WATER & SOIL - These are not the droids you are looking for.

More documents

Recommendations

Info

Appendix F Flood frequency analysis for Otago and Southland F.1 lntroduction At the time of developing the flood frequency curves for the eight regions covering New Zealand, there were only six relatively short flood records available for the Otago/Southland region. This region's flood frequency curve was therefore treated as provisional and was only extended to the 100-year return period; for the other regions the curves were drawn up to 200 years. The tentative nature of the analysis is best illustrated by the fact that one of the records used was for the Pomahaka River at Burkes Ford (Station 75232) for the period 1963-1975. The flood peak for 1972 of 1088 mtls was omitted because it appeared to be an extreme outlier, yet this peak has been exceeded three times over the period 1978-1980. The number of notably large floods in the area in the period 1978-1980, and the availability of substantially more data, suggested that reassessment of flood frequencies in this area was appropriate. This appendix gives the results of the reassessment, which has been completed just in time to be published as a supplement to the main study. F.2 Data collection With assistance of staff of the Otago and Southland Catchment Boards, annual maximum flows for stations with at least l0 years of reliable flow record were extracted. The catchments are listed in Table F.l and their locations are indicated in Figure F.l. The flood peak data are given in Table F.2. Additional historical data were sought. These data took two forms. The first was estimates of large floods which occurred before recording commenced and which were the largest for a known period. For example, the estimated p"it of 220 m3/s in tÈe Leith on 19-20 March 192í is the largest known in this area since settlement, which is taken as dating from 1850. The second form was when the largest recorded flood was also the largest known peak in a preceding interval. For example, the peak of 505 m',/s recorded on the Makarewa River on 15 October 1978 is known not to have been exceeded since 1895. Sources of historical information are "Hydrology Annuals" No. 3 No. 17 published by the Ministry of Works (1955-1969), and - "Floods in New Zealand (1920-1953)" published by the Soil Conservaton and Rivers Control Council (1957), supplemented by information from catchment boa¡ds and some early newspaper reports. As early historical estimates are of uncertain accuracy, only data considered to be reliable were used. Annual maximum l2-hr duration lake inflows calculated from records of levels and outflows (Gilbert 1978) for Hawea, Wanaka, Wakatipu and Te Anau were used. Local inflows to Manapouri were not used because they are calculated as Manapouri outflow, minus inflow from Te Anau, minus change in lake storage, and since inflow from Te Anau is 6690 of Manapouri outflow the residual local inflow is subject to large