The URL can be used to link to this page

Home My WebLink AboutNC0004979_Final Seep Report_20200828 DUKE James Wells ENERGY: Vice Preside Environmental,Health and Safe Programs&Environmental Sciences 526 South Church Street Charlotte,NC 28202 (980)373-9646 August 28, 2020 Via Overnight Mail RECEIVED S. Daniel Smith Director of Water Resources SEP 01 2020 North Carolina Department of Environmental Quality NCDEQ/DWR/NPDES 1617 Mail Service Center Raleigh,NC 27699-1617 Bob Sledge North Carolina Department of Environmental Quality Division of Water Resources Water Quality Permitting Program 1617 Mail Service Center Raleigh,NC 27699-1617 Subject: Report Under Special Order by Consent—EMC SOC WQ S 17-009 Duke Energy Carolina, LLC—Allen Steam Station NPDES Permit NC0004979 Final Seep Report Dear Messrs. Smith and Sledge: On behalf of Duke Energy Carolinas, LLC (DEC), I am submitting to you the Allen Steam Station Final Seep Report summarizing the findings of the comprehensive survey completed following completion of decanting as required by the Allen Steam Station NPDES Permit NC0004979 Special Order by Consent (SOC), SOC No. S17-009 Section 2.c.4). Completion of decanting occurred at Allen on June 2, 2020. Please direct any questions concerning the Allen Steam Station NPDES Permit NC0004979 SOC No. S 17-009 to Elizabeth Glenn at(980) 373-0530 and to Chris Hallman at(980) 373-7892 regarding this Final Seep Report. I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or Messrs. Smith and Sledge August 28, 2020 Page 2 persons who manage the system, or those persons directly responsible for gathering the information, the information submitted is, to the best of my knowledge and belief true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations. Sincerely, 1104241;6 - \. James Wells Vice President, Environment, Health& Safety- Programs and Environmental Sciences Duke Energy Attachment: Allen Steam Station 2020 Final Seep Report CC: Richard Baker, Duke Energy Elizabeth Glenn, Duke Energy Shannon Langley, Duke Energy Chris Hallman, Duke Energy Randy Gantt, Duke Energy Paul Draovitch, Duke Energy Matt Hanchey, Duke Energy RECEIVED 5 ')fri1TEE 'rr1 SEP 01 2020 NCDEQ/DWR/NPDES 2020 FINAL SEEP REPORT ALLEN STEAM STATION EMC SOC WQ S17-009 253 PLANT ALLEN ROAD BELMONT, NC 28012 AUGUST 2020 PREPARED FOR tio) DUKE ENERGY AROINAS DUKE ENERGY CAROLINAS, LLC Leonard W. Drago Staff Scientist Ch ' ophJ. Suttell, NC LG #2426 Project Principal 2020 Final Seep Report August 2020 Allen Steam Station-Duke Energy Carolinas,LLC SynTerra TABLE OF CONTENTS SECTION PAGE 1.0 INTRODUCTION 1-1 1.1 Inspection Details 1-1 2.0 FINDINGS 2-1 2.1 General Observations 2-1 2.2 Effects of Decanting 2-1 2.3 Changes to Seep Status 2-1 3.0 REFERENCES 3-1 LIST OF FIGURES Figure 1 Seep Locations and Inspection Areas LIST OF TABLES Table 1 Seep Locations and Descriptions—June 2020 Inspection LIST OF APPENDICES Appendix A Photographs Page i 2020 Final Seep Report August 2020 Allen Steam Station-Duke Energy Carolinas,LLC SynTerra 1.0 INTRODUCTION On June 4, 2020, Chris Suttell (NC L.G. #2426) of SynTerra inspected the Allen Steam Station (Allen or Site) property for existing and potential new seeps. Inspection activities were performed in accordance with North Carolina Environmental Management Commission (EMC) Special Order by Consent(SOC) WQ #S17-009. The SOC describes inspection requirements as follows: No later than 90 days following the completion of decanting at each Facility, and in the same manner as in the