Loading...
HomeMy WebLinkAboutNC0001422_4-Sutton May 22, 2015 response to DENR conditional approval_20150805DUKE= =M G7111v Shea[ ENERGY cnadone,�� Maa..—y Aad Q u r.V. MX ruro Mo., Wee ECr3K �ranone, � �r-rocs Flay «. �015 9W473v7rs Boa-;uuardo(r -) Mr. Geoff Kegley Mr- DENR Wilmington Regional Office ici Caminal Drive Extension Wilmington, ILL zazt0z-) RE: [.v.,uLLD„ Energy Complex Revised OrounawaterAzessment Work Plan Deke Energy Progress, Inc. Response to 13EI911-s Conditional Approval dated Felsruary 5, Lulb Dear Mr. Kegley: Dune Energy Progress, Inc. (DEP) is in receipt or the Department of Environment ant] Natural Rezivar�es (DENR) Conditional Approval letter referenced above for the [.v. Sutton Energy Complex. The purpose nr this letter is to provide a response to your buffeted comments within the Connitional Approval letter. Below are DEP's responses to DEAR's comment, tin italics) from the Conditional Npproval letter: Comment Section 7.1.Subsurface exploration: The presenr version of me GHr does not provide any description of now me confining unit Wit be evaluated as directed in General Comment #3 of the uivision s Keview of Groundwater Asaessmenr Work rlan retrer apted November 4, 2014. In order to refine me concepruar moacr at the site, install an adequate amount of oorinys to delineate the exrenr and thickness of the confining -n;t. In addition, conducr rests to evaruare me vertical gradient � c, ass the confining unit. Response: Wells AW-713 ant] Avv-60 were intended to be used to delineate the extent and AcRness of the confining unit. Rowever, the conrinins unit was not observed at either location. Regional geologic information suggests the conrini„6 unit pinches out in this general area. Therefore. DEP proposes to install additional deep wells at Avv-2D, AW-6E, AW-51), AW- 5E, MW-23E, AW-yD ant] jMvv-50 and 12 additional soil borings to t]etermine it tRe confnine unit is present and the thickness. i llese atIlMional wells and soil borings are shown on the attacllet] figure. The static water levels in these well clusters will be used to evaluate the vertical gradient across the confining unit, if located. i-ernment Section 7.2 Ash Pore water ana Groundwater Sampling and Analysis: rexr o- pages 41 and 42 refers to proposea .,a—vliny for radium at wells ►vrvv-ggaA ana BW-2S, which are nor i-ted in tables or maps. clarify cnis siruor;o,. nefore sampling or nose alternate sampling locations rear De documented. Response: water samples from the ash basin weirs A5lVIw-1/1S/1D and background wells IOlvv- Mp. Geett Kegley —ay 22, 2015 5a/B/C will be ana,yzea For radium and uraniarm. • Comment beft:or! r.3.1 Water Quality Samples: Timing of stream sampling should be conducred wirh consideration of the tidal influence on the Cape rear river ,n rn,s area which is a transition zone between the riverine and estuarine environmenr (e.g. upsrream samples snoura ae Me- Uu..ng an outgoing tide to be more epresentative of upstream river condirions). Response: Agree/ in aaairion, recnn.cw a;, —r..,,, that will serve as the basis of expectations for complerion of the site assessment are provided or Arracnmenr 1. Response: DEP also includes with this letter updated attachment L. i Ris Document Ras seen motlinetl sligRrly since tRe Conditional Approval for this site was received. However, DEP requests fu<<her direction regarding the sire Kssessmenr- Uara KeMQ:, e... e..ts and Samvi.ng �r, ateg,. j5l - solid phase samples for royal organic carbonate conrenr ... ar facilities located in the Coastal vlain. DEP Ras not Been able to determine a standard EPA or ASTM method for total organic carbonate analysis or a vender iaB familiar wiiR intrust --recognized standard method. Please advise on a standard method for this analysis, if available. alternatively, the relative carbonate content of a ,olio can be deduced from a combination of data such as total organic carbon (TOC) content and the Eoss of Ignition ([OI} analysis oeing conauctea. DEP respeciyully requests guiRance oonr-erning the test method or method of deduction that will be acceptable to determine the organic carbonate