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January, 2012

NC Safe Dams Program. 2012 Update on Recently Jurisdictional, Electric Power Generation Facility Dams. January, 2012. Today’s Briefing. Recall that our first and last briefing was in November, 2010 TODAY

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January, 2012

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  1. NC Safe Dams Program 2012 Update on Recently Jurisdictional, Electric Power Generation Facility Dams January, 2012

  2. Today’s Briefing • Recall that our first and last briefing was in November, 2010 • TODAY • Briefly review the history of jurisdictional transfer for the benefit of new commission members and provide a refresher of same to all other commission members • Take a closer look at the size and nature of the dams under jurisdiction • Look at the nature of deficiencies encountered during the inspection process and the status of resolution of these deficiencies • Look at recent amendments to the state Dam Safety Law and how they affect these dams • Look at where we stand today with these dams

  3. It all started with TVA - Kingston Plant Ash Pond Dike Failure in TN - December 22, 2008 - 84 acre impoundment - Released 5.4 million CY of coal ash slurry - Results are extensive damage but thankfully no loss of life.

  4. The EPA Responded to Kingston • The EPA inventoried ash ponds at coal fired power plants sites throughout the nation • Launched a nationwide inspection program • Retained consultants to perform field inspections and report on findings • Issued state by state report cards • EPA spotlighted NC

  5. You may recall this News & Observer headline in early July, 2009

  6. The NC General Assembly Responded • SB 1004 (ratified and signed into law July, 2009) amended G.S. 143-215.25A(a)(4) of the North Carolina Dam Safety Law of 1967 by: • eliminating the exemption for dams associated with electric generating facilities under jurisdiction of the NCUC • and continuing the exemption for those electric generating facilities dams under jurisdiction of the Nuclear Regulatory Commission which remain under shared jurisdiction with the NCUC • Effective date: January 1, 2010

  7. LQS Launches Initial Inspection Program - 2010What was the final count after initial field inspections? • 16 power plants sites were identified as containing jurisdictional dams, the owners, PGN and DUK • A total of 67dams were field identified at the 16 plant sites • Of the 67 dams • 57 were jurisdictional • 10 were exempt (by size and hazard class) • Of the 67 dams • 38 were identified as ash pond dams • 24 were active • 14 were inactive • 1 active and 3 inactive ash ponds were determined to be exempt (by size and hazard) • Final Count - 34 jurisdictional ash pond dams • Of the 67 dams, 29 were either • cooling pond dams • fuel containment dams • clear water waste processing dams • other clear water pond dams (including 1 hydro-power dam) • 6 were exempt (by size and hazard class) • Final Count - 23 jurisdictional clear water pond dams

  8. Final StatisticsWhat size facilities did LQS find? The real surprise. • Total length of jurisdictional dams identified = 184,445 LF or 35 miles • 50,147 LF for DUK (9.5 miles) • 134,298 LF for PGN (25.5 miles) – primarily in eastern portions of the state • Total length of high hazard jurisdictional dams identified = 127,663 LF or 24.2 miles • 49,107 LF for DUK (9.3 miles) • 78,556 LF for PGN (14.9 miles)

  9. Hazard Class – What does it mean? • Hazard Classification for Dams in North Carolina • HIGH Hazard – Loss of life; significant building damage; damage to major roads, highways and railroads; disturbance of major public utilities; and significant environmental damage for certain types of dams • INTERMEDIATE Hazard – No loss of life; minor damage to buildings; minor damage to roads, highways and railroads; disturbance of public utilities; and minor environmental damage for certain types of dams • LOW Hazard – No loss of life; damage to uninhabited buildings only, low volume roads, and agricultural land • Hazard classification refers to damage potential downstream and does not relate to the condition of a dam

  10. Summary of Final StatisticsHazard Classification

  11. Total number of Dams Categorized by Reservoir Size(in acres)

  12. Number of Coal Ash Dams Categorized by Reservoir Size (in acres)

  13. Total Number of Dams Categorized by Dam Length(in feet)

  14. Number of Coal Ash Dams Categorized by Dam Length (in feet)

  15. Recall how we normalized the workload with EDU’s • We realized the manpower required to inspect these dams was much greater than that required for 57 average size dams • IBEAM research indicated the average length of all dams inspected was approximately 750 LF (two and a half football fields) • As a result, the equivalent dam unit or EDU was established: • Intent = to reflect the true inspection workload • Principle = every 750 LF of dam length inspected equates to one dam • The 57 jurisdictional dams converted to 245.9 EDU’s, all of which were initially inspected in 2010 and again in 2011 • 66.9 EDU for DUK • 179.0 EDU for PGN • The 45 jurisdictional high hazard dams converted to 170.2 EDU’s, all of which were initially inspected in 2010 and again in 2011 • 65.5 EDU for DUK • 104.7 EDU for PGN

