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

Supporting Information

Regional Board 4 - Los Angeles Region

Water Body Name: Staircase Beach (Leo Carillo Beach, North of County Line)
Water Body ID: CAC4044500020090304001219
Water Body Type: Coastal & Bay Shoreline
 
DECISION ID
16279
 
Pollutant: Indicator Bacteria
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
 
Weight of Evidence: This pollutant is being considered for placement on the section 303(d) list under section 3.3 of the Listing Policy. Under section 3.3 a single line of evidence is necessary to assess listing status.
Section 3.3 of the Listing Policy states that a 4 % exceedance percentage shall be used when water quality monitoring was conducted between April 01 through October 31 (summer months) only. As such the referenced data set was analyzed in two portions and described in two separate LOEs due to differing sampling data time frames.
For summer months samples geometric mean values were calculated but not used due to an insufficient number of values necessary to re-run the binomial test in the Listing Policy for 4 % exceedance. Table 3.2 of the listing policy states that a minimum of 26 samples is required to apply the binomial test. A sample size of fewer than 26 is insufficient to determine with the power and confidence of the Listing Policy if standards are met.
2 lines of evidence are available in the administrative record to assess this pollutant. 3 of the samples exceed the water quality objective.
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. For year-round samples from station VC50000: 2 of 135 exceeded the single sample “updated Basin Plan water quality objective for indicator bacteria” (WQO) and 0 of 33 exceeded the geometric mean WQO and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy.
4. For summer months samples from station VC50000: 1 of 30 exceeded the single sample WQO and this does not exceed the allowable frequency described in Section 3.3 of the Listing Policy. 0 of 7 exceeded the geometric mean WQO and as stated above this sample size is insufficient to determine if standards are met.
5. Pursuant to section 3.11 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:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 16279
 
LOE ID: 27909
 
Pollutant: Indicator Bacteria
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 135
Number of Exceedances: 2
 
Data and Information Type: Other Agencies/Organizations provided monitoring data
Data Used to Assess Water Quality: 2 of 135 samples exceeded the Basin Plan single sample water quality objectives for indicator bacteria in marine water and 0 out of 33 samples exceeded the geometric mean limits. Water quality samples were taken and analyzed for indicator bacteria consistent with California Code of Regulations Title 17, sections 7958-7961 and related guidance issued by California Department of Public Health .
Data Reference: County of Ventura coastal beach bacteria monitoring data for AB411.
 
Water Quality Objective/Criterion: The Basin Plan bacteria objectives state that to protect water contact recreation in marine waters individual samples shall not exceed the following limits: the total coliform density shall not exceed 10000/100 ml; the fecal coliform density shall not exceed 400/100 ml; the enterococcus density shall not exceed 104/100 ml; and the total coliform density shall not exceed 1,000/100 ml, if the ratio of fecal-to-total coliform exceeds 0.1 as single samples. The bacteria objectives also establish that the geometric means of individual samples shall not exceed the following limits: the total coliform density shall not exceed 1000/100 ml, the fecal coliform density shall not exceed 200/100 ml, and the enterococcus density shall not exceed 35/100 ml, as a geometric mean. The bacteria objectives are found in Attachment A of Regional Board Resolution No. 2001-018.
Objective/Criterion Reference: Water Quality Control Plan Los Angeles Region R4 Basin Plan
  Basin Plan Amendments to the Water Quality Control Plan Los Angeles Region R4 Basin Plan as of 02/02/2009
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One Ventura County Environmental Health Division sampling location (VC50000) located at the bottom of the staircase. (Lat: 34.04608, Long: -118.95133).
Temporal Representation: Grab samples were taken and analyzed on a weekly basis from January 2003 to October 2005.
Environmental Conditions:
QAPP Information: Data was collected in compliance with the sampling and testing procedures detailed in the California Department of Public Health related guidance.
QAPP Information Reference(s): Draft Guidance for Salt Water Beaches. Last Update: April 10, 2006. Initial Draft: November 1997. Division of Drinking Water and Environmental Management, California Department of Health Services
  California Code of Regulations Title 17, sections 7958-7960.
 
LOE ID: 27910
 
Pollutant: Indicator Bacteria
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Water Contact Recreation
 
Number of Samples: 30
Number of Exceedances: 1
 
Data and Information Type: Other Agencies/Organizations provided monitoring data
Data Used to Assess Water Quality: A total of 1 out of 30 samples exceeded the Basin Plan limits for single sample exceedances. 0 out of 7 samples exceeded the Basin Plan geometric mean water quality objectives. Water quality samples were taken and analyzed for indicator bacteria consistent with California Code of Regulations Title 17, sections 7958-7961 and related guidance issued by California Department of Public Health .
Data Reference: County of Ventura coastal beach bacteria monitoring data for AB411.
 
Water Quality Objective/Criterion: The Basin Plan bacteria objectives state that to protect water contact recreation in marine waters individual samples shall not exceed the following limits: the total coliform density shall not exceed 10000/100 ml; the fecal coliform density shall not exceed 400/100 ml; the enterococcus density shall not exceed 104/100 ml; and the total coliform density shall not exceed 1,000/100 ml, if the ratio of fecal-to-total coliform exceeds 0.1 as single samples. The bacteria objectives also establish that the geometric means of individual samples shall not exceed the following limits: the total coliform density shall not exceed 1000/100 ml, the fecal coliform density shall not exceed 200/100 ml, and the enterococcus density shall not exceed 35/100 ml, as a geometric mean. The bacteria objectives are found in Attachment A of Regional Board Resolution No. 2001-018.
Objective/Criterion Reference: Water Quality Control Plan Los Angeles Region R4 Basin Plan
  Basin Plan Amendments to the Water Quality Control Plan Los Angeles Region R4 Basin Plan as of 02/02/2009
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: One Ventura County Environmental Health Division sampling location (VC50000) located at the bottom of the staircase. (Lat: 34.04608, Long: -118.95133).
Temporal Representation: Grab samples were taken and analyzed on a weekly basis from April 2006 to October 2006 in the summer months of April to October.
Environmental Conditions:
QAPP Information: Data was collected in compliance with the sampling and testing procedures detailed in the California Department of Public Health related guidance.
QAPP Information Reference(s): Draft Guidance for Salt Water Beaches. Last Update: April 10, 2006. Initial Draft: November 1997. Division of Drinking Water and Environmental Management, California Department of Health Services
  California Code of Regulations Title 17, sections 7958-7960.