Colusa Basin Drain

Waterbody ID (WBID): CAR5202100019980813170249
County / counties: Colusa, Glenn, Yolo
Regional Water Board: Regional Board 5 - Central Valley Region
Waterbody type: River & Stream
Condition category: Category 5 — 303(d) listed, TMDL required
Integrated Report cycle: 2026

303(d) listings (9)

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	134755	List on 303(d) list (TMDL required list)	Revised	5A — TMDL still required	—	Low
Azinphos-methyl (Guthion)Pesticides	116312	Do Not Delist from 303(d) list (TMDL required list)	Revised	5A — TMDL still required	—	Low
DDT (Dichlorodiphenyltrichloroethane)Pesticides	127458	Do Not Delist from 303(d) list (TMDL required list)	Revised	5A — TMDL still required	—	Low
DieldrinPesticides	116303	Do Not Delist from 303(d) list (TMDL required list)	Revised	5A — TMDL still required	—	Low
Group A PesticidesPesticides	72781	List on 303(d) list (TMDL required list)	Original	5A — TMDL still required	—	Low
IronMetals	134745	List on 303(d) list (TMDL required list)	Revised	5A — TMDL still required	—	Low
Low Dissolved OxygenNutrients	73424	Do Not Delist from 303(d) list (TMDL required list)	Original	5A — TMDL still required	—	Low
MercuryMetals	145017	Do Not Delist from 303(d) list (TMDL required list)	Revised	5A — TMDL still required	—	Low
Oxygen, DissolvedNutrients	146493	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: Aug 21, 2026, 12:44 AM UTC
Waterbody ID: CAR5202100019980813170249
CALWNUM: 5520.100001, 5520.100002, 5520.210000
WBD code: 180201040400, 180201040604, 180201040807, 180201041003, 180201041006, 180201041007, 180201041008, 180201041203
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: 72.31 Miles

Facilities with an NAL exceedance for a listed pollutant (5)

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

Farmers Fresh Mushrooms California Inc5S06I028675

Iron · most recent exceedance RY 2021 · association: derived watershed association

Parts R Us5R11I022650

Aluminum, Iron · most recent exceedance RY 2015 · association: derived watershed association

Simplot Grower Solutions Colusa5S06I028722

Iron · most recent exceedance RY 2025 · association: derived watershed association

Wadham Energy Ltd Part5S06I000534

Iron · most recent exceedance RY 2024 · association: derived watershed association

Wilbur Ellis Company LLC Colusa5S06I027570

Iron · most recent exceedance RY 2025 · association: derived watershed association

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

ACC Williams Bio Energy Project

Williams · No Exposure Certification

derived_watershed_association