To: Interested Parties
From: Environmental Services division
This is the Sabine River Authority Water Quality Summary for September 2001. Several changes have been made to the program as of this first month of the new fiscal year. The name of the report has been changed from Water Quality Monitoring Program to Monthly Water Quality Report. Bacteriological testing for E. coli in fresh water replaces previous bacteriological screening methods. Enterococcus will be the bacteriological indicator organism of choice in tidal waters. The stream standard for an average of at least 10 samples for E. coli is 126 mpn (most probable number) / 100 mls and, for Enterococci, the standard is 35 mpn / 100 mls. Single samples should not exceed 394 and 89 mpn / 100 mls for E. coli and Enterococcus respectively.
Water quality sampling was performed September 11th through September 13.th Recent weather was mild and with normal, to above normal, rainfall. The Upper Basin received 7.84 - 4.66 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 7.17 and 19.09 inches respectively during the 28 days preceding the sample run. Recent daytime high temperatures were in the 80's to low 90's throughout the Sabine Basin. Nighttime lows were in the 60's and 70's. Reservoirs were thermally stratified.
Upper Sabine Basin Above Toledo Bend Including Lake Fork and Lake Tawakoni
For the September sample run, most of the parameter's values seen at the Upper Basin sites were consistent with water of high quality. Two Upper Basin sites had at least 100% saturation of dissolved oxygen, indicating algal bloom conditions. These sites, LT23C and LT23D, also slightly exceeded stream standards for pH. Elevated pH is normally seen accompanying algal blooms as a result of photosynthesis and dissolved oxygen production by the algae. Bacteriological counts were within stream standards at most Upper Basin sites. SR14 exceeded stream standards for E. coli with 249 mpn / 100 mls. Lake Fork Reservoir was thermally stratified near nine meters. Lake Tawakoni was thermally stratified, probably at 9-10meters, but electronic meter failure at the site prevented exact determination.
Lower Sabine Basin Including Toledo Bend to Morgan Bluff
The September monthly sampling results were indicative of water of high quality at most sites. Toledo Bend Reservoir was below pool level at the time samples were taken. The reservoir was in the processing of being drawn down so repairs could be performed on the dam. Thermal stratification of the water profile was exhibited at deep-water stations. Anoxic conditions were only observed at the deep-water stations at the deepest depths. Stations TB6N, TB6L, and TB6M had an E. coli result that was above stream standards.
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. All values for the tidal sites were within the stream standards for this segment of the Basin. Salinity readings were < 1 ppt at the surface at all tidal stations. The only salinity readings were found at station SRT1, which had a value of 4 ppt at 5 meters and 6 ppt at 10.4 meters. Station SRT1 was also the only station that showed thermal stratification.
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
Cynthia Darbonne, Lower Basin Field Office Coordinator
If above are unavailable
Miles Hall, Assistant Division Manager Environmental Services
Printed Tuesday, November 20, 2001