TPWD 1955 F-2-R-2 #131: Job Completion Report: Basic survey of the remaining portions of the San Gabriel River and Brushy Creek within Region 6-B

--- Page 1 --- OTATE Texas PROJECT F-2-R-2, Job A-4 PERIOD June 1 through Nov. 31, 195% ra [commer i 1 Job Completion Report by Kenneth C. Jurgens and Billy D. Cooper Basic survey of the remaining portions of the San Gabriel River and Brushy Creek within Region 6-B, which were not covered in Job A-2, Project F-2-R-1. OBJECTIVES To gather fundamental data on the above waters in regard to their phys- ical, chemical and biological aspects. METHODS Seven stations were selected on the North San Gabriel River and the Rus~ sel Fork of the North San Gabriel River in Burnet County, Texas. Seven other stations on the San Gabriel River and Brushy Creek, in Milam County, were also se-= lected, These fourteen stations, combined, were considered sufficient to complete the overall survey of the San Gabriel River and its principal tributaries as be« gun under Job A~2, Project Fe2-R-1. The locations cf these stations are shown in Table 1 and on the accompanying maps. Hach of the stations selected were visited at least once during the course of the job. On these occasions the following data were gathered: average width and depth; turbidity; volume of flow (wherever possible); pool size, type and fre-~ quency; bottom types, both in the pools and on the riffles; kinds and abundance of aquatic vegetation; a description of the surrounding country and the immediate shoreline; a notation of the larger tributaries and evidences of pollution where indicated. PINDINGS Since the work done under the present job was a continuation of work done under an earlier job, the findings of this job must be reported upon in two sepe arate sections. The first section deals with that portion of the North San Gab- viel River which lies in Burnet County. The remainder of the report is concerned with those portions of the San Gabriel River and Brushy Creek within Milam County, Texas. The San Gabriel River, Burnet County: - The North San Gabriel River heads in Burnet County, approximately ten miles north of the town of Burnet. From its source, the river flows in a southeasterly direction to the Williamson County line and comtinues on, as described in the report for Job A-2, Project F-2-R-1, in a "southeasterly direction to the vicinity of Georgetown where it is joined by the South and Middle San Gabriel River." The North San Gabriel and Russel Fork of the North San Gabriel River, the only tributary of consequence in Burnet County, flow through country which is char- acterized by thin to medium bedded, hard, continuous limestone strata, alternat- [ir eS — --- Page 2 --- 2. ing with marls or marly limestones. The headwater sections of both streams flow through country with rough, rolling type of topography, with soils on the hills limited to a thin mantle of calcareous soils. Further east in Burnet County, the topography becomes more gently rolling with tillable valleys and flood plcins. Soils in this area are gray-black calcareous clays with thin seams of bedded lime- stone. Both the North San Gabriel and Russel Fork are intermittent, running only during periods of prolonged rainfall. Above the confluence of the North San Gab- riel and Russel Fork, both streams have bed rock bottoms with shallow to non- existent banks. Below the confluence, the river has a tendency to Lecome more deeply entrenched in the deeper soils and has medium to deep cut banks with sandy to silty gravel bottoms on both the riffles and in the pools. Very scanty aquatic vegetation; composed principally of filamentous green algae; musk grass (Chara sp.) and coontail (Ceratophyllum demersum) ;is limited to the small pools. Due to the extreme drouth, which this part of the country has undergone during recent years, these streams no longer flow. Water temperatures in the North San Gabriel River and Russel Fork varied from 79°F to 82°F during the study period. The pH in this portinn of the San Gab- riel River system ranged from 8.0 to 8.3. The fish populations of the San Gabriel River in Burnet County were found to be very limited not only in numbers but in species, occurring in the small pools, isolated by drouth conditions, and preyed upon by both animals and man. Fish kills in these pools, due to oxygen deficiencies caused by low water, almost never occur because the pools are cleared of fish by predation before the deficiency can come about. In the total of approximately 34 stream miles covered by this survey in Burnet County, 12 species, representing 4 fish families, were found in the North San Gabriel River and Russel Fork. A checklist of these species is given in Table