TPWD 1971 F-4-R-18 #1394: Region 2-A Fisheries Studies: Investigation of a Portion of the Brazos River, Job Progress Report, Project No. F-4-R-18, Job No. B-42

‘ / 4, JOB PROORESS REPORT aq- As required by FEDERAL AID IN FISHERIES RESTORATION ACT TEXAS Federal Aid Project No. F-4—R-18 Job NO. B-42: REGION 2-A FISHERIES STUDIES Investigation of a Portion of the Brazos River Assistant Project Leader: Allen A. Forshage Clayton Garrison Executive Director Texas Parks and Wildlife Department L. J. Peters _ Chief of Inland Fisheries Austin, Texas Robert J. Kemp, Jr. Director, Fish and Wildlife December 14, 1972 ‘, 5 ‘- a, J 'Abstract A survey of the Brazos River, extending from the tailrace below Possom Kingdom Reservior to the head waters of Lake Granbury was conducted. The results of this survey indicate that the tailrace, for the first four miles below the dam, would be suitable for a rainbow trout, (Salmo gairdneri), ”put-and-take" fishery. It was also found that, at high flow, the river has the potential for the reproduction Of striped bass, (Morone saxatilis). w= Job Progress Report State of Texas Project No. F-4-R-18 Name: Region 2-A Fisheries Studies Job No. B—42 Title: Investigation of a portion of the Brazos River Period Covered: January 1, 1971 to December 31, 1971 Objective: To determine the biological, chemical, and physical characteristics of the Brazos River extending from the tailrace waters below Possum Kingdom Dam to the headwaters of Lake Granbury. Introduction: At present, the only rainbow trout, Salmo gairdneri, fishery in Texas is located in the tailrace waters 9f Canyon Reservoir, Comal County, Texas. This fishery is maintained on a ”put-and-take” basis, but it has proven successful for the past five years and has contributed greatly to the economy and recreation of the area (White, 1968). Because of the success of this fishery, a survey of the tailwaters of Possum Kingdom Reservoir, in Palo Pinto County, was initiated to determine the suitability of the river for trout. Procedures: In January, sampling stations were set up along the first 20 miles of the Brazos River below Possum Kingdom Reservoir. Nine of the stations were selected in the first 11 miles and one was selected 20 river miles below the dam, see Figure 1. Water samples were collected at each sampling station each month and analyzed for pH, turbidity, oxygen, alkalinity, free carbon dioxide, chlorides and hydro- gen.sulfide. The width and depth of thestremnwes recorded and the type of substrate was noted. The air and water temperature was measured with a standard centigrade thermometer. The volume of flow was obtained through the courtesy of the U. S. Geological Survey. Benthic samples were collected monthly with a Surber square foot bottom sampler. Three samples were taken at each of the ten stations. These samples were pooled and washed through a U. S. No. 30 Standard Sieve. The sieved residue was placed in a jar and a preservative added to cover the entire sample. The sample was returned to the lab where it was sorted, identified to the family level and enumerated. The fish population was sampled by the use of a 20 foot seine and gill nets. In addition, a check of the available public access and a check of the current fishing pressure of the area was made. Figure I - Sampling sites on the Brazos River below Possum Kingdom ReServoir. Possum Kingdom_ Reservoir 7 4 6 5 8 9 Brazos River . - sampling sites Scale 0 % l 2 miles 10 FM4 K A review of the available literature pertaining to trout and striped bass was also made in conjunction with this survey. Results: Water Quality Characteristics The major limiting factor for a trout fishery in Texas waters, is water tem- perature. Rainbow trout have been reported to tolerate water temperature from below 32°F to over 80°F. The upper lethal limit varies considerably depending upon the oxygen content of the water, size Of fish, and degree of acclimation (Needham and-Jones, 1959). A.maximum of 83°F in well oxygenated waters was indicated lethal to rainbow trout by Needham (1938). During the summer months, when the water temperature is most critical, a con- siderable volume of water, being released from the hypolimnion, is required to sustain a low water temperature for any distance downstream. As most rivers in the region, the volume of flow of the Brazos River had been reduced due to drought conditions in the area. The level of Possum Kingdom Reservoir was down approximately 20 feet at one point during August. As a result, a minimal amount of water was released from the dam for the first eight months of the survey. Table 1 shows the volume of flow in cubic feet per second for 1971 recorded by the U. S. Geological Survey gauging station on the Brazos River near Palo Pinto. The water temperature of the tailrace below Possum Kingdom Reservoir stayed within tolerable levels for rainbow trout during the winter, spring and fall months (see Figure II and III). Due to the low volume of flow, the water temperature in the lower stations varied closely with the atmospheric tempera- ture. As summer