Sabine River Authority of Texas

Date: 8/4/98

To: Interested Parties

From: Environmental Services

RE: JULY 1998 Water Quality Monitoring Report

Here is Sabine River Authority Water Quality Report for July 1998. Water quality sampling was performed July 7 through July 9. Weather during the month can be characterized as warm and dry throughout the basin. The Sabine Basin received rainfall several days prior to the July WQM Sampling. The maximum recorded rainfalls were at Lake Fork (1.5 inches) and Toledo Bend (1.2 inches). Several locations (SR21, SR19, TB8, TB6L, and TB6H) had temperature values above stream standards, most likely due to the extreme weather conditions being experienced throughout the Basin.

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 strongly stratified. Percent saturation of dissolved oxygen was over 100% at Stations LT23C, LF4, LF2, LF20, and SR19 indicating high algal activity. Station LT23C also had an elevated pH value, which is probably due to natural conditions, especially in light of the high dissolved oxygen recorded there. Dissolved oxygen was slightly less than 5mg/l at BS18 and SR16. Stations BS18, SR14 and SR11 had elevated fecal coliform counts, and at Station SR14 the nitrite/nitrate value was significantly elevated. This value was approaching stream standards in the May sample and slightly exceeded the standard in the June sample. Stations SR11 and SR10 had elevated sulfate values. Hot, dry conditions in the Upper Basin have led to very low river flow. Closer association of water with bottom sediments, high algal activity (from warm water and high light intensity) and less dilution of effluents may be causing some of the values of concern seen during summer samples this year.

 

Lower Sabine Basin Including Toledo Bend to Morgan Bluff

Most of the values for this area of the Basin were normal for this time of the year. Stations TB6N and TB6I showed lower than normal dissolved oxygen values. Fecal coliform numbers were low at all Lower Basin lake sites. However, fecal coliform values in the Sabine River sites below Toledo Bend were elevated. This is most likely due to the rainfall event just prior to the WQM sampling. 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 conductivity, TOC, and orthophosphate. This may indicate higher than normal organic loading, possibly due to the wastewater treatment facility outfall upstream of this site. Bayou Anacoco (BA4) had elevated TOC, nitrite/nitrate, chloride, sulfate and the lowest secchi disk value. These have been elevated at this location for several months; SRA is investigating but does not have enough information to determine an exact cause at this time. Most lake sites at Toledo Bend are now 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. Tidal action was observed ebbing at stations BB1 and SRT1. Flow was eastward in the Intercoastal waterway. Salinity levels were detected at two of the five locations in the Tidal Area of the Basin, which may be a reflection of the rainfall event just prior to this sampling. The highest surface salinity (5ppt) was at SRT1. Conductivity, total hardness, chloride, and sulfate were also higher at these sites due to saltwater influence. Orthophosphate values for BB1 and SRT1 were also 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: