Clean Water Act discharge permit · NPDES WA0041165
PACIFICORP MERWIN HYDROELECTRIC PROJECT, Ariel, WA: NPDES WA0041165 discharge permit, effluent exceedances, inspections, penalties
- EffectivePermit status
- MinorDischarger class
- 5Pollutants under a numeric limit
- 1Pollutants with an effluent exceedance
PACIFICORP MERWIN HYDROELECTRIC PROJECT, held by PacifiCorp Merwin Hydroelectric Project, holds NPDES permit WA0041165. EPA’s file records it issued August 31, 2023 and expiring September 30, 2028. The status and dates are as EPA’s permit file stood when Velarion loaded it (September 14, 2026); EPA’s free Detailed Facility Report on ECHO carries the permit’s current standing.
Identity
| Facility as filed | PACIFICORP MERWIN HYDROELECTRIC PROJECT |
|---|---|
| Permittee as filed | PacifiCorp Merwin Hydroelectric Project |
| NPDES ID | WA0041165 |
| Permit status | Effective |
| Permit type | Individual permit |
| Discharger class | Minor discharger |
| Facility type | Not a publicly owned treatment works |
| Issued | August 31, 2023 |
| Expiration date | September 30, 2028 |
| Issuing agency | State |
| Address | Ariel, WA 98603 |
| Subwatershed | Lewis River (HUC 170800020606) |
Cited to the EPA ICIS-NPDES permit file (ECHO download).
Effluent limits and exceedances
- 5Pollutants on file
- 5Under a numeric limit
- 2With a violation of any kind
- 1With 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 |
|---|---|---|---|---|---|
| pH | 12 | 4 | 4 | May 31, 2024 | |
| Oil and grease [soxhlet extr.] tot. | 3 | 1 | 0 | ||
| Temperature, water deg. centigrade | 12 | 0 | 0 | ||
| Flow | 12 | 0 | 0 | ||
| Oil & Grease | 2 | 0 | 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 WA0041165.
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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Start the watch
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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 WA0041165 there.
Nearby on the register
Figures from EPA’s ICIS-NPDES download, loaded September 14, 2026.