To: Interested Parties
From: Environmental Services division
This is the Sabine River Authority Water Quality Report for July 2003. Water quality sampling was performed July 8th through July 10th. Recent weather in the Basin was warm with daytime high air temperatures from the high 80’s to the high 90’s at Lake Tawakoni and at Lake Fork. Toledo Bend Reservoir and Orange had daytime highs from the mid 80’s to the mid 90’s. Lows ranged from 72 to 73 at Lake Tawakoni and from 71 to 73 at Lake Fork. Toledo Bend and Orange had lows ranging from the upper 60’s to the mid 70’s. The Upper Basin received 3.99 and 6.26 inches of rainfall during the 28 days since the previous sample run as recorded at Lake Tawakoni and Lake Fork, respectively. Lake Tawakoni recorded 0.44 inches and Lake Fork recorded 0.07 inches of rain in the week prior to the sample run. Toledo Bend and Orange recorded 7.38 and 13.65 inches, respectively, during the 28 days preceding the sample run. Reservoir sites were thermally stratified.
Upper Sabine Basin Above Toledo Bend Including Lake Fork and Lake Tawakoni
For the July sample run, most of the parameter values seen at the Upper Basin sites were consistent with water of high quality. LT23C, LT23D, LT23A, LF3, SR19 and SR10 had over 100% saturation of dissolved oxygen indicating algal activity. LT23C, LT23D and LT23A exceeded the screening criteria for chlorophyll a. LT23C exceeded the numeric criteria for the stream standards for pH. All Upper Basin sites were within the numeric criteria for the stream standards for E. coli. Surface water temperatures were between 26.1 and 29.6ºC at river and reservoir sites. Surface water temperatures near the dams at Lake Tawakoni and Lake Fork were 26.6 and 26.1ºC, respectively. Thermal stratification was evident at reservoir sites.
Lower Sabine Basin Including Toledo Bend to Morgan Bluff
The July monthly sampling results were indicative of water of high quality at most sites. The last significant amount of rainfall occurred two days prior to the sample run. The level of Toledo Bend Reservoir was recorded at 170.61 feet with no discharge from the spillway or the generator at the time of sampling. Stratification was present at all the lake sites. Anoxic conditions were also present at all but one of the lake sites at the deepest depths. Stations TB6N, TB6M and TB6 displayed low dissolved oxygen readings. Stations TB6N and TB6M are located in headwater areas of small coves and do not represent the conditions of the main body of the reservoir. Stations in the main body of the reservoir showed no impact from the water quality conditions indicated in the backwater areas. Station TB6 is located in the discharge canal below the generator and low oxygen readings are not uncommon when the generator is not operating. Sites further down on the river showed no affects of the oxygen readings in the canal.
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. The area received a heavy amount of rainfall just before 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 only found at one tidal station, SRT1 at a depth 10.4 meters. Salinities were found at two of the tidal stations. The highest salinity, of 6 ppt, was found at station SRT1 at a depth of 8.7 to 10.4 meters. Station SRT2 had a bacterial count above the stream standard, but it was mostly likely caused by runoff from the heavy rains the area received.
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
Terry Wilson, Upper Basin Field Office Coordinator
Ø 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 Tuesday, October 07, 2003