content. If you require any additional information or have any fuRRer questions, please Do not Resitate to contact as. Re,pectfully submitted, I7. Edwin M. Sullivan Manager, waste s Grountl..ater Programs ZM: Figure 5, Revision 2, Dated 5/13/15 for L.V. Sutton Energy Complex DpMatea attacllmeni i cc: Richard Baker -Duke Energy Danny McCormicit - DuKe Energy Kent Tyndall - Duke Energy VJohn Toepfer- Duke Energy Kathy vveBB - Fyn i erra Corpor.tion 0 H 2 H 2 G P E - S W 2 P E - S W 4 P E - S W 3 P E - S W 5 P E - S W 6 A P E - S W 6 B P E - S W 6 D P E - S W 6 E 2 0 1 5 - 0 5 - 1 3 2 0 1 5 - 0 5 - 1 3 H . F R A N K J . C H A S T A I N P R O J E C T M A N A G E R : L A Y O U T N A M E : D R A W N B Y : C H E C K E D B Y : K A T H Y W E B B D A T E : D A T E : F I G U R E 5 P R O P O S E D M O N I T O R I N G W E L L A N D S A M P L E L O C A T I O N M A P R E V I S I O N 2 ( 2 0 1 5 - 0 5 - 1 3 ) 5/15/2015 11:49 AM P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment Plans\Sutton\Figures\DE SUTTON FIG 5 (MW & SAMPLE LOC MAP) REVISION 2 (2015-05-13).dwg F I G 5 ( M W A N D S A M P L E L O C M A P ) 1 2 0 0 G R A P H I C S C A L E ( I N F E E T ) 0 6 0 0 3 0 0 6 0 0 w w w . s y n t e r r a c o r p . c o m 1 4 8 R i v e r S t r e e t , S u i t e 2 2 0 G r e e n v i l l e , S o u t h C a r o l i n a 2 9 6 0 1 8 6 4 - 4 2 1 - 9 9 9 9 L . V . S U T T O N E N E R G Y C O M P L E X 8 0 1 S U T T O N P O W E R P L A N T R D W I L M I N G T O N , N O R T H C A R O L I N A N C W I L D L I F E L A K E A C C E S S S U T T O N L A K E R D C A P E F E A R R I V E R S U T T O N L A K E R D COOLING POND WATER LEVEL = 9.60 ftPROVIDED BY DUKE ENERGY 06-02-2014 M E T R O C I R C L E E Z Z E L L T R U C K I N G L C H H O L D I N G S S . T . W O O T E N C O R P O R A T I O N N C H I G H W A Y 4 2 1 T R A N S C O M C T B E V E L R D R O Y M A C D R N E W H A N O V E R C O U N T Y S A U N D E R S & S A U N D E R S , L L C R O Y M A C B U S I N E S S P A R K R O Y M A C P A R T N E R S H I P A B S O L U T E P R O P E R T I E S H U R R I C A N E P R O P E R T I E S M A O L A M I L K & I C E C R E A M C O . S O U R C E S : 1 . 2 0 1 4 A E R I A L P H O T O G R A P H W A S O B T A I N E D F R O M W S P F L O W N O N A P R I L 1 7 , 2 0 1 4 2 . 2 0 1 3 A E R I A L P H O T O G R A P H W A S O B T A I N E D F R O M T H E N R C S G E O S P A T I A L D A T A G A T E W A Y A T h t t p : / / d a t a g a t e w a y . n r c s . u s d a . g o v / 3 . D R A W I N G H A S B E E N S E T W I T H A P R O J E C T I O N O F N O R T H C A R O L I N A S T A T E P L A N E C O O R D I N A T E S Y S T E M F I P S 3 2 0 0 ( N A D 8 3 ) . 4 . P A R C E L D A T A W A S O B T A I N E D F R O M T H E N O R T H C A R O L I N A S T A T E L I B R A R I E S A T h t t p : / / w w w . l i b . n c s u . e d u / g i s / c o u n t i e s . h t m l F O R N E W H A N O V E R C O U N T Y . 5 . 2 f t C O N T O U R I N T E R V A L S F R O M N C D O T L I D A R D A T E D 2 0 0 7 h t t p s : / / c o n n e c t . n c d o t . g o v / r e s o u r c e s / g i s / p a g e s / c o n t - e l e v _ v 2 . a s p x 6 . W E L L L O C A T I O N S A N D M E A S U R I N G P O I N T S W E R E B A S E D O N A S U R V E Y B Y J A M E S L . H A I N E S & A S S O C I A T E S F O R I S H , I N C . D A T E D D E C E M B E R 2 3 , 2 0 0 8 . I S H D R A W I N G I S T I T L E D " P O T E N T I A L L O C A T I O N S F O R P R O P O S E D G E O P R O B E A N D W E L L I N S T A L L A T I O N S " , D A T E D F E B R U A R Y 2 5 , 2 0 0 9 W I T H A C A D F I L E N A M E F i g u r e 2 2 . d w g 7 . N E W W E L L L O C A T I O N S A N D M E A S U R I N G P O I N T S W E R E B A S E D O N A T A B L E B Y P A R A M O U N T E E N G I N E E R I N G , W I L M I N G T O N N C D A T E D 2 0 1 2 - 0 3 - 0 5 S U P P L I E D B Y P R O G R E S S E N E R G Y . H O R I Z O N T A L D A T U M I S N A D 8 3 ( N S R S 2 0 0 7 ) A N D T H E V E R T I C A L D A T U M I S N G V D 2 9 . 