errors. Although the l2-hr maxima inflows are less than instantaneous maxima, the reasonable assumption that the instantaneous maxima are a constant ratio (say 1.2) of the l2-hr maxima suggests these data can usefully supplement the maxima recorded on rivers for frequency analysis purposes. Flow records were also derived for two contributing areas in large catchments by subtracting, from downstream flows, the upstream flows lagged to allow for time of travel, Records of annual maxima were thus derived for the Waiau River between Tuatapere and the Mararoa confluence, and the Clutha River between Clyde and the Shotover and the three lakes. Because these data are derived by differencing hydrographs, after making assumptions about the travel times of the upstream hydrograph, the errors in the estimated peaks are significantly greater than for other records. They were therefore not used in deriving the regional curves; however, they provide a useful independent check on the curves derived from the other data. Table F.1 L¡st of catchments. Number of Stat¡on Catchment number in Fig. 1 Name of River and Recording Station Year Record starts Catchment atea (km2l 1 2 3 4 5 6 7 I I 10 11 12 13 14 15 16 17 18 19 20 21 22 73501 74308 74310 74314 74346 75259 75232 77504 77505 7A502 78607 78625 78633 78803 78906 75276 75253 23 24 84701 Water of Le¡th at University Footbridge Taieri at Outram Taier¡ at Sutton Taieri at Patearoa-Paerau Bridge Loganburn at Paerau Fraser at Old Man Range Pomahaka at Burkes Ford Mataura at Gore Mataura at Parawa Waihopai at Kennington Oreti at Lumsden Otap¡ri at McBridges Bridge Makarewa at Freezing Works Bridge Middle Creek at Otahuti Aparima at Dunrobin Lake Wakatipu inflow Lake Wanaka inflow Lake Hawea inflow Lake Te Anau inflow Shotover at Bowens Peak Manuherikia at Ophir 1 964 1 955 1 961 1 968 1 967 1 969 1 962 1 957 1 956 1 958 1 957 1 963 1 955 1 970 1 963 1927 1 930 1 931 1 926 1 968 197 1 Clutha tributaries above Clyde, and below Shotover and the lake outflows (see McKerchar, 1981. Table 4.1) 1963 Waiau tributa¡ies above Tuatapere and below Mararoa. {see McKerchar, 1981, Table 4.1} 1969 Cleddau at M¡lford 1964 45 4 705 3 066 738 150 122 1 924 3 465 766 152 1 160 108 1 040 27 215 3 133 2 624 1 384 3 124 1 088 2 036 3 839 2 336 155 Water & soil technical publication no. 20 (1982) t23
Table F.2 Flood peak data. NEW OTAGO DATA NEW SOUTHTAND DATA 3I TE 73501 I.EI18 TT UTI9EESÍTY POOIBNIDG? sITE 15232 POitñtKÀ À1 Do¡t(zs ¡oBD crrcHtBtT t8Et, 5Q Kü = tollBER oP ÀXtltÀL PEÀKS = IEIB PEÀI( IB¡I P¿TK CÀrCllAIl IREÀ¡ 5Q Klt = 47A5 !0;8EF OF IIXûÀL PE¡ñS = 25 IEI! PETK IEÀE 45 ¡Àp RBFpREì¡cE = s16q:i63?2s 17 P¡iFIoD 0P REc, = 196q-e0 YETR PBTK YEÀR PET T 1964 4.7 1965 6. t 1966 1,\ 196? 5.2 1968 r 13 1969 8.5 1911. 39.6 1971 95. 