Sabine River Authority of Texas
From: Environmental Services division
RE: October 1999 Water Quality Monitoring Report
This is the Sabine River Authority Water Quality Summary for October 1999. Water quality sampling was performed October 12 through October 14. Daytime high air temperatures during the seven days prior to the sampling dates were in the low to upper 80's, with nighttime lows 15-30 degrees cooler. Dry weather prevailed in the Upper Basin, and reservoir and river conditions were impacted little to none by the most recent rainfall. The lower and middle portions of the basin received significant rainfall during the week previous to the sampling dates. Due to failure of laboratory equipment, values for ammonia were not obtained.
Upper Sabine Basin Above Toledo Bend Including Lake Fork and Lake Tawakoni
For the October sample run, most of the water quality values observed at the Upper Basin sites were consistent with water of high quality. The most recent rainfall was a 0.6 inch rain thirty days prior to sampling. Lake Tawakoni recorded 1.73 inches of rain since September 1st (42 days previous) and Lake Fork recorded 2.11inches during the same period. The Lake Fork Reservoir sites ranged from a low of 21.6 degrees C at the bottom to 23.6 degrees C at the surface. Dissolved oxygen and temperature profiles indicated only a very weak stratification. Lake Tawakoni sites ranged from 21.5 degrees C at the bottom at one site to 24.9 degrees C at the surface at another site. LT23C was strongly stratified but other Lake Tawakoni sites were very weakly stratified. Oxygen was over 100% saturation at many of the reservoir sites, indicating high algal activity as algae utilize available nutrients after the recent mixing of the reservoirs. LT23A, LT23C and LT23D exceeded stream standards for pH. SRA has recommended an increase in the stream standards for pH on Lake Tawakoni since historical data indicates these values are natural and not due to water quality problems. River sites reflected good water quality conditions for the most part, although BS18 and SR10 had elevated fecal coliform levels.
Lower Sabine Basin Including Toledo Bend to Morgan Bluff
October WQM sampling results were indicative of water of high quality at most sites. Toledo Bend Reservoir levels were still lower than normal because of continuing drought conditions. Deep-water stations sampled on the reservoir exhibited profiles that were well mixed. Sites TB6K, TB6H, and TB6F had elevated pH levels and super-saturated oxygen levels at the surface due to an algae bloom. Higher conductivity readings, fecal coliform counts, and chloride levels were observed at Station TB6N. TB6N is located downstream from a municipal wastewater treatment plant. Higher conductivity readings and higher nitrate/nitrite and chloride levels were observed at Station BA4. Station BA4 is sampled from a bayou that receives discharge from a paper mill.
Tidal Section of the Sabine Basin below Morgan Bluff
Stations sampled in the tidal portion of the Sabine Basin had values that were consistent with water of high quality. All values measured were within stream standards criteria. Salinity was detected at all four tidal stations: SRT1, SRT2, BB1, and ICW1. The greatest salinity readings were observed at the deepest depths at Stations SRT1 and SRT2. Both sites had a maximum salinity of 15 ppt. A definite salt water wedge was observed at all tidal stations.
This Report and additional data for these monitoring stations are available on our World Wide Web site (www.sra.dst.tx.us). If you have any questions or comments concerning this report, please contact:
Printed Tuesday, May 23, 2000