dds The San Gabriel River and Brushy Creek, Milam County: - After entering Milam County, the San Gabriel River and Brushy Creek flow through three geolog- ical formations: the Taylor, the Navarro and the Midway. Taylor and Navarro formations are similar in that they consist of chalks, maris and sandy clays which have weathered into waxy, black soils which are used mostly for farming and for the most part, are gently rolling. Along a line running approximately NNE and ssw between the towns of San Gabriel and Thorndale, in Milam County, both the San Gabriel River and Brushy Creek enter the third of the three formations, the Midway. This formation differs from the other two in that it consists of sands and sandy clays and the soils derived from it are chocolate brown in color and are lighter, since they contain more sand . All three of these formations have provided soils which are easily erod- able and as a result the stream beds of both the San Gabriel River and Brushy Creek are progressively more deeply entrenched as the streams flow toward their confluence with each other and with the Little River about six miles northeast of Rockdale. The streams themselves consist of relatively deep pools, averaging from four to six feet in depth, with maximum depths up to ten feet. Bottom types in the pools are mostly silt with some gravel and the more infrequent riffles have bottoms --- Page 3 --- Loe) of sand and gravel with some silt. On the San Gabriel River, towards the confluence with the Little River, the stream bottom changes slightly in that some sandstone rubble occurs on some of the riffles and in some of the pools. What vegetation occurs in these streams is limited to filamentous green algae, on the riffles, and musk grass (Chara sp.) in the pools. Some arrow- head (Saggitaria platyphylla) occurs on the edges of some of the pools on the San Gabriel River. Physically, Brushy Creek differs only in that it is narrower and more deeply entrenched than is the San Gabriel River. It is also more heavily shaded. As a result, water temperatures in Brushy Creek were found to be somewhat cooler than those of the San Gabriel, averaging about 77°F. While the San Gabriel had temperatures ranging from 82°F to 87 F. The pH in the San Gabriel wnged from 7.2 to 7.9 and in Brushy Creek from 7.4 to 7.6. (Table 11). Fish populations in the San Gabriel River and in Brushy Creek are concen- trated into the larger pools because of the lack of flowing surface water. There are indications that these populations are out of balance due to silt pollution and predation. Many of the clearwater forms were reduced in numbers because of the necessity of their having to live in turbid pools. Thirty~one species, representing 8 families of fish, were found to be present in the 17 miles of the San Gabriel River surveyed in Milam County during the study period. A smaller number, only 18 species representing 7 families, were found in Brushy Creek during the survey. Approximately 15 miles of Brushy Creek were covered by the survey in Milam County. A checklist of the species found to occur in Brushy Creek and in the San Gabriel River in Milam County are also given in Table 111. Since neither Brushy Creek nor the San Gabriel River were flowing during the study period, data concerning the rate of flow was not obtained. Furthermore, the U. 5. Geological Survey records do not include stream flow data for either stream in Milam County. The only evidences of pollution encountered during the course of the sur- vey were instances of pollution due to silt which is a direct result of the poor land management practices which were common in this area during the last fifty to one~hundred years. Some positive efforts are being made at present to remedy this situation by farmers and ranchers. Perhaps in time these streams will once more become favorable habitats for the desired game species which, we are told, were once so abundant. SUMMARY 1. The work was divided between those portions of the North San Gabriel River in Burnet County and the remaining portions of the San Gabriel River and Brushy Creek, not overed previously, in Milam County. 2. The North San Gabriel and Russel Fork are typically small, shallow bedrock streams with a tendency to become more or less deeply entrenched with sand, silt and gravel bottoms below their confluence. --- Page 4 --- 4, 3. The San Gabriel River and Brushy Creek in Milam County are very deep- ly entrenched with silt and gravel bottoms and have long, deep pools and short, shallow riffles. 4. Aquatic vegetation occurs infrequently and in scant amounts in both the streams of Burnet County and those of Milam County covered in this survey. 