1. 1. After December 1, 2010, the discharge of diazinon or chlorpyrifos is prohibited during dormant and irrigation seasons if there was any exceedence of diazinon and/or chlorpyrifos water quality objectives in the previous season. The prohibitions do not apply if the discharge is subject to a waiver of waste discharge or waste discharge requirement.
2. 2. Requires dischargers to consider whether an alternative to diazinon or chlorpyrifos would degrade ground or surface water.
3. 3. Requires compliance by December 1, 2010.
4. 4. Requires Regional Water Board review of the allocations and implementation provisions by December 31, 2009 and every five years thereafter.

5. 5. Establishes the wasteload allocations for National Pollutant Discharge Elimination System-permitted sources, load allocations for nonpoint source discharges, and the Loading Capacity of the San Joaquin River from the Mendota Dam to Vernalis as defined below:

   TU =

   C_D

   +

   C_C

   ≤1.0

   WQO_D

   WQO_C

   where

   C_D = diazinon concentration in μg/L of point source discharge for the WLA; nonpoint source discharge for the LA; or San Joaquin River for the LC.

   C_C = chlorpyrifos concentration in μg/L of point source discharge for the WLA; nonpoint source discharge for the LA; or San Joaquin River for the LC.

   WQO_D = acute or chronic diazinon water quality objective in μg/L.

   WQO_C = acute or chronic chlorpyrifos water quality objective in μg/L.

6. 6. States that the Regional Water Board will require any additional reductions in diazinon and chlorpyrifos necessary to account for additive or synergistic effects or protect tributary waters.
7. 7. Requires dischargers to submit management plans to the Regional Water Board.
8. 8. Requires any waiver of waste discharge requirements to be consistent with the provisions of the implementation program.

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

   Monitoring

   Requires a monitoring and reporting program to determine:

10. 1. Compliance with diazinon and chlorpyrifos water quality objectives and loading capacity.
11. 2. Compliance with load allocations.
12. 3. Degree of implementation and effectiveness of management practices and strategies to reduce off-site migration of diazinon and chlorpyrifos.
13. 5. Degradation of surface water quality from alternatives to diazinon and chlorpyrifos.
14. 6. Additive or synergistic effects of multiple pollutants
15. 7. Management practices are achieving the lowest pesticide levels technically and economically achievable.

On October 21, 2005, the Central Valley Water Board adopted Resolution No. 2005-0138. The Amendment incorporates the following provisions into the Central Valley Regional Water Quality Control Board's (Regional Board's) Water Quality Control Plan for the Sacramento River and San Joaquin River Basins (Basin Plan):

Water Quality Objectives

A maximum chlorpyrifos concentration of 0.025 micrograms per liter (μg/L) (1-hour average) and 0.015 μg/L (4-day average) and a maximum diazinon concentration of 0.16 micrograms per liter (μg/L) (1-hour average) and 0.10 μg/L (4-day average) in the San Joaquin River from Mendota Dam to Vernalis not to be exceeded more than once in a three year period.

Implementation Provisions for Discharge into the San Joaquin River.

History

1. New section summarizing amendment of basin plan filed 6-30-2006; amendment approved by State Water Resources Control Board Resolution No. 2006-0025 on 5-2-2006; amendment approved by OAL pursuant to Government Code section 11353 on 6-30-2006 (Register 2006, No. 26).