2015 INSPECTION REPORT FLY ASH DAM and BOTTOM ASH POND COMPLEX JOHN AMOS PLANT ST. ALBANS, WEST VIRGINIA. June 2015

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1 2015 INSPECTION REPORT FLY ASH DAM and BOTTOM ASH POND COMPLEX JOHN AMOS PLANT ST. ALBANS, WEST VIRGINIA June 2015 PREPARED BY GEOTECHNICAL ENGINEERING AEP SERVICE CORPORATION 1 RIVERSIDE PLAZA COLUMBUS, OHIO

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4 2015 INSPECTION REPORT REV 1 BOTTOM ASH COMPLEX JOHN AMOS PLANT ST. ALBANS, WV TABLE OF CONTENT 1 INTRODUCTION SUMMARY OF VISUAL OBSERVATIONS GENERAL BOTTOM ASH POND COMPLEX POND COMPLEX CAPACITY AND DEPTH DATA ASSESSMENT OF INSTRUMENTATION DATA CONCLUSIONS AND RECOMMENDATIONS RECOMMENDATIONS THAT REQUIRE ATTENTION BEYOND REGULAR MAINTENANCE ACTIVITIES RECOMMENDATIONS REGARDING ROUTINE MAINTENANCE ITEMS... 5 Appendix A Inspection Photos Appendix B Figures NOTE: REVISION 1 SUPPLEMENTAL DATA ADDED ON MAY 10 TH, i

5 1 INTRODUCTION AEPSC Civil Engineering administers AEPSC s (American Electric Power Service Corporation) Dam Inspection and Maintenance Program (DIMP). As part of DIMP, staff from the Geotechnical Engineering Section conducts dike and dam inspections annually. This report presents a summary of the inspection and assessment of the condition of the ash disposal facilities at the John Amos plant. The 2015 dam and dike inspection at the Amos fly ash dam and the bottom ash complex was conducted by Mr. J.T. Massey-Norton on June 4 th, Mr. Rich Fuller served as the project facility contact and was present during the inspection. Weather conditions were overcast with a mixture of rain and snow, with temperatures ranging from a low of 65 F to a high of 75 F. There was intermittent precipitation on the proceeding day of inspection and 0.3 accumulative rainfall during the seven day period prior to the inspection. The Bottom Ash Complex consists of Bottom Ash Pond 1A (BAP-1A), Bottom Ash Pond 1B (BAP-1B), Reclaim Water pond (RCWP) Area 3and the Treatment pond (TP). The Main Perimeter Dike is located on three sides of the impoundment and grades into native ground along the southern boundary. The BAP-1B pond is bounded on the west by the filled former sedimentation pond and on the east by the BAP-1A. A splitter dike separates the BAP-1A and BAP-1B and the Reclaim Water pond. Figure 1 (aerial image plan view) illustrates the bottom ash pond complex. 2 SUMMARY OF VISUAL OBSERVATIONS 2.1 GENERAL This summary of the visual observations uses terms to describe the general appearance or condition of an observed item, activity or structure. The meaning of these terms is as follows: Good: A condition or activity that is generally better or slightly better than what is minimally expected or anticipated from a design or maintenance point of view.

6 Fair or Satisfactory: A condition or activity that generally meets what is minimally expected or anticipated from a design or maintenance point of view. Poor: A condition or activity that is generally below what is minimally expected or anticipated from a design or maintenance point of view. Minor: A reference to an observed item (e.g., erosion, seepage, vegetation, etc.) where the current maintenance condition is below what is normal or desired, but which is not currently causing concern from a structure safety or stability point of view. Significant: A reference to an observed item (e.g. erosion, seepage, vegetation, etc.) where the current maintenance program has neglected to improve the condition. Usually, conditions that have been previously identified in the previous inspections, but have not been corrected. Excessive: A reference to an observed item (e.g., erosion, seepage, vegetation, etc.) where the current maintenance condition is above or worse than what is normal or desired, and which may have affected the ability of the observer to properly evaluate the structure or particular area being observed or which may be a concern from a structure safety or stability point of view. 2.2 BOTTOM ASH POND COMPLEX The visual inspection indicated that the Bottom Ash Pond is classified as begin in good condition and is documented with the following visual observation of key features that pertain to dam safety. 1. The crest of the main perimeter dike was observed to be in good condition. No significant settlement, misalignment, erosion, or seepage could be observed on the crest or the slopes of the main perimeter dike (Photos 1, 2, 3). 2

7 2. A riprap revetment had been placed on the downstream toe of the main perimeter dike at the Reclaim and Treatment ponds to control erosion due to minor seepage along this area, reported in the previous inspection (Photo4). Minor seepage (approximate area 2ft x 5ft) discharging less than 0.1gpm was observed near the toe of the riprap area. 3. The inboard slope of the main perimeter dike exhibited a good vegetative cover. There were no visual signs of misalignment, settlement, sloughing, erosion, or bulging that would indicate any instability within the dike (Photo 5). 4. No erosion or seepage was noted along the pipe that extends out from outboard slope of the Main Perimeter dike at the Reclaim pond (Photo 6). A sounding test performed in 2010 on the accessible portion of the pipe did not reveal any change in the thickness of the wall thickness that would be an indication of internal corrosion of the pipe. This pipe was permanently abandoned by welding a steel plate at the discharge end of the pipe. 5. The vegetative cover on the inboard slope was also controlled by timely mowing. Drains (4 inch diameter HDPE) from the block wall were unobstructed and no erosion was noted downstream (Photo 7). 6. No settlement, misalignment or other defects were observed for the 2 emergency spillways (Photos 8). The inlet and outlet to both emergency pipes were observed to be in good condition (Photos 9 and 10). 7. The primary decant structure (outfall 003) was observed to be in excellent condition and a trash rack has been added to the structure (Photos 11). No concrete spalling or other defects were observed at the upstream decant structure or the downstream headwall where the effluent discharges into the Kanawha River. Flow from the pond is discharged thru the submerged diffuser. (Photos 12 and 13). Photo 30 also shows the discharge at the headwall from the storm water pond The staff gage in the Reclaim Pond measures the depth of the water in the pond but does not show the water elevation with respect to the sea level (Photo 14). 3

