Clean Water Act discharge permit · NPDES AR0049140
ENTERGY ARKANSAS, LLC. - UNION POWER STATION, El Dorado, AR: NPDES AR0049140 discharge permit, effluent exceedances, inspections, penalties
- Administratively continuedPermit status
- MajorDischarger class
- 11Pollutants under a numeric limit
- 8Pollutants with an effluent exceedance
ENTERGY ARKANSAS, LLC. - UNION POWER STATION, held by ENTERGY ARKANSAS POWER, LLC, holds NPDES permit AR0049140, which discharges to Ouachita R. EPA’s file records it issued October 31, 2016 and expiring November 30, 2021. The status and dates are as EPA’s permit file stood when Velarion loaded it (September 15, 2026); EPA’s free Detailed Facility Report on ECHO carries the permit’s current standing.
Identity
| Facility as filed | ENTERGY ARKANSAS, LLC. - UNION POWER STATION |
|---|---|
| Permittee as filed | ENTERGY ARKANSAS POWER, LLC |
| NPDES ID | AR0049140 |
| Permit status | Administratively continued (past its expiration date and still in force until reissued) |
| Permit type | Individual permit |
| Discharger class | Major discharger |
| Facility type | Not a publicly owned treatment works |
| Issued | October 31, 2016 |
| Expiration date | November 30, 2021 |
| Address | El Dorado, AR 71730 |
| Receiving water | OUACHITA R |
| Receiving water impaired | 303(D) Listed |
| Subwatershed | Crooked Creek-Ouachita River (HUC 080402010803) |
Cited to the EPA ICIS-NPDES permit file (ECHO download).
Effluent limits and exceedances
- 21Pollutants on file
- 11Under a numeric limit
- 21With a violation of any kind
- 8With an effluent exceedance
An effluent exceedance is a discharge monitoring report value over the permit’s numeric limit (EPA’s violation code E90). A violation of any kind also counts a report not filed. Each row is EPA’s own count for that pollutant.
| Pollutant or measure | Limits | Violations, any kind | Effluent exceedances | Latest exceedance | Largest exceedance, as filed |
|---|---|---|---|---|---|
| Solids, total suspended | 4 | 28 | 20 | March 31, 2017 | 343% over the limit |
| Oil & Grease | 8 | 38 | 17 | February 28, 2018 | 1,054% over the limit |
| Chlorine, free available | 4 | 17 | 5 | June 30, 2012 | 105% over the limit |
| Chromium, total [as Cr] | 0 | 12 | 4 | June 30, 2010 | 230% over the limit |
| Turbidity | 0 | 10 | 4 | January 31, 2013 | |
| pH | 6 | 30 | 1 | October 31, 2014 | |
| Zinc, total [as Zn] | 0 | 9 | 1 | April 30, 2004 | 420% over the limit |
| Temperature, water deg. fahrenheit | 0 | 1 | 1 | July 31, 2005 | 2% over the limit |
| Flow, in conduit or thru treatment plant | 6 | 32 | 0 | ||
| Mercury, total recoverable | 0 | 10 | 0 | ||
| Low Flow Pass/Fail Static Renewal 48Hr Acute Daphnia pulex | 2 | 6 | 0 | ||
| LF Pass/Fail Static Renewal 48Hr Acute Pimephales promelas | 2 | 6 | 0 | ||
| NOAEC Lethal Statis Renewal 48 Hr Acute Daphnia pulex | 2 | 6 | 0 | ||
| NOAEC Lethal Static Renewal 48Hr acute Pimephales promelas | 2 | 6 | 0 | ||
| Coef Of Var Static Renewal 48Hr Acute D. pulex | 2 | 6 | 0 | ||
| Coef Of Var Static Renewal 48Hr Acute Pimephales promelas | 2 | 6 | 0 | ||
| Oxygen demand, chem. [low level] [COD] | 0 | 2 | 0 | ||
| Oxygen demand, chem. [high level] [COD] | 0 | 2 | 0 | ||
| NOEC Sub-Lethal Static Renewal 7 Day Chronic Pimephales promelas | 0 | 1 | 0 | ||
| Coef Of Var Static Renewal 7Day Chronic Ceriodaphnia dubia | 0 | 1 | 0 | ||
| Coef Of Var Static Renewal 7Day Chronic Pimephales promelas | 0 | 1 | 0 |
Cited to the EPA ICIS-NPDES limits and effluent violations files (ECHO download); up to 60 rows shown, most exceedances first.
Inspections, violations and enforcement
- 0Single-event violations
EPA’s single-event violation file, as loaded, holds no violation for NPDES AR0049140.
Velarion’s copy of EPA’s ICIS-NPDES files does not include the inspections, formal enforcement actions and informal enforcement actions files, so this page shows none of them. EPA’s free Detailed Facility Report on ECHO lists this permit’s inspections, enforcement actions and penalties.
Cited to the EPA ICIS-NPDES violation, inspection and enforcement files (ECHO download); up to 50 rows of each shown, newest first.
Watch this permit
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How we handle your data → Privacy
EPA publishes a free Detailed Facility Report for every permit on ECHO: its compliance status quarter by quarter, its inspections, and its enforcement actions and penalties. EPA also sends free notices of new inspections and enforcement actions through ECHO Notify; enter NPDES ID AR0049140 there.
Nearby on the register
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- Every permit record in Arkansas, A to Z
Figures from EPA’s ICIS-NPDES download, loaded September 15, 2026.