  16. Where are the 16 Power Plant Sites? • Plant Sites Located in the Mountains of North Carolina (2 total) • Tuxedo Hydro Plant - Located in Henderson County - DUK • Asheville Power Plant – Located in Buncombe County - PGN • Plant Sites Located in the Piedmont of North Carolina (11 total) • Allen Steam Station – Located in Gaston County - DUK • Dan River Steam Station – Located in Rockingham County - DUK • Belews Creek Plant– Located in Rockingham and Stokes Counties - DUK • Buck Steam Station – Located in Rowan County - DUK • Cliffside Steam Station– Located in Rutherford and Cleveland Counties - DUK • Marshall Steam Station– Located in Catawba County - DUK

  17. Where are the 16 Power Plant Sites? • Plant Sites Located in the Piedmont of North Carolina (continued) • Riverbend Steam Station – Located in Gaston County - DUK • Lincoln Combined Cycle Plant – Located in Lincoln County - DUK • Cape Fear Plant – Located in Chatham County - PGN • Mayo Power Plant – Located in Person County - PGN • Roxboro Power Plant – Located in Person County - PGN • Plant Sites Located near the Coast of NC (3 total) • Weatherspoon Power Plant – Located in Robeson Countynow decommissioned- PGN • H. F. Lee Power Plant – Located in Wayne County - PGN • Sutton Power Plant – Located in New Hanover County - PGN

  18. Distribution of Fossil Fuel Electric Plant Sites in NC

  19. Summary of Deficient Dams Discovered During the Initial Inspection Effort (7 total) • Dams where a Notice of Deficiency (NOD) was issued • Allen Steam Station - Allen Active Ash Dam (GASTO-016-H) • Belews Creek Plant - Belews Lake Main Dam (ROCKI-236-H) • Belews Creek Plant - Belews Creek Active Ash Dam (STOKE-116-H) • Cliffside Steam Station– Cliffside Active Ash Pond Downstream Dam (CLEVE-049-H) • Cliffside Steam Station– Cliffside Inactive Ash Basin 1-4 Main Dam (CLEVE-047-H) • Dan River Steam Station – Dan River Active Primary Ash Basin Dam (ROCKI-237-H) • Weatherspoon Power Plant – Weatherspoon 1979 Ash Pond Dam (ROBES-009-I)

  20. NOD Status Report • Allen Active Ash Dam (GASTO-016-H) • The initial inspection noted excessive seepage along the toe of the dam near a transmission tower. • A NOD was issued on April 20, 2010. • On September 7, 2011, a repair plan was approved for installing a filtered drainage system to control the seepage. • The repairs have been completed. Final approval of the repairs was issued on December 13, 2011.

  21. NOD Status Report • Belews Lake Main Dam (ROCKI-236-H) • The initial inspection noted areas of excessive seepage, several hairline cracks in the spillway wing walls, excessive seepage in the gabion abutments, and undesirable vegetation on the dam. • A NOD was issued on February 9, 2010. • A repair plan was approved on May 23, 2011 which included measures to control seepage. Wing wall cracks were analyzed and determined to be surficial. Piezometers were installed for continuous monitoring. Undesirable vegetation was removed. • The repairs have been completed. Final approval of the repairs was issued on October 5, 2011.

  22. NOD Status Report • Belews Creek Active Ash Dam (STOKE-116-H) • A localized shallow slope failure and seepage containing sediments were observed during the initial inspection. • A NOD was issued on February 9, 2010. Studies were immediately initiated to include exploratory excavation. • An approval to repair was issued on December 23, 2010 for slope repair which included subsurface drainage improvements and installation of piezometers for continuous monitoring. • The repairs have been completed. Final approval of the repairs was issued on October 5, 2011.

  23. NOD Status Report • Cliffside Active Ash Pond Downstream Dam (CLEVE-049-H) • It was observed during the initial inspection that sediment deposits from the Broad River obstructed outlets from the subsurface drain system within the embankment. The actual extent of the subsurface drain system was questioned. • A NOD was issued on April 6, 2010. • Duke Energy investigated historic documentation of the dam which depicted the location of the subsurface drainage system. Duke cleared all obstructed outlets and initiated a maintenance program to ensure that the outlets remain unobstructed. • Required maintenance and investigation were completed. Final approval was issued on July 14, 2010.

