TPWD 1963 F-5-R-10 #882: A Preimpoundment Survey of Twin Buttes Reservoir and Its Included Watershed

JOB CQMPLETION REPORT As required by FEDERAL AID IN FISHERIES RESTORATION ACT TEXAS Federal Aid.Project No. F—S—R—lO FISHERIES INVESTIGATIONS AND SURVEYS OF THE WATERS 0F REGION l—B Job No. 3—33 A Preimpoundment Survey of Twin Buttes Reservoir and Its Included watershed Project Leader: Lawrence S. Campbell J. Weldon watson Ereoutive Director Perks and Wildlife Department Ans tin, Texas Narion Toole Eugene.A. Walker D—J Coordinator Director, Program.Planning May 8: 1963 ABSTRACT Fish populations of Twin Buttes watershed were surveyed by making 81 gill net collections and 18 seining collectionsa Investigations also determined plans for structures and the Operational procedures for the project, Essential ecological data for streams was also obtained, and watershed usage and develoP- ment determined, All four major tributaries of the watershed are dominated by problematic fish, None of the tributaries have less than 93 per cent problematic species by number or less than 88 per cent problematic species by weighto The lack of productivity in usable game fish is primarily the result of excessive with- drawals from streams and from sub-surface aquifers for irrigation purposesa This exploitation of area waters results in extreme fluctuations in stream vol- ume and flow, and native fish are no longer controlled through natural phenome- na, The fishery problem is further complicated by excessive reproduction and ‘ stunting of some game fish, by insufficient or failure in reproduction by pri- mary control species such as largemouth bass and channel catfish, and by the inadvertent introduction of many exotic or invader species, The only practical means of reducing the problem, and improving game fish production, is by dras- tically reducing existing fish p0pulations through the use of chemicals and subsequent restocking with fish desired, The completion of this work is urgent, since treatment costs will probably be greatly increased within the next few weeks, If the required renovation work is completed for Twin Buttes, future reconnaissance investigations should include a detailed study of downstream waters with the view of continuing the watershed renovation program to its logi- cal conclusion. JOB COMPLETION REPORT State of Texas Project No, F-S—R-lO Name: Fisheries Investigations and Surveys of the Waters of Region l-B, Job No. B-33 ‘ Title: A Preimpoundment Survey of Twin Buttes Reservoir and Its Included Watershed e_Februar 28. 1963 Period Covered: _March_l _l962 Objectives: To inventory fish populations of the included watershed that have not been previously surveyed and to resurvey impounded portions of the Middle and South CondhaRivers, To examine plans and structures to determine if such construction can be used to provide the means of evolvement of a watershed development program. To obtain basic data on hydrology, water usage, pro- posed recreational facilities, and other conditions or circumstances that may materially affect the fishery resource or its harvest by the public. Techniques Used: 1. Eighteen seining collections and 81 netting collections were made at 2. Routine data recorded for fish captured by gill nets included relative abundance, distribution, stomach contents, and coefficients of con- dition, Where determined, spawning success and other functions of propagation were also noted, 38 Other investigations to provide basic data for stream areas included a study of water quality, Turbidity, dissolved oxygen, dissolved car- bon dioxide, pH, temperature, hardness, chloride content, flow and bottom types were examined, 4. An examination was made of the t0pography of the watershed and of the reservoir basin, Principal types of aquatic and shoreline vegetation and other aquatic life were noted, 5. Responsible authorities were contacted, and information was obtained on public access, planned recreational facilities and on other cir— 6. In the course of survey work endemic and/or rare flSh were captured and relocated to assure their surv1valo Results: Basic and Background Information Watershed and Climate The South and Middle Concho Rivers are two of three principal tributaries for the Concho River, of the Colorado River System in Texas. The 2,687 square miles of contributing watershed begins in the Edwards Plateau to extremities. Topographically, the area is rolling hills, plains, and river valleys. Vegetative cover is mesquite-grassland association for upland areas, and Pecan-Oak timberland along streams. Grazing is the pri— mary land usage, but fertile loam soils of the plains are highly productive farm lands when sufficient moisture is available. The climate for the Concho River watershed is semi-arid. Annual rainfall, based upon records for 41 years, is 21.99 inches. Heavy rainfall is usually spasmodic and, as a result, stream flow is subject to great fluctuations. Precipitation of .54 inches or less does not result in run-off, and during drouth periods 1.54 inches of rainfall may occur within 24 hours without significant increase in stream flow resulting. Evaporation averages 72 inches per year. Flooding occurs on an average of once in each six year period. ' or early fall. In the past flood damage to the city of San Angelo, located at the confluence of the three principal tributaries, has been extensive. A U. S. Corps of Engineers flood control structure, San Angelo