Vedretta Pi an a Glacier is situated in Valle di Trafoi, near Stelvio P ass (Italian Alps ). Summer skiing has been a popular sport on this glacier for over
seventy yea rs. On this glacier a stu dy for determining its recent evolut ion was carried out by means of a quantitative, detailed an alysis (G P S and GPR
surveys) carried out in 1999 and in 2000 . Th e data elaboration shows th at the loss of ice and snow during the September 1999 - September 2000 period
was equal to 938.920 rn'. The specific net ma ss balance for th e 1999/2000 hydrological year thus amounts to - 2.138 mm. The glacier's mean thickness
proved to be equal to 71 m. Th e glacier volume proved to be equal to 72.500 .000 m' over a surface area of about 1 km ' . The survival time of the glacier
is valu ed of about 35 yea rs (KEY W ORDS: Glaciers , Tourism, Vedretta Pi an a, Alps

CARLO D'AGATA

CARLO LANZI

CLAUDIO SMIRAGLIA

GIORGIO paolo maria VASSENA

GUGLIELMINA DIOLAIUTI

MANUELA

MARIO PINOLI

MASSIMO PECCI

MAURO PAVAN

English

Archivio istituzionale della ricerca - Università di Brescia

Geogr. Fis. Dinam. Quat .24 (200 1), 199-201, 2 /igg.Nota BreveShort communicationGUGLIELMINA DIOLAIUTI (~':), CARLO D'AGATA (~':), MAURO PAVAN (~h':),GIORGIO VASSENA (;'dd:) , CARLO LANZI (~h'd:), MARIO PINOLI (~'ddd:),MANUELA PELFINI (;':), MASSIMO PECCI (~hhh':~':) & CLAUDIO SMIRAGLIA C. (~':)THE PHYSICAL EVOLUTION OF AND THE ANTHROPIC IMPACT ONA GLACIER SUBJECTED TO A HIGH INFLUX OF TOURISTS:VEDRETTA PlANA GLACIER (ITALIAN ALPS)ABSTRACT: DI OLAIUTI G ., D 'AGATA C , P AVAN M., VASSENAG ., LANZI C , PINOLI M., P ELFINI M., P ECCI M. & SMIRAGLIA C , Th e physical evolution0/and the anthropic impact on a glacier subjected to a high influx 0/tourists: Vedretta Piana Glacier (Italian A lps). (IT ISSN 0391-9 838, 2001).Vedretta Pi an a Glacier is situated in Valle di Trafoi , near Stelvio P ass (Italian Alps ). Summer skiing has been a popular sport on thi s glacie r for overseventy yea rs. On thi s glacier a stu dy for determining its recent evolut ion was carried out by means of a quantitative, detailed an alysis (G P S and GPRsurveys) carried out in 1999 and in 2000 . Th e data elaboration shows th at the loss of ice and snow during the September 1999 - September 2000 periodwas equa l to 938.920 rn'. The specific net mass balance for th e 1999/2000 hydrological year thus amounts to - 2.138 mm. The glacier 's mean thicknessproved to be equal to 71 m. Th e glacier volume proved to be equal to 72.500 .000 m' over a surface area of about 1 km ' . The survival time of the glacieris valu ed of about 35 yea rs (KEY W ORDS: Glaciers , Tourism, Vedretta Pi an a, Alps) .RIASSUNTO: DIOLAIUTI G. , D 'AGATA C , PAVAN M., VASSENA G ., LANZI C , PINOLI M., PELFINI M., P ECCI M. & SMIRAGLIA C, L'euoluzione fisica el'impatto antropico di un ghiacciaio sottoposto ad intensa fr equentazione turistica: la Vedretta Piana (Alpi l taliane). (IT ISSN 0391 -9838,2001).I! Ghiacci aio della Vedretta Pi ana e situato nella Valle di Trafoi vicino al P asso dello Stelvio (Alpi It aliane). Su questo gh iacciaio, do ve da olt re 70ann i viene p raticato 10 sci esti vo , son o stati effettua ti nel 1999 e nel 2000 rilievi dettagliati per determinare la su a evoluzione in att o mediante GPS eGPR. L 'elaborazione dei dati ha indicato ch e fra il Settembre 1999 ed il Sett embre 2000 vi estata una perdita di nevato e di ghi accio pari a 938.920 rn' .I! bilancio di massa netto specifico calcolato per l'anno idrologico 1999/2000 ammonta a -2138 mm. Lo spessore medio del ghiacciaio e stato stimatopari a 71 m. I! volume calcolato epari a 72.500.000 rn' di ghiaccio su una superficie di circa 1 km' , II tempo di sopravvivenza dell'apparato glacia le esta-to valutato pari a circ a 35 anni (TERMINI CHIAVE: Ghiacciai, Turismo, Vedretta Piana, Alpi ).Vedretta Piana Glacier is situated in Valle di Trafoi, avalley incised by a torrent bearing the same name on theAdige side of the Ortles-Cevedale Massif (Italian Alps).