To: Interested Parties
From: Environmental Services division
This is the Sabine River Authority Water Quality Report for September 2003. Beginning this month (Fiscal Year 2004), several changes were made to the list of stations included in this report, including: replaced the Upper Sabine Basin site BS1 with BS9 due to safety concerns (BS9 is located about 2 miles downstream of the old BS1 site); replaced several backwater stations on Toledo Bend with stations on the main lake or larger arms (these new stations will help provide better coverage of the main body of the reservoir); and added several Tidal stations.
Water quality sampling was performed September 8th through September 11th. Recent weather in the Basin was warm with daytime high air temperatures from the upper 70’s to the low 90’s at Lake Tawakoni and at Lake Fork. Toledo Bend Reservoir and Orange had daytime highs from the mid 80’s to the lower 90’s. Lows ranged from 56ºF to 70ºF at Lake Tawakoni and from 58ºF to 70ºF at Lake Fork. Toledo Bend and Orange had lows ranging from the low 60’s to the upper 70’s. The deeper reservoir sites remained thermally stratified. During the 28 days since the August sample run, the Upper Basin received 2.59 and 1.89 inches of rainfall as recorded at Lake Tawakoni and Lake Fork, respectively. The week prior to the sample run, Lake Tawakoni received 0.3 inches and Lake Fork received 0.12 inches of rain. Toledo Bend and Orange received 5.84 and 5.26 inches, respectively, during the 28 days preceding the sample run.
Upper Sabine Basin Above Toledo Bend Including Lake Fork and Lake Tawakoni
For the September sample run, most of the parameter measurements at Upper Basin sites were consistent with water of high quality. LT23C and LT23D exceeded the stream standards numeric criteria for pH by less than one-half unit. These sites also had elevated chlorophyll a and high dissolved oxygen. Elevated chlorophyll a with high dissolved oxygen indicates algal bloom conditions and this combination may lead to elevated pH levels. SR10 also had slightly elevated pH levels. SR10 had a high level of dissolved oxygen with greater than 100 percent dissolved oxygen saturation, indicating algal activity. Three other reservoir sites, LT23A, LF3 and LF4 had elevated chlorophyll a levels as well. Chlorides at SR11 were slightly elevated above screening levels. All Upper Basin sites were within the stream standards numeric criteria for E. coli. Deeper reservoir sites remained thermally stratified.
Lower Sabine Basin Including Toledo Bend to Morgan Bluff
The September monthly sampling results were indicative of water of high quality at most sites. The last significant amount of rainfall the area received was five days prior to the sample run. The level of Toledo Bend Reservoir was recorded at 167.46 feet with no discharge from the spillway, but the generator was operating at the time of sampling. Stratification was present at all the lake sites, and anoxic conditions were only present at the deepest stations at most sites. Stations TB6LN, TB6J, TB6K, and TB6H all displayed higher than normal pH levels, but each station also had high dissolved oxygen readings with supersaturation at the surface and very good transparency. These conditions indicate an algal bloom on the reservoir likely caused the high pH results.
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. Three new tidal sites on the lower river have been added. These sites will help provide better coverage of the tidal section of the Basin. The last significant rainfall the area received was over a week prior to sampling. Most sites in this section of the Basin showed some signs of stratification with slight oxygen differences throughout the water column. Anoxic conditions were found at only one tidal station. Surface salinity was found at all but the two most northern stations. Among the stations that did record surface salinity, the salinity values ranged from 1.4 ppt at station SRT1A to 2.5 ppt at station SRT1. The highest salinity values, 13.8 ppt and 12.9 ppt, were found at stations SRT1C and SRT1 at their deepest depths. Stations SRT1C and BB1 had bacterial counts that exceeded the numerical criteria in stream standards.
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
Terry Wilson, Upper Basin Field Office Coordinator
Lower and Tidal Sabine Basin
Jerry Wiegreffe, Lower Basin Field Office Coordinator
If above are unavailable
John Payne, Special Projects Administrator
Miles Hall, Resource Management/ Project Development Division Manager
Printed Monday, December 01, 2003