6 1972 65. I 1973 8.5 1974 51.8 tq?5 ta?, 9 t976 46.7 1971 28.7 1978 49.4 19?9 23.5 t9B0 1 30 lBtf = 41.16 STD. DEv. = 39.9€ coEF. Op sKEs = 1.01Â tolBs: 1. rflE t929 pElK, ESIltttTED tÎ 220 CUiECS, rtS THE LtRcESl ST¡CE SETTLEI'EIIT À¡TD TÀKET IS ÎIIE LÀRGÈsT Tll TfE PERIOD ts50-1980. sIîB 7¡308 1955 10S5 1957 '1960 181 ¡961 1964 37.6 1965 1968 845 1969 1972 832 1973 I 9?6 t 43 1977 1980 2600 Pr¡[ 2009 12't0 119 152 151 326 1ÀI8RI À1 OIITRÀñ llÀP REPEREIICE = S163:9337q(¡ PERIoD 0P 8Ec. = 1955-F0 YEÂR PBÀK TEÀR PEÀI( 1958 425 1959 21Ã 1962 205 1963 368 1966 300 1961 19( 1970 266 t97t 43f 1914 864 19?5 J34 1978 1133 1919 r¡Oo ;!Àt = 593.2 STD. DEg. = 62t¡.5 Copp, Op SÍEc = 1.965 tolE5: 1. T_8!'l?qo-g_Err, rRE r868 pE¡t (Bslrt!llED À1 2179 coiEcsl rfD ÎE?.1957 PEÀi ¡ERE IIKEI rS ÎIIE 1ÍRN8 L¡RGEST rìI TI¡E PIRIOD 1858-1980. 5I1E 7q3 10 cllcfliliT À¡Er, sQ K; 3366 xltllBtg OP ¡¡[0ÀL pEÄis = t8 I'IR PgTf TEÀR PETK 1961 06¡t 1962 108 t966 56.6 1968 3OO 1971 115 1972 207 1975 96.2 1976 156 1979 96-2 1980 800 TIIERI tÎ S0110tl lllP EEPEnEICE - s15¡t:939092 PeÂIOD oP REc, = t96l-90 TPÀR PETi t¿ÀR PEÀX 1963 t30 1e65 66.5 1969 59.4 r97o 76. ! 1973 113 1974 311 1911 67,9 19?8 ¿ü? t8¡¡ = 204.0 sTD, DEt. = 196.3 coEp. op siE3 = r.986 tolEs: l. PB¡Ís, irssl¡c FoR 1964 rxD 196?. cÀTCHllELT tREA, S0 Klt = 1924 ilP REPEREItCg 5711.221472 llullBEF oP Àf,tlûÀL PEI(S = tq PEnIoD oF R¡)c. = 1962-S0 IETR PEÀK fEÀR PETI( IEÀR PETß PI¡f 1962 1?6 1963 337 1964 96. I 'E¡¡ 1965 3lo 1966 216 1967 467 t968 516 1969 2¡9 't 970 2s5 1971 369 1972 t08? 1973 170 t 97q 206 1975 32A 1916 201 1917 375 t 978 1217 1979 352 1980 1210 ÍEltl = 435,2 STD. DEV. = 353.6 COPF. op SiE¡ = 1.?tO ltotEs: 1. Tfir 1978, 1980 ÀXD t972 pEtKS íERE TlFEL tS TEE Î[tBr LTRGPST TI THE PERTOD 1920-1980. s rlE 17504 tlTl0Sl lT coRt c^TcHiEtT rt8l, s0 ¡ü = llUllBER OP IUtaUÀL PEÀRs = IEIE PRIK 1 957 1 047 1962 586 1966 352 1970 252 197r¡ 21O 1 978 22f5 TETE PE¡( 1959 6CS 1963 tt33 1e61 656 19?1 443 t9?5 51C 1979 52t) 3q 65 23 766 25 llP REtEnutc? st70:013¡t3 PERIoD oP EEc. = 1957-S0 tEtR PEtß tzl¡ Pllf 1960 tt52 1961 35t 1964 260 1965 292 1968 1290 t969 62a 1912 121A 1973 2O1 1916 453 1971 1300 1980 1625 ËEtl¡ = 6c2.3 stD. DEI. = 520.3 coEp. op sf,B¡ = t.59o ùtoTEs: 1. rflE 1978, 19t3 (1700 cu;Ecsl rrD t98o pErxs tB¡E î¡ßE¡ ls îfl¡ L^RGESÎ fIf TflE pFRTOD t870-1980, srlE 77505 ctIcHllEN? ttEr, sQ ßÍ = llUllEER 0P rXXuÀL PEÀKS = PEIX IEIA YDT R 1956 1950 t 961¡ t 960 197 2 1916 1 980 PETK 68 1957 !2\ rc,t 1961 92 117 1965 103 276 1969 259 214 1973 1 lC 165 1977 266 215 rrT¡str Àr P¡llt¡ ËtP REPEEE¡CE st5t:¡9t058 PEDIoD 0P REc. = 1956-80 IEIR PEÀÌ fBTÂ PIT¡ t95S rq3 1959 2tt5 1962 103 1963 55 1 966 106 1967 292 19 70 84 197t 2t¡ 197tt 93 1e75 136 1978 590 t979 29t iEtü = 190.¡ STD. DEV. = "124,0 CoEp. o¡ srEt = 1.638 SIlE 78501 ¡TIROPÀI TT ¡ETIII6IOI SIÍI ?131¡ 1ÀIEtr tÎ PtTEtROI-P¡lt¡u cÀrcflllFl¡T ÀREt, SO till = 152 nlP REFERE¡cr NUIBER O? = sl773t3t0¡5 ÀTI'OÀL PEÀKS = 19 PERIoD 0P REc, - t95B-77 c¡lcElt¡î rRElr SQ fr 738 iÀP BEPEfiEICI tUiBEn OF À¡lott. pEtÍS = St45:675374 = l3 PEBIoD oP IEIR nEC. PFTK TE¡ R PEÀß = 1968-S0 IETR Pttf( tEtR 1958 Pttt tt.6 1959 26,6 1961 2q.1 1962 IIIB PETf, 1953 31.3 2¡. t IEIß PEÀi t964 1t68 PEII 25.tt 61.0 '1969 IEIR PETI 196 IBAB 5 39,1 196? 