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DECISION ID |
11610 |
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| Pollutant: |
Nitrate |
| Final Listing Decision: |
Do Not List on 303(d) list (TMDL required list) |
| Last Listing Cycle's Final Listing Decision: |
New Decision |
| Revision Status |
Revised |
| Impairment from Pollutant or Pollution: |
Pollutant |
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| Weight of Evidence: |
This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status.
One line of evidence isavailable in the administrative record to assess this pollutant. None of the 20 samples exceed the water quality objectives for either Agricultural Supply or Muncipal and Domestic Supply. However, there are an insufficient number of samples to make a "use rating" decision. Central Coast Water Board staff require a minimum of 16 samples to make a "use rating" decision of Fully Supporting.
Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category.
This conclusion is based on the staff findings that:
1. The data used satisfies the data quality requirements of section 6.1.4 of the Policy.
2. The data used satisfies the data quantity requirements of section 6.1.5 of the Policy.
3. None of the 20 samples exceed the water quality objectives for either Agricultural Supply or Muncipal and Domestic Supply and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy.
4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. |
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| RWQCB Board Decision / Staff Recommendation: |
After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards are not being exceeded. |
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| SWRCB Board Decision / Staff Recommendation: |
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| USEPA Decision: |
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| LOE ID: |
13730 |
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| Pollutant: |
Nitrate |
| LOE Subgroup: |
Pollutant-Water |
| Matrix: |
Water |
| Fraction: |
None |
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| Beneficial Use: |
Municipal & Domestic Supply |
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| Number of Samples: |
20 |
| Number of Exceedances: |
0 |
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| Data and Information Type: |
PHYSICAL/CHEMICAL MONITORING |
| Data Used to Assess Water Quality: |
Central Coast Regional Board Staff assessed Central Coast Watershed Studies (R3_CCOWS) data for Big Oak Creek to determine beneficial use support and results are as follows: 0 of 20 samples exceed the criterion for Nitrate as N. |
| Data Reference: |
Final Data File used for assessment: CCoWS (Central Coast Watershed Studies) Water Quality Data |
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| Water Quality Objective/Criterion: |
The Water Quality Control Plan, Central Coast Basin Objective for municipal and domestic supply uses of inland surface waters (Section II.A.2) states the following: waters shall not contain concentrations of chemical constituents in excess of the limits specified in California Code of Regulations, Title 22, Article 4, Chapter 15, Section 64435, Tables 2 and 3 as listed in Table 3-2. The maximum contaminant level listed in Table 3-2 (inorganic and fluoride concentrations not to be exceeded in domestic or municipal supply) for nitrate is 10.0 mg/L (NO3 as N). |
| Objective/Criterion Reference: |
Title 22, Division 4, Ch. 15, Article 4, Section 64431, Table 64431-A |
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Water Quality Control Plan Central Coast Region (R3) Basin Plan |
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| Evaluation Guideline: |
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| Guideline Reference: |
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| Spatial Representation: |
Data for this line of evidence for Big Oak Creek was collected at 1 monitoring site [ Old Stage Rd] |
| Temporal Representation: |
Data was collected over the time period 1/7/2001-2/18/2001. |
| Environmental Conditions: |
Staff is not aware of any special conditions that might effect interpretation of the data. |
| QAPP Information: |
Data quality is good and Standard Operating Procedures are well documented in QAPP. However, data documentation is poor and replicate samples and other quality assurance measurements are not consistently documented in this data set. |
| QAPP Information Reference(s): |