Background to Fisheries Studies of the Lower Glutha River
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Background to fisheries studies of the lower Glutha River Fisheries Research Division N.Z. Ministry ofFisheries Agriculture environmental report no. 76 (1986) and Fisheries lssN 0111-4794 Fi sheri es Envi ronmental Repot^t No. 76 Backgnound to fisherjes studies of the I ower Cl utha Ri ver by M .J . Ha rvey D.J. Jel lyman Fi sheri es Research Di v'isì on N.Z. Minìstr^y of Agniculture and Fishen'ies Ch ri stchu rch Novembe n 1986 Fisheries environmental report no. 76 (1986) FISHERITS ENVIRONMENTAL REPORTS This report js one of a series of reports 'issued by Fisheries Research Division on important issues nelated to environmental mattens. They are i ssued under the f ol ì owi ng cr^i teni a: (1) They ane informal and should not be cited without the author's pe rmi s s'i on . (2) They are for limited circulatìon, so that persons and onganisations normally receiving Fisheries Research Division publ i cati ons shoul d not expect to rece'i ve copì es automati caì ìy. (3) Cop'ies wilì be issued initjally to organ'isat'ions to which the neport i s d'i rectly nelevant. (4) Copies will be'issued to othen appropriate organisat'ions on request to Fisheries Research Division, Ministry of Agrìculture and Fisheries, P.0. Box 8324, Riccarton, Chnistchur.ch. (5) These reports wiì1 be 'issued where a substantjal report is nequ'ired with a t'ime constraint, ê.g., a submiss'ion fon a tribunal heari ng. (6) They wi'11 also be issued as interim reports of on-going envinonmental studies for wh'ich year by yean olintermittent report'ing 'is advantageous. These i nten j m reports wi 1ì not preclude fonmal sc'ientjfic publication. ISBN 047703229X Fisheries environmental report no. 76 (1986) CONTENTS Page Summa ry 7 1. Intnoduct'ion B 2. Clutha River and Catchment i1 2.L Physicaì Description and Hydrology 11 2.L.I Geol ogy 13 2.I .2 La ke s 14 2.I.3 River and Major Tributaries L4 2.I.4 Fl oodi ng 16 2.1.5 Cl 'imate 16 2.2 Aquatic B'iology T7 2.2 .l Ve get at i on t7 2.2.2 Benthos 18 2.3 F'ish - Introduced Speci es 19 2.3.I Brown Trout 19 2.3.2 Rai nbow Tr"out 20 2.3.3 Bnook Char 2L 'i 2.3 .4 Qu n nat Sa I mon 2I 2.3 .5 Sp l ake 22 2.3 .6 Pe rch 22 2.3.7 Unsuccessful Intnoductìons 23 2.4 Fish - Native Species 23 2.4.I Lamprey 23 2.4 .2 Short-f i nned Ee I 23 2.4.3 Long-f ì nned Eel 24 2.4.4 Common Smelt 24 2.4.5 Gi ant Kokopu 24 2.4.6 Common Ri ver Gal ax'ias 24 2.4.7 Koaro 25 2.4.8 Inanga 25 2.4.9 Torr"entf i sh 25 2.4.10 Common Bu1 ly 25 2.4.I1 Upl and Bu11y 26 2.4 .I2 Bl ack Fl ounde r 26 2.5 Uses of t^later 26 2.5.L Fi sh and Wi l dl'i f e 26 2.5.2 Recreati on 27 2.5.3 Hydro 28 2.5.4 Irrigation 28 2.5.5 Frost F'ighti ng 30 2.5.6 Industry 30 2.r.7 !.lbqn Suppìy 30 2.5.8 Mi ni ng 31 Fisheries environmental report no. 76 (1986) Pa ge 3. Hydro Development 32 3.1 Lake Control Structures 32 3.2 Roxburgh 34 3.2.L Phys'i cal Descri Pti on 34 3.2.2 Operati ng Regime of Roxburgh Power Stat'ion 36 3.2.3 Impact on F'ishenies 40 3.3 Uppen Cl utha 42 3.3.1 Cìyde and Lake Dunstan 42 3.3.2 Potential Dams (Upper Clutha and Kawarau 44 Rivers) 3 .3 .2 .I Lu g gate 45 3.3.2.2 QueensbenrY 46 3.3.2.3 Kawarau 46 3.3 .3 Impact on F'i s he ri es 47 3.4 Lower Clutha (Potential Options) 49 3.4.1 Scheme A 52 3.4.2 Scheme B 52 3.4.3 Scheme C 53 3.4.4 Scheme D 53 3 .4 .5 Ope rat i ng Re g'i me 54 4. Lower Clutha Study Anea 55 4.1 Land use 55 4.2 Physi caì Descri pt'i ons and Hydrol ogy 57 4.2.I Lake Roxburgh 57 4.2.2 Cl utha R'iver Mai nstem 62 4.2.2.I HYdt ol ogY 63 4.2.2.2 Water TemPeratures 67 4.2.2.3 Water QualitY 6B 4.2 .3 Tri buta ri es 6B 4.2.3.1 Coal Creek 7L 4.2.3.2 Cnossans Cneek 72 4.2.3.3 Teviot R'iver 73 4.2.3.4 Bengen Burn 74 4.2.3 .5 Ti ma Bu rn 80 4.2.3.6 Talla Bunn B2 4.2 .3 .7 Canad'i an St ream 83 4 .2 .3 .8 Be aumont Ri ve r