To: Interested Parties
From: Environmental Services division
This is the Sabine River Authority Water Quality Summary for August 2000. Water quality sampling was performed August 8th through August 10th. Recent weather in the Basin was hot and very dry with the exception of the Orange region where 3.02 inches of rain was recorded in the nine days prior to the sampling event. Daytime high air temperatures during the seven days prior to the sampling dates were in the upper 90's and low 100's in the Upper and Lower Basin. Nighttime lows were in the 70's.
Upper Sabine Basin Above Toledo Bend Including Lake Fork and Lake Tawakoni
For the August sample run, most of the water quality values seen at the Upper Basin sites were consistent with water of high quality. Lake Fork and Tawakoni reservoirs had only slight temperature differences from surface to bottom but dissolved oxygen gradients were seen at six to eight meters depending on the location. Percent saturation of oxygen was over 100% at LT23C, LT23D, and at three river sites (LF20, SR21, and SR19). Dissolved oxygen was less than 5mg/L near the dams at Lake Fork and Lake Tawakoni. Additional measurements at Lake Tawakoni indicated oxygen was well over 5mg/L about ¼ mile from the dam. Warming of deeper water by convection heating from the dam may have caused hypoxic water from the bottom to circulate to the surface. Some consideration should be given to move LF2 at Lake Fork and LT23A at Tawakoni a little farther away from the structure in order to reduce possible localized effects from the dam. Orthophosphate was slightly elevated at LT23D. River sites were unusually clear after the period without rainfall. Only one site, SR15, had elevated fecal coliform. Since high coliform counts are unusual during dry weather, SRA notified the City of Longview of a possible wastewater leak. Further sampling and groundwork by SRA and the City of Longview led to the discovery and repair of a leaking wastewater pipeline in a secluded area near the city limits of Longview. Other water quality parameters compared at upstream and downstream sites indicate no impairments other than slightly elevated ammonia at SR15.
Lower Sabine Basin Including Toledo Bend to Morgan Bluff
August WQM sampling results were indicative of high water quality at most sites. Toledo Bend Reservoir was near pool level during this sampling event. Profiles taken at deep-water stations on the reservoir exhibited thermal stratification and had anoxic conditions at deeper depths. Oxygen levels at Stations TB6N, TB6I, TB6M and TB6 were below stream standards. Sulfate levels at Stations TB8 and BA4 exceeded stream standards. Stations BA4 and TB6N had higher nitrite/nitrate levels and conductivity readings compared to other stations sampled during this time. Station BA4 is sampled from a bayou that receives discharge from a paper mill. Station TB6N is sampled from a bayou that receives effluent from a municipal wastewater treatment plant.
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. A definite salt-water wedge was observed at tidal stations. The greatest salinity measured occurred at SRT1 with a reading of 22 ppt at 9.7 meters deep.
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:
Upper Sabine Basin
John Payne, Upper Basin Field Office Coordinator
Lower and Tidal Sabine Basin
Cynthia Darbonne, Lower Basin Field Office Coordinator
above are unavailable
Miles Hall, Assistant Division Manager Environmental Services
Printed Friday, September 29, 2000