Sabine River Authority of Texas

To: Interested Parties

From: Environmental Services division

RE: july 2000 Water Quality Monitoring Report

This is the Sabine River Authority Water Quality Summary for July 2000. Water quality sampling was performed July 18 through July20. Daytime high air temperatures during the seven days prior to the sampling dates was in the upper 90s and low 100s in the Upper and Lower Basin. Nighttime lows were in the 70s. There was no significant rainfall in the 14 days prior to the sample run.

Upper Sabine Basin Above Toledo Bend Including Lake Fork and Lake Tawakoni

For the July sample run, most of the water quality values seen at the Upper Basin sites were consistent with water of high quality. Hot, dry conditions and warming of surface waters were the primary causes for some elevated data points for this month. Lake Fork and Tawakoni Reservoirs were thermally stratified at around five meters. Percent saturation of oxygen was over 100% at most reservoir sites and at four river sites (SR21, SR19, SR11, and SR10). Chlorophyll a was high at most of the reservoir sites, with a strong correlation between high algal growth and super saturation of the water with oxygen. Water temperature was in the low 30s (degrees C) near the surface at most sites. SR19 slightly exceeded stream standards for temperature. Orthophosphate was elevated at LT23D and pH was slightly under stream standards at BS18.

Lower Sabine Basin Including Toledo Bend to Morgan Bluff

July 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 with near-anoxic conditions near the bottom. Oxygen levels at stations TB6N, TB6I, TB6M, and TB6 were below stream standards. pH levels at stations TB6J and TB6K were slightly above stream standard limits. Station BA4 had higher nitrite/nitrate levels and conductivity readings compared to other stations. This station 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. Profiles were well-mixed with no discernable salt-water wedge at most sites. The greatest salinity measured occurred at SRT1 with a reading of 16 ppt at 9.6 meters depth.



This Report and additional data for these monitoring stations are available on our World Wide Web site ( If you have any questions or comments concerning this report, please contact:


      Upper Sabine Basin
John Payne, Upper Basin Field Office Coordinator
903-878-2420 (

      Lower and Tidal Sabine Basin
Cynthia Darbonne, Lower Basin Field Office Coordinator
409-746-3284 (

      If above are unavailable
Miles Hall,
Assistant Division Manager Environmental Services
409-746-3284 (



Printed Monday, September 18, 2000