La Nana Bayou is a 32-mile freshwater stream that extends from the confluence of the Angelina River south of Nacogdoches in Nacogdoches County to the upstream perennial portion of the stream north of Nacogdoches in Nacogdoches County. Routine water quality monitoring began in 1996 and led to the inclusion of La Nana Bayou on the Texas 303(d) List in 2000 as being impaired for bacteria. It remains impaired for not meeting its primary contact recreation standard. Concerns for elevated ammonia-nitrogen, nitrate-nitrogen and total phosphorous exist in the downstream portion of the bayou.
TWRI performed an initial analysis of the La Nana Bayou Watershed by completing a Watershed Characterization Report in 2019. This report analyzed potential causes and sources of pollution through the collection of water quality and watershed-related data, which will inform the upcoming watershed protection plan (WPP) development process. TWRI, the Angelina and Neches River Authority, and Stephen F. Austin State University will work with local stakeholders to create a plan that will address water quality issues in the watershed.