Welcome to the Calleguas Creek Watershed

Bacteria Work Plan

Various reaches within the Calleguas Creek watershed are listed on the California 2002 Clean Water Act (CWA) Section 303(d) list of water quality limited segments as impaired due to fecal coliform bacteria. As fecal coliform bacteria are used as an indicator organism for pathogens that impair beneficial uses, this work plan focuses on relevant indicator bacteria as a whole. The goal of the Bacteria Work Plan is to identify the tasks required to develop and implement a plan to address the beneficial uses impaired by bacteria.

Addressing bacteriological impairments in the Watershed is a challenging task. Bacteriological contamination is a common occurrence throughout California and the United States. However, only a few TMDLs have been developed to control this pollutant, partially due to the many complexities associated with this task. Bacteria TMDLs are complicated by the fact that the standards are based on indicator organisms, not the actual pathogenic bacteria. As a result, it is difficult to ascertain whether a particular water concentration of non-pathogenic indicator bacteria will cause human illness. Adding to the complexity is the fact that wildlife and other naturally occurring sources contribute to bacterial pollution in the CCW. Naturally occurring sources of bacteria have the potential to impact human health, but are extremely difficult to control. Additionally, the warm waters of southern California provide ideal conditions for supporting bacteria populations naturally present in creek bed sediments. Finally, bacteria are ubiquitous throughout the watershed at levels that significantly exceed water quality standards. Developing control measures to reduce observed bacteria concentrations to meet water quality standards will be challenging. Treatment measures to address bacteria are likely to be costly and difficult to implement (especially with respect to contaminated stormwater runoff). As a result, implementing measures that will result in compliance with the existing water quality objectives at all times will be extremely difficult. Consequently, the tasks in this work plan are designed to address these complexities to the extent possible and provide mechanisms for protecting the identified beneficial uses in the watershed as is feasible.

The strategy outlined in this work plan will assess the beneficial uses and risks to human health from bacteria and use that information to develop a TMDL to address bacteriological impairments.

Responsible Agencies

The complete accounting of the responsible agencies and parties to carryout the Bacteria Work Plan has not yet been formalized, however the Flood Protection and Sediment Management Subcommittee is taking responsibility for providing policy guidance to the technical consultant. An MOU similar to the Salts Work Plan MOU will eventually be developed to formalize the funding of the Bacteria Work Plan.

Beneficial Use and Human Health Risk Assessment

The difficulties in addressing bacteriological impairments necessitate an assessment of the risks to human health that can occur in the CCW as a result of bacteria contamination. The Draft Use Attainability Analysis for REC-1 Beneficial Uses of Ballona Creek and Water Quality Objective Change recently completed by the LARWQCB will serve, in conjunction with other appropriate documents, as guidance in evaluating the feasibility of developing SSOs or Use Attainability Analyses for current designated uses and bacteria objectives.

TMDL Development

A TMDL for Bacteria will be developed as part of this work plan and work on the TMDL will begin in conjunction with the work discussed above. Work necessary to the completion of the TMDL will include the identification of sources of bacteria and options for reducing bacteria concentrations in the watershed.

Early Actions Items to Address Bacteria Related WQ impairments

As domestic animal waste contributes to bacterial pollution, an educational program focusing on the requirements of local domestic animal waste ordinances and the effects of domestic animal waste on the watershed may be helpful in reducing the loading of bacterial pollutants. As such, an educational program may be developed as an early action item in an attempt to reduce bacteria loading.

Timing

The timing of the completion of the various tasks outlined in this work plan is contained in the work plan time schedule summary. The Bacteria TMDL Work Plan is projected to be completed by December 2006. There is no Consent Decree deadline for the bacteria TMDL.

Bacteria Work Plan

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