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

Supporting Information

Regional Board 4 - Los Angeles Region

Water Body Name: Tuna Canyon Creek
Water Body ID: CAR4041200020050607194935
Water Body Type: River & Stream
 
DECISION ID
16393
 
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
 
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 is available in the administrative record to assess this pollutant. Zero 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. Zero of five samples exceeded the Basin Plan water quality objective for nitrate 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.
 
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.
 
SWRCB Board Decision / Staff Recommendation:
 
USEPA Decision:
 
 
Lines of Evidence (LOEs) for Decision ID 16393
 
LOE ID: 28220
 
Pollutant: Nitrate
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: None
 
Beneficial Use: Warm Freshwater Habitat
Aquatic Life Use: Wildlife Habitat
 
Number of Samples: 5
Number of Exceedances: 0
 
Data and Information Type: Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: Zero of five samples exceeded the Basin Plan water quality objective for nitrate in Tuna Canyon Creek. Water quality samples were taken and analyzed for nitrate in accordance with the Surface Water Ambient Monitoring Program monitoring and testing parameters.
Data Reference: Surface Water Ambient Monitoring Program data for all watersheds in the Los Angeles Region 2001-2005.
 
Water Quality Objective/Criterion: The Basin Plan lists a water quality objective of 10 mg/L for nitrate as nitrate-nitrogen (NO3-N).
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: Sampling were collected at monitoring station 404SMB040, located in Upper Tuna Canyon (Lat: 34.04678, Long: -118.59061) and at monitoring station 404SMB041, located in Lower Tuna Canyon Creek (Lat: 34.04028, Long: -118.58904).
Temporal Representation: Grab samples were taken on March 10, 2003 and March 27, 2003 for sample station 404SMB040 and 404SMB041, and on February 25, 2004 for sample station 404SMB040.
Environmental Conditions:
QAPP Information: Data was collected in compliance with the sampling and monitoring procedures detailed in Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program.
QAPP Information Reference(s): Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program. Sacramento, CA. State Water Resources Control Board. SWAMP. December 2002 (1st version)