annual surveys, Duke Energy shall conduct a comprehensive survey of areas down gradient of ash basins identifying new seeps, and documenting the physical characteristics of previously documented seeps. All examinations of seeps must include identification of seeps by approximate latitude and longitude and date-stamped digital photographs of their appearance. A report summarizing the findings of this survey, including a section analyzing the effect decanting of the basins(s) has had on seep flows, accompanied by copies of the photographs noted above, shall be submitted to the Director of DWR ("Final Seep Report"). This Final Seep Report must list any seep that has been dispositioned (as described in subparagraph (3) above) during decanting process, including an analysis of the manner of disposition. The determination of whether a seep is dispositioned rests with the Director of DWR. At, or at any time prior to, submission of the Final Seep Report, Duke Energy shall seek formal certification from the Director of DWR, certifying the disposition of any seep that Duke Energy has characterized as dispositioned. Any seeps not certified as dispositioned by the Director of DWR shall not be deemed as dispositioned. Each location documented as a seep in the current version of the SOC, updated in May 2019, and listed in Table 1, was observed and documented with photographs during the inspection. General inspection observations include: • No previously unidentified seeps or pipes were observed during the inspection. • Notable shoreline erosion was observed. 1.1 Inspection Details During the inspection, the weather was clear and no precipitation occurred. The most recent rain event was 0.12 inches on May 30, 2020, as indicated by data from the on-Site rain gauge. Temperatures during the inspection ranged from approximately 70 to 90 degrees Fahrenheit (F). Page 1-1 2020 Final Seep Report August 2020 Allen Steam Station-Duke Energy Carolinas,LLC SynTerra The inspector reviewed previous seep inspection reports and the weekly dam safety inspectionreports pertainingeach p to ash basin. Mr. Scott Harris (Duke Energy system owner) conducted the ash basin dam safety inspections and prepared the reports. Mr. Harris and Mr. Chris Hallman (Duke Energy Subject Matter Expert) were interviewed about recent rainfall amounts, projects associated with the ash basins, and general Site conditions in and surrounding the ash basins. Observations from the dam safety • inspection reports were consistent with observations made during the seep inspection. The inspection included the following areas (Figure 1): • The east dam,between the coal pile and the retired ash basin (RAB) • The north dike,between the RAB and the active ash basin (AAB) • The east dam,between Lake Wylie and the RAB • The east dam,between Lake Wylie and the AAB • South and southeast of the AAB, extending to Lake Wylie Seep locations and inspection areas are shown on Figure 1. Observations noted during the inspection are summarized on Table 1. Photographs taken of each seep location during the inspection are included in Appendix A. Page 1-2 2020 Final Seep Report August 2020 Allen Steam Station-Duke Energy Carolinas,LLC SynTerra 2.0 FINDINGS 2.1 General Observations Inspection observations of each seep are shown in Table 1. Details include: • No previously unidentified seeps or pipes were observed during the inspection. • Conditions were similar to those reported in recent Dam Safety Inspection Reports. • While notable, shoreline erosion was less than observed during the previous inspection in February 2019. 