8 . T H E P R O P E R T Y B O U N D A R Y F O R T H E L . V . S U T T O N S T E A M E L E C T R I C P L A N T W A S B A S E D O N A C O M P O S I T E M A P P R E P A R E D B Y D A V I S - M A R T I N - P O W E L L & A S S O C . , I N C . T H E D R A W I N G S A R E D A T E D J U N E , 1 9 9 5 W I T H R E V I S I O N N O T E F O R M A R C H 4 , 2 0 0 4 . F I L E N A M E I S L - D - 9 0 2 2 - 7 . D W G . H O R I Z O N T A L D A T U M I S N A D 8 3 A N D T H E V E R T I C A L D A T U M I S N G V 2 9 . 9 . T H E L O C A T I O N O F T H E F O R M E R A S H D I S P O S A L A R E A S W A S B A S E D O N A F I G U R E 2 - 2 P R E P A R E D B Y B L A S L A N D , B O U C K & L E E , I N C . T H E F I G U R E I S T I T L E D " H O R I Z O N T A L E X T E N T O F T H E A S H W I T H I N T H E F O R M E R D I S P O S A L A R E A " . 1 0 . M O N I T O R I N G W E L L S / P I E Z O M E T E R S / S O I L B O R I N G S C O M P L E T E D A T P A R T O F P R E V I O U S A S S E S S M E N T A C T I V I T I E S . L O C A T I O N S A R E A P P R O X I M A T E . N O T E : 1 . C O N T O U R L I N E S A R E U S E D F O R R E P R E S E N T A T I V E P U R P O S E S O N L Y A N D A R E N O T T O B E U S E D F O R D E S I G N O R C O N S T R U C T I O N P U R P O S E S . D U K E E N E R G Y P R O G R E S S P R O D U C T I O N W E L L ( A P P R O X I M A T E ) P E - S W 2 N H C - S W 4 C F P U A P R O D U C T I O N W E L L ( A P P R O X I M A T E ) 0 H 2 I N V I S T A R E P O R T E D P R O D U C T I O N W E L L L O C A T I O N D U K E E N E R G Y P R O G R E S S P R O D U C T I O N W E L L ( S U R V E Y E D ) P E - S W 2 M W - 3 2 C P R O P O S E D A S H / S O I L B O R I N G ( A B ) A N D M O N I T O R I N G W E L L ( A B M W ) L O C A T I O N O L D A S H B A S I N A R E A N E W A S H B A S I N A R E A F O R M E R A S H D I S P O S A L A R E A C A N A L C A N A L A S T C O N C R E T E P A D R A I L R O A D S O L A R F A R M COOLINGPOND COOLINGPOND S U T T O N S T E A M P L A N T R D T R A N S C O M C T R O Y M A C D R F R E D R I C K S O N R D C A N A L A C C E S S R O A D N H C - S W 4 N H C - S W 3 N H C - S W 2 ( N O T I N U S E ) IN T E R S T A T E 1 4 0 ( U S H I G H W A Y 1 7 ) F R E D R I C K S O N R D A P P R O X I M A T E R O U T E O F T H E N E W W I L M I N G T O N B Y P A S S ( I - 1 4 0 ) N C H I G H W A Y 4 2 1 N C H I G H W A Y 4 2 1 N C H I G H W A Y 4 2 1 R A I L R O A D R A I L R O A D R A I L R O A D R A I L R O A D N H C - S W 1 ( A B A N D O N E D ) I N V I S T A C F P U A M W - 4 B M W - 5 C M W - 3 3 C M W - 3 2 C M W - 2 7 B M W - 3 1 C M W - 2 4 C M W - 2 4 B M W - 2 3 C M W - 2 3 B M W - 2 2 C M W - 2 2 B M W - 1 9 M W - 2 1 C M W - 2 8 B M W - 2 8 C M W - 7 C M W - 1 1 M W - 1 2 S W - 3 S M W - 5 B M W - 5 A M W - 9 M W - 8 P Z - 1 P Z - A P Z - B P Z - 7 P Z - 9 P Z - 1 2 P Z - 1 0 D P Z - 1 0 S P Z - 1 1 M W - 1 0 P Z - 1 4 P Z - 1 6 M W - 1 3 P Z - 1 8 P Z - 1 5 P Z - 1 7 P Z - 1 9 P Z - 2 1 M W - 3 4 C P Z - 2 A P Z - 2 B P Z - 1 P Z - 1 B P Z - 3 B M W - 3 6 C P Z - 3 A C P T - 4 P Z - 4 B P Z - 4 A P Z - 5 A S P T - 6 P Z - 6 A C P T - 7 A P Z - I N T C P T - 5 S P T - 3 A S P T - 8 S C P T - 5 A S P T - 6 S P T - 2 P Z - 2 3 P Z - 2 2 P Z - 2 4 P Z - 2 6 S P T - 4 M W - 6 B M W - 6 A M W - 6 C P Z - 2 0 M W - 4 M W - 4 A P Z - 1 1 D G P - 5 B - 1 H A - 1 - 2 H A - 1 - 1 G P - 3 G P - 6 G P - 2 S P T - 7 S P T - 4 C P T - 3 C P T - 2 B - 1 H A - 2 - 1 H A - 2 - 2 S P T - 1 B - 3 H A - 3 - 1 H A - 3 - 2 G P - 1 P Z - 1 9 7 1 S P T - 3 C P T - 8 S C P T - 1 G P - 4 M W - 1 8 M W - 1 7 P Z - 3 0 M W - 1 4 M W - 1 3 M W - 1 3 D M W - 1 6 M W - 1 6 D M W - 3 A M W - 3 B M W - 2 A M W - 2 B M W - 2 C S B - 2 M W - 7 B M W - 7 A M W - 1 5 M W - 1 5 D M W - 2 0 M W - 2 0 D A S H L A N D F I L L L E A C H A T E M O N I T O R I N G L O C A T I O N ( A P P R O X I M A T E ) P - 2 E X I S T I N G M O N I T O R I N G W E L L S / P I E Z O M E T E R S / S O I L B O R I N G S ( A P P R O X I M A T E ) M W - 5 B 5 0 0 f t C O M P L I A N C E B O U N D A R Y D U K E E N E R G Y P R O G R E S S S U T T O N P L A N T L E G E N D W A S T E B O U N D A R Y B A C K G R O U N D M O N I T O R I N G W E L L ( S U R V E Y E D ) C O M P L I A N C E M O N I T O R I N G W E L L ( S U R V E Y E D ) M W - 1 2 M W - 4 B G E N E R A L I Z E D G R O U N D W A T E R F L O W D I R E C T I O N x