1966 26.A 56,0 19?0 23. I 1968 t¡1,3 65. 6 1972 30.9 1971 1969 26.1 1970 25. O ¡02.r¡ 1913 q6.0 1971 17.7 7912 55. R 197¡a 1976 55,3 191 1975 3 68.5 19.8 1974 31. ó 39.0 1971 69,9 19?5 't 21.8 t9?6 30.7 51. 1980 978 t 37. 5 1917 ql.6 1979 I 205 Ëxlt{ = 28.93 SrD, DEc. = 1C.û2 COEP, op S(Et = 0.9960 iEl¡ = 76.07 SfD. DEt. = 47.67 COEP. oP SrEs = 1.98F sITe 7860" OF¡:îI T1 LOËSDEI s¡ ÎE 743¡6 LOGIXBoÀX tÎ PtERto CÀTCflll¡ll1 àRP^¡ SQ ßñ = 116C FÃp fiEpFRENCE = SrSO:lBr¡g62 c¡lc8llrT rSEr¡ sQ l(r ùU;BEF = t50 llP REPERBICE OP lIilûAL ÞEIKS = 22 PERIOD OF RDC. = 1957-80 ¡0lBB¡ OF ¡lIÛÀL PBIÍS = Stqtt:62¡t217 = t3 PEBIOD 0p nEc, = 1967-79 YEAR PfAK IFÀ8 PEÀK ÍNTR PRÀI( TEÀR PEI II¡g ÞE¡Í IE¡8 PE¡R IEAR PEÀX TEÀR 666 1e58 f 1957 334 ÞIÀt( 1959 378 1960 271 t957 5.48 t968 20.7 't95| t969 12.2 19?O 352 1962 352 22.9 1963 183 1964 211 19?r 35,5 1972 50.0 1973 196 5 21.7 -lc 197¡t 1 1q66 232 15.6 tc67 416 1968 352 t975 26.4 19?6 1s,7 1977 t969 20.3 t97B 211 l97C 21C 58.s 19'11 t69 1912 139 7yr9 1 8. 9 1 975 765 1976 453 '1917 871 1978 1171 197C 131 1980 I 10c lBlf . 24.91 STD. DEt. = trt.92 COEp. oF SßEr = 1.2ge ñE¡tl È 454. I 51r\. DRv. = 29Ê. I coFF. oF s(Ft = t.27tt Ìorts : 1. TBE 1980 pEti oF 365 CUTECS NOTES 3 tÀS OñIÎTED FFOil TltE ITTLISTS: I1 9Ts IT BITRETE oOT¡,IER 1. lIIF ÀIID T¡tE IYÀrLIEL! 1C-8 ÀNTJ 198C PEIKS Y¡]FII ÌÀKE¡r ÀS lHf L¡RGEST I¡ LpxGTft ot ¡EcoRD ¡rs fùstrFFlcrEilT TO Rltt¡L8 THE PPFIOD REÀLISTIC 1879-198i. TETIIEI¡ PEBIOD 1O BB ISS¡GIIBD 10 Iî. ^ srtt 7a625 OlTÞIRT ÀT iCBRfDES BRIDGI PRÀZEF :l::__--- _ t:::: IT OLD ItTN R¡IIGF c¡tc¡rrir tBEt, s0 [t = 180 ItP AEFEREIICE = S169:|t22516 c¡fcfitBlT rREr, SQ Kü !ûIBEB = llÀP ol REF¡ll?Eilcr ¡IlûrL PEÀIS 5143:03't485 = 1B 122 PEAIOD OP REC. = 1963-80 XUÚBER OP TT¡Of,L PEÀKS = 12 PERIoD 0r 8EC. = 1969-80 r'¡¡ PEIf, TET¡ PEÀK IETS PPÀK fEtS PEIX IE¡R PEÀT YEÀK PRTß 1965 31.2 1 TETR 1963 tt2.3 196¡ PEÀÍ 29.1 966 YEIF 30. 3 PEI f, 1969 23.4 1970 1911 t967 19,3 52,5 1968 85.5 11,9 1969 60.0 1970 70.3 1912 '19t3 22.3 1975 1971 43.5 1972 65.8 16.2 1973 1976 25.9 1 31. rl t974 tq.2 974 12.7 34.7 1971 11.9 1919 1915 1?,0 3q,2 1976 rt3.9 t978 88. 1977 90.2 1978 198 O t980 26. 0 1979' 52.8 1980 r15 ¡E¡i = 26.29 sTD. DEY. = 20,29 COFP, OF SÍF:C = 2,911 tE¡x = 61.3r¡ sÎD. DEÍ. = 41.93 COEP. oF SIEc = 2.28A tu Water & soil technical publication no. 20 (1982) a
Page 1 and 2:
WATER & SOIL TECHNICAL PUBLICATION
Page 3 and 4:
Regional flood est¡mat¡on in New
Page 5 and 6:
Tables 1.1 Risk ofexceedence for sp
Page 7 and 8:
Preface Water & soil technical publ
Page 9 and 10:
annual flood Q (the mean of the ann
Page 11 and 12:
Water & soil technical publication
Page 13 and 14:
Doto ovoiloble on TIDEDA Figure 2'1
Page 15 and 16:
P=45 O= 15 x4 (l) '= o o t.25 2'.O
Page 17 and 18:
Êv2 ( ko) Reduced Voriote y I'O t1
Page 19 and 20:
turn period. A plotting position fo
Page 21 and 22:
'o ,l\, I zl l- I Water & soil tech
Page 23 and 24:
