← Impaired waters

Waterbody profile

Official Water Board record · 2026 cycle

Harkins Slough

Waterbody ID (WBID)
CAR3051001320080603122917
County / counties
Santa Cruz
Regional Water Board
Regional Board 3 - Central Coast Region
Waterbody type
River & Stream
Condition category
Category 5 — 303(d) listed, TMDL required
Integrated Report cycle
2026

303(d) listings (5)

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

Pollutant / stressorDecision IDFinal listing decisionDecision statusTMDL requirement statusTMDL projectTMDL priority
Chlorophyll-aNutrients112479List on 303(d) list (TMDL required list)Original5A — TMDL still required—High
Indicator BacteriaPathogens131602Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)Revised5B — Addressed by USEPA-approved TMDLWatsonville Slough Pathogen—
Oxygen, DissolvedNutrients112490Do Not Delist from 303(d) list (being addressed with USEPA approved TMDL)Revised5B — Addressed by USEPA-approved TMDLPajaro River Watershed Nutrients—
ToxicityTotal Toxics112493List on 303(d) list (TMDL required list)Revised5A — TMDL still required—Low
TurbiditySediment112495List on 303(d) list (TMDL required list)Revised5A — 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
CAR3051001320080603122917
CALWNUM
3305.100301, 3305.100303
WBD code
180600020804
Geometry
Official Water Board GIS (CA_WATERBOARDS_GIS_FINAL_2026)

Location

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

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Watershed
—
Assessed size
7.27 Miles

Derived facility associations

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

Derived
A and S Metals

Watsonville · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

A&I Transport Inc

Watsonville · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Abdul Motors

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

AGRON Bioenergy

Watsonville · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

American Medical Response West

Watsonville · Notice of Non-Applicability

derived_watershed_association

Derived by California Stormwater Intelligence

Americold

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Annieglass

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Ballenger Spar Systems Inc

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Berry Chill

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Coast Auto Supplies Dism Inc

Watsonville · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Coastal Manufacturing

Watsonville · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

CSC LABS

Watsonville · No Exposure Certification · 0.96 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

Del Mar Food Prod Corp

Watsonville · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Del Mar Seafoods Inc

Watsonville · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Eisenring Inc

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Fabrication Effects Inc

Watsonville · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

FedEx Ground ZSLI

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Finesse Mills LLC

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Granite Rock Co Watsonville Co

Watsonville · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Greenwaste Recovery Inc

Watsonville · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Icarus Fermentation LLC

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

JOHI

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Larges Metal Fabrication Incorporate

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Marinos Automotive Machine Shop

Freedom · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Millers Transfer and Storage Company

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Mizkan America Inc

Watsonville · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Monterey Bay Cast Stone

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

MSB Technology

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

new west cooling co

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Pacific Continental Truss - Watsonville Office

Watsonville · Notice of Non-Applicability · 0.94 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

Pack Fresh Processors

Watsonville · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Pajaro Valley Cold Storage

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Pajaro valley fabrication

Watsonville · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

REACH 044 Watsonville CA

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Reach Medical Air Services LLC

Watsonville · Notice of Non-Applicability

derived_watershed_association

Derived by California Stormwater Intelligence

S Martinelli Co

Watsonville · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

S Martinelli Co

Watsonville · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

SAGE INSTRUMENTS INC

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Santa Cruz Cider Company

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Santa Cruz Cnty Buena Vista La

Watsonville · Notice of Intent · 0.34 km away

derived_nearby_in_watershed

Derived by California Stormwater Intelligence

Santa Cruz Pet Naturals

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Schmid Thermal Systems

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Seascape Lamps

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Southern Counties Lubricants Watsonville

Watsonville · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Specialized Aviation LLC

Watsonville · Notice of Non-Applicability

derived_watershed_association

Derived by California Stormwater Intelligence

Specialized Helicopters

Watsonville · Notice of Non-Applicability

derived_watershed_association

Derived by California Stormwater Intelligence

Specialized Helicopters

Watsonville · Notice of Non-Applicability

derived_watershed_association

Derived by California Stormwater Intelligence

Spectramat Inc

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

StorageMart 2470

Watsonville · Notice of Non-Applicability

derived_watershed_association

Derived by California Stormwater Intelligence

SV Labs

Watsonville · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

The Slough Brewing Collective

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

TruFocus Corporation

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

VitalBulk

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Watsonville - Freedom Blvd (Site 0144)

Watsonville · Notice of Non-Applicability

derived_watershed_association

Derived by California Stormwater Intelligence

Watsonville Airport Business Center

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Watsonville Airport Business Center

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

Watsonville Bin

Watsonville · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Watsonville City Airport

Watsonville · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Watsonville Municipal Ser Cen

Watsonville · Notice of Intent

derived_watershed_association

Derived by California Stormwater Intelligence

Westek Electronics Inc

Watsonville · No Exposure Certification

derived_watershed_association

Derived by California Stormwater Intelligence

WESTLAKE TRANSPORT INC

Watsonville · Notice of Intent

derived_watershed_association

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.