S U P P O R T E D B Y G R O U N D W A T E R E L E V A T I O N D A T A P O I N T S O R T O P O G R A P H I C D A T A P R O P O S E D G E O L O G I C C R O S S S E C T I O N M O N I T O R I N G W E L L ( S U R V E Y E D ) P A R C E L L I N E S ( R O X B O R O C O G I S ) P R O P O S E D M O N I T O R I N G W E L L L O C A T I O N B I - A N N U A L W A T E R L E V E L P I E Z O M E T E R N P D E S O U T F A L L 0 0 3 N P D E S O U T F A L L S W - 2 P R O P O S E D W A T E R Q U A L I T Y A N D S E D I M E N T L O C A T I O N P Z - 1 2 SW-8A P Z - 9 A N P D E S O U T F A L L S W - 0 0 4 SW-CFP S W - 1 C SW-6A N P D E S O U T F A L L S W - 0 0 2 N P D E S O U T F A L L S W - 0 0 1 S W - C F 0 0 1 C O O L I N G P O N D S W - 6 A S W - C F U P C A P E F E A R R I V E R I N S E T A U P S T R E A M S A M P L E L O C A T I O N O N T H E C A P E F E A R R I V E R 1 2 0 0 G R A P H I C S C A L E ( I N F E E T ) 0 6 0 0 3 0 0 6 0 0 SEE INSET A (THIS FIGURE) FORUPSTREAM SAMPLE LOCATIONON THE CAPE FEAR RIVER S W - 0 0 4 M W - 2 8 T M I N E B O U N D A R Y R E V I S E D L O C A T I O N S C U B - 1 P R O P O S E D C O N F I N I N G U N I T A S S E S S M E N T B O R I N G C U B - 1 C U B - 2 C U B - 3 C U B - 4 M W - 2 3 E C U B - 5 C U B - 6 C U B - 7 C U B - 8 S E E I N S E T B ( T H I S F I G U R E ) F O R M O R E C U B S A M P L E L O C A T I O N S . INSET BCUB SAMPLE LOCATIONS1200GRAPHIC SCALE(IN FEET)0600300600 CUB-10 CUB-9CUB-11 CUB-12 CUB-8 Attachment 1 Page 1 of 6 Duke Energy GAP Review Issues The items identified in this Groundwater Assessment Plan (GAP) review summary are provided for general discussion for the various parties to agree upon technical direction and content in the revised GAPs , comprehensive site assessments (CSAs), and corrective action plans (CAPs). Groundwater Monitoring 1. A schedule for continued groundwater monitoring is mandated by the Coal Ash Management Act 2014. An interim plan should include at least two rounds of groundwater samples collected and analyzed in 2015 . The analytical results of the first round of data collected in 2015 would be included in the CSA report, while the results of the second round would be submitted as a CSA addendum . After CSA data can be evaluated, a plan for continued groundwater monitoring can be developed for implementation in 2016 . 2. Sites impacted by inorganics are typically managed using a tiered site analysis which includes four elements as referenced in EPA/600/R-07 /139: • Demonstration of active contaminant removal f rom groundwater & dissolved plume stability; • Determination of the mechanism and rate of attenuation; • Determination of the long-term capacity for attenuation and stability of immobilized contaminants, before, during, and after any proposed remedial activities; and • Design of performance monitoring program, including defining triggers for assessing the remedial action strategy failure, and establishing a contingency plan. This reference and the framework described above should be used as applicable to meet the corrective action requirements found in 15A NCAC 02L .0106 . 3. Because of uncertainty concerning the site 's ability to attenuate contaminants over the long term given potentially changing geochemical conditions, there is a need to address the elements of the tiered site analysis described above and collect appropriate samples as part of the CSA, CAP development, and continued groundwater monitoring. 4. The Division of Water Resources (Division) Director is responsible for establishing background levels for COPCs in groundwater. This determination is based on information and data provided by the responsible party and may include formal statistical testing using background wells with at least four rounds of data . Wells identified as "background" are subject to periodic r eview based on a refined understanding of site chemistry and hydrogeologic conditions. In general, each facility must have a background well or wells screened or open to each of the dominant flow systems that occur at the site and are associated with groundwater contamination . Any questions concerning adequacy of