TPWD 1960 F-5-R-7 #592: Inventory of Species Present in Lake Colorado City near Colorado City, Texas

Msrion Tools Coordinator Report of Fisheries Investigations Inventory of Species Present in Lake Colorado City Near Colorado City, Texas by Lawrence S. Campbell Project Leader lingell—Johnson Project FeS-Rh7, JEb 3-27 April 16, 1959 - April 1, 1960 H, D. Dodgen - Executive Secretary Texas Game and Fish Commissiem Austin , Texas 'Kbnneth c. Jursens and William H. Brown Assistant Coordinators- A B S T R A C T lake Colorado City is primarily to provide cooling water for a Texas Electric Service Company power plant. The lower half of the lake, where the power plant is located, is prohibited to public access. A.circulation effect produced by the intake and expulsion of water through the power plant resulted in unique thermal and hydrological conditions that were found to be attractive to gizzard shed and channel catfish. Fortybthree gill net collections were made at thirty-seven stations and 819 fish were captured. These populations were dominated by Channel catfish (38.83 percent) and river carpsuckers (2h.05 percent). Twelve seining collections were made and these data together with netting data established knowledge of the presence of seventeen species of fish from nine families. Although it is known that sampling is not yet adequate to provide sufficiently complete information on the lake's fishery resource, a continuation of this 30b is not recommended. Other work on the reser- voir will be included in future resurvey work. The production of fish in Lake Colorado City appears to be excel- lent. The fishing reputation is good, creels indicated a successful harvest, and no management effort is needed or practical at this time. It is recommended that future resurvey work include additional sampling of the fish pepulations, that further study of the thermal and hydro- logical conditions and their attraction or repulsion tendencies to fish be made, and that all possible assistance be afforded to prevent further encroachment by trespassers into the restricted area. Job Completion Report State of TEXAS Project No. F~5mR~7 Name: Fisheries Investigations and Surveys of the waters of Region fiuB. ' JOb No. B~27 Title: Inventory of Species Present in Lake , . Colorado Cityz near Colorado City, Texas. _ W Period Covered: April 162 1959 w April 1: 1960 PROCEDURE Thirty-seven gill net stations were selected and note were set in such a manner to permit part of the resulting data to be comparative of the basic ecolOgical in» fluences on the resulting catch. All stations were netted at lease once and dupliw cate netting at six stations in the restricted area of the reservoir permitted a comparison of summer and winter sampling. However, only winter netting data was Obtained for the unrestricted portions of the lake.. It was proposed in the planned procedure to set hoop and fyke nets in such a manner as to provide data on the attraction influence of the water being released -from the steamnelectric power plant. However, the force of the current was tee great to permit this type of sampling. Experimental nylon gill nets l2S-feet long, Safest deep, and made up in 25~foot sections were used. Mesh sizes for these nets increased progressively in each follOWw ing section, at onemhalf inch intervals, beginning with a onewinch square mesh section and terminating with a threeeinch square mesh section. Fortymthree sets were made during the period. Seining was done more or less in accordance with what the gradient and bottom Obstructions would permit. For that reason systematic collection-of data by seining was impossible. Twelve locations in the lake permitted limited seining collections. ago weighed, measured, and sexed- This work was done in the field. Stomachs and other organs that were needed for laboratory examination were preserved in 10 percent formalin solution, and specimens not readily identifiable in the field were simn ilarly preserved for laboratory identification. FINDINGS -Lake Description Reservoir and Dam a Lake Colorado City is situated on Morgan Creek, a small tribun tary of the Upper Colorado River in northncentral Texas. The dam was built in 19h9 by the Texas Electric Service Company to provide a supply of cooling water for the steammelectric power plant constructed at the same time on the shore of the lake. The dam is five miles southwest of Colorado City and one and five-tenths miles above the confluence of Morgan Creek. The reservoir area is owned by the power company. Reservoir Ca acit _~ The capacity of the reservoir at service spillway level is . 