A proactive sampling program

TRWD has had an active water quality program since 1990 and each lake is sampled continuously at multiple sites for various parameters on the district’s four lakes: Bridgeport, Eagle Mountain, Cedar Creek and Richland-Chambers. Water quality sampling is also performed at Lake Worth, Lake Arlington and Benbrook Lake. The program is designed to provide information to assess the lakes for meeting their intended uses, such as water supply, fish and wildlife habitat and contact recreation.

Special Programs and Studies

Evolving technology
The taste and odor causing compound geosmin has been sampled for seasonally since 2003. Complaints regarding taste and odor in finished drinking water spiked in the winter time, causing the parameter to be monitored from November through March each year. The severity of geosmin levels vary from year to year. A genetic study TRWD had done in 2015 tied the geosmin to blue green algae. Although a nuisance, the geosmin does not have any known toxicologic effects.
Monthly sampling for cryptosporidium and E. coli in all source water for a 2 year period is a TCEQ requirement for all water treatment plants. Since TRWD provides source water to multiple customer cities, they collect a monthly sample from each source water reservoir and the Trinity River, and provide the data to the customer cities. Although the sampling program is mandated for 2 years, TRWD has a continuous record of monitoring for cryptosporidium since 2001.
Learn more.
In 2015, the Environmental Protection Agency issued Drinking Water Health Advisories for two algal toxin compounds, microcystin and cylindrospermopsin. The toxins can be produced from naturally occurring algae that grow in all lakes. The toxins are specific to the bluegreen group of algae. Although the EPA advisory only applies to finished drinking water, the District initiated a special study to screen the raw water in all of the lakes in its water supply system for algal toxins. Samples have been collected during the summer growing season in both 2015 and 2016 from all reservoirs and the Trinity River. Samples have been analyzed for microcystin, cylindrospermopsin, and anatoxin. At this time, no toxins have been detected in any of the district reservoirs.
The arrival of zebra mussels to North Texas Reservoirs has been anticipated since their appearance of Lake Texoma in 2009. TRWD has placed settlement samplers in each of its reservoirs and performs vertical tows in the spring and fall for the detection of veligers (juvenile mussels). Adult mussels have been found in TRWD’s West Fork system. For these systems, the tows serve to document population estimates. For more information on zebra mussels, visit the Texas Parks and Wildlife website.

Routine Monitoring

Long-term history and trends
The Texas Commission on Environmental Quality assesses all major water bodies in Texas against EPA approved stream standards. The parameters for the standards represent source protection based on the designated use for the water body. The TRWD system contains 9 different stream segments and 60 assessment units. TRWD is a partner in the Clean Rivers Program coordinated by the Trinity River Authority. Almost all of the data TRWD collects is done according to an approved QAPP and submitted to TCEQ for use in the assessment process. The data TRWD collects can be found in the TCEQ online database of CRP data. Each water body is assessed every two years.

• Total Dissolved Solids
• Chlorides
E. coli
• Temperature
• Dissolved Oxygen
• Chlorophyll-a
• pH
• Total phosphorus
• Sulfate
• Nitrate
• Ammonia

Quick Links:
CRP Data Tool
2014 Assessment
20-year Trend Study

Every reservoir sampled under the routine water quality monitoring program has intakes for municipalities that utilize the water for treated drinking water. A special set of parameters is collected for the treatment plants to determine water treatability.

Treatability Parameters:
• Alkalinity
• Calcium
• Manganese
• Magnesium
• Iron
• Nitrate+Nitrite
• Potassium
• Sodium
• Total Organic Carbon

Water Quality Models used to simulate reservoir and river dynamics are an important tool for understanding impacts and evaluating changes to source waters.Select parameters that are included in the routine monitoring program are collected specifically to make detailed models more robust. For more detailed information on models, please visit the models section of the website.

Modeling Parameters
• Total Suspended Solids
• Chlorides
• Photometer
• Secchi
• Temperature
• Nitrogen Series (NH4, NOx, TKN)
• Phosphorus Series (TP, OPO4)
• Total Organic Carbon/Dissolved Organic Carbon
• Silica/Dissolved Si
• Chlorophyll-a
• Phytoplankton

Special monitoring is done to provide information to recreators to ensure safety in the water. The primary contact recreation standard is based on measurements of E. coli. The presence of certain types of blue-green algae that can potentially be harmful are documented through phytoplankton counts. Fish tissue measurements are used to determine if fish are safe for human consumption.

Recreation Parameters:
E. coli
• Phytoplankton
• Fish Consumption

Quick Links:
Recreational E. coli Data
Blue Green Recreation Page
TPWD Fish Consumption Advisory

Although the primary focus of TRWD is water supply from reservoirs, the water quality of loading sources to the reservoir is important information for modeling efforts and the overall health of the reservoir. TRWD includes sampling of tributaries and wastewater treatment plants in the routine monitoring program to document loading sources to the reservoirs.

Watershed Parameters:
• Total Dissolved Solids
• Chlorides
E. coli
• Total Suspended Solids
• N-series (NH4, NOx, TKN)
• P-series (TP, OPO4)