The Texas Two-Step: Developing the Numeric Nutrient Criteria for the Second Largest State in the U.S.

The Texas Commission on Environmental Quality (TCEQ) has been working with the U.S. EPA and numerous stakeholders for more than 14 years to develop the numeric nutrient criteria (NNC) for Texas. On June 30, 2010, TCEQ adopted revisions to the Texas Surface Water Quality Standards (Standards) that include NNC based on chlorophyll a for 75 major reservoirs, and its companion document, the Standards Implementation Procedures (IPs). A month later, TCEQ submitted the Standards and the IPs to EPA for approval. The Standards were developed with a Nutrient Criteria Development Plan (Plan) mutually agreed upon by EPA and TCEQ. However, even after almost two years of extensive correspondence between the two agencies, Texas still doesn't have approved NNC. This paper provides an overview of the Texas NNC development, including a discussion of the Standards, the IPs, the Plan, and methods of implementing the nutrient criteria with appropriate discharge permit limits.