Reservoir of 650,000 acre-feet capacity, was completed in 1952 to contain flood waters from the North Concho River. Lake Nasworthy, completed in 1930, is a 12,500 acre-foot reservoir and is located .3 miles below the confluence of the South and Middle Concho Rivers. This latter reservoir was designed and is operated solely for municipal water storage, and does not provide adequate protection from flood waters. This history of damag— ing floods, the most recent occuring in 1957 and 1959, resulted in federal approval and congressional appropriation of funds for the construction of additional facilities to control flow from the South and Middle Concho River watersheds. Twin Buttes Reservoir Twin Buttes project is constructed under the auspices of the Bureau of Reclamation. The reservoir will serve to provide flood control and as a source of water for municipal, industrial and irrigation purposes. The impacted earth dam that will create the reservoir is eight miles long. Two basins are connected by an equalization channel. The lesser basin is located on the South Concho River and is capable of impounding 6,200 acre- feet of water before flow, through the equalization channel, effects a union with waters of the larger basin on the Spring CreekeMiddle Concho River watershed. No outlet structures are included in portions of the dam that divert flow from the South Concho watershed. Four concrete equipped with suitable release facilities, are installed in the vers the old stream bed of the Middle Concho River and Water released through these outlet conduits, dam where it se creates the larger reservoir basin. structures enters Lake Nasworthy, the control reservoir, and is redirected by additional structures into the irrigation canal system or to facilities associated with the city water supply. Due to basin topography and ex— cavations created in obtaining earthern materials for the construction of the dam, the Middle Concho-Spring Creek basin is capable of impounding 4,800 acre-feet of water before flow can be released through outlet struc- tures into Lake Nasworthy. The canal system is made up of 16 miles of primary canals with 39 miles of laterals and will supply water for irriga- tion of 10,000 acres located in the Lipan Flat area, 10 miles east of the city of San Angelo. Twin Buttes will contain 51,000 acre-feet at dead storage, 164,900 acre-feet at conservation pool level, and is capable of impounding 600,000 acre-feet. The maximum area of the reservoir is 23,000 acres. San Angelo Water Supply Corporation will control water releases and will ultimately purchase the structures. However, releases may not be made prior to the impoundment of 40,000 acre-feet. The average quantity 6f water that will annually be contributed to storage is 43,000 acre-feet. Of this quantity 25,000 acre-feet will be allocated for irrigation. Twin Buttes is also a secondary water supply for the city of San Angelo. In compliance with existing city ordinances, Twin Buttes will not contribute to industrial or municipal usages unless or until San Angelo Reservoir is virtually depleted. Recreational Potential and Plans Twin Buttes Dam is within nine miles of the center of San Angelo, a municipality of 64,630. Within 50 miles of the reservoir are six addi- tional counties, predominantly rural, whose combined population is 27,428. According to a public use plan, prepared by the National Parks Service for Twin Buttes, approximately 92,058 people reside less than 20 miles from the reservoir. The estimated day-use for Twin Buttes should be approxi- mately 63,406. Sixteen additional counties are near enough to the new reservoir to contribute normal weekend and overnight visitation as well as occasional trips completed in one day. The combined 23 county popula- tion exceeds one-third million. Tom Green County is expected to have a population of 100,000 by 1975. By the year 2010 the corresponding popula- tion projection is 145,000. The seven county area referred to above as within day-use proximity of Twin Buttes, according to the same estimates, will have a 1975 population of 126,300. Projected totals of the other neighboring counties, whose peOple will add to Twin Buttes visitation, show comparable increases. A detailed basic recreation development plan has been drawn up by the National Parks Service, and required contracts between the Bureau of Re- clamation and the City of San Angelo are awaiting ratification. Funds to permit the completion of this program are expected to be approved by Con- gress. Facilities to be constructed include launching ramps, toilet buildings, access roads, picnic areas, camping areas, organized camps, a marina, a beach shore area, lodge developments, play fields, a golf course, and the supplying of utilities and services. An area is also set aside for residential deve10pment. In all, $1,698,600 is allocated and approved for recreational develOpment. Ecology of the Watershed The great variation of stream conditions makes general discusSion of tribu- taries difficult. For that reason the four principal tributaries are discussed separately. The South Concho River The southern watershed is primarily fed by Springs that flow from crevices in Cretaceous limestone. The primary springs, called Anson Springs, are located on the Ford Boulware ranch. These are the most stable springs on the Conchos.. Flow varied slightly from 12.2 c.f.s. to 13.2 c.f.s. during the study period. The water from these