NC0004961_DEC Review_20210212

DMR REVIEW RECORD
Mooresville Regional Office
Facility Name: Riverbend Steam Station Permit Number: NC0004961
Report Period: December 2020
Prior Assessments: 0 Enforcement Factor: 1.00
Waterbody
Outfall # Outfall Description Waterbody Name Classification
102 Seep discharge CATAWBA RIVER (Mountain Island Lake below WS-IV,B;CA
elevation 648)
Monthly Average Limit Violations
Sample Location: Outfall 102 - Effluent
Violation Unit of Limit Calculated % Over
Date Parameter Frequency Measure Value Value Limit
Action
12/31/2020 Hardness, Total (as CaCO3)
Quarterly mg/I 100 120 20.0
Daily Limit Violations
Sample Location: Outfall 102 - Effluent
Violation Unit of Limit Calculated % Over
Date Parameter Frequency Measure Value Value Limit
Action
12/2/2020 Hardness, Total (as CaCO3)
Quarterly mg/I 100 120 20.0
Other Violations/Staff Remarks:
ORC comments "The site noted a sample above 100 mg/I for hardness on current outfall 102. We request that this matter be
closed without further action for the following reasons: 1.) The Division has public noticed a permit renewal for this site that
removes this outfall confirming it does not need permit coverage as it is not a wastewater outfall. Any actions needed to address
any concerns would be best addressed through evaluation within the sites groundwater corrective action plan. 2.) Duke Energy
has completed excavation of the ash basin at Riverbend. 3.) The flow at this outfall is minimal and typical flow average -5 Liters
per minute and has been as low as 0.5 Liters per minute 4.) There was no evidence of typical coal ash constituents in the sample
results which include arsenic, selenium, and mercury "
Given the seep discharge comes from underground, hardness value could be BPJ
Supervisor Remarks:
will require co permitting review and comment.
Completed by: Ori Tuvia
Assistant Regional
Supervisor Sign -off:
Regional
Supervisor Sign -off:
DocuSigned by:
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Date:
Date:
Date:
2/12/2021
2/15/2021

Prior 12-Month Enforcement History
Permit Number: NC0004961 Report Period: December 2020