2.2 Effects of Decanting Wastewater inflows to the AAB ceased on February 9, 2019. Decanting of free water from the active ash basin began on June 5, 2019. Duke Energy provided a Notification for Completion of Decanting letter to the North Carolina Department of Environmental Quality (NCDEQ) Division of Water Resources (DWR) on July 9, 2020. The notification indicated that decanting of the AAB was completed on June 2, 2020. The final seep inspection occurred two days after the completion of decanting, approximately one year after decanting began. Decanting of the AAB has reduced seep flow southeast of the AAB where conditions were dry at S-2 and between S-2 and S-1. No apparent flow was observed at S-2, S-5, S- 6, S-7, and S-9. No surficial flow was observed at S-10 and S-12. The S-10 seep collection system appeared functional. Minimal flow,which dissipated prior to reaching Lake Wylie, was observed at National Pollutant Discharge System (NPDES) Outfall 108 (S-8) and no apparent flow was observed at NPDES Outfall 108B (S-8B). Flow rates at NPDES Outfalls 103 (S-3) and 104 (S-4) appeared similar to rates observed during previous inspections. 2.3 Changes to Seep Status Mr. Suttell inspected each seep to evaluate whether it met requirements to be dispositioned in accordance with the SOC. The requirements for dispositioning a seep are as follows: For purposes of this Special Order, "dispositioned" includes the following: (1) the seep is dry for at least three consecutive quarters; (2) the seep does not constitute, and does not flow to, waters of the State or Waters of the United States for three consecutive quarters; (3) the seep is no longer impacted by flow from any coal ash basin such that concentrations of all pollutants listed in Attachment B meet State Page 2-1 2020 Final Seep Report August 2020 Allen Steam Station-Duke Energy Carolinas,LLC SynTerra criteria for four consecutive sampling events with at least seven days separating each event; or(4) the seep has been otherwise eliminated (e.g., through an engineering solution). If a seep that has been dispositioned through drying up reappears in any subsequent survey, such a seep will no longer be deemed dispositioned and can be subsequently re-dispositioned as specified above. Seeps S-2, S-5, S-6, S-7, S-8, and S-8B have been observed as dry or not reaching waters of the State or Waters of the United States for three consecutive quarters. These seeps are candidates for dispositioning and Duke Energy requests the NCDEQ review and certify that they be dispositioned in accordance with the terms of the SOC. Page 2-2 2020 Final Seep Report August 2020 Allen Steam Station-Duke Energy Carolinas,LLC SynTerra 3.0 REFERENCES Duke Energy Carolinas, LLC. (July 9, 2020).Allen Steam Station, Special Order by Consent, EMC SOC WQ S17-009, Notification for Completion of Decanting. Environmental ali 2018 . S ecial Order Consent North Carolina Department ofQuality.t3' ( ) P by EMC SOC WQ S17-009. North Carolina Department of Environmental Quality. (2018). Issuance of NPDES Permit, Permit NC0004979,Allen Steam Station, Gaston County, Facility Class I. Page 3-1 2020 Final Seep Report August 2020 Allen Steam Station-Duke Energy Carolinas,LLC SynTerra FIGURES • +1164 r • 11 010, II r' - .. .._I . ATAWBA RIVER . - f,A, • (LAKE WYLIE) I s r — „. .01.11104 ........ •: ,, . •,,i.:---- - ...;," ,... .. '. - ,,.. . . • J x � .1 y� 'Y\y D/SCHgRGE CANA, ',, ; ,`. ' -.5, ,...461,, jai''. • )I ',.,_ . ' ... . , ,..' -'. iir,' , 0-ir -'f' a • v, a-4 - • .: . r'"�� RETIRED '—.1 - I ASH BASIN '' , R 1 I •....'1 / 1 r • r T 4 1 I Toe Drain }F°"`''°Pu .} _ e a" . Outfall108 PnNs , '7.x .. !/(S-8) F'•� - d Y .. s ' II Toe Drain _r—---I J,' -rt: - Outfall 1088 r:' I El a j " ACTIVE �'e,;S-6 - a@ ASH BASIN • q F . D . ._ r. , Toe Drain _ Outfall 104 '.= IS 4) Toe Drain LEGEND jOutfall103 i NPDES CONSTRUCTED SEEP I (S-3) . • SOC NON-CONSTRUCTED SEEP • SEEP DISPOSITIONED BY SOC ; -ACTIVE ASH BASIN WASTE BOUNDARY 1 .. � • ---RETIRED ASH BASIN WASTE BOUNDARY 1*- I' ......•DUKE ENERGY CAROLINAS PROPERTY LINE I . 1223 SPECIAL ORDER BY CONSENT(SOC) .1 INSPECTION AREA , ----)0--STREAM(AMEC NRTR 2015) ' ��.- CATAWBA RIVE WETLAND(AMEC NRTR 2015) •, 7 - *SURFACE WATER FLOW DIRECTION ' '� ' V. NOTES: t_ _^ _ 1 I 1.SEEP LOCATIONS ARE DESCRIBED IN EMC SOC WO S17-009. . -- ` /1 2.NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM(NPDES, • •- LOCATIONS ARE DESCRIBED IN PERMIT NC0004979 M r .I t' ; 3 SEEP LOCATIONS WERE DERIVED FROM VARIOUS SOURCES AND F:- ill:, - �� A MIX OF SURVEYED AND APPROXIMATE LOCATIONS.THEREFORE.Si-. • LOCATIONS ARE TO BE DEEMED APPROXIMATE. 1! r - 4 THE WATERS OF THE U S DELINEATION HAS NOT BEEN APPROVED THE U.S.ARMY CORPS OF ENGINEERS AT THE TIME OF THE MAP � CREATION.THIS MAP IS NOT TO BE USED FOR JURISDICTIONAL "'�Y.tG • C• DETERMINATION PURPOSES.THE WETLANDS AND STREAMS .tP ... BOUNDARIES WERE OBTAINED FROM STREAM AND WETLAND "' - " DELINEATION CONDUCTED BY AMEC FOSTER WHEELER ENVIRONMENTAL a INFRASTRUCTURE,INC.NATURAL RESOURCE 400 0 400 800 TECHNICAL REPORT(NRTR)FOR ALLEN STEAM STATION DATED MAY 29, DUKE FIGURE 1 2016. V'ENERGY. GRAPHIC SCALE IN FEET SEEP LOCATIONS AND INSPECTION AREAS 5.PROPERTY BOUNDARY PROVIDED BY DUKE ENERGY CAROLINAS. CAROLINAS 6 ALL BOUNDARIES ARE APPROXIMATE. DRAWN BY:K.KING DATE:04/10/2019 2020 FINAL SEEP REPORT REVISED BY:R.KIEKHAEFER DATE:07/23/2020 7.AERIAL PHOTOGRAPHY OBTAINED FROM GOOGLE EARTH PRO ON CHECKED BY:T.HARTMAN DATE:07/23/2020 ALLEN STEAM S TAT I O N DECEMBER 13,2018.AERIAL WAS COLLECTED ON MARCH 30,2018 APPROVED BY:L.DRAGO DATE:07/23/2020 8.DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA �1��1 PROJECT MANAGER:C.SUTTELL BELMONT, NORTH CAROLINA STATE PLANE COORDINATE SYSTEM FIPS 3200(NAD83). s r Teri ya '�J www.svnterracorp.com 2020 Final Seep Report August 2020 Allen Steam Station-Duke Energy Carolinas,LLC SynTerra TABLES TABLE 1 SEEP LOCATIONS AND DESCRIPTIONS —JUNE 2020 INSPECTION 2020 FINAL SEEP REPORT ALLEN STEAM STATION DUKE ENERGY CAROLINAS, LLC, BELMONT, NC Location Coordinates Receiving Receiving Facility Seep ID Number Waterbody Waterbody Description*** SOC Monitoring Interim Action Levels Notes from Inspection Latitude Longitude Classification Located south of active ash basin. Flow is in approximately 3 foot • Allen S-1* 35.170632 -81.010093 Catawba River WS-V; B wide channel flowing southeast to Lake Wylie.Via sampling-No CCR NA-Seep Dispositioned NA-Seep Dispositioned Steady stream flow that emerges from within an a naturally incised channel side- (Lake Wylie) gradient of the ash basin. No apparent pparent discoloration of water or substrate. Catawba River Located south of active ash basin at toe of dike. Flows to Monitoring at point prior to pH 5-10 S.U. Allen 5 2 35.173761 -81.00578 (Lake Wylie) WS-V; B approximately 3 foot wide channel that flows to Lake Wylie entering Lake Wylie Hardness 400 mg/L No apparent flow.Orange aerobic bacteria/floc/iron-oxidation