springs is semi—hard having a hardness of 220 p.p.m., but is much ”sdfter” than for most of the other stream areas. Findings indicated that pH was 8.2, chloride content was 27 p.p.m., and that water temperature was relatively constant near 730 F. The upper stream areas are clear, of unrecordable turbidity, and a variety of aquatic plants and microscopic bottom fauna abound. This relatively stable stream condition continues for a distance of approximately four miles until flow enters the county park at Christoval. Here turbidity in- creases to 38 inches and flow has been increased by the discharge of minor springs to 16 c.f.s. Christoval Dam creates a public reservoir and also serves to divert flow for irrigation. From immediately below this dam to Twin Buttes Dam, a distance of 16 stream miles, flow and water level are disrupted due to seasonal withdrawals for irrigation. The area irrigated by this means is about 400 acres. Additional springs tend to rebuild the stream, and the South Concho more nearly represents a native spring fed clear water association than does any stream in Region 1—B. Four major diversion dams that range in height from 3 feet to 12 feet normally pro- vide barriers to upstream movement of fish. Dove Creek For three miles, from the headwater Springs on the Charles Schreiner ranch to Guinn Dam, Dove Creek nearly duplicates the ecology of the upper por— tions of the South Concho. At the dam, water is diverted for irrigation purposes, and thereafter flow is drastically reduced and expanded as irri— gation withdrawals demand. The initial springs discharged from 9.83 c.f.s. to 6.66 c.f.s. during the survey period. Flow was increased to over 11 c.f.s. at Guinn Dam. Water quality for the upper permanent flow stream is similar to that of the South Concho, but turbidity increases more dras- tically downstream, beginning where large pools are created by impoundments on the XQZ Ranch. Turbidity is 28 inches in these pools and increases to 18 inches as the stream enters the reservoir area. Thereafter the stream is indolent and flow and water temperatures and quality are less favorable to fish production. Five diversion dams ranging in height from 6 to 18 feet are located between the reservoir area and the headwater springs. Except in periods of extreme flooding, these structures are effective bar— riers to upstream movement of fish. Over 600 acres are irrigated from Dove Creek annually. Spring Creek Beginning on the Reginald Atkinson ranch at ”mammoth spring” and terminating six miles downstream at Mertzon Dam, Spring Creek is permanent flow clear water association. Mammoth springs had the greatest discharge recorded for any spring on the watershed, 15.2 c.f.s., but exhibited variation of flow in receding to 9.6 c.f.s. before the end of the study period. The ecology of the upper stream area of Spring Creek is similar to that described for Dove Creek and the South Concho River. At Mertzon Dam withdrawals begin for irrigation of approximately 300 acres. Contributions from lesser springs maintain some permanent flow for over 17 miles to the dam at Boy's Ranch. This flow is subsurface in some locations, traveling through gravel deposits, but even this slight exchange and movement of water pre— vents stagnation to the degree experienced elsewhere in the lower reaches of the watershed. Nine dams ranging from 10 to 22 feet in height are located on Spring Creek, and except in times of flooding are barriers to upstream migration of fishes. Middle Concho River In times past, the Middle Concho River, like other tributaries of this watershed, was spring fed. However, for many years springs have not been individually significant and only rarely have their collective contributions been sufficient to result in surface flow. Seepage ground waters tend to restore pools during the winter, but these are drastically reduced by irri- gation withdrawals during the summer. No flow has been recorded for this tributary since September 1961. During the intervening time pools have been reduced to the lowest levels ever recorded, and much of the stream bed is dry. Fish ”die-offs” from oxygen deficiency are common, and for practical purposes the entire Middle Concho River may be regarded as be- ing a series of stagnant mud puddles. Basin Areas The water included in basin areas may be considered to be semi-permanent due to man-made circumstances. Stream pools were often pumped dry in ”wetting down” earth materials used in construction of the dam. Most of the game fish had already been “salvaged” by construction workers by the time the study was initiated. The basin areas had been cleared of timber and brush before sites for fish attractors could be selected. However, future arrangements include provisions for adding these facilities. Fish Populations Seining Collections lieved to be the best expression of findings from 18 seining collections. Thirty-four species of fish of 14 families were captured and identified. ated Checklist of Species of Fish Taken From the Middle Annot and South Concho River Watersheds Family: LEPISOSTEIDAE - Gars Lepisosteus osseus - longnose gar. Common throughout the watersheds. Most abundant in irrigation reservoirs and below such structures. Family: CLUPEIDAE - Herrings Dorosoma cepedianum — gizzard Shad. The most common and widely distributed species of the watersheds. Most fish captured were of a large size, and there was a notable absence of Spawning evidence. Family: