San Diego Region - Bacteria Impaired Waters TMDL Project I for Beaches and Creeks

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Bacteria TMDLs Adopted on December 12, 2007

On December 12, 2007, the San Diego Water Board adopted a Basin Plan amendment to incorporate the 19 TMDLs developed in Project I - Beaches and Creeks in the San Diego Region. This action meets requirements of section 303(d) of the Clean Water Act (CWA). The Basin Plan amendment process is authorized under section 13240 of the Water Code. The Basin Plan amendment is a project subject to the California Environmental Quality Act (CEQA) and the San Diego Water Board is the lead agency.

Background

Fecal bacteria originate from the intestinal flora of warm-blooded animals, and their presence in surface water is used as an indicator of human pathogens. Pathogens can cause illness in recreational water users. Bacteria have been historically used as indicators of human pathogens because they are much easier and less costly to measure than the pathogens themselves.
According to section 303(d)(1)(A) of the CWA, "Each state shall identify those waters within its boundaries for which the effluent limitations…are not stringent enough to implement any water quality standard (WQS) applicable to such waters." The CWA also requires states to establish a priority ranking of Water Quality Limited Segments and to establish Total Maximum Daily Loads (TMDLs) for such waters. The purpose of a TMDL is to attain water quality objectives (WQOs) and restore and protect the beneficial uses of an impaired waterbody. TMDLs represent a strategy for meeting WQOs by allocating quantitative limits for point and nonpoint pollution sources. A TMDL is defined as the sum of the individual waste load allocations (WLAs) for point sources and load allocations (LAs) for nonpoint sources and natural background such that the capacity of the waterbody to assimilate pollutant loading (i.e., the loading capacity) is not exceeded.

Total Maximum Daily Loads for Indicator Bacteria, Project I - Beaches and Creeks in the San Diego Region

TMDLs for indicator bacteria were developed to address 12 bacteria-impaired watersheds in the San Diego Region. This project, referred to as 'Project I - Beaches and Creeks in the San Diego Region,' is one of two bacteria TMDL projects. Project II addresses bacteria impaired shorelines in San Diego Bay and Dana Point Harbor. Bacteria and other impairments in coastal lagoons will be addressed in TMDLs to be developed for the lagoons and their tributary watersheds.

Final Technical Report & Appendices Now Available

The Final Technical Report and Appendices are dated December 12, 2007. For a summary overview of these TMDLs, please see the Executive Summary in the Final Technical Report. To download the Final Technical Report and Appendices, please see Public Documents below.

Mailing Lists for Project I - Beaches and Creeks in the San Diego Region

To receive updates on the TMDLs in Project I - Beaches and Creeks in the San Diego Region, please subscribe to our electronic mailing list. You may also obtain information at your convenience from our Website or by appointment at the San Diego Water Board office.

Any questions or comments regarding the TMDLs in Project I - Beaches and Creeks in the San Diego Region may be sent to Mr. Benjamin Tobler, Water Resource Control Engineer, at (858) 467-2736, or email at BTobler@waterboards.ca.gov.

Public Documents

(All documents are PDF format unless otherwise noted)

• Resolution & Basin Plan Amendment (12-12-07)
• Final Technical Report dated (12-12-07)
• Appendices
  • Appendix A - Peer Review
  • Appendix B - Resolution and Basin Plan Amendment
  • Appendix C - What are Indicator Bacteria?
  • Appendix D - Bacteria-Impaired Waterbodies Addressed in the TMDLs
  • Appendix E - Maps of Impaired Watersheds
  • Appendix F - Water Quality Objectives for Indicator Bacteria
  • Appendix G - Data Sources
  • Appendix H - Shoreline Bacteria Data Water Quality Objectives Exceedance Analysis
  • Appendix I - Methodology for Calculating TMDLs for Impaired Beaches and Creeks and Allocating to Sources
  • Appendix J - Wet Weather Model Configuration, Calibration and Validation
  • Appendix K - Dry Weather Model Configuration, Calibration and Validation
  • Appendix L - Assumptions
  • Appendix M - Wet Weather Model Hydrology, Calibration, and Validation Summary Statistics
  • Appendix N - Comparison of Wet Weather Modeling Results to Observed Densities
  • Appendix O - Wet Weather Interim Period Bacteria Load Duration Curves
  • Appendix P - Wet Weather Final Bacteria Load Duration Curves
  • Appendix Q - Small MS4s in the Project I Watersheds
  • Appendix R - Environmental Analysis and Checklist
  • Appendix S - Responses to Comments
  • Appendix T - Unimpaired Beaches
  • Appendix U - Response to Comments II