Arroyo Seco Reach 2 (West Holly Ave to Devils Gate Dam)

Waterbody ID (WBID): CAR4051501019990202133129
County / counties: Los Angeles
Regional Water Board: Regional Board 4 - Los Angeles Region
Waterbody type: River & Stream
Condition category: Category 4a — TMDL completed
Integrated Report cycle: 2026

303(d) listings (2)

Each row is one official listing decision from Appendix A of the Final 2026 California Integrated Report. Source terminology is preserved as published.

Pollutant / stressor	Decision ID	Final listing decision	Decision status	TMDL requirement status	TMDL project	TMDL priority
Indicator BacteriaPathogens	70162	List on 303(d) list (being addressed by USEPA approved TMDL)	Original	5B — Addressed by USEPA-approved TMDL	Los Angeles River Pathogens (15)	—
TrashTrash	70164	List on 303(d) list (being addressed by USEPA approved TMDL)	Original	5B — Addressed by USEPA-approved TMDL	Los Angeles River Trash (12)	—

Source & provenance

Agency: California State Water Resources Control Board
Report: Final 2026 California Integrated Report
Dataset: Appendix A — 2026 303(d) List of Impaired Waters
Imported: Sep 16, 2026, 10:57 PM UTC
Waterbody ID: CAR4051501019990202133129
CALWNUM: 40515010
Geometry: Official Water Board GIS (CA_WATERBOARDS_GIS_FINAL_2026)

View official Water Board fact sheet ↗Download Appendix A source file ↗

Location

Official 2026 Water Board geometry. Demonstration facility markers are shown for context only.

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Watershed: —
Assessed size: 4.42 Miles

Derived facility associations

Industrial stormwater facilities geographically associated with this waterbody. These are derived spatial associations, not Water Board findings.

Derived

Caleb Y Lee Design

South Pasadena · No Exposure Certification · 0.55 km away

derived_receiving_water

Derived by California Stormwater Intelligence

Nasa

Pasadena · Notice of Intent · 0.08 km away

derived_receiving_water

Derived by California Stormwater Intelligence

Facility records are official Industrial General Permit registrations, but the association between a facility and this waterbody is derived geographically (proximity or shared HUC12 subwatershed) and is not a Water Board receiving-water determination. Where a permit carries a Water Board-stated TMDL requirement naming this water, it is listed separately above.