background monitoring locations or conditions at the facilities should be directed to the Regional offices. Attachment 1 Page2of6 5. Delineation of the groundwater contaminant plume associated with coal combustion residuals is a requirement of the investigation and if off-site monitoring wells are ultimately required to perform this task, then it is expected that these activities will be completed as part of the groundwater assessment activities and included in the final report. Documentation of the effort to gain off-site access, or right of way permits, will be provided if off-site access is denied or alternate means of assessing the area were not available within the allocated timeframe (such as within right-of-ways}. Site Assessment Data Requirements and Sampling Strategy 1. Robust data collection is warranted to support timely completion of site assessments and subsequent corrective action plans because of the impending deadlines for completion of CSAs and CAPs, scale and geologic complexity of the sites, the challenges of modeling heterogeneous systems, and site proximity to potential human and sensitive ecosystem receptors. 2. Robust data collection will be focused along strategically positioned flowpath transect(s} -from ash pond source to potential receptor -as an efficient approach for model development (analytical, geochemical, groundwater flow, and transport} in support of risk assessment and CAP development. Data collected to support evaluation of site conditions along the flowpath transects should be located along or defensibly proximate to the modeled transects. 3. The dataset developed along proposed flowpath transects shall include any information needed to determine constituent concentrations, conduct Kd tests, and perform batch geochemical modeling in multiple flow horizons as appropriate . This data will include a} solid phase sample collection for Kd measurement and batch geochemical modeling, inorganic analysis and speciation, and other parameters identified in General Comment #4 of the November 4, 2014 GAP comments issued by DWR, b) solution phase sample collection for total and dissolved inorganic analysis of total concentrations, small pore filtration for dissolved samples, etc., and c) slug, constant/falling head, and packer testing . The solid phase sample mineralogy, total concentration results, re-dox measurements, and other geochemical parameters will be used as input for equilibrium speciation calculations of redox sensitive constituents calculated by PHREEQC or similar program (EPA/540/S-92/018}. This geochemical modeling will be performed to identify potential mineral phases, estimated species speciation and concentrations, and will be performed varying key solubility controlling parameters to predict mineral phases, speciation, and concentrations under varying conditions. Solid samples for Kd tests collected from along from proposed flowpath transects will be handled and preserved in order to eliminate exposure to ambient air in the field. Kd samples should be collected in plastic bags and sealed with a conventional vacuum plastic bag sealer. The samples will be then placed on ice in a cooler for transport and kept out of direct sunlight . Once received by the analytical laboratory, the Oxidation-Reduction Potential (ORP} of the sample will be measured using an ORP probe and meter in accordance with ASTM method G200-19 (Reapproved 2014}. Based on this ORP measurement, either normal or "glove-box" processing of a sample will be applied Attachment 1 Page 3 of 6 (EPA/600/R-06/112). An additional sample will be retained, pending confirmation of subsequent ORP and DO testing. ORP and dissolved oxygen will be measured in the groundwater monitoring wells subsequently installed at these sample locations. In the event that the groundwater field- measured ORP and DO reveal reducing conditions, the additionally-retained sample will be subject to glove box processing for the Kd analyses. Refer to EPA/600/R-07 /139 Section Ill for the data collection and characterization needed to support the four-tiered analysis discussed above. 