To: Interested Parties

From: Water Resources Branch

RE: may 2006 monthly Water Quality Report

This is the Sabine River Authority Water Quality Report for May 2006. Water quality sampling was performed May 8th through May 11th. Recent weather (previous seven days) in the Sabine River Basin was warm, with daytime highs in the low 70s to upper 80s at Lake Tawakoni and at Lake Fork. Toledo Bend Reservoir and Orange had daytime highs from the mid 70s to the upper 80s. Lows ranged from the upper 50s to upper 60s at Lake Tawakoni and at Lake Fork. Toledo Bend and Orange had lows ranging from the mid 50s to the mid 70s. During the 28 days prior to the sample run, the Upper Basin received 4.87 and 3.72 inches of rainfall as recorded at Lake Tawakoni and at Lake Fork, respectively. Lake Tawakoni received 2.80 inches of rain and Lake Fork received 1.88 inches of rain the week preceding the sample run. Toledo Bend and Orange received 4.57 and 4.47 inches of precipitation during the 28 days prior to the sample run.

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

Water quality parameter measurements at the Upper Basin sites were consistent with water of high quality for the May sample run. The level of Lake Fork was recorded at 400.76 feet msl with 8 cfs releases and the level of Lake Tawakoni was recorded at 432.17 feet msl with 6 cfs releases at the time of sampling. All Upper Basin stations were within acceptable stream standards numeric criteria and recommended screening criteria for parameters measured except Lake Tawakoni stations LT23A, LT23D, and LT23C, which exceeded the recommended screening criteria for chlorophyll a. High chlorophyll a levels in conjunction with dissolved oxygen saturation values exceeding 100% and an elevated pH often indicate algal bloom conditions. Algal blooms may occur in the warmer summer months when nutrients in lake waters are exposed to high temperatures, sunlight, and calm water conditions. At the time these stations were sampled there were overcast skies, which would reduce photosynthetic activity and may explain the normal pH and dissolved oxygen saturation values in the presence of elevated chlorophyll a.

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 area received 0.18 inches of rainfall the week prior and during sampling. The level of Toledo Bend Reservoir was recorded at 168.72 feet msl with 204 cfs discharge at the time of sampling. Most reservoir stations were stratified with dissolved oxygen and temperature differences throughout the water column. Anoxic conditions were found at several of the deep-water lake stations. Texas stream standards numeric criteria were exceeded at station TB6LN for chloride and at station TB6A for sulfate. The recommended screening criteria was exceeded at station TB6A for chlorophyll a, nitrate + nitrite and orthophosphate. No abnormal conditions were noted at this site while sampling to explain the higher than normal results.

Tidal Section of the Sabine Basin below Morgan Bluff

Most sites sampled in the tidal portion of the Sabine Basin had values that are consistent with water of high quality. The tidal stations received just less than one inch of rainfall in the seven days prior to the sample event. Surface salinities were found at only two tidal stations. The largest salinity value, 4 ppt, was found at stations SRT1C and BB1 at the deepest profile depth of each. All parameters measured fell within stream standards numeric criteria.


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
Terry Wilson, Upper Basin Field Office Coordinator
903-878-2420 (

      Lower and Tidal Sabine Basin
Jerry Wiegreffe, Lower Basin Field Office Coordinator
409-746-3284 (

      If above are unavailable
John Payne, Special Projects Administrator
409-746-2192 (
Miles Hall, Resource Management/ Project Development Division Manager
409-746-2192 (


Printed Wednesday, August 23, 2006 at 13:07