Mad River HU, Mad River

Waterbody ID (WBID): CAR1091001119980706155140
County / counties: Humboldt, Trinity
Regional Water Board: Regional Board 1 - North Coast Region
Waterbody type: River & Stream
Condition category: Category 5 — 303(d) listed, TMDL required
Integrated Report cycle: 2026

303(d) listings (6)

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
AluminumMetals	168865	Do Not Delist from 303(d) list (TMDL required list)	Revised	5A — TMDL still required	—	Low
SedimentSediment	168866	List on 303(d) list (being addressed by USEPA approved TMDL)	Revised	5B — Addressed by USEPA-approved TMDL	Mad River	—
Sedimentation/SiltationSediment	69622	List on 303(d) list (being addressed by USEPA approved TMDL)	Original	5B — Addressed by USEPA-approved TMDL	Mad River	—
Specific ConductivitySALINITY/TOTAL DISSOLVED SOLIDS/CHLORIDES/SULFATES	163039	List on 303(d) list (TMDL required list)	Revised	5A — TMDL still required	—	Low
Temperature, waterOther Cause	155280	Do Not Delist from 303(d) list (TMDL required list)	Revised	5A — TMDL still required	—	Low
TurbiditySediment	157189	Do Not Delist from 303(d) list (TMDL required list)	Revised	5A — TMDL still required	—	Low

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, 10:56 PM UTC
Waterbody ID: CAR1091001119980706155140
CALWNUM: 1107.300103, 1109.100103, 1109.300201, 1109.300302, 1109.300404, 1109.300405, 1109.300503, 1109.300602, 1109.400301, 1109.400302
WBD code: 180101020301, 180101020302, 180101020401, 180101020402, 180101020403, 180101020404, 180101020405, 180101020406, 180101020407, 180101020408
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: 1882.01 Miles

Facilities with an NAL exceedance for a listed pollutant (2)

Geographically associated industrial stormwater facilities whose reported results exceeded an Industrial General Permit Numeric Action Level for a pollutant this waterbody is listed for.

Derived

Kernen Construction Glendale Yard1 12I017319

Aluminum · most recent exceedance RY 2019 · association: derived nearby in watershed

Royal Gold LLC1 12I025790

Aluminum · most recent exceedance RY 2023 · association: derived nearby in watershed

This is derived co-occurrence between a calculated NAL comparison and the official 303(d) listing for this waterbody. An NAL exceedance triggers Exceedance Response Actions under the permit; it is not a violation and does not establish that any facility caused or contributed to this impairment.

Derived facility associations

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

Derived

Almquist Lumber Company

Arcata · Notice of Intent · 0.22 km away

derived_nearby_in_watershed