4. Speciations for groundwater and surface water samples should include Fe, Mn, and any COPCs whose speciation state may affect toxicity or mobility (e.g . As, Cr, Se, or others if applicable). This speciation will apply for groundwater samples collected at wells located along proposed flowpath transects and in wells where these constituents exceed 2L groundwater standards as well as for surface water samples collected within ash impoundments. 5. Solid phase samples shall be analyzed for: minerals present, chemical composition of oxides, hydrous Fe, Mn, and AL oxides content; moisture content; particle size analysis; plasticity; specific gravity; porosity; permeability, or other physical properties or analyses needed to provide input to a chosen model. These analyses for physical properties will be conducted at up to 15 locations along proposed flowpath transects where Kd samples are collected. Solid phase samples at up to 15 additional locations will be collected and analyzed for hydrous ferric oxide (HFO) content. At these additional locations where HFO content is analyzed, analyses for physical properties will not be performed. Solid phase samples will be analyzed for total organic content from the same locations where samples are collected for Kd determination. Solid phase samples will be analyzed for total organic carbonate content from the same locations where samples are collected for Kd determination only at facilities located in the coastal plain. 6. In addition to conducting the SPLP leachable inorganic compounds analysis for selected ash samples to evaluate the potential for leaching of constituents to groundwater, the leachable analysis should also be conducted for some soil samples from locations beneath the ash ponds, within the plume, and outside the plume to evaluate potential contributions from native soils. 7. In addition to collecting solid phase samples onsite for Kd procedures, soil samples should be also collected from unaffected soils within groundwater flow pathways to evaluate Kd(s) or hydrous ferrous oxide. 8 . Rock samples for laboratory analyses should be collected as commented in General Comment 4 of the November 4, 2014 GAP comments issued by DWR. This GAP review comment indicated that the sample(s) collected from bedrock well soil and rock cores shall be analyzed, at a minimum, for the following : type of material, formation from which it came, minerals present, chemical composition as oxides, hydrous Fe , Mn, and AI oxides content, surface area, moisture content, etc.; however, these analyses were not mentioned in the GAP. The Division reserves the right to request analysis for organic carbon content, organic carbonate content, and ion exchange capacity if needed to complete the site assessment process. 9. The coal ash and soil analyte lists should match the groundwater analyte lists. 10. Total uranium analysis should be analyzed where total radium is analyzed for groundwater. Attachment 1 Page 4 of 6 11. If analytical results from a seep sample exceed 2L standards, then the area in the vicinity ofthe sample location should be investigated for groundwater contamination. If analytical results from a surface water sample exceed 2B standards, then the area in the vicinity of the sample location should be investigated for groundwater contamination . 12. Surface water/seep samples should be collected during baseflow conditions and the groundwater monitoring (water levels and sampling) should occur at about the same time. 13. Measurement of streamflow in selected perennial streams is expected as needed in support of simulation/calibration of flow and transport models ; major rivers that serve as groundwater divides are not included in this expectation . Conceptual Model Elements 1. In the CSA report, data gaps remaining should be specifically identified and summarized. 2. Site heterogeneities should be identified and described with respect to: a) their nature, b) their scale and density, c) the extent to which the data collection successfully characterizes them, d) how the modeling accounts for them, e) and how they affect modeling uncertainty. 