Authors: Elena Lundeen, Amanda Tague, Audrey McCrary, and Ed Rhodes

The Texas Commission on Environmental Quality (TCEQ) conducts a water body assessment on a biennial basis to satisfy requirements of the federal Clean Water Act (CWA) Sections 305(b) and 303(d). The resulting Texas Integrated Report of Surface Water Quality (Texas Integrated Report) describes the status of water bodies throughout Texas. The most recent report, the 2022 Texas Integrated Report, includes an assessment of water quality data collected from December 1, 2013, to November 30, 2020 (TCEQ, 2022).

The Texas Integrated Report assesses water bodies at the assessment unit (AU) level. An AU is a sub-area of a segment, defined as the smallest geographic area of use support reported in the assessment (TCEQ, 2022). Each AU has homogeneous chemical, physical, and hydrological characteristics, which allows assignment of site-specific standards (TCEQ, 2022). Each water body is assigned a segment identification number and an AU designation.

Deer Creek and Pond Creek are located within the larger Brazos River Basin. Deer Creek begins west of the unincorporated community Chilton, and flows east to its confluence with the Brazos River within Falls County. Pond Creek begins northwest of the unincorporated community, Belfalls, and flows southeast to the Brazos River in Milam County. AUs within both watersheds are listed as impaired in the Texas Integrated Report (TCEQ, 2022). This report will focus on impaired AUs, Deer Creek (1242J_01) and Pond Creek (11242F_01).

Water quality in these creeks currently exceed primary recreational use standards for bacteria concentrations. Deer Creek was first listed in the 2006 Texas Integrated Report (TCEQ, 2006) and an AU of Pond Creek was designated impaired in 2010 (TCEQ, 2010). In the 2022 report, the Escherichia coli (E. coli) geometric means for these creeks ranged from 171 to 288 most probable number (MPN) /100 mL; above the applicable water quality primary contact recreation standards of 126 MPN/100 mL in place for the tributaries (TCEQ, 2022).

Under Texas State Soil and Water Conservation Board (TSSWCB) the Brazos River Authority (BRA) conducted a recreational use attainability analysis (RUAA) in 2013. The results of the RUAA confirmed the primary contact recreational use classification for both Deer and Pond Creeks (TCEQ, 2013). Likely, future action to address these water quality impairments will be necessary. The RUAA conducted by BRA was an initial step to appropriately address these water quality impairments.

It was necessary to supplement water quality and quantity data collection to fill data gaps and to inform future water-shed planning and implementation activities. Additionally, expanded data collection allows for a more accurate assessment of each waterbodies’ condition, and aids in identifying potential causes and sources of pollution. Each of these actions requires a reasonable amount of water quality data to assess current conditions and estimate pollutant loading reductions necessary to meet applicable water quality standards.

This project increased the spatial and temporal distribution of water quality monitoring activity to better define in-stream water quality conditions. This provides an increase in the quantity of water quality data available for future water body assessments. It is through monitoring and adequate data that watershed managers will be able to get a true assessment of water quality inhibitors.

Authors: Luna Yang, Lucas Gregory, and Elena Lundeen

Brushy Creek is in the Brazos River Basin and flows through one of the fastest-growing urban areas in Texas – the I-35 corridor. The headwater of Brushy Creek is in Williamson County and flows east to its confluence with the San Gabriel River in Milam County (TCEQ 2022). Brushy Creek consists of one segment (1244) and four AUs (1244_01 through 1244_04). In the 2006 Texas Integrated Report, AUs 1244_01 and 1244_03 are first listed as impaired for primary contact recreation use due to elevated Escherichia coli (E. coli) concentrations (TCEQ 2006). In September 2009, a Recreational Use Attainability Analysis (RUAA) was initiated for Brushy Creek and the results later confirmed that the primary contact recreation use designated to Brushy Creek was appropriate (TCEQ 2010). This RUAA signifies the importance of addressing the bacteria impairment in the creek.

Authors: Elena Lundeen and Amanda Tague

Throughout this project, routine water quality monitoring was conducted with a focus on E. coli concentration data. Data was collected monthly for 32 months at six sites, including TCEQ monitoring stations 18750, 11840, and 11838 in Middle Yegua Creek (Figure 1) and 11729, 21420, and 18349 in Davidson Creek (Figure 2), resulting in 192 total monitoring events. Out of the 192 monitoring events, only 187 water grab samples were collected due to some monitoring sites running dry. All sampling procedures, methods, sampling sites, and planned project activities are fully described in the project quality assurance project plan (QAPP). Monthly sampling included field parameters, streamflow measurements, and E. coli grab samples.

Water quality and quantity data was uploaded to the TCEQ surface water quality monitoring information system (SWQMIS) for future waterbody assessments. Collected data, water quality findings, and trends are summarized in this final project report to provide an informational basis for any future work conducted in these watersheds.