Cal. Code Regs. tit. 23 § 3949.2

Current through Register 2024 Notice Reg. No. 49, December 6, 2024

Section 3949.2 - Program to Control Dissolved Oxygen in the Stockton Deep Water Ship Channel

Resolution No. R5-2005-0005, adopted by the Central Valley Regional Water Quality Control Board (Central Valley Water Board) on January 27, 2005, modified the regulatory provisions of the Water Quality Control Plan for the Sacramento and San Joaquin River Basins by incorporating a program for the control of factors contributing to the dissolved oxygen impairment in the Stockton Deep Water Ship Channel (DWSC). Impairment is defined in terms of excess net oxygen demand (ENOD) and responsibility for reducing ENOD is apportioned to the entities responsible for three factors that contribute to the impairment (low flow, increased channel geometry, and loads of oxygen demanding substances and their precursors (ODS)).

The program includes a Total Maximum Daily Load that allocates percent of relative responsibility for the ENOD to the point source and nonpoint source discharges that contribute ODS to the DWSC: 30 percent for a waste load allocation for the City of Stockton Regional Wastewater Control Facility; 60 percent for a load allocation for nonpoint sources (defined as discharges from irrigated lands); and 10 percent as a reserve for impacts from unknown sources and/or minor sources. An explicit margin of safety of 20 percent is incorporated. The Central Valley Water Board has committed to reviewing and updating the load allocations, waste load allocations, and prohibitions (mentioned below) by December 2009.

Entities responsible for sources of ODS are required to perform studies by December 2008 that identify and quantify:

1) sources of ODS in the source area;

2) growth or degradation mechanisms of ODS in transit to the DWSC; and

3) the impact of ODS on dissolved oxygen concentrations in the DWSC under a range of environmental conditions. Within 60 days from the effective date of this amendment, responsible entities must submit a study plan for the Central Valley Water Board describing how ongoing studies and future studies will address information needs.

Upon the effective date of this amendment, any increases in the discharge of ODS into waters tributary to the DWSC is prohibited unless the discharge is regulated by a waiver of waste discharge requirements, or individual or general waste discharge requirements or National Pollution Discharge Elimination System (NPDES) permits, which either implement the amendment or include a finding that the discharge will have no reasonable potential to cause or contribute to the dissolved oxygen impairment in the DWSC.

After December 31, 2011, the discharge of ODS into waters tributary to the DWSC is prohibited when net daily flow in the DWSC is less than 3,000 cubic feet per second, unless dissolved oxygen objectives in the DWSC are being met or the discharge is regulated by a waiver of waste discharge requirements, or individual or general waste discharge requirements or National Pollution Discharge Elimination System (NPDES) permits, which either implement the amendment; or include a finding that the discharge will have no reasonable potential to cause or contribute to the dissolved oxygen impairment in the DWSC.

The United States Army Corps of Engineers must submit by December 31, 2006 a technical report identifying and quantifying:

1) the chemical, biological, and physical mechanisms by which loads of substances into, or generated within the DWSC, are converted to oxygen demand; and

2) the impact that the Stockton Deep Water Ship Channel has on re-aeration and other mechanisms that affect dissolved oxygen concentrations in the water column.

Any project that requires a Clean Water Act Section 401 Water Quality Certification and that has the potential to impact dissolved oxygen conditions in the DWSC must evaluate and fully mitigate those impacts. The Central Valley Water Board may consider alternate measures, as opposed to direct control, of certain contributing factors if these measures adequately address the impact on the dissolved oxygen impairment and do not degrade water quality in any other way. Compliance with waste load allocations and load allocations for ODS, and development of alternate measures to address non-load related factors must be achieved by December 31, 2011.

Cal. Code Regs. Tit. 23, § 3949.2

1. New section summarizing amendment of Basin Plan filed 8-4-2006; amendment approved by State Water Resources Control Board Resolution No. 2006-0086 11-16-2005; amendment approved by OAL pursuant to Government Code section 11353 8-4-2006 (Register 2006, No. 31).