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Download Excel NPDES Self Monitoring Program
City of Colusa, WWTP
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Organization
City of Colusashow partners CVRWQCB
Program website
view
Plan contactFrank Garofalo
530-458-2032
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| Start date | 12/05/2008 |
| End date | None |
| Objectives | The City of Colusa provides sewerage service for the City of Colusa and serves a population of approximately 5,500. The WWTP design average dry weather flow capacity is 0.90 mgd. The treatment system consists of prliminary comminution, wastewater stabilization ponds, overland flow, chlorination, and dechlorination with sulfur dioxide. Treated wastewater is discharged into an unnamed tributary to Powell Slough. The receiving stream is an unnamed tributary to Powell Slough, which is tributary to the Colusa Trough and the Colusa Basin Drain. The Report of Waste Discharge describeds the receiving stream as having "no reliable dilution without further study". Based on the available information, the worst-case dilution is assumed to be zero to provide protection for the receiving water beneficial uses. The impact of assuming zero dilution within the receiving water is that discharge limitations based on acute and chronic toxicity are end-of-pipe limits with no allowance for dilution within the receiving water. The beneficial uses of the unnamed tributary to Powell Slough are not individually identified in the Basin Plan. However, the Plan requires that the beneficial uses of any specifically identified water body apply to its tributary streams. Upon review of the flow conditions, habitat values, and beneficial uses of the unnamed tributary to Powell Slough the Board finds that the beneficial uses identified in the Basin Plan for the Colusa Basin Drain are applicable to the unnamed tributary to Powell Slough. The Basin agricultural stock watering, body contact water recreation, canoeing and rafting, warm freshwater aquatic habitat, cold freshwater aquatic habitat, warm fish migration habitat, warm spawning habitat, and wildlife habitat. |
| Annual budget | None |
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Basins & sub-basins monitored
- Sacramento River (Sacramento River)
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map
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Sites Monitored
| Name |
Code |
Latitude |
Longitude |
Map |
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Unnamed tributary to Powell Slough, US below, up to 50 ft, of first upstream agricultural discharge
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RSW-001U |
39.180662 |
-122.031417 |
locate |
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Unnamed tributary to Powell Slough, above, up to 200 ft, of first DS agricultural discharge
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RSW-001D |
39.179521 |
-122.031402 |
locate |
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Powell Slough, 250 ft US from confluence of the unnamed tributary
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RSW-002U |
39.174674 |
-122.037452 |
locate |
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Powell Slough, 400 ft DS from the confluence of the unnamed tributary
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RSW-002D |
39.172442 |
-122.036265 |
locate |
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Parameters Monitored
| Group | Parameters | Frequency |
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| General Water Quality |
Dissolved Oxygen (DO), Electrical Conductivity (EC) , Hardness, pH, Specific Conductance [EC @ 25 deg C], Temperature, Turbidity |
Monthly, Weekly, Quarterly |
| Pathogens & Bacteria |
Fecal Coliforms |
Quarterly |
| Priority Pollutants |
Priority Pollutants |
Other |
| Radioactivity |
Radionuclides |
Annual, Quarterly |
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Data Products Available
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