Total Maximum Daily Load (TMDL) and the 303(d)

This project was developed as a TMDL alternative as part of the Palo Verde Agricultural General Order and addresses DDT and toxaphene impairments in the Palo Verde Outfall Drain and Lagoon. The Palo Verde Agricultural Order was approved by the Regional Water Board on May 15, 2019 and the associated TMDL a alternative is currently under review by the USEPA.

This TMDL is part of the Imperial Valley Agricultural General Order and will address PCBs, chlordane, chlorpyrifos, DDT, diazinon, dieldrin, and toxaphene impairments in Alamo River, Imperial Valley Drains, and New River. The TMDL was adopted by the Regional Board on May 10, 2022.

The following documents are now available:

• Resolution R7-2022-0032
• Basin Plan Amendment
• TMDL Staff Report

This TMDL will address bifenthrin, cypermethrin, and lambda-cyhalothrin impairments in the New and Alamo Rivers.

This TMDL will address chloride, indicator bacteria, and toxicity impairments in the Alamo River.

This TMDL will address dissolved oxygen and nutrient impairments in the Salton Sea.

The TMDL was adopted by the Regional Board June 27, 2001, approved by the State Board on February 19, 2002, approved by the Office of Administrative Law on May 3, 2002, and approved by U.S. EPA on June 28, 2002.

This TMDL addresses sedimentation and siltation in the Alamo River. Information about this TMDL can be found in Chapter 4, section V.B of the Basin Plan. Documents, such as the Staff Report and Appendices are available upon request.

The TMDL was adopted by the Regional Board on October 10, 2001, approved by the State Board on March 21, 2002. It was also approved by the Office of Administrative Law on March 23, 2002, and approved by U.S. EPA on August 14, 2002.

This TMDL addresses pathogens in the New River. Information about this TMDL can be found in Chapter 4, section V.A of the Basin Plan. Documents, such as the Staff Report and Appendices are available upon request.

The TMDL was adopted by the Regional Board on June 26, 2002, approved by the State Board on November 19, 2002, approved by the Office of Administrative Law on January 13, 2003, and approved by U.S. EPA on March 31, 2003.

This TMDL addresses sedimentation and siltation in the New River. Information about this TMDL can be found in Chapter 4, section V.C of the Basin Plan. Documents, such as the Staff Report and Appendices are available upon request.

The TMDL was adopted by the Regional Board on June 21, 2006, approved by the State Board on April 18, 2007, approved by the Office of Administrative Law on August 2, 2007, and approved by U.S. EPA on September 24, 2007.

This TMDL addresses trash in the New River at the International Boundary. Information about this TMDL can be found in Chapter 4, section V.F of the Basin Plan. Documents, such as the Staff Report and Appendices are available upon request.

The TMDL was adopted by the Regional Board on January 19, 2005, approved by the State Board on July 21, 2005, approved by the Office of Administrative Law on September 8, 2005, and approved by U.S. EPA on September 30, 2005.

This TMDL addresses sedimentation and siltation in Imperial Valley Drains. Information about this TMDL can be found in Chapter 4, section V.D of the Basin Plan. Documents, such as the Staff Report and Appendices are available upon request.

The TMDL was adopted by the Regional Board on May 16, 2007, with revision later adopted by the Regional Board on June 17, 2010. The TMDL was subsequently approved by the State Board on July 19, 2011, approved by the Office of Administrative Law on February 2, 2012, and approved by U.S. EPA on April 27, 2012.

This TMDL addresses bacterial indicators in the Coachella Valley Stormwater Channel. Information about this TMDL can be found in Chapter 4, section V.H of the Basin Plan. Documents, such as the Staff Report and Appendices are available upon request.

The TMDL was adopted by the Regional Board on May 20, 2010. The TMDL was subsequently approved by the State Board on December 6, 2011, approved by the Office of Administrative Law on March 21, 2012, and approved by U.S. EPA on November 16, 2012.

This TMDL addresses dissolved oxygen in the New River at the International Boundary. Information about this TMDL can be found in Chapter 4, section V.G of the Basin Plan. Documents, such as the Staff Report and Appendices are available upon request.

The Colorado River Region tries to foster public participation during all phases of TMDL development to address as many technical and social issues as possible early in the process. Each TMDL project will have a unique approach to public participation dependent on the size of the watershed, the nature of the problem, who and how many interested parties or stakeholders emerge, etc. Public participation will at times take on one or more of these forms: occasional public workshops, regularly scheduled steering committee meetings, Technical Advisory committee meetings, Regional Board staff presentations at other organization's meetings, or written solicitations or request for comments sent by mail.

The public has the opportunity and legal right to review and comment on TMDLs before they are made a part of the Basin Plan. Essentially this means that the public has the opportunity to comment on Draft TMDLs in writing prior to Regional Board Hearings or verbally at Regional Board Meetings before a TMDL is adopted and implemented.

Bodies of water are listed as impaired after several steps. One of the steps is the review of information and/or data by Regional Board staff pertaining to a body of water. Regional Board staff will notify the public when the review process will occur, and publicly solicit information or data that would lead to a listing of a body of water.

This section provides other opportunities for the public to be involved in the TMDL process. If the section below is empty, this implies that no specific event is on the agenda in the near future. However, remember that the waters of the state belong to its citizens, and you are encouraged to participate in the process designed to protect this resource. Simply call the Regional Water Quality Control Board office and make inquiries to the staff person working on the body of water near you.