Draft 2008 California 303(d)/305(b) Integrated Report

Supporting Information

Regional Board 9 - San Diego Region

Water Body Name: Reidy Canyon Creek
Water Body ID: CAR9046200020010927085916
Water Body Type: River & Stream
 
DECISION ID
4531
 
Pollutant: Phosphorus
Final Listing Decision: Delist from 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2006)
Revision Status Original
Reason for Delisting: Flaws in original listing
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for removal from the section 303(d) list under section 4.2 of the Listing Policy. Under this section 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. Two of two of samples exceeded the Basin Plan water quality objective for phosphhorus.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for removing this water segment-pollutant combination from the section 303(d) list.

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. Two of two of samples exceeded the Basin Plan water quality objective for phosphhorus, and this does not exceed the allowable frequency listed in Table 4.2 of the Listing Policy.
4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation: After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should be removed from the section 303(d) list because applicable water quality standards for the pollutant are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation: After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should be placed on the section 303(d) list because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem.
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 4531
 
LOE ID: 3214
 
Pollutant: Phosphorus
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 2
Number of Exceedances: 2
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Data was collected on 3/12/2001 at Reidy Creek near Mountain Meadow Mushroom Farm at two locations; one upstream and one downstream. Samples in exceedance: 2 of 2 (SDRWQCB, 2001).
Data Reference: Placeholder reference 2006 303(d)
 
Water Quality Objective/Criterion: From the Basin Plan, the WQO for Total Phosphorus for inland surface waters-streams and other flowing waters is 0.1 mg/L. This appears to be desired goal in order to prevent plant nuisance in streams and other flowing waters; not to be exceeded more than 10% of the time.
Objective/Criterion Reference: Placeholder reference 2006 303(d)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected at Reidy Creek near Mountain Meadow Mushroom Farm at one upstream location and one downstream location.
Temporal Representation: One sample was taken at each location on one day, 3/12/2001.
Environmental Conditions:
QAPP Information: QA Info Missing
QAPP Information Reference(s):
 
DECISION ID
4530
 
Pollutant: Nitrogen, Nitrite
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2006)
Revision Status Original
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2, one line(s) of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. Neither of the two the samples exceeded the Basin Plan water quality objective for nitrite.

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. Neither of the two the samples exceeded the Basin Plan water quality objective for nitrite and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of five samples is needed for application of table 3.2.
4. Pursuant to [SECTION 3.11/4.11] of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
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 it cannot be determined if applicable water quality standards are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 4530
 
LOE ID: 3213
 
Pollutant: Nitrogen, Nitrite
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 2
Number of Exceedances: 0
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Data was collected in Reidy Creek at the Mountain Meadow Mushroom Farm on 3/12/01. Two samples were collected; one upstream and one downstream. Both samples were ND. The detection limit is below the WQO. (SDRWQCB, 2001).
Data Reference: Placeholder reference 2006 303(d)
 
Water Quality Objective/Criterion: From the Basin Plan, the numeric objective for Nitrate as N is 1.0 mg/L.
Objective/Criterion Reference: Placeholder reference 2006 303(d)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Two samples were collected, one upstream and one downstream, near Mountain Meadow Mushroom Farm on 3/12/2001.
Temporal Representation: Samples were collected once on 3/12/2001.
Environmental Conditions:
QAPP Information: QA Info Missing
QAPP Information Reference(s):
 
DECISION ID
4483
 
Pollutant: Total Nitrogen as N
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2006)
Revision Status Original
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2, one line(s) of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. One of two of the samples exceed the Basin Plan water quality objective for total nitrogen.

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. One of two of the samples exceed the Basin Plan water quality objective for total nitrogen and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of fivesamples is needed for application of table 3.2.
4. Pursuant to [SECTION 3.11/4.11] of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
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 it cannot be determined if applicable water quality standards are not being exceeded.
 
SWRCB Board Decision / Staff Recommendation: After review of the available data and information, SWRCB 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 exceeded.
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 4483
 
LOE ID: 3212
 
Pollutant: Total Nitrogen as N
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 2
Number of Exceedances: 1
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Data was collected at Reidy Creek near Mountain Meadow Mushroom Farm on 3/12/2001. Two samples were collected; one upstream and one downstream. In 1 of 2 samples, the N:P ratio exceeds 10:1. The exceedance occurs in the upstream sample. Both phosphorus samples are in exceedance. (SDRWQCB, 2001).
Data Reference: Placeholder reference 2006 303(d)
 
Water Quality Objective/Criterion: From the Basin Plan, Narrative Objective for Biostimulatory Substances: Inland surface waters, bays and estuaries, and coastal lagoon waters shall not contain biostimulatory substances in concentrations that promote aquatic growth to the extent that such growths cause nuisance or adversely affect beneficial uses. Concentrations of nitrogen and phosphorus, by themselves or in combination with other nutrients, shall be maintained at levels below those which stimulate algae and emergent plant growth.
Narrative Objective for Nitrogen: Analogous threshold values have not been set for nitrogen compounds; however, natural ratios of nitrogen to phosphorus are to be determined by surveillance and monitoring and upheld. If data are lacking, a ratio of N:P = 10:1, on a weight to weight basis shall be used.
Objective/Criterion Reference: Placeholder reference 2006 303(d)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Data was collected in Reidy Creek near the Mountain Meadow Mushroom Farm at one upstream and one downstream location.
Temporal Representation: Data was collected on 3/12/2001.
Environmental Conditions:
QAPP Information: QA Info Missing
QAPP Information Reference(s):
 
DECISION ID
4532
 
Pollutant: Turbidity
Final Listing Decision: Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: Do Not List on 303(d) list (TMDL required list)(2006)
Revision Status Original
Impairment from Pollutant or Pollution: Pollutant
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2, one line(s) of evidence is necessary to assess listing status.

One line of evidence is available in the administrative record to assess this pollutant. Two of two of the samples exceed the Basin Plan water quality objective for turbidity.

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. Two of two of the samples exceed the Basin Plan water quality objective for turbidity, and this sample size is insufficient to determine with the power and confidence of the Listing Policy if standards are not met. A minimum of five samples is needed for application of table 3.2.
4. Pursuant to [SECTION 3.11/4.11] of the Listing Policy, no additional data and information are available indicating that standards are not met.
 
RWQCB Board Decision / Staff Recommendation:
 
SWRCB Board Decision / Staff Recommendation: After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because applicable water quality standards for the pollutant are not exceeded.
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 4532
 
LOE ID: 3215
 
Pollutant: Turbidity
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Municipal & Domestic Supply
 
Number of Samples: 2
Number of Exceedances: 2
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Data was obtained from samples collected on 3/12/2001 in Reidy Creek near the Mountain Meadow Mushroom Farm. One upstream sample and one downstream sample were collected. For the MUN beneficial use, 2 of 2 samples are in exceedance (SDRWQCB, 2001).
Data Reference: Placeholder reference 2006 303(d)
 
Water Quality Objective/Criterion: From the Basin Plan, the Turbidity WQO for inland surface water with Municipal (MUN) Beneficial Uses is 5 units.
The Turbidity WQO for inland surface waters with all other beneficial uses is 20 NTU. Waters shall be free of changes in turbidity that cause nuisance or adversely affect beneficial uses.
Objective/Criterion Reference: Placeholder reference 2006 303(d)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Two samples, one upstream and one downstream, were collected at Reidy Creek near the Mountain Meadow Mushroom Farm.
Temporal Representation: Samples were collected once on 3/12/2001.
Environmental Conditions:
QAPP Information: QA Info Missing
QAPP Information Reference(s):