| Water Body Name: | West Branch Struve Slough (Santa Cruz County) |
| Water Body ID: | CAR3051003020191211026828 |
| Water Body Type: | River & Stream |
DECISION ID |
126062 |
Region 3 |
West Branch Struve Slough (Santa Cruz County) |
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| Pollutant: | Escherichia coli (E. coli) |
| 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 |
| Regional Board Conclusion: | This pollutant is being considered for placement on the Clean Water Act section 303(d) List under sections 3.2 and 3.3 of the Listing Policy. Under these sections, a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Zero out of the 2 samples exceed water quality objective (ISWEBE, SWRCB 2019) for water contact recreation. This sample size is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. A minimum of 26 samples is needed to determine if a beneficial use is supported and a minimum of five exceedances is needed to determine if beneficial uses are not supported using Table 3.2 of the Listing Policy. Therefore, the use support rating is set to 'insufficient information'. 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. 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. Zero out of the 2 samples exceed water quality objective (ISWEBE, SWRCB 2019) for water contact recreation and this does not exceed the allowable frequency listed in Table 3.2 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. |
| Regional Board Decision 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. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. |
| State Board Review of Regional Board Conclusion and Recommendation: | |
| State Board Decision Recommendation: | |
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| LOE ID: | 149856 | ||||
| Pollutant: | Escherichia coli (E. coli) | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | None | ||||
| Beneficial Use: | Water Contact Recreation | ||||
| Number of Samples: | 2 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | PATHOGEN MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed data for West Branch Struve Slough (Santa Cruz County) to determine beneficial use support and the results are as follows: 0 of the 2 samples exceeded the Statistical Threshold Value (STV) water quality threshold for E. coli. The STV is based on a 10% exceedance rate that is calculated monthly. | ||||
| Data Reference: | Field, Habitat, Water data for the 2020/2022 integrated report in Region 3. | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | The bacteria water quality objective applicable to all non-saline waters, is a Statistical Threshold Value (STV) of 320 cfu/100 mL. The applicable STV shall not be exceeded by more than 10 percent of the samples collected in a calendar month, calculated in a static manner (ISWEBE 2018). | ||||
| Objective/Criterion Reference: | Inland Surface Waters, Enclosed Bays, and Estuaries Plan. Part 1: Trash Provisions; Part 2: Tribal Subsistence Beneficial Uses and Mercury Provisions; Part 3: Bacteria Provisions and Variance Policy | ||||
| Evaluation Guideline: | |||||
| Guideline Reference: | |||||
| Spatial Representation: | The samples were collected at 1 monitoring site(s), station(s): 305-WSTRU-21 | ||||
| Temporal Representation: | The samples were collected between the days of 2011-05-07 and 2012-05-05 . | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Monterey Bay NMS. 2003. California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP). | ||||
| QAPP Information Reference(s): | California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP) | ||||
DECISION ID |
128276 |
Region 3 |
West Branch Struve Slough (Santa Cruz County) |
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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 |
| Regional Board Conclusion: | This pollutant is being considered for placement on the CWA 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. Two lines of evidence are available in the administrative record to assess this pollutant. Zero of the three samples exceed the water quality objective for Municipal and Domestic Supply or the evaluation guideline for aquatic life. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. 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 CWA 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. Zero of the three samples exceed the water quality objective for Municipal and Domestic Supply or the evaluation guideline for aquatic life 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. |
| Regional Board Decision 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. |
| State Board Review of Regional Board Conclusion and Recommendation: | |
| State Board Decision Recommendation: | |
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| LOE ID: | 172505 | ||||
| Pollutant: | Nitrogen, Nitrate | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Dissolved | ||||
| Beneficial Use: | Municipal & Domestic Supply | ||||
| Number of Samples: | 3 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | PHYSICAL/CHEMICAL MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed MBNMS Snapshot Day data for West Branch Struve Slough (Santa Cruz County) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality threshold for Nitrate as N. | ||||
| Data Reference: | Field, Habitat, Water data for the 2020/2022 integrated report in Region 3. | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | All inland surface waters, enclosed bays, and estuaries shall not contain concentrations of inorganic chemicals in excess of the maximum contaminant levels for primary drinking water standards specified in California Code of Regulations, Title 22, Division 4, Chapter 15, Sections 64431 and 64433.2. | ||||
| Objective/Criterion Reference: | Water Quality Control Plan for the Central Coastal Basin | ||||
| Evaluation Guideline: | The California Maximum Contaminant Level for nitrate (as N) 10.0 mg/L (California Code of Regulations, Title 22). | ||||
| Guideline Reference: | California MCLs - Title 17 and Title 22 documents for 2019 - California Regulations Related to Drinking Water | ||||
| Spatial Representation: | The samples were collected at 1 monitoring site (305-WSTRU-21) | ||||
| Temporal Representation: | The samples were collected between the dates of 2011-05-07 and 2013-05-04 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Monterey Bay NMS. 2003. California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP). | ||||
| QAPP Information Reference(s): | California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP) | ||||
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| LOE ID: | 172785 | ||||
| Pollutant: | Nitrogen, Nitrate | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Dissolved | ||||
| Beneficial Use: | Warm Freshwater Habitat | ||||
| Number of Samples: | 3 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | PHYSICAL/CHEMICAL MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed MBNMS Snapshot Day data for West Branch Struve Slough (Santa Cruz County) to determine beneficial use support and results are as follows: 0 of 3 samples exceeded the water quality threshold for Nitrate as N. | ||||
| Data Reference: | Field, Habitat, Water data for the 2020/2022 integrated report in Region 3. | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect beneficial uses (Water Quality Control Plan, Central Coast Basin). | ||||
| Objective/Criterion Reference: | Water Quality Control Plan for the Central Coastal Basin | ||||
| Evaluation Guideline: | Technical approach to develop nutrient numeric endpoints for California, Tetra Tech, June 2006. The Central Coast Region numeric target for maximum nitrate concentration is based on the Tetra Tech NNE (Nutrient Numeric Endpoint) Model and CCAMP data for 193 sites, monitored monthly for at least 1 year between January 1998 and December 2006. The model numeric target for aquatic life habitats in the Central Coast Region is 1.0 mg/L Nitrate as N. | ||||
| Guideline Reference: | Central Coast RegionTechnical Paper: Interpreting Narrative Objectives for Biostimulatory Substances for California Central Coast Waters. This method uses the Technical Approach for Developing California Nutrient Numeric Endpoints. | ||||
| Spatial Representation: | The samples were collected at 1 monitoring site (305-WSTRU-21) | ||||
| Temporal Representation: | The samples were collected between the dates of 2011-05-07 and 2013-05-04 | ||||
| Environmental Conditions: | |||||
| QAPP Information: | Monterey Bay NMS. 2003. California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP). | ||||
| QAPP Information Reference(s): | California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP) | ||||