Cal. Code Regs. tit. 23 § 3949.4

Current through Register 2024 Notice Reg. No. 50, December 13, 2024

Section 3949.4 - Amendment to the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins for the Control of Diazinon and Chlorpyrifos Runoff into the Sacramento-San Joaquin Delta

On June 23, 2006, the Central Valley Regional Water Quality Control Board (Central Valley Water Board) adopted Resolution No. R5-2006-0061, and on May 22, 2007, it was approved by the State Water Resources Control Board. This amendment incorporates the following provisions into the Water Quality Control Plan for the Sacramento River and San Joaquin River Basins.

Water Quality Objectives

This amendment establishes a maximum chlorpyrifos concentration of 0.025 micrograms per liter (1-hour average) and 0.015 micrograms per liter (4-day average) and a maximum diazinon concentration of 0.16 micrograms per liter (1-hour average) and 0.10 micrograms per liter (4-day average) that are not to be exceeded more than once in a three-year period. These objectives apply to 146 named Delta waterways within the legal boundaries of the Delta as described in section 12220 of the California Water Code.

Implementation Provisions for Discharge into the Delta Waterways

This amendment:

1. Prohibits, beginning December 1, 2011, the discharge of diazinon or chlorpyrifos into Delta waterways during the dormant or irrigation season if there was any exceedance of the chlorpyrifos or diazinon water quality objectives or loading capacity during the previous season. These prohibitions do not apply if the discharge is subject to a waiver of waste discharge requirements or waste discharge requirements. These prohibitions apply only to dischargers causing or contributing to the exceedance of the water quality objective or loading capacity.

2. Requires dischargers to consider whether an alternative to diazinon or chlorpyrifos would degrade ground or surface water.

3. Requires compliance by December 1, 2011.

4. Requires Central Valley Water Board review of the allocation and implementation provisions by December 31, 2010 and every five years thereafter.

5. Establishes the waste load allocations for all National Pollutant Discharge Elimination System-permitted point source discharges, load allocations for nonpoint source discharges, and the loading capacity of each of the Sacramento-San Joaquin Delta waterways as defined below:

S = [C(d) / WQO(d)] + [C(c) / WQO(c)] <= 1.0

Where:

S = the sum.

C(d) = diazinon concentration in mcg/L of point source discharge for the waste load allocations; nonpoint source discharge for the load allocations; or a Delta waterway for the loading capacity (LC).

C(c) = chlorpyrifos concentration in mcg/L of point source discharge for the waste load allocations; nonpoint source discharge for the load allocations; or a Delta waterway for the LC.

WQO(d) = acute or chronic diazinon water quality objective in micrograms per liter.

WQO(c) = acute or chronic chlorpyrifos water quality objective in micrograms per liter.

6. States that the Central Valley Water Board will require any additional reductions in diazinon and chlorpyrifos necessary to account for additive or synergistic effects to protect tributary waters.

7. Requires dischargers to submit management plans.

8. Requires any waiver of waste discharge requirements or waste discharge requirements to be consistent with the provisions of the implementation program.

9. Includes estimates of the cost of the program for agriculture.

Monitoring

This amendment requires a monitoring and reporting program for pesticide discharges to determine:

1. Compliance with diazinon and chlorpyrifos water quality objectives, loading capacity and load allocations;

2. Degree of implementation and effectiveness of management practices to reduce off-site movement of diazinon and chlorpyrifos;

3. Surface water quality impacts of alternatives to diazinon and chlorpyrifos;

4. If the pesticide discharges contribute to additive or synergistic effects of multiple pollutants; and

5. If management practices are achieving the lowest pesticide levels technically and economically achievable.

Cal. Code Regs. Tit. 23, § 3949.4

1. New section summarizing amendments to basin plan filed 8-9-2007; amendments approved by State Water Resources Control Board Resolution No. 2007-0028 on 5-22-2007; amendments approved by OAL pursuant to Government Code section 11353 on 8-9-2007 (Register 2007, No. 32).