3 . The impact of data gaps and site heterogeneities should be described in relation to the elements developed in the Site Hydrogeologic Conceptual Model and Fate and Transport Model subsections . 4. For sites in the Piedmont or Mountains, the CSA Report should include a subsection within the Site Geology and Hydrogeology Section titled 'Structural Geology'. This section should describe : a) foliations, b) shear zones, c) fracture trace analysis, and d) other structural components anticipated to be relevant to flow and contaminant transport at the site . 5 . Duke Energy will include a poster-sized sheet(s) (ANSI E) combining tabulated analytical assessment results (groundwater, surface water, and leachate samples); multiple sheets may be needed to present the data . This should be provided in addition to the individual analytical results tables that will be prepared for the CSA reports. Any questions concerning format or content of the analytical result summaries should be directed to the Regional offices. Geochemical Modeling 1. The Division agrees that a geochemical model"coupled" to a 3-D fate and transport model is inappropriate given the size and complexity of the sites and the extremely large amount of data required to calibrate such a model. Rather, a "batch" geochemical model approach should be sufficient for successfully completing the site assessment and/or corrective action plan. 2. Samples collected for "batch" geochemical analysis should be focused along or defensibly proximate to flowpath transects. 3. To support successful batch geochemical modeling, dissolved groundwater samples collected along a contaminant flowpath transect should be obtained using a 0.1 um filter. This will help ensure a true dissolved phase sample . Note that the dissolved samples are for assessment purposes only and may not be used for purposes of compliance monitoring. If there is uncertainty about which areas/wells will be used in the batch geochemical modeling, the initial round of assessment sampling at the facility can utilize the 0 .45 um filter until the contaminant Attachment 1 Page 5 of6 flow path transects are selected. Once determined, Duke Energy can go back and re-sample the wells needed for geochemical modeling using the 0.1 um filter. It is recognized that the use of a 0 .1 um filter will be difficult for wells with elevated turbidity; in this case, it is recommended that Duke Energy use two filters in series (the water initially passes through a 0.45 um filter to remove larger particles prior to passing through the 0.1 um filter). Information for a disposable 0.1um field filter designed specifically for sampling groundwater for metal analysis is provided at the following link: http://www.vosstech.com/index.php/products/filters. If field comparisons of 0 .1 versus 0.45 micron filtration at several transect wells at a given site show no significant differences between the two methods, then 0.45 micron filters may be used for evaluating the dissolved phase concentrations at that site. 4. In support of the objectives of General Comment #2 of the November 4, 2014 GAP comments issued by DWR , Duke Energy should add a column titled 'relative redox' to the analytical results tables to record the geochemical conditions for that location/sample date. The redox determination should be based on observed DO, ORP, and any other relevant measures and presented for historic and new samples (wells, ash pore water, surface waters, etc.). Relative redox designations may include "iron reducing", "sulfate reducing", mildly oxidizing, moderately oxidizing, etc. and should be footnoted with a statement about the degree of confidence in the designation based on amount and quality of available data . 