("') Dipartimento di Scienze della Terra, Unioersita degli Studi di Milano.(""-') Dipartimento per 10 Studio del Territorio e delle sue Risorse,Uniuersita degli Studi di Genova.(""''''') Dipartim ento di Ingegneria Civile, Uniuersitadegli Studi di Brescia.( ,-, ~",,,-, ) Montana S.r.!.( ,-,~",,,-,,,,) ISPESL , Roma.Commu nication presented at the EGS (European Geophysical Society)Meeting in Nice (26 march 2001, Glaciology and Climatology poster session,Glaciers and lcesbeets). This study was part 0/the research program «A lpineGlacier and Environmental variations», COHN MURST 40% 1999 and of theprogram 0/ Comitato di Gestione Lombardo del Parco Nazionale dello Stel-vio «Vedretta Piana in the Stelvio National Park: geometric and vo-lumetric variations». The authors thank the Centro NivometeorologicoRegione Lombardia in Bormio and the Laboratorio A lte Prestazioni at S.Caterina Val/urva for the logistic support.This structure has a particular morphology that extendsover the Punta degli Spiriti crest in a north-northwest di-rection and without well-defined boundaries. In fact, theupper sector is subdivided into differentiated flows,which in the eastern sector feed the Madaccio Glacier,while in the western sector, they flow into the Vitelli Gla-cier (Desio , 1967).Summer skiing has been a popular sport on this gla-cier for over seventy years. The area utilized for this sportalso includes part of the catchment area of the Vitelli Gla -cier, which flows towards Valtellina and of the MadaccioGlacier, which flows towards Val Venosta.The use of the glacier for tourist activities and the con-struction of lifts and infrastructures serving for those ac-tivities have undoubtedly influenced the dynamics of theglacier , in addition to changing the natural landscape(Diolaiuti, Pelfini & Smiraglia , in press).199The number of lifts and their size have varied overtime , depending upon the changes in the glacier's exten-sion and snow cover over which the y stand. In fact , as inother areas whe re summer skiing is popular, several liftsat Stelvio Pass have been abandoned due to the completedisappearance of the underlying ice, which served to sup-port the ski trails (this is the case of the ski lifts located onPlatigliole Glacier) following the glacial recession in re-cent years caused by global warming. With the change inclimate, the area available for tourist activities (summerskiin g) on the glacier has also undergone changes. In con -clusion, on the one hand, the presence of man has influ -enced the glacier system and its evolut ion over time , andon the other hand, the change in climate has broughtabout changes in the glacier (its volume and extension ),which, in turn, have limited the influ x of tourists andman 's use of the glacier.On this glacier a study for determining its recent evo-lution was carried out by means of a quantitative, detailedanalysis carried out in 1999 and in 2000 (Smiraglia & Die-laiuti, 2000). The analysis was aimed at determining th eglacier' s main geometric features and thos e pertaining toits dynamics. More specifically, quantitative data werecollected on its thickness and current volume, on the dy-namic phase in progress and on the pace of its transfer-mation and the response times to forcing phenomena of aclimatic type (response, reaction and relaxation times).All of this is directed towards the construction of data-base with essential information serving for a more in-depth knowledge of this glacier as a natural resource, forthe purpose of quantifying the impacts brought about byman and postulating possible measures for the preserva-tion and compatible use of this natural asset.This research was organized in stages, a fieldworkstage carried out during the summers of 1999 and 2000and a later stage serving for data processing and analysis.In the summer of 1999 the following fieldworks werecarried out:1) two topographic surveys using Real Time