progressed, and the atmospheric temperature increased, the water temperature also increased. The extent of this increase on the down- stream.waters was dependent on the volume of water being released from the reservoir. At lowjflow 17 cubic feet per second, during August, the water temperature increased to 82°F six miles below the dam. An over—all annual average temperature plus the range at each station is illustrated in Figure IV. Dissolved oxygen concentrations ranged from 7.8 to 10.2 ppm. The only fluctuations from this occurred during large releases from the reservoir. The oxygen concentration dropped to 2.6 ppm during September at sample station # l, with a release of 12,800 cubic feet per second and only increased to 6.2 ppm at station # 10. The low oxygen concentrations were likely due to the large volume of anerobic water coming from the hypolimnion plus the higher organic load of this water. Total alkalinity ranged from 94.0 ppm to 132 ppm, pH ranged from 7.4 to 8.8 and carbon dioxide concentrations ranged from 0.0 to 10.1 ppm. Volume of flow or season had little effect on any of these parameters. Hydrogen sulfide was only encountered at stations #1 and #2 in trace amounts. This occurred during August and September with large releases from the dam. The concentrations of hydrogen pulfide never exceeded 0.1 ppm. 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HH Q.“ Hm MH Hw Hm Hm Ho mm Mow mm 00 (0F) \ Temperatu' 100 90 70 50 40 -5- FIGURE II Water Temperature FrOm January Through June, 1971 A 1A A 2 A 3 A. 4 5 6 A 7 .A 8 9 [I 10 River Miles Below Dam A -Sample Station A June March February January Temperature (OF) -6— FIGURE III Water Temperature From July Through December, 1971 100 I 90 .. -eemmw l- Augus t ‘ “'Wa“ "fiibgmtah . , .. . J 11 TY .. I; WITWM.ma-mm 80 September 70 FflflflflI/L_n____—————————————-——-wH—r——”—-*——"_—""‘::::::::::::::: October 60 . -~:‘"' _ —_—mHn_n—flIz//,z’FflflflflflflflpflflFflflflflflflFahaahhFHuhfifihhhfinfifl““‘“‘*-—HH.December 50 ___________fl___flflflfl_H__________fi__________________i___hflm_______——w-November 40 l 2 3 4 5 6 7 8 9 10 20 River Miles Below Dam A - Sample Station Water Temperature \JF.) -7- FIGURE IV Average Water Temperature and Range for 1971 100 90 80 60 50 40 4 5 6 River Miles Below Dam A - Sample Station 10 volume flow. Chloride content ranged from 510 to 1037 ppm. The higher concentrations were noted during June and July and were likely due to the drought conditions of the area. The water quality studies indicate that the tailrace area will provide suitable trout habitat for the first four miles below Possum Kingdom Reservoir. It is believed that the survey was conducted in an atypical year, due to drought conditions, and that during a normal year, with an increase in the volume of flow, suitable trout habitat would extend further downstream. Benthic Organisms The compositions of the bottom fauna is shown in Table II and IIa. Three orders of aquatic invertebrates, Trichoptera, Diptera, and themeropters, comprised 78 per cent of the total bottom fauna. These three orders of insects are most significant in the food demands of rainbow trout, (Kennedy, 1967). From all indications, the food supply in the form of invertebrates, in Possum Kingdom tailrace area is more than adequate for a trout fishery. Fish Population Table III shows the list of fish collected and their relative abundance. This list was compiled from the composite findings of collections with 20 foot seines, gill nets and spot creel checks. Aquatic Vegetation The upper reaches of the study area had a large amount of green algae (Cladop— hora_§p;) covering up to 90 per cent of the substrate. It has been reported that rainbow trout ingest great amounts of this algae. In addition to its food value, it provides a habitat for large numbers of invertebrates (Pfitzer, 1960). Bushy pondweed (Najas EBL) was also abundant in the study area. Other aquatic plants found in the reach are parrot feather (Myriophyllum_§p;), star grass (Heteranthera EEL)3 pondweed (PotamogetonlgpL), cattail (Typha.§p;), muskgrass (Chara EEL>1 bulrush (Scirpus gp;), cut-grass (Cladium gpL), spike rush (Eleo- charis 22;): three-square rush (Scrirpus gpL), and willow (SaliX.§2i) Public Access At present there is limited public access to the major portion of the said, area in that the land along the river is under private ownership, but this will not eliminate fishing the area because the river is considered public; there- fore, wade and float fishing will be allowed. A further investigation of the Brazos River was made during this segment to deter- mine if the Brazos River has the potential for a reproducing pOpulation of striped bass (Morone saxatilis). The Brazos River flows 110 miles from Possum Kingdom Reservoir to the headwaters of Lake Granbury. The average width of this section is 150 feet with an average depth of 3 feet. The width and depth vary conside 1y with the releases from Possum Kingdom Dam. The average volume of Flow, as recoided by the U. S. Geological Survey for March and April is 1,960 cubic feet per second.