|
DECISION ID |
15877 |
|
Pollutant: |
Pathogens |
Final Listing Decision: |
List on 303(d) list (being addressed by USEPA approved TMDL) |
Last Listing Cycle's Final Listing Decision: |
New Decision |
Revision Status |
Revised |
Sources: |
Source Unknown |
TMDL Name: |
Watsonville Slough Pathogen |
TMDL Project Code: |
35 |
Date TMDL Approved by USEPA: |
07/19/2007 |
Impairment from Pollutant or Pollution: |
Pollutant |
|
Weight of Evidence: |
A TMDL has been approved by USEPA (July 19, 2007) for pathogens in Watsonville Slough and four of its tributaries (specifically Gallighan Slough).
Gallighan Slough was not specifically identified on the 2006 Section 303(d) list for this pollutant but was included in the TMDL because it is impaired and the source controls are overlapping.
This pollutant is being considered for removal from the section 303(d) list under section 4.3 of the Listing Policy. Under this section a single line of evidence is necessary to assess listing status.
Four lines of evidence are available in the administrative record to assess this pollutant. Four of the 9 samples, tested for E. coli) and 3 of the 9 samples, tested for Fecal Coliform, exceed the water quality objective for Water Contact Recreation. A minimum o f 26 samples are required to determine if water quality standards are being met.
Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against 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. Four of the 9 samples, tested for E. coli) and 3 of the 9 samples, tested for Fecal Coliform, exceed the water quality objective for Water Contact Recreation and these exceed the allowable frequency calculated from the equation in Table 4.2 of the Listing Policy. However, the sample size is insufficient to determine with the power and confidence of the Listing Policy if water quality standards are met or exceeded.
4. Pursuant to section 4.11 of the Listing Policy, no additional data and information are available indicating that standards are 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 placed on the section 303(d) list (being addressed by TMDL category) because applicable water quality standards are exceeded and a pollutant contributes to or causes the problem. |
|
SWRCB Board Decision / Staff Recommendation: |
|
|
USEPA Decision: |
|
|
|
|
LOE ID: |
13676 |
|
Pollutant: |
Escherichia coli (E. Coli) |
LOE Subgroup: |
Pollutant-Water |
Matrix: |
Water |
Fraction: |
None |
|
Beneficial Use: |
Water Contact Recreation |
|
Number of Samples: |
9 |
Number of Exceedances: |
4 |
|
Data and Information Type: |
PATHOGEN MONITORING |
Data Used to Assess Water Quality: |
Central Coast Regional Board Staff assessed Central Coast Watershed Studies (R3_CCOWS) data for Gallighan Slough to determine beneficial use support and results are as follows: 4 of 9 samples exceed the criterion for Escherichia coli. |
Data Reference: |
Final Data File used for assessment: CCoWS (Central Coast Watershed Studies) Water Quality Data |
|
Water Quality Objective/Criterion: |
USEPA Ambient Water Quality Criteria for Bacteria -1986. |
Objective/Criterion Reference: |
Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002 |
|
Evaluation Guideline: |
Single sample maximum allowable density for E. coli in freshwater is 235 MPN/100mL (as stated in Table 4, page 15) |
Guideline Reference: |
Ambient Water Quality Criteria for Bacteria - 1986. EPA440/5-84-002 |
|
Spatial Representation: |
Data for this line of evidence for Gallighan Slough was collected at 1 monitoring site [ Buena Vista Rd] |
Temporal Representation: |
Data was collected over the time period 2/18/2003-11/18/2003. |
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): |
|
|
LOE ID: |
13677 |
|
Pollutant: |
Escherichia coli (E. Coli) |
LOE Subgroup: |
Pollutant-Water |
Matrix: |
Water |
Fraction: |
None |
|
Beneficial Use: |
Non-Contact Recreation |
|
Number of Samples: |
9 |
Number of Exceedances: |
0 |
|
Data and Information Type: |
PATHOGEN MONITORING |
Data Used to Assess Water Quality: |
Central Coast Regional Board Staff assessed Central Coast Watershed Studies (R3_CCOWS) data for Gallighan Slough to determine beneficial use support and results are as follows: 0 of 9 samples exceed the criterion for Escherichia coli. |
