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Central Valley Diazinon and Chlorpyrifos TMDL and Basin Plan Amendment

To request a copy of documents listed on this page, please contact Jessica Rader at Jessica.Rader@waterboards.ca.gov or (916) 464-3199.

On 28 March 2014, the Central Valley Water Board adopted Resolution R5-2014-0041; adopting the Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for The Control of Diazinon and Chlorpyrifos Discharges (Amendment) and approving the supporting Substitute Environmental Documentation and Staff Report. The Amendment establishes water quality objectives and implementation and monitoring requirements to protect water bodies in the Sacramento and San Joaquin Valleys from impairment due to discharges of diazinon and chlorpyrifos associated with uses of these pesticides in agricultural operations and in urban areas. The goal of the Amendment is to reduce diazinon and chlorpyrifos concentrations in Sacramento and San Joaquin Valley water bodies to levels that are protective of aquatic life (WARM and/or COLD) beneficial uses. This Amendment was approved by the State Water Resources Control Board on 16 June 2015, the Office of Administrative Law on 8 March 2017, and USEPA on 16 August 2017. The Amendment is now fully approved and effective 16 August 2017.

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Current Events

  • U.S Environmental Protection Agency Approval: 16 August 2017

  • Office of Administrative Law Approval: OAL File No. 2017-0124-04S, 8 March 2017

  • Executive Officer Corrections, 7 March 2017

  • State Water Board Action: Approved by the State Water Board on 16 June 2015 under Resolution 2015-0043.

  • On 28 March 2014, the Regional Board held a public hearing during its regular Board meeting and adopted amendments to the Basin Plan
    • Final Staff Report, March 2014
      • Appendix A - Summary of Monitoring Programs, Studies, and Databases Used as Sources of Diazinon and Chlorpyrifos Concentration Data
      • Appendix B - Cost Calculations
      • Appendix C - Proposed Basin Plan Amendment
      • Appendix D - Responses to Comments on the March 2013 Draft
      • Appendix E - Responses to Comments on the January 2014 Draft
      • Appendix F - Category 4b Demonstration to USEPA

  • March 2014 Board Meeting Agenda Materials for the Proposed Diazinon and Chlorpyrifos Basin Plan Amendment

  • January 2014 Notice of Public Hearing and Notice of Filing of Draft Environmental Documents - Diazinon and Chlorpyrifos Basin Plan Amendment

  • January 2014 Draft Staff Report - Amendments to the Water Quality Control Plan for the Sacramento and San Joaquin River Basin for the Control of Diazinon and Chlorpyrifos Discharges
    • Appendix A - Summary of Diazinon and Chlorpyrifos Concentration Data Sources
    • Appendix B - Cost Calculations
    • Appendix C - Proposed Basin Plan Amendment
    • Appendix D – Responses to Comments

  • July 10, 2013 - Notice of Postponement and Tentative Board Hearing Date - Diazinon and Chlorpyrifos Basin Plan Amendment

  • Central Valley Pesticide Basin Plan Amendment Fact Sheet, (Updated October 2006)
    Outlines an effort to develop a pesticide Basin Plan Amendment for the Sacramento and San Joaquin River watersheds, including the Delta, and identifies the objectives of the effort, the primary documents that are likely to be produced, and key contacts.

  • March 2013 Draft Staff Report - Amendments to the Water Quality Control Plan for the Sacramento and San Joaquin River Basin for the Control of Diazinon and Chlorpyrifos Discharges
    • Appendix A - Summary of Diazinon and Chlorpyrifos Concentration Data Sources
    • Appendix B - Cost Calculations
    • Appendix C - Proposed Basin Plan Amendment

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