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Entergy Arkansaas, LLC - Lake Catherine Plant

Electric Services, major discharger, Malvern, Arkansas. NPDES permit AR0001147, in force until Apr 30, 2031. Last 12 months: no values over a limit. Source: EPA ECHO, Oct 22, 2026.

Reports due
About 25 days after each period: outfall 001 form A monthly (11 values), outfall 003 form A monthly (6 values), outfall 005 form A monthly (6 values), outfall 003 form Q quarterly, outfall 005 form Q quarterly, outfall TX1 form Q quarterly
Last report on file
August 2026
Oct 2024 – Sep 2025
0 values over a limit, 5 required values missing, 1 of 68 reports late

Limits in force (43)

ParameterStatisticLimitMonthsOutfall
Temperature, water deg. fahrenheitinstantaneous maximum≤ 95 deg Fall year001
pHminimum≥ 6 SUall year001
pHmaximum≤ 9 SUall year001
Flow, in conduit or thru treatment plantmonthly average≤ 425 MGDall year001
Flow, in conduit or thru treatment plantdaily maximum≤ 476 MGDall year001
Chlorine, total residualdaily maximum≤ .2 mg/Lall year001
Chlorine, total residualdaily maximum≤ 66.2 lb/dall year001
Chlorine, free availablemonthly average≤ .2 mg/Lall year001
Chlorine, free availabledaily maximum≤ .5 mg/Lall year001
Chlorine, free availablemonthly average≤ 59.1 lb/dall year001
Chlorine, free availabledaily maximum≤ 165.4 lb/dall year001
pHminimum≥ 6 SUall year003
pHmaximum≤ 9 SUall year003
Solids, total suspendedmonthly average≤ 30 mg/Lall year003
Solids, total suspendeddaily maximum≤ 100 mg/Lall year003
Oil & Greasemonthly average≤ 10 mg/Lall year003
Oil & Greasedaily maximum≤ 15 mg/Lall year003
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year003
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)all year003
pHminimum≥ 6 SUall year005
pHmaximum≤ 9 SUall year005
Solids, total suspendedmonthly average≤ 30 mg/Lall year005
Solids, total suspendeddaily maximum≤ 100 mg/Lall year005
Oil & Greasemonthly average≤ 10 mg/Lall year005
Oil & Greasedaily maximum≤ 15 mg/Lall year005
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year005
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)all year005
Whole effluent toxicity - retest #17-day minimumreport only (pass=0;fail=1)all yearTX1
Whole effluent toxicity - retest #27-day minimumreport only (pass=0;fail=1)all yearTX1
WET, sublethal retest #17-day minimumreport only (pass=0;fail=1)all yearTX1
WET, sublethal retest #27-day minimumreport only (pass=0;fail=1)all yearTX1
Whole Effluent Toxicity - Retest #37-day minimumreport only (pass=0;fail=1)all yearTX1
Whole Effluent Toxicity, Sub-Lethal Retest #37-day minimumreport only (pass=0;fail=1)all yearTX1
Pass/Fail Static Renewal 7 Day Chronic Ceriodaphnia dubia7-day minimumreport only (pass=0;fail=1)all yearTX1
Pass/Fail Static Renewal 7Day Chronic Pimephales promelas7-day minimumreport only (pass=0;fail=1)all yearTX1
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Ceriodaphnia dubia7-day minimumreport only (pass=0;fail=1)all yearTX1
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Pimephales promelas7-day minimumreport only (pass=0;fail=1)all yearTX1
NOEC Lethal Static Renewal 7 Day Chronic Ceriodaphnia dubia7-day minimumreport only (%)all yearTX1
NOEC Lethal Static Renewal 7 Day Chronic Pimephales promelas7-day minimumreport only (%)all yearTX1
NOEC Sub-Lethal Static Renewal 7 Day Chronic Ceriodaphnia dubia7-day minimumreport only (%)all yearTX1
NOEC Sub-Lethal Static Renewal 7 Day Chronic Pimephales promelas7-day minimumreport only (%)all yearTX1
Coef Of Var Static Renewal 7Day Chronic Ceriodaphnia dubia7-day minimumreport only (%)all yearTX1
Coef Of Var Static Renewal 7Day Chronic Pimephales promelas7-day minimumreport only (%)all yearTX1

How strict are these limits?

Cited limits by parameter: Arkansas's rules and the federal ones.

Same industry: the 18 Electric Services permits in Arkansas.

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On EPA ECHO: Facility report · DMR history

Your permit document is the final word. As JSON: /api/v1/permits/AR0001147 · MCP: https://passage-data.com/mcp