TPWD 1962 F-6-R-9 #802: Resurvey of Lake Corpus Christi, Job Completion Report, Federal Aid Project No. F-6-R-9

JOB COMPLETION REPORT As required by FEDERAL AID IN FISHERIES RESTORATION ACT TEXAS Federal Aid Project No. F-6-R-9 FISHERIES INVESTIGATIONS AND SURVEYS OF THE WATERS OF REGION 8-B Job No. B-Zl Resurvey of Lake Corpus Christi Project.Leader: Alvin G. Flury H. D. Dodgen Executive Secretary Texas Game and Fish Commission Austin, Texas Marion Toole Eugene A. Walker D-J Coordinator Director, Program Planning March 23, 1962 ABSTRACT In order to furnish the City of Corpus Christi with a more depend- able water supply, a new dam was built on the Nueces River just below the old dam in 1958. Surface elevation of the lake was raised from 74 to 94 feet above sea level. The old lake had been surveyed from 1953 to 1955 and a survey of the "new lake” was carried out in 1961. The principal change in water quality was a significant reduction in turbidity with a resulting improvement in fisheries conditions. Game fish increased from 39 per cent by numbers in netting collec- tions made in the old lake to 47 per cent in the new lake but showed slight decreases from 31 per cent to 29 per cent of the total weight. This is believed due to the three most common rough fish species'attaining a greater average weight than most game fish and to the large numbers of young catfish (usually the heaviest of the game fish) being taken° Overall, the gill net catch from the ”new lake” appears to indicate a 15 per cent increase in total fish production over the old lake. Recommendations are made to continue periodic investigations of the lake to determine if management work will be required in the future. JOB COMPLETION REPORT State of Texas Project No. F-6nR-9 Name: Fisheries Investigations and Surveys of the Waters of Region 8-B Job No. B-21 Title: Resurvey of Lake Corpus Christi Period Covered: January 1 - December 31, 1961 Objectives: To determine the present status of the fish populations of Lake Corpus Christi and any other physical, chemical and biological changes in the lake that have taken place since the last fisheries survey. Techniques Used: Fish populations were regularly sampled at monthly intervals from 16 gill netting and 7 seining stations distributed over the lake. In addition, water samples were also collected at monthly intervals from four water sampling stations (Figure 1). Fish taken in nets were collected with 125- by 8-foot experimental gill nets consisting of five 25~foot long sections of square mesh webbing, ranging from 1- to 3-inches in % inch intervals. Seined specimens were collected in a 4w by 20—foot nylon seine with a % inch mesh. Findings: Introduction Old Lake Corpus Christi, then named Lake Lovenskiold, was first formed in 1930 by a dam across the Nueces River about five miles SW. of Mathis. Failure of the dam caused the loss of the first lake and a more permanent structure was completed in 1934. This lake originally covered some 5,500 acres and had a volume of 55,000 acre-feet. By 1948, according to a Soil Conservation Service report, the lake had lost over one-fourth of its volume because of siltation. The need of a larger water supply for the City of Corpus Christi brought about the formation of the Lower Nueces River Water Supply District. Engineering surveys showed the site of the old lake to be most feasible for the impounding of a larger lake and a new dam was completed in April 1958 about one mile downstream from the old dam. hum“. ...o mow—«mzozh fillJ.|l.I«l.lIl..l|—I|_ u4¢2<m KER? ...... m n. a. m o m o mzozksm oz_z_um ...... mm ”4400 mzopdkm 02_._..—.U2 ...... w 3.2: Czaoosll 8353:; 83m E3283 ::::::: wraixexllall mZOFSuFm haikma himnm mmhd.‘ cult mwumnz £9304 m1... mom wad: mOFO—E Jaime. no @254”; Z ...—.mEro msmmoo mg“: no n32 ...OE \ \.. \ \ \ \ an m: \ x \ 9.854 2% _ 9. II I: \ \. a xm... \ \ \ \ \ x x \ - 1-x \. - u I .. ‘ - \ Q ¢ .. (II\\ \ was. 090.7 can...» \ 09 #9 one on a: o» ..., 1 9352.: the. 63...: n a rwzzrim ... .rhzaoo xao m2.— xmmmu diam—Ed». 34.3mm 2. a can on... x”: .../z afiMfimon on? _ _ \ n . . a 6.3.5.... . .. 