Sabine River Authority of Texas

Date: 10/23/98

To: Interested Parties

From: Environmental Services

RE: August 1998 Water Quality Monitoring Report

Here is the Sabine River Authority Water Quality Report for August 1998. This report was delayed due to equipment problems caused by lightning. Water quality sampling was performed August 11 through August 13. Weather during August can be characterized as warm with variable rain throughout the Basin. The Upper Basin was relatively dry, while Toledo Bend and the Lower Basin were relatively wet as compared to the same period in recent years. Flow values throughout the Basin were comparatively low for the August WQM.

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

Most of the parameter's values seen in the Upper Basin sites are consistent with water of high quality. Lake Fork and Lake Tawakoni were stratified with respect to dissolved oxygen and only the Lake Fork sites exhibited strong thermal stratification at seven to nine meters. Percent saturation of dissolved oxygen was over 100% at LT23C, LF3, LF4, and SR19 indicating high algal activity. Two sites, LT23A and SR16, had dissolved oxygen at levels below 5mg/l. SR14 had an elevated nitrate/nitrite and SR11 and SR10 had elevated sulfate. Hot, dry conditions in the Upper Basin have led to very low river flows. These low flows cause closer association of water with bottom sediments, high algal activity (from warm water and high light intensity) and less dilution of effluents in some areas. These combination of phenomena may be contributing to the values of concern seen recently.

Lower Sabine Basin Including Toledo Bend to Morgan Bluff

Values in the Basin were typical for this time of the year. Percent saturation of dissolved oxygen was over 100% at TB8, TB6J, TB6K, TB6H and TB6F indicating high algal activity. Stations TB6N, TB6I, TB6S, and TB6 showed lower than normal dissolved oxygen values. Fecal coliform numbers were low at most Lower Basin sites. Station TB8 had a slightly elevated fecal coliform value of 420col/100ml. Several stations (TB6N, TB8, TB6I, and BA4) had higher than normal conductivity and chloride values. Most secchi disk numbers were high throughout the basin indicating good water transparency. In addition to low dissolved oxygen, other values of concern recorded at Station TB6N were elevated levels of TOC, fecal streptococcus and ammonia. This may indicate higher than normal organic loading, possibly due to the wastewater treatment facility outfall upstream of this site. Most lake sites at Toledo Bend are well stratified with respect to dissolved oxygen and temperature.

 

 

Tidal Section of the Sabine Basin below Morgan Bluff

Values for stations in the tidal portion of the Sabine Basin were in a range that was normal and consistent with waters of high quality. Incoming tidal action was observed at stations BB1 and SRT1. Flow was westward in the Intercoastal Waterway. Salinity levels were detected at three of the five locations in the Tidal Area of the Basin. The highest surface salinity (6ppt) was at BB1. Conductivity, total hardness, chloride, and sulfate were also higher at these sites due to saltwater influence. The nitrate and nitrite value for BB1 was elevated.

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: