Research Areas > Nutrients > Nutrient Criteria Support Studies > Technical Support for Nutrient Numeric Endpoint and TMDL Tool Development

Project: Technical Support for Nutrient Numeric Endpoint and TMDL Tool Development

Background and Objective

The State Water Resources Control Board (SWRCB), with the support of USEPA Region IX, is working to develop nutrient numeric endpoints (NNE) to regulate nutrient levels in the State’s waters. Nutrient criteria must be developed within the context of the Clean Water Action Plan, with a primary goal of maintaining nutrient levels that support the health of aquatic systems. The criteria should also limit excessive growth of macrophytes or phytoplankton, potentially harmful algal blooms leading to oxygen declines, imbalance of aquatic species, public health threats, and a general decline in aquatic resources. The effort to develop NNEs was initiated in 1999 and has focused primarily on fresh water systems including streams, rivers, lakes, and reservoirs. Because estuaries and coastal lagoons are an important resource, defining NNEs for these water bodies has become a priority for the SWRCB.

The objective of this project is to provide technical support for the development of NNEs in California’s estuaries and lagoons. This project is phased, with three major phases: 1) conceptual framework development, 2) development of an implementation plan defining the technical support required to develop NNEs, and 3) initiation of research activities to support NNE development for California estuaries.

Status

This project was initiated in 2006 with anticipated completion in 2011.
 

Methods

Phase 3 consists of four types of activities:

1. Support for the SWRCB to conduct outreach with stakeholder communities regarding the conceptual approach and implementation plan for estuarine NNE development

2. Preparation of a series of technical documents, including:

a) Summary of existing data on California estuaries
b) Finalized classification scheme and candidate biological response indicators used for NNE development
c) Review of the existing science on eutrophication in San Francisco Bay
d) Expert review of existing data on impacts of dissolved oxygen (DO) on selected indicator species in California estuaries

3. Technical support to facilitate numeric endpoint selection for dissolved oxygen

4. An ambient survey of eutrophication in southern California estuaries, conducted in conjunction with the Southern California Bight’08 Coastal Ecology study

Partners

This project is being conducted in collaboration with the SWRCB, USEPA Region IX, Tetra Tech Inc., and numerous other regulated, regulatory and non-governmental organizations.

Presentation

• Science to Support Nutrient Criteria Development (Video) - January 2010 presentation to SCCWRP member agencies