8:34.. .. .. . . .. redo: .. osmwmfi K, 2848 . \\\ ...... ......I \u |. If! m. A p— . I a m A. ._ X r w o<om.:<m .., . X n ...... 0:64.. .. X «x \ 252.58 . 26¢ a... .X {.233 \ ... i238 ...: .. .mjms ...... K .3 a: o... awameri; mm ..-... Physical Description Although the new dam was designed to maintain a lake surface elevation of 94 feet above mean sea level, the gates were left down so that the surface is presently maintained at 88 feet. This was done in order to prevent interference with some old oil wells. At an elevation of 88 feet m.s.l. the new lake now covers approxi— mately 16,730 acres and has a capacity of 185,920 acre-feet. Because of steep caliche hills surrounding the lower part of the lake, the 14-foot rise caused little change in this area; however, low islands in the middle and upper parts of the old lake were flooded and the impounded heads of several arroyos were extended in length. Above Collins' Islands of the old lake, the terrain flattens considerably, especially on the east shore, and here, a large area was flooded by the new lake level. The banks and lowlands along the old lakeshore above Lagarto Bridge, which is now flooded and replaced by a ferry, and about four miles upstream were flooded upstream from that area. The lake in the Nueces River channel is still contained by the natural levees. Water level fluctuations, summarized from records on file with the Lower Nueces River Water Supply District, show that the total variation during 1961 amounted to only 3.01 feet. A low of 86.20 feet m.s.l. occurred on June 8 and a high of 89.21 feet m.s.l. was recorded on June 28. These variations in water level had little apparent effect on the fisheries and were insignificant compared to the almost 8-foot fluctuations in level which occurred in the lake prior to completion of the new dam. Because the larger volume, due to the new dam, allows river borne silt to settle farther up the lake, the water is not nearly so turbid as it once was. Clearer water, together with an improved local economy, has resulted in considerable develOpment of the lake shore as housing and resort subdivisions. Where, prior to the new dam, the lake area contained only two or three develop— ments with a total of about 100 private homes, and most of them on 15-year land leases from ranch owners, there are now more than 400 homes on the lake shore in 15 or more subdivisions. This develOpment is continuing and will increase when the lake is raised to the 94-foot level. Chemical Analyses Water samples, collected monthly from four regular stations (Figure 1), were analyzed for dissolved oxygen, carbon dioxide, phenolthalien and methyl- orange alkalinity, turbidity and pH (Tables 1 through 4). In addition, records were made of temperatures at the depths from which samples were collected. The most noticeable change in water quality of Lake Corpus Christi during 1961, as compared with records of water quality from previous years, was in turbidity. Prior to the building of the new dam, turbidities of less than 25 p.p.m. were never recorded. In fact, most readings ranged from 40 to 60 p.p.m. and some were far over 100 p.p.m. During 1961, at Station A, almost 75 per cent of the turbidity readings were less than 25 p.p.m. Only two were over 100 p.p.m. and these were for samples collected at the bottom in 60 feet NH.0 00.0mfi 00.0 na.mH an.N 00.00 00.0 00.NOH 00.0 00.0 00.0 00.00 00.0 0m.~mH 00.0 00.N 00.0 00.00 00.0 mm.qu 00.0 N¢.H 00.0 00.00 00.0 00.00H 00.0 00.0 00.0 00.0h 00.0 00.ndH 00.0 00.0 N0.0 00.0w 8» r nmsu mmma # Gmxmu quu 02 any .5. naaa0_suaeunn=a Aanav .o.z Asamv nusem suuunfia Ha assay 00 —————————_ Asmav suaeaanss Asaav .o.z Aaaav ausea suunuflm H4 Asaav 00 Ana RV NO .mo m- Aaaav suaannnas Asaav .o.z nauav Juana .00 suaaaflaeaa Aaaav moo .00 cm 00 Asaav suueaauas Aaaav .o.z maamv pause .0m suuuaamxHa Aaaav museuppse mauav .o.z namdv nuIna .0N suanaamena —————““—_ nfinav No .09 Hfiua< zonmz hnmnnnmm mpm=500 mammamcd . uwmm . ma spawn .H0mH .0 noaumum .Humansu msnuoo mqu .mwamamm uwuwa mo mwmmfimnm Hmoaauso .H wanmw Asaav sunuupnny Aaaav .o.z Aaaev au-ea suaaaflmenm Asaav sausagusa nsmav .o.z “sang au-sa Sundae? Asaav Nov Eaawxmz Enfiwnfiz Hmnfiwqu umnfimboz HwDOuoo umnfiwunmm 00.0 00.00 H0.00H 00.0 00.0 00.0 00.00. 