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I.e E.J. 8.........II',E, ""bl~/Jt.nuJlofH,VlII'IJIo"y216flm) lJ7-1-U 200 ,.. ,.. E .s 140 ~ 120 c .. a: ". . .. .. .. "5 E " , U .. " . ]: c .!l .. > . iij ~~ ~ . " " " West Distance (km) East F:i" ~ ~.... ilr.UiJnPby aIoa, a transect of Il stillSllll<ir.U1I ,au",'lCrofoi the Kaimai R:u:I,e. Ne,,'uablld. The lillel antUUllpolariOll ;;>.wlllilllo,ubw>'ecn ...u.faUe"""1 mubon lhe ,lII,e tilmrcoonhfllOl $bo\\'III. ThehlJ/lcSl ele"JliODIJlllete<:orded II raine"eat<. Oaul" ;,o,;.wnll,ldiarnoodsl&DdthelfU,",CllOpO,np/licprofileareobow1ailltbelowerdiarram. .ug:ree of gauge vertical exaggeration. A large eug- jention coupled wilh a rapid marking effecl can re..ol"c small evcnts, bUI at Ihc expense offrequcnl gaugc emptying or crealinll a high gaugc. Some indi- cation of Ihc accuracy of our Slillstand gauge set is e\ident from Fig. 3. which shows paired records of adjacent stillstand and lipping buckct gauges. There is a slight differcncc in somc evcnl magnitudcs recorded by the different gaugc types, but these effects could be caused in pan by Ihe bucket nOI filling 10 the tipping threshold allhe end of rainfall eyenlS. The field setting of Ihe gauges appears 10 have been the most important faclOr influencing accuracy. The stillsland gauges were sel up with their full height above the pound surface, so undercatch was a possi- bility in windy conditions because ofthc 1.5 m projec- tion. -This effecl appears evident in Fig, 4 where there is under.rccording of the larger rainfall events, which were 'presumably accompanied by high winds. This is nol a specific problem of stillsland gauges as such and could be avoided in the usual way by mounting the gauges below the ground so their apcnures are in flush with the IllIld surface. Below-ground emplacement would also provide a buffer against temperalure extremes and reduces the risk of radiation elposure by accidental or deliberate breakage of the gauges. . 4. D1uslradon EJ. B......... W.E. B""h/~.y I JO/lmul of H:..lroIory 1/6 (1999) IJ7-1.u '" Fi,. S illustr:lles the kind of rainfall detail that can be achieved from a set of stillstand a:auges. A transect of 12 gauges was set up extendin. across the Kaimai Ranges, neM Tauranga, New Zealand. 1b.= transect was selecled bec::ause there was likely to be some topographic rainfall enhancement and it was. of inter- est 10 check the extent of orographic effects on indi- vidual rainfall events.1lIc uanscctvaries in c1evalion from 100 to 630 m at the mountain crest, and the gauges were in operation over the period from 3rd July to Sth September 1997. After developing the X-ray films, spatial linking of the rainfall events was canied out to build up the transect rainfall sttatisnphy, shown in FiS. S. Most of the stillsllllld marken could be readily traCed from one gaLLiC to the ncxt along the lraDscct. although there was inevitably an clement of subjectivity when Iinkina: a few poorly defined marker lines. The fourth and sixth gauges from the west appear 10 be sulferins from some degree ofundcr<atch. probably because of more windy site locations. It is evident that a considerable amount of rainfall detail has been captured by the gauges. The transect is presented here for iIIustrotive purposes only. but some feaNres sussest fulUrC investigation possibilities for rainfall process studies in this region. In particular, only some of the rainfall layers show a stronS orographic enhancement and this might be related 10 particular synoptic conditions on the days concerned. In this regard. the dates of OCCUlTCnce of rainfall events could be readily obtained by cOlTClating the stillstand eVenlS to some reference aUlOmatic gauges. 5. Conclusion Tbc immediate application of stillstand gauges would probably be to replace some existing storage gauge networks. This would produce a considerable increase in rainfall infonnalion derived from the networks. and at worst the stillsland gauges could operate as storage gauges in the event of malfunc- tions such as Roat failure. The new rainfall event data could assist estimates of maximum probable rainfalls and Rood event return periods. Also, probabililY distributions of rainfall event magnitudes could be constructed for measuring l1Iinfall reliability for agri- cultural or waler supply purposes. The other application is likely to be in support of specific scientific investigations where there is a need for accurate spatial descriptions of the footprint of individual rainfall events. In' such studies. thecstab- lishment of a number of supporting slillst:lIld gauges may considerably reduce the rainfall interpolation errors which could arise from using a few recording gaugesalonc. We arc not aware of the previous articles dealinll with the simple slillsWld concept bUI there arc varia- tions which might be developed with respec[ 10 the marking process. For example. a film of dye lIoatinll on the waler surface in the lIauge might be used to slain a suitable recording paper. Alternatively, some water line precipitation process might be used to generate identifiable marker lines. The stillstand rain gauge is clearly a minimaltcch- nology instromcnt in an age of sophisticated sensors and solid state electronics. No doubt there will come a time when inexpensive coin-size devices will be dropped inlo storage gauges to carry out the multiple functions of pressure sensing, time clock, and data storage. Until thcn, thestillslllnd gauge cOllcept offers a useful cost-effective approach for obtaining rainfall event magnitudes. Acknowledgements The construction phase of [he CAperimental still- stand lauges was greatly aided by Ihc advice of Professor Alan Langdon and Mr John Unle. respec- tively of the Department of Technology and Depart- ment of Chemistry. University of Waikato. References Bcmdtuon. R.. Nien:ll:I.Ynowicl.. J.. 1988. Sp~W and Lempgnl ..:oIe. ill rainfatlll'llJ)'IiI.""""" up<Hydrol.lOO.l93-313. 0.::.... M.M.N,.NiemclYnowic~ J.. 1996. Spatial yariabtlity ofrai... faU ill Kuala Lumpw, MoI~yua' 1011& a.nd """" letlll dwaclc.. i.I".. H~drol. Sci.J, ,U,345-362. Faure.. J.. Goodrich. D,C.. Woolhise.. O,A.. SoroodliaJI. $" 1995. Impacl ofomall...:aJe 'P'Uial minr.1I .-mobility on runoff modclliRJ.J. Hydrol.11l.3O\I-J26.