Wright patman Lake Special Study

Atrazine Study In Big Creek Lake

March 2002 marks two years of monitoring Big Creek Lake for atrazine, a widely used herbicide. Big Creek Lake, a small, unclassified reservoir of about 700 acres was listed as threatened by contamination on the 2000 303(d) list due to atrazine in finished drinking water.

The Big Creek Lake study is part of a larger project conducted by the TNRCC involving several Texas reservoirs, titled "Targeted Monitoring and BMP implementation in Seven Atrazine Threatened Lakes." The two major components of the project are: (1) surface water quality monitoring to better distinguish the threat of atrazine to drinking water sources, and (2) implementation of best management practices (BMP'S) to reduce the addition of atrazine in the subject watersheds.

The TNRCC Region 5 staff has conducted monthly surface water quality monitoring in Big Creek Lake for atrazine, alacholr, metolachlor and simazine. To eliminate the effects of water treatment, only raw (untreated) water has been sampled. These first two years of data will be reviewed by the TNRCC to assess the degree of atrazine contamination and to determine if further action is warranted.


Days Creek Special Studies Summary 2006 Appendix A Appendix B Appendix C Appendix D part 1 Appendix D part 2 Questions Concerning This Summary Call: Robert Cook (903) 535-5100	Wright Patman lake Special Study The State of Texas 2000 Clean Water Act Section 303(d) assessment indicated depressed dissolved oxygen and pH concerns for Qright Patman Lake. TNRCC guidelines require ten sampling events on a water body over a period of five years to make an assessment concerning impairment. Because the number of samples previously collected is too small to define the impairment or justify expenditure of funds to initiate a TMDL, additional sampling was needed. A Special Study within the Sulphur River Basin supplemented efforts by the TNRCC by supplying additional monitoring events including pH and 24-hour diurnal dissolved oxygen sampling at two stations on Wright Patman Lake. The sites selected for the study are routine monitoring stations of interest to stakeholders due to their proximity to water intake stations for local water utilities. In addition, this study has also collected more information about nutrient levels, which may indirectly influence the dissolved oxygen and pH concerns. The TNRCC regional office completed two monitoring events that included diurnal monitoring during the summer of 2001. This Special Study, conducted from June to October 2001, supplied four additional monitoring events. Six monitoring events at three sites are scheduled for routine monitoring by SRBA during FY 2002. After the FY 2002 data has been collected, there should be a sufficient amount of data to make a decision about the current impairments for Wright Patman Lake. The results of sampling to date supports the 303(d) listing of Wright Patman Lake for high pH values and low levels of dissolved oxygen during some of the sampling events. The TNRCC criterion of 8.5 during all six of the monitoring events at North Shore Intake and four times at the International Paper Intake. The average value of the 24-hour diurnal DO was at times below the 5.0 mg/L criterion established by TNRCC. However, the levels of dissolved oxygen have not been shown to be persistently low, but rather to be extremely variable from day to day as well as over a 24-hour period. The lake also exceeded the screening level for chlorophyll during the six monitoring events. The elevated pH and depressed DO averages are thought to be the result of high levels of photosynthetic activity occurring during weather conditions favorable for algae growth. Photosynthesis can a depletion of dissolved oxygen during the night and a rise of pH during the daylight hours by removing carbon dioxide from the water. Further sampling may be needed to identify the source of the nutrients that support the abundant algae growth. A study of the nutrients in the streams contributing to Wright Patman Lake as well as a study that illustrates the recycling of nutrients from sedimentary material may help identify the source.	Lake Wright Patman Special Study Report Map of Lake Wright Patman Water Users Map of Other Surface Water Users
	Taste and Odor Study of Wright Patman Lake Although taste and odor problems are not considered a direct threat to public health, they constitute the greatest public relations issue many water utilities face. Consumers generally rely on the taste and odor of their water as an indicator of its safety. In response to local concerns and to prompt stakeholders participation, a survey focusing on taste and odor issues of local water utility customers was conducted by the SRBA. A survey was mailed to local water systems that utilize Wright Patman Lake water. The questions contained in this survey focused on the frequency, magnitude, and timing of taste and odor problems. For purposes of comparison, the survey was also sent to three water utilities that utilized other sources. The results of the survey show that many of the cities that are serviced by Wright Patman Lake do experience problems with taste and odor, while few complaints were reported at the three utilities that do not use Wright Patman Lake water. The problem seems to occur most frequently during the summer months and subsides in the fall. Because the water produced for the cities serviced by Wright Patman Lake arrives as treated water, standby chlorination is the only chemical treatment utilized by local utilities. Some strategies applied to combat the taste and odor problem are the mixing of ground water and flushing of water mains. The potential causes of taste and odor problems are thought to be trace amounts of several organic compounds whose sources include certain species of algae, weeds, standing timber, soil and sediment. High levels of chlorophyll indicate that algae may be the dominant factor in Wright Patman Lake. The need for collection of more data to help to explain why the taste and odor issues exist for Wright Patman Lake is supported by this study. A study of the algae levels and the algae type may be warranted in order to identify which types of algae dominate Wright Patman Lake and to what extent they contribute to the taste and odor issues.
	Atrazine Study In Big Creek Lake March 2002 marks two years of monitoring Big Creek Lake for atrazine, a widely used herbicide. Big Creek Lake, a small, unclassified reservoir of about 700 acres was listed as threatened by contamination on the 2000 303(d) list due to atrazine in finished drinking water. The Big Creek Lake study is part of a larger project conducted by the TNRCC involving several Texas reservoirs, titled "Targeted Monitoring and BMP implementation in Seven Atrazine Threatened Lakes." The two major components of the project are: (1) surface water quality monitoring to better distinguish the threat of atrazine to drinking water sources, and (2) implementation of best management practices (BMP'S) to reduce the addition of atrazine in the subject watersheds. The TNRCC Region 5 staff has conducted monthly surface water quality monitoring in Big Creek Lake for atrazine, alacholr, metolachlor and simazine. To eliminate the effects of water treatment, only raw (untreated) water has been sampled. These first two years of data will be reviewed by the TNRCC to assess the degree of atrazine contamination and to determine if further action is warranted.