31, 850 acremfeet and the corresponding surface area is 2,030 acres. The lake is about three and onewhalf miles long and two miles wide at the dam. Since its con- struction the reservoir has not spilled. Imgoundment and watershed m The dam is rolled-earth construction and approximately , 00 feet long and 5 feet above stream bed. .The drainage area of Morgan Creek above the dam is 267 square miles. Average inflow (two years measurement) is how tween 13.t and 17.3 cfs. For periods of as long as several months inflow is prac» tically nil and the above figures may be somewhat misleading for that reason. Climatology The climate of the Colorado City area is semi-arid. The average annual temperaw ture is about 66.20 F. Normal rainfall is 19.8 inches and average wind velocity is 10.h m.p.h. Approximately onemfourth of the annual rainfall occurs in April and May. Geology The general formations for the contributing watershed that lie about_30 to #0 miles below and southeast of the Llano Estacado cap rock, are dominated by groups from the Triassic and Permian periods. The Dockum group, along the eastern edge of the escarpment in Borden, Scurry, Howard, ananitchell _counties, has a thickness of from 300 to MSO feet and consists largely of dark-red clay with interbedded layers of gray, crossebedded sandstone, and coarse sandstone conglomerate. The sandstone is micaceous. The lower part of the Dockum group, near Colorado City, in Mitchell county, though predominantly red clay, contains numerous beds of massive gray crossm bedded sandstone. Outcropping of the Dockum group occurs in the stream bed of Morgan Creek. Soils are clay and sandy looms. Utilization The primary purpose of this reservoir is to provide water for cooling the thermOwelectric plant located.near the dam. Water is withdrawn from Lake Colorado - City at an intake on the north shore, off the peninsula, and is pumped to the plant where it is used for cooling. The water is then returned to the lake through two canals. The Canals discharge into the reservoir nearly one mile distant from the plant. Returning water flows over a weir and falls freely into the reservoir. “.3... The reservoir also provides municipal water for Colorado City, although this is a minor function when quantity of water consumed is considered. The upper half of About 175 privately owned cabins are located on the lake's shores. A public park is maintained on the north shore by Colorado City. A recreation charge (used to maintain access roads, docking facilities, the public park, and to pay the lake patrolman) is levied and collected by the city. Twentwaive cents for a day per» mit and three dollars for an annual permit is the current charge. Fees collected from this source during 1958 (about $10,000), exceeded the sum paid by the city for the water consumed in municipal use. Fishermen are the primary and most numerous recreationists. The lake has had a favorable reputation for fishing. The lower half of the lake, or the restricted area, is an important resting area for waterfowl and the aesthetic value of this bird life is of unmeasured, but considerable importance. ' ' Thermal and hydrological Conditions_ - e following data and discussion are included because much of this dataais unavailable for other reservoirs within the region. For that reason this informs: tion may be used as the only general indicator available for this region. The minimum temperature recorded for the.outflow of water resentering the lake from the plant was 8 degrees 0., or about h6.4 degrees F. The maximum temperature for the outflow was 36 degrees 0., or 96.8 degrees F. Thus, it would appear that the general tendency of this circulating effect on the restricted area of the lake, which is over onemhalf the total storage, was to reduce extreme temperatures during the winter and to increase them during the summer. The possible effects of this condition upon fish life will be taken up later in this report. The effect of the addition of this_heat from a power plant on the thermal structure and evaporation rate of.Lake Colorado City was studied intensively by the U.S. Geological Survey Service during 195h.and 1955. The results were published by the United States Department of Interior in 19583' The following is a summarizes tion of that study. - .1... Figure l . Lake Colorado City near Colorado City, Texas } COLORADO CITY Texas Electric Service. - S ram Electric Plant Steam ilectric Plant Discha-ge Canal c3" - ‘ Scale in Miles m5:- Figure 2 ~ 9:9 _ ._ 9139 July 19511 Aug. 195 ' ' ' Sep. 195 """ Oct. 195 —' Nov. 195 ' Dec. 95 I ' Jan. 1955 Feb. ' April 955 ‘ 11.3.1955 June m 1955 ' ' ' Aug . 19 55 ' -19_.-55 _ . _ _ . 19.. Ai. an. Mate 00.91999 Ci __Iake.o Ave Air . __ . . _ ._ _. . _ . . __ . __ . _ _ _ . Our-.1919... _ __ -6- Evaporation rate normally would reduce the lake level by about 85 inches. The thermal increase brought about by the circulation of the water through the plant, resulted in 93 inches lost by evaporation, or an increase_of about ten percent. The average change in temperature in the affected area was about 1.6 degrees C., or 2.89 degrees F. The difference in temperature of the water entering the plant and that immediately surrounding the outflow'below the weirs was usually about h.6 degrees C., or 8.28 degrees F. (Figure 2). The upper portions of the lake were not affected to any measurable degree. Although temperatures were higher in the lower lake in the winter, they were apparently the same in the upper and lower lake during the summer. The increase in surface evaporation produced by this heat was about 910 acrewfeet of water, or about the amount that was consumed by Colorado City for municipal purposes. A comparison between average lake temperatures, as determined from thermal surveys,and plant intake water temperatures indicates that water was withdrawn from all levels of the lake above the pump intakes. The degree of thermal influence of the circulation