B3 4.2.3 .9 Low Bu rn 84 4.2.3.10 Ca rsons St ream 85 4.2.3.11 Bl ackcl eugh Bu rn B6 4.2.3.12 Tuapeka Ri ver 87 Fisheries environmental report no. 76 (1986) Pa ge 4.3 Study Programme B9 5. Acknowl edgments 91 6. L'iterature Ci ted 92 TABLES 1. Dai ìy I ake I evel vari at'ion i n Lake Roxburgh 36 2. Rate of sp'illway discharge per month at Roxburgh 39 power station, ApriI 1983 - February 1985 3. Proposed hydro-electric schemes for lower 50 Cl utha Ri ver 4. Lake Roxbungh volumes from siltation sunveys 58 5. Temperature profi les of Lake Roxburgh at Fl ag 60 Beach, December 1983 - October 1984 6. Main tributar''ies with'in the study area - catchment t0 area, stneam grad'ient and length, and flow (mean and ran ge ) F I GURES 1. The Cl utha Ri ver catchment I2 2. Cl utha Ri ver near Beaumont 15 3. Roxburgh hydro (dam and powerhouse), Lake Roxburgh 35 and Cl utha Ri ver 4. Mean hounly discharge, Roxburgh power statìon, 38 June and November 1983 and 1984 5. Spil'lway dìscharges, Roxburgh hydro 40 6. Proposed schemes for lower Clutha hydro-electric 51 devel opment 7. Mean month'ly temperatures (and ranges) for the two 61 study years at Roxburgh dam 8. Mean monthly flows of the Clutha River, pre-Hawea 64 and post-Hawea o Mean monthly fìows of the Clutha R'iver fon the two 66 study years and the "average year" 10. The study area wjth tributaries surveyed by FRD underl'ined 69 Fisheries environmental report no. 76 (1986) Pa ge 11. Upper Coaì Creek 72 12. Coal Creek below S.H.8 bridge 13 13. Teviot R'iver (residual river above powerhouse) 75 14. Teviot River powenhouse 75 15. Schematìc d'iagram of the Teviot Rjver power scheme 76 16. Benger Burn, middle reach 77 17. Benger Bur'n, lower reach 17 18. Mean monthly temperatures fon the Tima Burn, Benger 79 Burn, and Carsons Stream 19. T'ima Burn , mi ddì e reach 81 20. Tima Burn, lower reach 81 'l 21. Ta I I a Bu rn , ower reach 82 22. Beaumont Riven above the gonge 84 23. Low Burn, m'iddle reach 85 24. Carsons Stream, lowen reach 86 25. Blackìeugh Burn, upper reach 87 26. Tuapeka Ríver, middle reach B8 Fisheries environmental report no. 76 (1986) 7 SUMMARY The Clutha River has the largest catchment anea (21 400 fm2) and the largest mean annual dìscharge (Sff m3/s) of any New Zealand niver. It has a diversìty of uses ìncìud'ing recreat'ion, irrigatìon, frost fighting, min'ing, and ìndustrial and public supply, and it also supponts i mportant f i sheri es. Use of the Cl utha Ri ver i s domi nated by hydro-electri c power devel opment whi ch stanted 'i n the mi d 1950s w'ith the i nstal I ati on of Roxburgh dam and power stat'ion. Hydro development in the upper Clutha i s proceedi ng wj th Clyde dam present'ly under constructi on and cons'i derati on bei ng gi ven to furthen devel opment i n the mai n ri ven (Luggate and Queensberry) and 'in the Kawarau River. The potential of the lower Clutha is current'ly being investigated and, at the time of wrìting, thnee scheme options have been proposed. Flows in the Clutha River have been modifìed by the Hawea control dam which was installed to pnovide additional storage for Roxburgh power statìon. Consequently average flows during the low-flow period of winten have'increased and average flows in summer have decreased. The 'instal I at'ion of Roxburgh dam has caused l arge dai ìy fluctuations in downstneam flow and van'iat'ions in water level. Th'is has resulted'in de-watering of the njver mangins and has supposedly ìed to bank instability. As no fish pass was insta'l1ed, Roxburgh dam is a barrier for m'igratory fìsh, such as quinnat salmon and sea run brown trout and at least three species of native fìsh (lampreys, short-finned and I ong-fi nned eel s ) . The 75-km-l ong study area of the I owen Cl utha from Roxbu rgh to Tuapeka Mouth has been investigated to assess the hydro'logy and fish Fisheries environmental report no.