apparent on substrate. Catawba River Located east of active ash basin,between dike and river bank. Instream Monitoring of Allen S-5 35.17698 -81.006087 (Lake Wylie) WS-V; B Intermittent,unconfined diffuse flow towards Lake Wylie. Lake Wylie NA-02B Standards Apply No apparent flow. No apparent discoloration of water or substrate. Catawba River Located east of active ash basin,between dike and river bank. Instream Monitoring of Allen S-6 35.177049 -81.006128 (Lake Wylie) WS-V; B Intermittent,unconfined diffuse flow towards Lake Wylie. Lake Wylie NA-02B Standards Apply No apparent flow. No apparent discoloration of water or substrate. Catawba River Located east of active ash basin,between dike and river bank. Instream Monitoring of Allen S-7 35.177736 -81.006334 WS-V; B NA-02B Standards Apply No apparent flow. No apparent discoloration of water or substrate. (Lake Wylie) Intermittent,unconfined diffuse flow towards Lake Wylie. Lake Wylie Allen S-9** 35.185838 -81.00585 Catawba River(Lake Wylie) WS-V; B Former seep with flow through 24"corrugated metal pipe. Pipe has NA-SeepDispositioned NA-SeepDispositioned Dispositioned. No y ) been grouted; discharge eliminated. P P p apparent flow. NA-flow is collected and pumped Located north of active ash basin in grassy area that is dewatered by Allen 5-10 35.18055 -81.01354 back into NPDES permitted NA a French drain system down gradient ofPond 1. Captured NA Monitoring not Primary y g NA No a wastewater system in accordance with required by SOC apparent flow. French drain system and pumping station functioning. the pumping system's design capacity water is pumped back into the active ash basin. Overflow discharge of seepage collected from S-10 occurring during temporary,infrequent power outage episodes.Seepage would flow Instream Monitoring of No apparent flow received from S 10 as the French drain system and pumping Allen S-12 35.18101 -81.01349 Catawba River(Lake Wylie) WS-V; B to a stormwater drainage channel. Seep flow is collected and Lake Wylie NA-026 Standards Apply station at S-10 was functioning. pumped back into the ash basin during normal operations. NPDES Locations Toe Drain Outfall Moderate and steady flow that emerges from low areas at the east toe of the active Catawba River NA-Monitored per terms NA-NPDES Permit Effluent ash basin that is captured by a toe drain system (rip rap blanket)and channeled Allen 103 35.1752 -81.006 Lake Wylie) WS-V; B Constructed toe drain. of the NPDESpermit Limitations Apply toward Lake Wylie. Slight iron-oxidizingbacteria on substrate and biofilm on (S-3) ( Y ) PP Y Y 9 headwaters and within stream. Toe Drain Outfall Moderate and steady flow that emerges from low areas at the east toe of the active Catawba River NA-Monitored per terms NA-NPDES Permit Effluent ash basin that is captured by a toe drain system (rip rap blanket)and channeled Allen 104 35.17569 -81.00606 WS-V; B Constructed toe drain. (Lake Wylie) of the NPDES permit Limitations Apply toward Lake Wylie. Water is generally clear but has some biofilm on the water (S 4) surface and orange iron-oxidizing bacteria observed on substrate. Toe Drain Outfall Catawba River NA-Monitored per terms NA-NPDES Permit Effluent Flow that emerges from low areas at the east toe of the active ash basin that is Allen 108 35.1785 -81.0064 Lake Wylie) WS-V; B Constructed toe drain. of the NPDESpermit Limitations Applycaptured within a 12-inch metal culvert. Flow infiltratesprior to reachingLake Wylie. (S-8) ( Y ) P Y Toe Drain Outfall