5. Duke Energy shall also evaluate: a) spatial geochemical trends across the facility and along selected flow paths, b) temporal geochemical trends where observable (such as for compliance boundary wells), along with the likely reason for the change (e.g. increase in seasonal recharge, pond de-watering and subsequent reversal of groundwater flow direction, inundation of well from river at flood stage, etc.) in support of the CAP. This evaluation step will require a comparison of geochemical conditions over time with rainfall data, notable ash capping, dewatering, disposal/removal, or other plant operations, etc. The quality of existing geochemical data will be evaluated using field notes, calibration records, and consistency in redox measurements (e.g. eH vs. raw ORP). Groundwater Models 1. The technical direction for developing the fate and transport modeling will follow guidelines found in Groundwater Modeling Policy, NCDENR DWQ, May 31 , 2007, and discussions conducted between Duke Energy and their consultants with the Division . Ultimate direction for completion of fate and transport models will be provided by the Division. 2 . The CAP Report should include a subsection within Groundwater Modeling Results titled 'Site Conceptual Model' that succinctly summarizes, for purposes of model construction, the understanding of the physical and chemical setting of the site and shall include, at a minimum : a) the site setting (hydrogeology, dominant flow zones, heterogeneities, areas of pronounced vertical head gradients, areas of recharge and discharge, spatial distribution of geochemical conditions across the site, and other factors as appropriate), b) source areas and estimated mass loading history, c) receptors, d) chemical behavior of COPCs, and e) likely Attachment 1 Page 6 of 6 retention mechanisms for COPCs and how the mechanisms are expected to respond to changes in geochemical conditions. 3. Model ing will be included in the Corrective Action Plan (CAP). The four-tiered analysis previously referenced and appropriate modeling should be conducted, and the mass flux calculations described in the EPA/600/R-07 /139 should be performed . 4 . The CAP Report shall provide separate subsections for reporting groundwater flow models and fate and transport models . 5. The CAP Report should include subsections within Groundwater Modeling Results titled 'Groundwater Model Development' that describes, for each chosen model: a) purpose of model, built-in assumptions, model extent, grid, layers , boundary conditions, initial conditions, and others as listed in Division guidance . Include in this section a discussion of heterogeneities and how the model(s) account for this (e .g. dual porosity modeling, equivalent porous media approach, etc.). Separate subsections should be developed for the groundwater flow model, fate and transport model, and batch geochemical models, respectively. 6. CAP Reports should include a subsection within Groundwater Modeling Results titled 'Groundwater Model Calibration' that describes, for each model used, the process used to calibrate the model, the zones of input and calibration variables (for example, hydraulic conductivities) that were used, the actual (measured) versus modeled results for all key variables, and others. Separate subsections should be developed for the groundwater flow model, fate and transport model, and batch geochemical model(s), respectively. 7. CAP Reports should include a subsection within Groundwater Modeling Results titled 'Groundwater Model Sensitivity Analysis' that describes, for each model used , the process used to evaluate model uncertainty, variable ranges tested, and the key sensitivities. Separate subsections should be developed for the groundwater flow model, fate and transport model, and batch geochemical model{s), respectively. Development of Kd Terms 1. Kd testing and modeling in support of CAP development should include all COPCs found above the NCAC 15A 02L .0106(g) standards in ash leachate, ash pore water, or compliance boundary well groundwater samples. 2 . The selected Kd used in transport modeling often will profoundly affect the results. Duke Energy should acknowledge this concept and document within the transport modeling section(s) of the CAP all widely recogn ized limitations inherent in the estimation of the Kd term. Risk Assessment 1. Provide references for guidance and potential sampling methodology related to conducting a baseline ecological risk assessment or habitat assessment, i f warranted .