The Texas surface water quality standards currently include narrative nutrient criteria that apply to all waters in the state and site-specific numeric nutrient criteria (NNC) for chlorophyll a for 75 reservoirs. The Texas Commission on Environmental Quality (TCEQ) plans to continue to develop criteria (1) to maintain water quality in water bodies that are relatively unimpacted, (2) to maintain uses of water bodies, and (3) to identify and restore eutrophic water bodies associated with excessive nutrients.
TCEQ’s initial focus in developing NNC is on reservoirs that are not eutrophic based on historical ambient data. Termed least-impacted reservoirs, those water bodies require NNC to maintain and protect their existing uses. The same focus will be subsequently applied to rivers; however, determining least-impacted rivers is more challenging. Developing NNC for estuaries will follow reservoirs and rivers in sequence because the high variability of nutrient loading and sources, complex relationship between nutrients and response variables, and paucity of research and data make this resource the most challenging water body type for which to develop NNC.
Texas shares boundary waters with Arkansas, Louisiana, New Mexico, Oklahoma, and Mexico. Any eventual criteria for those waters will be developed in close coordination with the adjacent states, the U.S. Environmental Protection Agency (EPA), and the International Boundary and Water Commission (IBWC) (for reaches and reservoirs on the Rio Grande) (Texas CEQ 2014).
Reference:
Texas CEQ (Texas Commission on Environmental Quality). 2014. Nutrient Criteria Development Plan – Texas Surface Water Quality Standards. Accessed November 2016.
https://www.tceq.texas.gov/assets/public/waterquality/standards/ncdawg/NCDP/ncdevplan091014.pdf Exit.