California Code of Regulations
Title 23 - Waters
Division 4 - Regional Water Quality Control Boards
Chapter 1 - Water Quality Control Plans, Policies, and Guidelines
Article 8 - Santa Ana Region
Section 3977 - Resolution NO. R8-2003-0039 - Amending the Water Quality Control Plan (Basin Plan) for the Santa Ana Region to Include a Total Maximum Daily Load (TMDL) for Chlorpyrifos and Diazinon in San Diego Creek and Upper Newport Bay
Current through Register 2024 Notice Reg. No. 38, September 20, 2024
Regional Board Resolution No. R8-2003-0039, adopted on April 4, 2003 by the Santa Ana Regional Water Quality Control Board, modified the regulatory provisions of the Water Quality Control Plan [Basin Plan] for the Santa Ana Region by establishing a TMDL for chlorpyrifos in Upper Newport Bay and diazinon and chlorpyrifos in San Diego Creek.
The amendment addresses water quality impairment due to aquatic toxicity caused by the presence of diazinon and chlorpyrifos in runoff to San Diego Creek and Upper Newport Bay. The amendment establishes load and wasteload allocations for San Diego Creek as listed in Table 1.
Table 1: Load and Wasteload Allocations for San Diego Creek
| Diazinon (ng/L) | Chlorpyrifos (ng/L) | ||
| Acute | Chronic | Acute | Chronic |
| 72 | 45 | 18 | 12.6 |
The amendment establishes load and wasteload allocations for Upper Newport Bay as listed in Table 2. These apply to chlorpyrifos only.
Table 2: Chlorpyrifos Load and Wasteload Allocations for Upper Newport Bay
| Acute (ng/L) | Chronic (ng/L) |
| 18 | 8.1 |
The amendment includes an implementation plan that specifies completion of the following four tasks by stakeholders in the watershed and by the Regional Board:
(1) Revision of WDR and NPDES discharge permits to include the TMDL allocations;
(2) Implementation of monitoring program by the stakeholders in the watershed for diazinon and chlorpyrifos;
(3) Development of a pesticide runoff management plan by the Regional Board and the stakeholders in the watershed;
(4) Special Studies: the Regional Board will lead studies into the significance of chlorpyrifos atmospheric deposition for Upper Newport Bay and the adequacy of the freshwater allocations for San Diego Creek to protect Upper Newport Bay.
1. New section filed 1-5-2004; basin plan amendment regulatory provisions approved by OAL and effective 1-5-2004 pursuant to Government Code section 11353(b)(3) (Register 2004, No. 2).