2+ Prolonged drouth has all but dried these streams up and during most of the survey period very little flow was observed and none could be measured. 6. <A total of 33 species, representing 10 families, were found to occur in these waters. Of these, only 12 species were found in the North San Gabriel in Burnet County, all but one species was found in the lower San Gabriel in Milam County and 17 species were found in Brushy Creek. 7. Other than pollution due to silt, no evidences of pollution were encountered during the survey. --- Page 5 --- North San Gabriel River (Burnet County) Station No. Location Russell Fork North San Gabriel, 6 mi. NE Bertram Russell Fork North San Gabriel 5 mi. N Burnet on Farm Road 963 North San Gabriel River, 5 mi. SE Lake Victor North San Gabriel River, 3 mi. NNW Tamega North San Gabriel River, crossing at Joppa Russell Fork North San Gabriel, 2 mi. S. Joppa North San Gabriel River, 4 mi. SW Mahomet on Farm Road 243 County) Location 3 mi. S town of San Gabriel, Farm Road 486 6 mi. SE town of San Gabriel on county road 7 mi. NW Rockdale on county road 6 mi. N. Rockdale on Farm Road 487 Brushy Creek (Milam County) Station No. Location 12, 1 mi. E Thorndale on Texas Highway 79 13. 6 mi. E Thorndale on county road 14. 5 mi. NW Rockdale on county road Table 1. Locations of Survey Stations Used During Study Period under Job A-4, Project F-2-R-2, Basic Survey of the Remaining Portions of the San Gabriel River and Brushy Creek Within Region 6-B, Which Were Not Covered in Job A-2, Project P-2-R-1. --- Page 6 --- 6. Temperature and pH Conditions, San Gabriel River and Brushy Creek in Burnet and Milam Counties Air Temp Water Temp. _Station No. Date oF oF pH 1. June ll 89 80 8.1 2. June 11 90 81 8.1 3. June 11 92 : 82 B.e h, June 11 94 82 8.1 5, June 11 96 79 8.3 6. June 11 94 . 81 8.1 ie June 11 93 81 8.0 8. July 7 86 82 Tk &. Aug. 9 8h 86.5 TG 9. July 7 no water 10. July 16 no water 11. July 16 95 85 | 7.6 11. Aug. 10 85 . 87 7.9 12. July 16 no water 13. Bens. 15 92 76.5 Th 1k, Sept. 16 88 77 7.6 Table 11. Record of Temperature and pH Conditicns on the North San Gabriel River and Russell Fork of North San Gabriel River In Burnet County and on the San Gabriel River and Brushy Creek in Milam County During the Study Period, June through September 1954. --- Page 7 --- mM aaa ta cae aa x £aunop werTtw yeerig Aysnig °sexay, ‘AjUNGO WETIW UT yeerg Aysnag pue JeaTY Tetaqey ueg ayy pue Aqgunod yeusing Ul JOATY Tetagey ues YLIGN oy UT aN9DQ 04 pUNOW SoyusTY Teqyemyserg™ Jo ystTyoeuO V MP MM PO Pt OM OM ad NOM MOM OM 4 A oT ry P 4d ta Aquneg werrw I8ATY Tetaqey ues ar pS Aqguneg .eurM_ “IOATM TeTIgqey ueg Ss mip tevemusery Jay_Tep Teor Vesue.10 Ta.Iep ssouyuntaq yored Sot zaqyrep Aysnp UuStguns 1ee88u0T ustjguns pe_.odse8uezo TTESenTq ustguns uses UQNOULTeA sseq yoetTq yynowesze7 sseq yoetTq peyqods UST FO UTNDsom vUMUIGD mouutmda, sdtay.syoerq morpenm etodpey USTFIeO peeyLeLls pesyuTiTng yoertq peesytt—ng AoTtssé uSTyZ7e0 Teuueyo IITTOLIue 7s MOUUTM peey es MOUUTH JorTTed AcuUTM AZOATTS zeuTys .soys IsuTysS OTMTH IouUTUS pet TOUTYS TPB VyoeyTg dzeo uweedoim7 essoupar LeiB aayonsdzeo Iaata peus pazezzta ae8 pesacds azeS esouy71oys omen uommAD fq Jaqeayserg Jo ysTTyoeyO SUT IBUC IOS °TTI Staeh ‘sueTuUNAs snj.oUTpoTdy ST rqejoods BuojpSooyTa WMUGSCIGTYo BioTs0suAy Sepodides Buporeg “Snaetos snaeidoipey sTjO[ ese STmodST ‘ST tangy StTuodeT Snityooioen STmodey snvTTouekds StTmodST snq 7 Aagqoueey) Seprompes Ssntejdcsomy ‘enjetnqound snierdototh STUTIJe STSnquey ‘enqeqou Ssnitnoung snutaks SseposqrTtitog STIEATTO SNISTHCT Ta SepTou Shanromy ‘STTeyeu SnainTouy snyejtound Sninpteyvor tinTemoue emo scdme5 ‘seToudad soteudeutg XeTTetA SoTeydourd STLeyonu snyyeusoqry ‘FueuByonG STdozz0N ‘Ent TSoupToa SstTdor oh ‘STsueryn, STdorqon Snisnued STdor oN ‘oTdaies snuradr5 TN {sesucs BSUOTSOxGy ‘OTdres sopotdiep MMuetTpedes Bucsarog sn}onpoad sneisostdey snmo iso .eTd sneasostdey aad ae fa ro o eo . . . ° ° e . e OMAN Ot INO hr ONAO MN OM ra fl amex, OT IT\uetog --- Page 8 --- T-U-e-g qooforg “)-q pue g-y sqap ees ‘AquNOD WOSMeTTTIM UT eucp yYaom a0g T-u-crd qoefcag ‘o-g pue [-y sqor aes ‘Aqunop Ted UT eucp YOM Jog 72a90N OT"ad geL yr gor (AQ,unGD wWeTTH) yeeap Aysnag OT-a acer qr V Gor (Aqun0D WeETTN) TeaTY Tetaqed ueg Of-ad ace q-V gor (Aqun09 jouang) Jeaty Tetzaqep ueg yyzon 6-a ace C-y gop (h4unGD WETTH) Teaty eT49tT7 6-a gor f-y gor (setyuncD jauIng pue seseduey) Taaty seseduey satoedg Jo setzcaueautr SXdAING oTseg TOATY d-9g uoTsey SOVNIVEC MATEY GILGIT st rae owxN gi a sen FANN Lavy9@ x m We ~~ mes ® rade NYS HLIOV r ne * voausen $ ‘vigor naar = Sway TEVA -~ el yoL7id’ ayv7 ae a ee Q pue @ - SUMO TL @ ~ suot1e1¢g uoTIOETTAO pue Asarng ie ~ suctqyerg Aaamng ¢pusseT