Table 3.2 Flow stat¡ons used. SITE
Page 25 and 26:
e process of examining the simtrend
Page 27 and 28:
Iì_ t_ I I I I I I I t-. I I tñ I
Page 29 and 30:
Þ I"IEST COFST 0 o I E 6o o o 25 3
Page 31 and 32:
SOUTHEBN REDUCEO Y VRBIßTE NETURN
Page 33 and 34:
SOUTH ISLFND HEST COFST I]ÊTR èo
Page 35 and 36:
SOUTH CÊNTERBURY DRTÊ NEOUCEO Y V
Page 37 and 38:
COMB I NED ,,IE5T CORST DRTR o rt
Page 39 and 40:
BÊY OF PLENTY DRTF o o o NEOUCEO Y
Page 41 and 42:
NOBTH ISLRND ßEGIONÊL CUBVES 1.50
Page 43 and 44:
data for this area are required bef
Page 45 and 46:
NELSON REGIONFL CURVE BEOUCEO Y VRR
Page 47 and 48:
46 EÊSTEFìN NEI,,I ZEFLÊND DÊTI
Page 49 and 50:
Table 3.9 The grouping and the grou
Page 51 and 52:
allowing curves rather than just st
Page 53 and 54:
3.5.5 Extension method The NERC (19
Page 55 and 56:
Table 4.1 South lsland catchment ch
Page 57 and 58:
I 2 t l¡ 5 5 7 I 9 l0 t1 ,12 I5 1{
Page 59 and 60:
decided instead to use estimates of
Page 61 and 62:
\Í l{ I t, ìj( Fþurc 4.4 Distrib
Page 63 and 64:
62 Fþurc 4,6 Logarithmic rcsidual
Page 65 and 66:
Table 4.6 Final equations for South
Page 67 and 68:
I ++ ++ * E 4.6 Analysis of North l
Page 69 and 70:
Non Pumice = õ = 3-24xto'6 AREA'7
Page 71 and 72:
Northlond f C"ro^ondel f Eost Cope
Page 73 and 74: Table 4.11 Comparable equations for
Page 75 and 76: Poo led cv Pooled o.40 F¡guro 4.12
Page 77 and 78: mates of Cp typically range between
Page 79 and 80: -J æ 'll o Eo !¡ Assemble llood p
Page 81 and 82: Year 1958 1959 1960 l96r t962 1963
Page 83 and 84: The estimate of Q from the regional
Page 85 and 86: Water & soil technical publication
Page 87 and 88: Maguiness, J.A.; Blackwood, P.L.; B
Page 89 and 90: The liequency factor K is a functio
Page 91 and 92: e.9., Linsley et ol. (1915); lrish
Page 93 and 94: Maguiness, J.A.; Blackwood, P.L.; B
Page 95 and 96: sltt 930 t [rûltRÀict ¡ l? s;¡t
Page 97 and 98: 3950't flrlÀRt R tr îlt¡Ît ;tP
Page 99 and 100: S ITI 29202 RuNttiltcl I ¡t tllEtt
Page 101 and 102: ïI-'_____ ::19: lt¡IPt0r n À1 i
Page 103 and 104: 9100r GNE? R ¡T DOBSO| s¡18 93207
Page 105 and 106: 6800 1 sBlrri R tT SrITEC¡,tttS 6I
Page 107 and 108: APPENDIX C Summary of tho data for
Page 109 and 110: oæ ON LAT. STATION NA ATION LAT. N
Page 111 and 112: o NUI,IBER HHAKAIIARU 854801 38 L7'
Page 113 and 114: l9 AT NU¡IB ËR AR',tËtlANA ÂRAI
Page 115 and 116: A ON LAT. STATION NA NUMBER AHUNA 5
Page 117 and 118: â NUI,IBER Lü{G.E ON NU14EER I,IU
Page 119 and 120: æ TATI ¡rouNT sor.tERS 7L740? 43
Page 121 and 122: N) o STATIoN NAr{gmLfï3---ffij NUI
Page 123: APPENDIX E Compadson of Regional Fl
Page 127 and 128: F.3 Analysis and results tatively p
Page 129 and 130: ét êt REOUCEO VßFIHTE 2. 33 5 l0
Page 131 and 132: SOLITH I EA l') COAST soUTH CANTERB
Page 133 and 134: 0tiftflt a itÉitut5 ü¡. il/5 tg?
Page 135: Water & soil technical publication
show all

WATER & SOIL - These are not the droids you are looking for.

Create successful ePaper yourself

Delete template?

Save as template?