CHARACIDAE - Tetras — banded tetra. Found only in clear water associations. Astyanax mexicanus he South Concho River. Also taken from Dove Creek Common but not abundant in t below Guinn Dam. Family: CATOSTOMIDAE - Suckers and buffalofishes lctiobus bubalus - smallmouth buffalo. Common but never abundant. No evidence of spawning. Carpiodes carpio — river carpsucker. Common and abundant throughout the water— shed. This species is regarded as the scourge of the Conchos, and dominates any turbid water association where it is found. Common and particularly abundant in the sh reproduced in areas where the Moxostoma congestum - gray redhorse. upper clear water associations. These fi Common and abundant in localities. Particularly turbid pool associations, and above the Cyprinus carpio — carp. abundant in the Middle Concho indolent, dam on the South Concho River. Common but never abundant. An invader Notemigonus crysoleucas - golden Shiner. or exotic introduction, but apparently not problematic. Notropis venustus - spottail Shiner. cularly numerous near Gardner Dam on the South Common and abundant in localities. Found spawning in the lower por- Notropis lutrensis - redhorse Shiner. Apparently more adaptable than most species. tions of Spring Creek. Dionda episcopa — roundnose minnow. Common and the most abundant species pre- sent in shallow—rapid flow-clear water associations. An invader or exotic in— troduction that apparently is gaining dominance over endemic species. Pimephales vigilax - parrot minnow. Common and abundant in the lower portions of the entire watershed. Particularly numerous below dams on Spring Creek. Family: AMEIURIDAE — Freshwater catfishes Ictalurus punctatus - channel catfish. Common but not abundant. Virtually no young discovered during survey work. Probably the most adaptable and widespread in distribution of principal game Species. Ictalurus melas - black bullhead. Common and very abundant in some Spring fed associations. Especially abundant at headwaters of Spring Creek and Cold Creek of the South Concho River. Pylodictus olivaris - flathead catfish. Common and widely distributed but 3 seldom numerous. Several natural Spawning sites were located on Spring Creek and the South Concho River. Family: CYPRINODONTIDAE - Killifishes and topminnows Fundulus kansae — plains killifish. Restricted to the Middle Concho watershed. An exotic introduction or invader. Family: ATHERINIDAE - Silversides Menidia beryllina — tidewater Silversides. in Dove Creek and the South Concho River. created by Guinn Dam. An invader that dominates localities Especially abundant in the reservoir Family: POECILIIDAE — Mosquitofishes Gambusia affinis - mosquitofish. Common in pools where flow is not prohibitive. Family: SERRANIDAE - Basses ,Roccus chrysops - white bass. Common in the lower reaches of Spring and Dove Creeks and the South Concho River. Extends its distribution up the Middle Concho River to the Len Mertz ranch. Irrigation dams may be effective barriers to upstream migrations by this Species. Family: CENTRARCHIDAE ~ Black basses and sunfishes Micropterus salmoides - largemouth bass. Common but not abundant. Micropterus punctulatus - spotted bass. Rare but found in mid-stream areas of Dove Creek and the South Concho River. Chaenobryttus gulosus — warmouth bass. Rare, but found throughout the watershed. Lepomis cyanellus - green sunfish. Common and abundant throughcmu;the watersheds. Stunted populations of these sunfish occur in the lower watersheds. Lepomis microlophus — redear sunfish. Rare, but widely distributed. An exotic introduction that apparently does not create a problem. Lepomis macrochirus é bluegill. Common, abundant and widely distributed. A problematic species through overpopulating and stunting. An exotic introduc- tion or invader. Lepomis megalotis — longear sunfish. Common and relatively abundant. Most common in the South Concho and Dove Creek in the upper stream areas. Lepomis auritus - yellowbelly sunfish. Common and relatively abundant. From the anglers' standpoint the most desirable sunfish in the Conchos. Pomoxis annularis — white crappie. Common,abundant and widely distributed. Re- garded as a problematic species. Only on XQZ ranch were crappie captured of sufficient size to provide sport. Not found in abundance in the South Concho River. Family: PERCIDAE — Perches and darters Common to all watersheds, but seldom numerous. Percina caprodes - logperch. Found in backwater pools. Etheostoma lepidum - greenthroat darter. Abundant in spring areas. Found as far downstream as the Christoval area on the South Concho River. Family: SCIAENIDAE - Croakers, drum and weakfishes Aplodinotus grunniens - freshwater drum. Rare but widely distributed._ More common in deep indolent pools with silty bottoms. Family: CIOEILIDKE-LCichlids Common in the South Concho River Cichlasoma cyanoguttatum - Rio Grande cichlid. and Dove Creek. An exotic introduction. Netting Results Data obtained through examination of 2,906 individuals captured by gill nets adequately expresses relative abundance of existing fish populations. Previously presented seining data is less reliable in establishing species occurance and distribution. All tributaries of the watershed are heavily dominated by problematic Species. Probably Dove Creek has more favorable game fish populations than do other waters, but none of the sub—watersheds surveyed have less than 93per cent problematic Species by number or less