0.0 00.00 00 “N .00.0. .0.0 00.00H 00H 00 00.H 00 0 00.0 0.00 0 00.0 0.00 0.0 00.00 00 _ 00 00.0 00.000 00.0 00.0 00.0 00.00 00.0 00.00H 00.0 00.0 0.0 0 00.0 0.0a 0.0 “00.Hm_ g0 A-0 A-0 Aav T0 Agv A10 0.0 00 00 00 00 000 000 000 000 0 0 0 0 0.0 0 0.00 0.00 0.0 0.0 0.0 0.0 00 00 00 00 0.0 0 0 0 0.0 0.0 0.00 0.0 000 H0 00 ”N0 .000 0 .>02. .000 i .0000 _. .0 i .0000 .0 0000000 .00000. 00 00H 0.00 0.0 00 .3 00 000 0.00 0 0.0 050000 @004 .meQEMm 00003 00 wflmhamnw Hmofiamsv .0.0 0.0 00 00 000 000 0 0 0.0 0.00 0.0 0.0 00 00 0.0 0.0 00 00 000 000 0 00 0.00 0.0 0.0 i 0.0 00 00 .0.0 mm 000 0 0 0.0 00 0.0 00 000 0 0 0 0.00 0.0 00 00 . H07... 00000“ 00 00H 0.0 0.0 0.0 0.00 00 m0 _c>c> .. 3 ' NChN .000 .000 .N 00000 Chemical analysis of. water samples, Lake Corpus Christi, Station C3 1961. Table 3. .0000 00 3000000 “Humflufiu msmHoo @000 00000500 00003 00 mfimhamfim 00008000 00 maan Own? L 0"“;fo VVVMI 3 fl 5 I"; fa'N (“MS v V V II an 3 $ VV vvv Lm-k 3%“.th of water after the influx of flood waters into the reservoir (Table 1). Less significant changes in water quality occurred in general, though slight, reductions in water temperatures and pH. This is most probably due to the increased depth and volume of water in the reservoir. Generally speaking, dissolved oxygen and carbon dioxide levels harmful to fish life were not encountered except during the late summer and fall months and these were usually restricted to water at 20 or more feet below the surface (Tables 1 through 4). Only twice were less than 3.0 p.p.m. of dissolved oxygen found at the surface. This was at Station C at Dinero Bridge, in the impounded channel of the Nueces River, during July and November (Table 3). The reason for these low oxygen records was not readily apparent. It is clear that the higher lake level elevation, brought about by the new dam, has materially improved the habitat for fish life in Lake Corpus Christi since 1958. Undoubtedly raising of the gates on the new dam to the 94-foot elevation to raise the water an additional six feet would decrease the turbidity even more and further improve fishing conditions, especially fOr largemouth bass. Fish Collections Netting - A total of 5,486 fish of 21 Species were collected in gill nets from Lake Corpus Christi during 1961. In all, a total of 203 nets were set at the 16 netting stations during the year. All of the nets used at the stations were set at the surface except at Station 1 where each month one net was set at the surface and an additional net was set on the bottom_in 65 feet- of water. Of the total fish taken, 2,587 were game fish. These included: channel, blue and flathead catfish, white and largemouth bass, warmouth, blue- gill, redear and longear sunfish, and white and black crappie. The other 2,899 specimens were classed as rough fish and included: alligator, Spotted and longnose gars, threadfin and gizzard shads, smallmouth buffalo, carp, freshwater drum and Rio Grande perch (Tables 5, 6, and 7). Although the species list for Lake Corpus Christi in 1961 varies some- what from what it was in 1953 through 1955 (see job completion reports for Jobs A-3 and B-3, D.J. Projects F-6-R-l and F-6-R-2) the game fish-rough fish ratio of the fish pOpulation shows considerable improvement. Netting results in l953~l955 indicated a game fish-rough fish ratio of 39.7 per cent game fish to 60.3 per cent rough fish. Presently the ratio is 47.16 per cent game fish to 52.84 per cent rough fish. This apparent increase in abundance of game fish is largely due to reductions in the relative abundance of freshwater drum and small- mouth buffalo and to the increases of white bass, which were not present in 1953-1955, and of largemouth bass. The 5,486 fish taken in nets weighed a total of 5,867 pounds (Table 8). Of this weight, game fishes comprised 29.4 per cent and rough fishes comprised 70.6 per cent. Opposed to the marked rise in numbers of game fish in the lake since the completion of the new dam, the relative weight of game fish has de- creased somewhat. This is due to the fact that three common rough fish species