Draft California 2020 Integrated Report (303(d) List/305(b) Report)

Supporting Information

Regional Board 3 - Central Coast Region

Water Body Name: Soda Lake
Water Body ID: CAL3110005019980805102204
Water Body Type: Saline Lake
 
DECISION ID
86530
Region 3     
Soda Lake
 
Pollutant: Ammonia
Final Listing Decision: List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: List on 303(d) list (TMDL required list)(2016)
Revision Status Original
Sources: A Source Unknown
Expected TMDL Completion Date: 2023
Impairment from Pollutant or Pollution: Pollutant
 
Regional Board Conclusion: No new data were assessed.

The pollutant name was changed to ¿Ammonia¿ in the 2014 assessment cycle. This decision replaces the pollutant unionized ammonia. This decision contains all of the LOEs from the original decision.

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.

One line of evidence (LOE) is available in the administrative record to assess this pollutant. One LOE summarize unionized ammonia data in which three of the 7 samples exceed the water quality objective for unionized ammonia set to protect aquatic life.

Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of 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. Three of the 7 samples exceed the water quality objective for unionized ammonia and this exceeds 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: This is a decision previously approved by the State Water Resources Control Board and the USEPA. No new data were assessed by the Regional Board for the current cycle. The decision has not changed.
 
State Board Review of Regional Board Conclusion and Recommendation:
 
State Board Decision Recommendation: After review of this Regional Board decision, SWRCB staff recommend the decision be approved by the State Board.
 
 
Line of Evidence (LOE) for Decision ID 86530, Ammonia
Region 3     
Soda Lake
 
LOE ID: 698
 
Pollutant: Ammonia (Unionized)
LOE Subgroup: Pollutant-Water
Matrix: Water
Fraction: Total
 
Beneficial Use: Warm Freshwater Habitat
 
Number of Samples: 7
Number of Exceedances: 3
 
Data and Information Type: PHYSICAL/CHEMICAL MONITORING
Data Used to Assess Water Quality: Three out of seven samples exceeded the general water quality objective (CCAMP, 2004; SWAMP, 2004).
Data Reference: Placeholder reference 2006 303(d)
 
SWAMP Data: SWAMP
 
Water Quality Objective/Criterion: The discharge of wastes shall not cause concentrations of unionized ammonia (NH3) to exceed 0.025 mg/L (as N) in receiving waters (Region 3 Basin Plan, Section II.A.2. Objectives for All Inland Surface Waters, Enclosed Bays, and Estuaries, II.A.2.a. General Objectives, page III-4)
Objective/Criterion Reference: Placeholder reference 2006 303(d)
 
Evaluation Guideline:
Guideline Reference:
 
Spatial Representation: Samples were collected from two sites. Exceedances were detected in samples collected from both sites.
Temporal Representation: Samples were collected from January 2000 to May 2000.
Environmental Conditions: The water body is located in the Carrizo Plain hydrologic unit, Carrizo Plain hydrologic subarea. Sites are located at Soda Lake Northeast (311SLE) and Soda Lake Culverts at Seven Mile Road (311SLN).
QAPP Information: CCAMP, SWAMP QAPP.
QAPP Information Reference(s):