of the water through the plant is directly related with the Quantity of water within the lake m the less water the greater the heating effect and inversely, the greater the quantity of water the less the total influence. Hydrology e As shown in Figure 3, Lake Colorado City is somewhat more stable than many of the reservoirS‘within this region of the state, and this favorable circumm stance is reflected in its fishery populations as discussed later. However, it is relatively certain that the late spring fluctuations would prdbably have adverse influences for specific years, and that the previously described thermal influences, accompanied by reductions in water level during the hottest part of the year, could or might be detrimental for short periods of time. water Quality water quality for Lake Colorado City may be generally described as shows aver» age for the region and is particularly superior to the waters of the Upper Colorado River, only 1.9 miles below the dam. Examples for the two would be about as follows: A. Lake Colorado City Solids pH Alkalinity Chlorides Sulfate hh2 p.p.m. 7.8 126 p.p.m. 78 p.p.m. 10h p.p.m. B. Upper Colorado River near Colorado City Solids pH Alkalinity Chlorides Sulfate 15,530 p.p.m. 8.2 1,000 p.p.m. h,500 p.p.m. 900 p.p.m. Other work indicated that theretere no oxygen deficiencies or excessive diam solved carbon dioxide during the inventory. However, this type analysis was not done during the extreme summer months when it might easily‘be most likely to take place. Turbidity at the upper lake stations was usually from 8 to 1% inches and no record of turbidity greater than 38 inches was made near the dam. Aguatic and Shore Vegetation Bullrushes, 591:3DS.EE:: are abundant and to a degree prohibit access to portior" of the upper reservoir. Muskgrass, Chara pp}, and Sagittaria are also present in limited concentrations. Vegetation is not regarded as a prdblem of importance at this time. - ”Te. 1.. 1.. 991999 . :phate. . I_Elevationu;Ft.;___YolumeJhcre_Ft.__ Monthl Fluctuation Ft._ Fluctuation Vol 6110 AF 1,150 1,350 800 . _ FiSLPd ul-a’fiions The production of fish populations in Lake Colorado City appears to be excellent, and game fishwrough fish ratios are more favorable than for most of the area reservoirs. The existing populations of undesirable species constitute a dormant threat to future production of game species for sportsmen. The ability of river carpsucker,.Carpiodes carpio, and carp, Cyprinus carpio, to expand'to overwhelming dominance has been fre» quently demonstrated in the regionis public waters. The occurrence of questionable species as freshwater drum, Aplodinotus runniens, and gizzard shad, Dorosoma cepedianum, is not regarded as undesirable. W999 011.9919’99 9f F1911 1’9 Lake 0919999 LEPISOSTEIDAE 9 Cars Lepisosteus osseus m longnose gar. Not taken in netting or seining but actually observed in several localities. ' CLUPEIDAE m Earrings Dorosoma cepedianum a giszard shade Abundant but not indicated as ex= cessively numerouso Apparently concentrated to some extent during the summer months about the discharge weir from the power plant, possibly for spawning activity CATOSTOMIDAE m Suckers *- Carpiodes carpio m river carpsucker Common and abundant throughout the reservoir, High average coefficient of condition, the most significant aspect of this pepulation is the question of what apparently controls or limits their increaseo CYPRINIDAE w Minnows Cyprinus carpio e_carp, Common but not numerous in the sense of concenn trationsa Apparently more numerous in the upper reservoir areaso Notrdpis lutrensis m redhorse shinero Common and numerous in specific localities, possibly the most abundant minnow in the reservoiro Pimephales vigilax w parrot minnow. About as common as the redhorse shiner and found throughout the reservoirs AMEIURIDAE m Catfishes Ictalurus punctatus a channel catfish° Common and abundant throughout the reservoir, but particularly numerous at the outlet of water from the power plant during the summer months, gylodictus olivaris - flathead catfish° Common but not abundant; also, found more abundantly near the dam. ' CYPRINODONTIDAE m Killifishes and topminnows _ Fundulus kansae w plains killifisho Common and abundant in the upper reser- voir areaso' Gambusia affinis a mosquitofish, Common and occurring wherever protection 'was affordeda SERRANIDAE a Basses Roccus chrysops m white or striped bass. Common but not excessive in any portion of the reservoira LMost common near the dam within the restricted areao CENTRARCHIDAE w Black basses and sunfish - Micropterus salmoides e largemouth basso Common, numerous, and in excellent condition, Taken in all size classes and particularly numerous when the seining conditions are taken into account, Chaenobryttus gulosus a warmouth bass, Rare but taken at three seining collection stations, Lepomis cyanellus a green sunfish, The most common sunfish in the reservoir but not particularly numerous. Lepomis macrochirus n bluegillo About as numerous as green_sunfish, but possibly more widely distributeda -~ Pomoxis annularis m white crappieo Common but not abundant° No evidence of stuntingo SCAENIDAE m Drum Aplodinotus grunniens w freshwater drumo Common but not numerous, evenly distributed throughout the reservoiro ~