  24. NOD Status Report • Cliffside Inactive Ash Basin 1-4 Main Dam (CLEVE-047-H) • A NOD was issued on April 6, 2010 requiring a Hydrologic and Hydraulic (H&H) analysis of the spillway. Also, the condition of the CMP principal spillway conduit was questioned. • An H&H analysis was performed which indicated that the spillway could pass the storm required by Code (1/3 PMP) without overtopping the dam. • A camera inspection of the principal spillway conduit was provided which showed the pipe to be in good condition. • Studies were completed and reviewed. The NOD was deemed satisfied on March 24, 2011.

  25. NOD Status Report • Dan River Active Primary Ash Dam (ROCKI-237-H) • During the initial inspection, a localized shallow slope failure was noticed along with: excessive seepage, localized depressions, animal burrows, and undesirable vegetation on the downstream slope. • A NOD was issued on February 10, 2010. • An approval to repair addressing these deficiencies was issued on May 9, 2011. • The repairs have been completed. Final approval of the repairs was issued on November 30, 2011.

  26. NOD Status Report • Weatherspoon 1979 Ash Dam (ROBES-009-I) • Initial inspection noted severe seepage along the southern downstream slope of the dam, isolated areas of steep downstream slope, and isolated areas of numerous large tree growth. • A NOD was issued on April 29, 2010. • An approval to repair was issued on May 12, 2011. The repairs consisted of measures to control seepage, stabilize steep slopes and remove large trees. Piezometers were also installed for continuous monitoring. • The repairs have been completed. Final approval of the repairs was issued on October 12, 2011.

  27. Summary of NOD ResolutionThe Overall Report Card

  28. Frequency of Inspections post SB 1004 • Initial inspection - Winter of 2010 – all jurisdictional electric power dams were inspected (57 Total (246 EDU’s)) • After 1 year - Winter of 2010/2011 - all jurisdictional electric power dams were re-inspected (57 Total (246 EDU’s)) NO NEW NOD’S ISSUED • Entering the third round of inspections within a two year period to be performed this winter (2012)

  29. Repair PicturesBelews Creek Main Dam Repair (layered aggregate filter)

  30. Repair PicturesWeatherspoon Repair (layered aggregate filter)

  31. How is this workload funded? • Session Law 2010-31, Section 13.6 and 13.7 provided for: • One-time Dam Evaluation Fee • The Fee was set at $1,100 per EDU for High Hazard dams under ownership • The Fee to be paid in 2 even annual installments (invoiced in October of 2010 and 2011) • The Dam Evaluation Fees total $187,242 • PGN - $115,214 • DUK - $72,028 • Use of Funds • One, time limited, Assistant Dam Safety Engineer position for a two year period • Position focuses on submittals and other business specific to the electric power dams • After the two year period, October, 2012, the workload must be absorbed by the program within the regular budget

  32. HB 119 Changed the Dam Safety LawEffective July 1, 2011 One exemption was revised and one was added • Current exemption revised by HB 119: • Raised the jurisdictional threshold for dam height from 15 feet to 25 feet, • and raised the jurisdictional threshold for impoundment capacity from 10 acre-feet to 50 acre-feet • UNLESS THE DAM IS DETERMINED TO BE OF HIGH HAZARD CLASSIFICATION BY THE DEPARTMENT, THEN THE DAM IS JURISDICTIONAL REGARLESSS OF SIZE • Exemption added by HB 119! Dams constructed for the purpose of providing water for agricultural use, provided a Professional Engineer designs and oversees construction and the new dam is registered with the Division of Land Resources, UNLESS THE DAM IS DETERMINED TO BE OF HIGH HAZARD CLASSIFICATION BY THE DEPARTMENT, THEN THE DAM IS JURISDICTIONAL REGARLESSS OF SIZE

  33. How Did HB 119 Affect the Electric Power Dam Inventory12-31-2011 • 45(45) - High Hazard Dams • 3(3) – Intermediate Hazard Dams • 3(9) – Low Hazard Dams • Grand Total 51 Dams (57) • Red denotes numbers prior to passage of HB 119, effective on July 1, 2011

  34. Sutton Plant – September 28, 2010

  35. Sutton Plant – September 28, 2010

  36. Sutton Plan – September 28, 2010

  37. Sutton Plant – September 28, 2010

  38. QUESTIONS?Steven M. McEvoy, PENC Land Quality Section steve.mcevoy@ncdenr.gov

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