8 2.3 POND COMPLEX CAPACITY AND DEPTH DATA Based on the previous measurements and estimates and operational variation in the pond system, the capacity and volume estimates for the bottom ash ponds are provided below: Maximum Minimum Present* Pond Media Depth/Elevation ( feet) Water NA/NA NA/NA 6/580 Bottom Ash 1A Solid NA/NA** NA/ NA 14/574 Water NA / NA NA / NA 5/581 Bottom Ash 1B Solid NA / NA** NA / NA 16/576 Capacity (acre-feet) Pond Water Solid Total Bottom Ash 1A Bottom Ash 1B NA Not Available *Date of measurement May 6 th, 2015 ** Assumes base of impoundment to be at an elevation of 560 ft. based on design drawings. 3 ASSESSMENT OF INSTRUMENTATION DATA In 2005 four piezometers were installed in the main perimeter dike, three on the crest and one at the toe. Currently, only the crest piezometers are monitored as a part of the inspection program. The piezometric water levels have been relatively constant with no unusual fluctuations (Figure 2). The March15th, 2015 static water level measurements reflect a sudden spring snowmelt which increased Kanawha River stages with a corresponding increase in piezometric levels. 4 CONCLUSIONS AND RECOMMENDATIONS Visual inspection of the bottom ash pond performed on June 4 th, 2015 and a review of the instrumentation data along with the plant inspection reports did not reveal any adverse or significant condition that would raise concerns on the stability and safety of the facilities. Routine inspections, monitoring, and maintenance by plant personnel should continue. A site 4

9 specific summary of conclusions and recommendations of the visual inspection is presented in the following sections. 4.1 RECOMMENDATIONS THAT REQUIRE ATTENTION BEYOND REGULAR MAINTENANCE ACTIVITIES 1. The plant should install easily readable staff gages in all the ponds that are a part of the bottom ash disposal facility. Pond stage levels should be monitored and recorded during the regular inspections. 2. The pond water level elevations along the main perimeter dike is a key element that is used in conjunction with the piezometric data in interpreting the phreatic surface through the dike. It is recommended that the piezometer that has been installed at the toe of the embankment should also be monitored. This location may require a small walk way to be installed over the rip rap to access the piezometer. 4.2 RECOMMENDATIONS REGARDING ROUTINE MAINTENANCE ITEMS 1. Plant personnel should continue to perform maintenance as currently scheduled. 2. Plant personnel should perform monthly measurements of the four piezometers. 3. Plant personnel should implement and document weekly inspections of the bottom ash perimeter dike. In general, routine inspections, monitoring, and maintenance by plant personnel should continue. AEPSC Geotechnical Engineering Section will continue to inspect the facilities on an annual basis. If you have any questions with regard to this report, please contact J.T. Massey-Norton at (audinet ) or Gary F. Zych (audinet ). 5

10 APPENDIX A INSPECTION PHOTOS 6

11 Photo 1. Photo of the perimeter dike. No cracks, sloughing, bulges, erosion or other defects were observed. Photo 2. Photo of the exterior embankment along the Reclaim Pond showing established vegetation. No erosion, bulges or other signs of slope instability were observed.

12 Photo 3. Photo of the perimeter dike along the bottom ash pond 1A. Vegetation is well established and controlled. Photo 4. Typical view of rip rap along the outboard toe of the reclaim pond. View also shows the backwater area of Bills Creek. Minor seepage along the toe of the rip rap area was observed.

13 Photo 5. Typical view of the inboard slope and block wall. Photo 6. Typical view of the abandoned steel pipe along the outboard slope of the reclaim pond. A steel plate is welded to the end of the pipe.

14 Photo 7. Typical view of the outboard slope and 4 inch diameter HDPE drain pipe. Photo 8. Photo of emergency spillway pipe from bottom ash pond 1B.

15 Photo 9. Photo of emergency spillway pipe headwall from bottom ash pond 1B. Photo 10. View of the (downstream outlet) showing the addition of an animal guard / trash rack for the 36 inch diameter HDPE emergency spillway pipe.

16 Photo 11. View of the primary decant structure (upstream inlet) showing the unobstructed flow through the trash rack with effluent discharge into the elliptical 24 x 38 concrete pipe. Photo 12. View of the primary outfall structure (#003) showing the 6 inch diameter vent pipe.

17 Photo 13. View of the primary outfall structure (#003) showing the transition from the 24 x 38 concrete elliptical pipe to the 36 inch diameter steel pipe. The flange connection from the steel pipe to the 36 inch diameter HDPE is also partially exposed and showed no indication of leakage. The 36 diameter pipe conveys the effluent discharged from the bottom ash pond to 6 diffuser ports submerged along the bottom of the Kanawha River. Photo 14 Typical view of the reclaim pond showing the pond s staff gage. The numeric readings on the staff gage indicate a depth of water within the pond as opposed to a water level elevation.

18 APPENDIX B FIGURES 7

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20 Water Level (ft) Figure 2 Amos Plant Bottom Ash Pond Piezometers B -1 B-3 B /10/06 02/22/08 07/06/09 11/18/10 04/01/12 08/14/13 12/27/14 05/10/16 Date