Catawba River NA-Monitored terms NA-NPDES Permit Effluent No per Allen 108E 35.17816 -81.006517 WS-V; B Constructed toe drain. apparent flow. Historically,flow emerged from low areas at the east toe of the (Lake Wylie) of the NPDES permit Limitations Apply active ash basin toward a culvert directed away from dike toward Lake Wylie. (S-8B) Prepared by:BOB Checked by:EEL Notes: Revised by:LWD Checked by:0J.8 *-Location previously investigated as a seep.Monitoring has not indicated the presence of coal combustion residuals. **-Seep dispositioned ma repair and/or non-flowing condition to potentially reach Waters of the U.S.,or other,as noted. ***-Some descriptions have been updated from the original text found in the SOC Attachment A table for accuracy and currency. The information provided in this table,except for the"Notes From Inspection"column,was derived from Special Order by Consent EMC SOC WQ 517-009,Attachment A and NPDES Permit NC0004979. 02B-15A NCAC 02L.0202 Standard CCR-Coal Combustion Residuals FERC-Federal Energy Regulatory Commission mg/L-milligrams per liter NA-Not applicable NPDES-National Pollutant Discharge Elimination System OHWM-Ordinary High Water Mark S.U.-Standard Units Page 1 of 1 2020 Final Seep Report August 2020 Allen Steam Station-Duke Energy Carolinas,LLC SynTerra APPENDIX A PHOT OGRAPHS 2020 Final Seep Report August 2020 Allen Steam Station-Duke Energy Carolinas,LLC SynTerra t • O 167*SE(f) ``rw ' , - c• ." .fir -+, ,�. ' ilit . . ,t.-,- - - --„-......, . -.A.,.,. ,,, 4 >.• yam•- 4 ~h► .'I' At -1 ,r, ', " aice V��" h L.lit 9 F,� ' r1wv' ,j unb1020. r> S-1 View of dispositioned seep location S-1, facing south. riall111/1111.1 0 142'SE(T)1 35.173806,"t„Of),73 t7m A 1 Q7 ny -vi . ICI F f • y r- S-2 View of seep location S-2,facing southeast. r. Page 1 of 6 2020 Final Seep Report August 2020 Allen Steam Station-Duke Energy Carolinas,LLC SynTerra E `anI4 t! r)S 35.175348, 81.006034.5m•1 cJ-3 View of seep location S-3(NPDES Outfall 103),facing northeast towards Lake Wylie. NL L n w 'N (T)i .17 71 :111.1:: . m 14:m M • kk, E III v p, , View of seep location S-4(NPDES Outfall 104),facing northeast towards i �-4 Lake Wylie. Page 2 of 6 2020 Final Seep Report August 2020 Allen Steam Station-Duke Energy Carolinas,LLC SynTerra sw w oo9,$700614twn•1' - d • 1 I S-5 View of seep location S-5 from Lake Wylie,facing southwest. itetiWtt t P S-6 View of seep location S-6 from Lake Wylie,facing,outh‘\ mot. Page 3 of 6 2020 Final Seep Report August 2020 Allen Steam Station-Duke Energy Carolinas,LLC SynTerra otdi NW ..':1 0062-: m 141 m Er .4 S-7 View of seep location S-7 from Lake Wylie,facing northwest. SE S SW .m 1731 MP$5.178522,-81.0064,42 Om♦158 m 1i �`f '•� 44011 to View of seep location S-8(NPDES Outfa11108)from bank along Lake S-8 Wylie,facing south. Page 4 of 6 2020 Final Seep Report August 2020 Allen Steam Station-Duke Energy Carolinas,LLC SynTerra elsommin111111111.11111111111111111111111111111W- 1 C:=.1`W(1 • ,,1'8254, 81001,39t6m♦138m 3.,1440 It: _ 11441, 41/1gi a1 y. ti y. rK''4- T�A f l. S-$B View of seep location S-8B(NPDES Outfa11108B)from bank along Lake Wylie,facing west-northwest. SW. ` t SW(T)*35.1`,1, 81005344tam 1 Al - , 1' S-9 View of dispositioned seep location S-9 from Lake Wylie,facing west. Page 5 of 6 2020 Final Seep Report August 2020 Allen Steam Station-Duke Energy Carolinas,LLC SynTerra SE S S-ZQ View of dispositioned seep location S-10,facing southeast. A 17u is S-12 View of seep location S-12,facing north-northeast. Page 6 of 6