California Code of Regulations
Title 23 - Waters
Division 4 - Regional Water Quality Control Boards
Chapter 1 - Water Quality Control Plans, Policies, and Guidelines
Article 3 - Central Coast Region
Section 3929.12 - Total Maximum Daily Loads for Nitrogen Compounds and Orthophosphate in Lower Santa Maria River Wathershed and Tributaries to Oso Flaco Lake
On May 30, 2013, the Regional Water Quality Control Board, Central Coast Region (Water Board) adopted Resolution No. R3-2013-0013, amending the Water Quality Control Plan for the Central Coastal Basin (Basin Plan). Resolution No. R3-2013-0013 establishes the Lower Santa Maria River Watershed and Tributaries to Oso Flaco Lake Total Maximum Daily Loads (TMDLs) and Implementation Plan for nitrate, unionized ammonia and orthophosphate. The TMDLs address nutrient-related impairments of the lower Santa Maria Valley, which include the waterbodies Blosser Channel, Bradley Canyon Creek, Bradley Channel, Greene Valley Creek, Main Street Canal, North Main Street Channel, Orcutt Creek, Oso Flaco Creek, Little Oso Flaco Creek, Santa Maria River, and Santa Maria River Estuary.
Current nutrient and nutrient-related impairments in lower Santa Maria River Valley waters are impairing a range of current or potential designated beneficial uses including aquatic habitat (COLD, WARM, SPWN), drinking water supply (MUN), groundwater recharge (GWR), water contact recreation (REC-1), and agricultural supply (AGR). The TMDLs set numeric targets for nitrate, unionized ammonia, orthophosphate, dissolved oxygen, chlorophyll a, and microcystins consistent with Basin Plan narrative and numeric water quality objectives protective of the aforementioned beneficial uses.
Responsibility for achieving waste load allocations and load allocations falls upon several entities as described in the Resolution. An implicit margin of safety is utilized in the TMDL to account for uncertainties. The Water Board is relying on existing regulatory measures (i.e., the Agricultural Order and storm water permits) to ensure implementation actions are carried out by implementing parties. Interim and final implementation milestones of 12, 20 and 30 years are established for showing progress and achieving the TMDL. The Water Board will track progress towards achieving the TMDL through review of implementation actions and monitoring conducted by the implementing parties. Water Board staff will conduct triennial reviews of implementation actions and monitoring results. If existing efforts are not expected to achieve the TMDL as scheduled (as determined by triennial reviews), the Executive Officer or the Water Board may require changes to existing monitoring, reporting, or implementation efforts pursuant to California Water Code Sections 13263, 13267 or 13383.
1. New section summarizing amendments to basin plan filed 5-22-2014; amendment approved by State Water Resources Control Board Resolution No. 2014-0009 on 2-4-2014; amendment approved by OAL pursuant to Government Code section 11353 on 5-22-2014 (Register 2014, No. 21).