Data Reference: |
Final Data File used for assessment: CCoWS (Central Coast Watershed Studies) Water Quality Data |
|
Water Quality Objective/Criterion: |
The Water Quality Control Plan, Central Coast Basin objective for non-contact water recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: Fecal coliform concentration, based on a minimum of not less than five samples for any 30-day period, shall not exceed a log mean of 2000/100 ml, nor shall more than ten percent of samples collected during any 30-day period exceed 4000/100 ml. E. coli is a fecal coliform. |
Objective/Criterion Reference: |
Water Quality Control Plan Central Coast Region (R3) Basin Plan |
|
Evaluation Guideline: |
|
Guideline Reference: |
|
Spatial Representation: |
Data for this line of evidence for Gallighan Slough was collected at 1 monitoring site [ Buena Vista Rd] |
Temporal Representation: |
Data was collected over the time period 2/18/2003-11/18/2003. |
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): |
|
|
LOE ID: |
13795 |
|
Pollutant: |
Fecal Coliform |
LOE Subgroup: |
Pollutant-Water |
Matrix: |
Water |
Fraction: |
None |
|
Beneficial Use: |
Water Contact Recreation |
|
Number of Samples: |
9 |
Number of Exceedances: |
3 |
|
Data and Information Type: |
PATHOGEN MONITORING |
Data Used to Assess Water Quality: |
Central Coast Regional Board Staff assessed Central Coast Watershed Studies (R3_CCOWS) data for Gallighan Slough to determine beneficial use support and results are as follows: 3 of 9 samples exceed the criterion for Coliform, Fecal. |
Data Reference: |
Final Data File used for assessment: CCoWS (Central Coast Watershed Studies) Water Quality Data |
|
Water Quality Objective/Criterion: |
The Water Quality Control Plan, Central Coast Basin objective for water contact recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: Fecal coliform concentration, based on a minimum of not less than five samples for any 30-day period, shall not exceed a log mean of 200 MPN/100 ml, nor shall more than ten percent of total samples during any 30-day period exceed 400 MPN/100 ml. |
Objective/Criterion Reference: |
Water Quality Control Plan Central Coast Region (R3) Basin Plan |
|
Evaluation Guideline: |
|
Guideline Reference: |
|
Spatial Representation: |
Data for this line of evidence for Gallighan Slough was collected at 1 monitoring site [ Buena Vista Rd] |
Temporal Representation: |
Data was collected over the time period 2/18/2003-11/18/2003. |
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): |
|
|
LOE ID: |
13796 |
|
Pollutant: |
Fecal Coliform |
LOE Subgroup: |
Pollutant-Water |
Matrix: |
Water |
Fraction: |
None |
|
Beneficial Use: |
Non-Contact Recreation |
|
Number of Samples: |
9 |
Number of Exceedances: |
1 |
|
Data and Information Type: |
PATHOGEN MONITORING |
Data Used to Assess Water Quality: |
Central Coast Regional Board Staff assessed Central Coast Watershed Studies (R3_CCOWS) data for Gallighan Slough to determine beneficial use support and results are as follows: 1 of 9 samples exceed the criterion for Coliform, Fecal. |
Data Reference: |
Final Data File used for assessment: CCoWS (Central Coast Watershed Studies) Water Quality Data |
|
Water Quality Objective/Criterion: |
The Water Quality Control Plan, Central Coast Basin objective for non-contact water recreation uses (Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a) states the following: Fecal coliform concentration, based on a minimum of not less than five samples for any 30-day period, shall not exceed a log mean of 2000/100 ml, nor shall more than ten percent of samples collected during any 30-day period exceed 4000/100 ml. |
Objective/Criterion Reference: |
Water Quality Control Plan Central Coast Region (R3) Basin Plan |
|
Evaluation Guideline: |
|
Guideline Reference: |
|
Spatial Representation: |
Data for this line of evidence for Gallighan Slough was collected at 1 monitoring site [ Buena Vista Rd] |
Temporal Representation: |
Data was collected over the time period 2/18/2003-11/18/2003. |
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): |