Per 40 CFR , an existing CCR landfill must not be located in an unstable area unless the owner or operator demonstrates that recognized and generally accepted good engineering practices have been incorporated into design to ensure that the integrity of the structural components of the CCR unit will not be disrupted. The following factors must be considered as part of the unstable area determination: On-site or local soil conditions that may results in significant differential settling, On-site or local geologic or geomorphologic features, and On-site or local human-made features or events (both surface and subsurface). Based on a review of available subsurface information, the materials beneath the Monofill are not susceptible to large scale differential settling, including settlement caused by placed CCR and fill or from liquefaction during a design seismic event. Inspections do not indicate any indications of detrimental settlement features such as cracking of the embankment. There are also no noted geologic features prone to settlement, such as karst, and no man-made features, such as mines, indicated near the site. Therefore, the Monofill meets the requirements of (a). MidAmerican Energy Company 3-1 Burns & McDonnell

10 LGS Monofill Location Restriction Demonstration Report Limitations 4.0 REPORT LIMITATIONS This report is based on the information reviewed and described herein. A review of permits, available design documents, geotechnical investigations, and inspection reports was performed as part of this demonstration to aid in the understanding of previous work performed. This review is not an assurance of the work performed by others as indicated in the documents reviewed including design, construction, quality assurance, and inspection of the Monofill. MidAmerican Energy Company 4-1 Burns & McDonnell

11 APPENDIX A EXCERPT FROM CCR RULE

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15 APPENDIX B SITE PLAN

16 OGILVIE AVE CCR MONOFILL F AVE 2018 BURNS & M cdonnell ENGINEERING COM PANY, INC. COPYRIGHT date designed OCT. 9, 2018 K. WYLAM MIDAMERICAN ENERGY COMPANY LOUISA 0 400' 800' SCALE IN FEET project contract LOCATION RESTRICTIONS SITE PLAN SK N Z:\Clients\ENR\MidAmEnr\86505_MECLouisaCCRPr\Design\Civil\Dwgs\Sketches\CCR Compliance Report\86505SK002_LR.dgn

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