MEMORANDUM 

TO: Steam Electric Rulemaking Record 

FROM: Elizabeth Sabol, ERG 

TJ Finseth, ERG 

DATE: April 19, 2013 

SUBJECT: Surface Impoundment Listings Supporting the Steam Electric Rulemaking 

ERG is providing technical support to the U.S. Environmental Protection Agency’s Office of 

Water, Engineering and Analysis Division (EAD) for development of effluent limitations 

guidelines and standards (ELGs) for the Steam Electric Power Generating Industry. EPA, with 

the support of ERG, distributed the Questionnaire for the Steam Electric Power Generating 

Effluent Guidelines (Steam Electric Survey) to 733 power plants in the summer of 2010 to gather 

plant-specific data on the steam electric industry. The Steam Electric Survey requested data on 

plant operations in 2009. The Steam Electric Survey comprised the following nine parts: 

Part A: Steam Electric Power Plant Operations 

Part B: FGD Systems 

Part C: Ash Handling 

Part D: Pond/Impoundment Systems and Other Wastewater Treatment Operations 

Part E: Wastes from Cleaning Metal Process Equipment 

Part F: Management Practices for Ponds/Impoundments and Landfills 

Part G: Leachate Sampling Data for Ponds/Impoundments and Landfills 

Part H: Nuclear Power Generation 

Part I: Economic and Financial Data 

EPA used the collected data to inform various analyses including, but not limited to, estimating 

the compliance costs and pollutant removals associated with the proposed ELGs, developing the 

profile of the industry, and obtaining characterization data for the wastestreams generated by the 

industry. EPA analyzed the Steam Electric Survey responses, stored in the Steam Electric 

Technical Questionnaire Database (technical database) [DCN SE01958], to determine the listing 

of impoundments reported in the Steam Electric Survey and the types of materials stored in each 

impoundment (e.g., fly ash, bottom ash, FGD solids). This memorandum describes the 

impoundment information in the Steam Electric Survey and the two impoundment listings used 

to support the Steam Electric ELGs. 

1.0 SUMMARY OF POND/IMPOUNDMENT INFORMATION IN THE STEAM ELECTRIC SURVEY 

Part A, Section 3 of the Steam Electric Survey (Pond/Impoundments) requests a listing of all 

onsite surface impoundments at the plant. For each impoundment reported, plants provided the 

following information: plant designation, location, liner (yes/no), leachate collection (yes/no), 
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April 19, 2013 

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closest distance to nearest surface water, year initially brought online, inactive status (yes/no), 

and solid waste/process wastewater stored in the surface impoundment. 

Part D, Section 4.1 (Active/Inactive/Open and Planned Pond/Impoundment Unit Information) 

requests more specific information (e.g., type of liner, dimensions of the pond, pond expansions) 

for those impoundments that contain combustion residuals. In addition, Part D, Section 2 

(Pond/Impoundment System and Wastewater Treatment System Identification) requests the plant 

to identify all the impoundment systems at the plant containing combustion residuals. For each 

impoundment system, the plant provided a system diagram and the influents and effluents to the 

impoundment system (including flow rates). 

Additional information for surface impoundments can be found in certain plant-submitted 

supplemental survey files including the water balance diagrams, pond/impoundment system 

diagrams, and questions requesting the destination of certain process wastewaters (e.g., Question 

C2-9, Table C-4 (Storage Destinations that Receive Fly Ash)). 

2.0 EPA IMPOUNDMENT LISTING FROM PART A OF THE STEAM ELECTRIC SURVEY

EPA analyzed the survey responses from Part A, Section 3 (Tables A-4 and A-5), using a 

Statistical Analysis System (SAS) program, to create a complete listing of all impoundments 

(active/retired/planned) reported in the survey and the type of combustion residuals (if any) 

disposed of or stored in the impoundment. The responses of Table A-5 (Wastes Stored or 

Disposed of in Plant Pond/Impoundment Units) were examined and EPA noted which 

impoundments contained fly ash, bottom ash, FGD, or no combustion residuals. EPA identified 

2,608 impoundments (active, inactive, open, retired or planned) reported in Part A, Section 3 of 

the Steam Electric Survey. EPA flagged 1,169 active, inactive, open or retired impoundments 

containing ash and/or FGD solids. See DCN SE00986 for the complete listing of impoundments 

reported in response to Part A of the Steam Electric Survey, the types of materials stored in each 

impoundment, and a summary of the search criteria used to identify impoundments containing or 

storing ash and/or FGD materials. 

This impoundment listing was generated using only the Part A, Section 3 data. EPA used this 

impoundment listing in industry profile analyses supporting the Steam Electric ELGs, including 

the numbers presented in the Technical Development Document for the Proposed Effluent 

Limitations Guidelines and Standards for the Steam Electric Power Generating Point Source 

Category (Steam Electric TDD) [DCN SE01964]. 

3.0 EPA IMPOUNDMENT LISTING FROM ALL DATA IN THE STEAM ELECTRIC SURVEY

EPA has coordinated the data and analyses for the EPA Office of Water (OW) Steam Electric 

ELG rulemaking and the EPA Office of Resource Conservation and Recovery (ORCR) Coal 

Combustion Residuals (CCR) rulemaking. In doing so, EPA determined that the Part A data 

alone were not sufficient for the coordination effort and therefore, ERG re-evaluated the listing 

of surface impoundments reported in response to the Steam Electric Survey and the types of 

materials disposed of or stored in the impoundments, using Part A, Section 3 data in combination 

with water balance diagrams, fly ash transport water/bottom ash transport water/ FGD scrubber 

blowdown and purge destination information in Parts B and C, and impoundment system 

information in Part D of the Steam Electric Survey. ERG identified 1,305 impoundments (active, 
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April 19, 2013 

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inactive, open, or retired) using data from Parts A, B, C, and D of the Steam Electric Survey 

containing fly ash, bottom ash, FGD, and/or leachate.1 Based on those impoundments identified, 

ERG flagged 1,187 active, inactive, open or retired impoundments containing ash and/or FGD 

materials (i.e., impoundment flagged as leachate only were not included in the 1,187). 

Additionally, there are 1,097 impoundments included in the listing if retired impoundments were 

excluded. See DCN 01327 for the complete listing of impoundments identified from this analysis 

and the types of materials stored in each pond. 

EPA used this impoundment listing for analyses associated with coordinating with ORCR, 

analyses identifying impoundments as potential closures and partial closures as a result of the 

Steam Electric ELGs [DCN SE02125], and the identification of impoundments requiring best 

management practice (BMP) costs for the estimated compliance costs for the Steam Electric 

ELGs [DCN SE01957]. 

 

1

 EPA flagged impoundments including leachate for this analysis. However, because EPA cannot confirm whether 

the leachate is from landfills containing combustion residuals or landfills containing other plant wastes based on the 

information provided in response to the Steam Electric Survey, EPA did not include leachate only impoundments in 

many of the analyses conducted with the impoundment listing.