To: Interested Parties
From: Environmental Services division
This is the Sabine River Authority Water Quality Summary for May 2002. Water quality sampling was performed May 14th through May 16th. Recent weather in the Basin was mild with air temperatures in the 70s and 80s during the daytime and lows in the 60s and 70s at night. Temperatures were 10-15 degrees cooler during the most recent two days. The Upper Basin received 7.23 – 6.83 inches of rainfall during the 28 days since the previous sample run as recorded at Lake Tawakoni and Lake Fork respectively. Toledo Bend and Orange received considerably less rainfall with 0.35 and 0.07 inches respectively during the 28 days preceding the sample run. Reservoir profiles indicated stratification of the water column with a distinct thermocline in each reservoir. The thermocline was still deep, running about 14m at the dam at Lake Tawakoni, 11 m at the Lake Fork dam, and 10-15 m at Toledo Bend Reservoir.
Upper Sabine Basin Above Toledo Bend Including Lake Fork and Lake Tawakoni
For the May sample run, most of the parameter's values seen at the Upper Basin sites were consistent with water of high quality. The most recent rain was 1.31 inches at Lake Tawakoni and 0.88 inch at Lake Fork two days prior to the first sample date. Surface water temperatures were between 20 and 23.6 C. E. coli exceeded the single-grab stream standard limit at SR22 and SR21. These sites were most influenced by the recent rain that was heavier in the Lake Tawakoni region than in downstream areas. Nitrate/nitrite exceeded screening guidelines at LT23D and LT23A. LT23D also exceeded the screening guideline for orthophosphate. LT23C had 105% saturation of dissolved oxygen, indicating significant algal growth. Surface temperatures near the dams at Lake Tawakoni and Lake Fork respectively were about two and eight degrees warmer than bottom temperatures.
Lower Sabine Basin Including Toledo Bend to Morgan Bluff
The May monthly sampling results were indicative of water of high quality at most sites. The last significant rainfall occurred over one week prior to the sampling event. The level of Toledo Bend Reservoir was recorded at 171.64 feet with no discharge from the spillway gates at the time of sampling. The generator was not operating at the time of sampling. All lake sites were thermally stratified with some of the deep-water stations showing anoxic conditions at the deepest depths. Stations TB6N and TB6M had oxygen levels that were below the stream standard, and station BA4 had a sulfate result that was above the stream standard.
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 at most sites. It had been over a week since the last significant rainfall. All sites showed some slight differences in the oxygen levels as the depths increased, but all sites were well mixed with respect to temperature. The stations BB1 and SRT1 were the only sites that showed surface salinity results. The values at these sites were recorded at 2 ppt. The highest salinity value, of 5 ppt, was recorded at station SRT1 at a depth of 8.8 m. All values recorded in this section of the Basin were within their stream standard.
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:
Ø Upper Sabine Basin
John Payne, Upper Basin Field Office Coordinator
Ø Lower and Tidal Sabine Basin
Jerry Wiegreffe, Lower Basin Field Office Coordinator
If above are unavailable
Miles Hall, Assistant Division Manager Environmental Services
Printed Tuesday, July 02, 2002