Kinematic(RTK) GPS in June and September for the acquisition ofreference points and the subsequent calculation of twoDEMs (Digital Elevation Model) on the glacier; 2) place-ment of measurement points to assess the entity of sum-mer ablation using the traditional method with ablationstakes; 3) two radar surveys (GPR techniques) to deter-mine the thicknesses of the ice. We used 35 and 50 Mhzantennas; 4) measurement on the variations in thicknessand density at the stakesIn the Summer of 2000 the fieldworks were the fol-lowing ones:1) two topographic surveys (July-September) usingRTK GPS for the acquisition of reference points and forthe subsequent calculation of two DEMs on the glacier; 2)Post-Processing (PP) GPS monitoring of variations in theextension of the surface occupied by ski slopes and thenumber of crevasses present; 3) preparation of geomor-phologic sketches and thematic maps using GIS , servingto represent the variationsin area over time.200The data processing and analysis followed those steps:1) comparison of four topographic DEMs in order todetermine the variations in glacier thickness during thesummer months and to evaluate the mass balance; 2) pro-cessing of the stake measurement variation data to deter-mine the ablation rates; 3) filtering of the radar tracks sur-veyed and interpretation of GPR profiles to determine thethicknesses and to prepare an isopach map (fig. 1) show-ing the morphology of the bedrock; 4) seasonal evaluationof the variations in the extension of the ski-trails sur faceand in the evolution of the number of crevasses present; 5)comparison of the historical maps (1955-1981) by meansof digitalization and the evaluation of the variations inthickness that took place; comparison of the 1981 mapwith the map prepared in 1999 using the GPS surveys.The main results of the research especially deri vingfrom the comparison of four DEMs led to an assessmentof the thickness and volume variations of the glacier un-der examination.The loss of ice and snow during the 1999 J un e-September period amounted to 441,890 rn' correspondingto a mean thickness of 871 mm. The loss of ice and snow":t00 46.~ l'~ 46.5081~~~ I46.506-j46.50546.504'46.50346.46.501Fig. 1 - Isopach Map obtained from elaboration of GPR survey data.Fig. 2 - H uman impact on Vedretta Piana Glacier , snow pit at the beginningof the summer season in or de r to prepare the ski area for tourist activity.in the 2000 July-September period amounted to 605,876m' corresponding to a mean thickness of 1227 mm. Th eloss of ice and sno w during the September 1999 - Septem-ber 2000 period was equal to 938.920 m'. The specific netmass balance for the 1999/2000 hydrological year thusamounts to -2.138 mm. The glacier's mean thickness wascalculated from the isopach map derived from the radarsurvey and it proved to be equal to 71 m. The glacier vol-ume proved to be equal to 72.500.000 m' over a surfacearea of about 1 km".The GPR surveys reported only partial informationabout glacier' s thickness because scattering and signal ad-sorption, du e to crevasses and to liquid wat er that whichis contained in them, have limited the response of thebedrock surface in the lateral part of the glacier. Themaximum measured thickness is of about 100 m, but thecentral area of Vedretta Piana seems to be deeper.The comparison between the historical maps datingfrom 1955 to )981 revealed a slightl y positive balance,with a mean increase of 2 m. Th e balance for the nexttwenty-year period 0981-1999) proved to be markedlynegative with a mean decrease of slightly over 7 m inthickness.Accumulation as detected by GPS monitoring provedto be influenced by snowcats bringing snow down fromthe upper sections , demonstrating the strong influ ence ofant hropic activities on the dynamics and evolution of theglacier (fig. 2).In conclusion what do es the future hold in store forVedretta Piana? How much longer will it still be possibleto use it for summer skiing? Will this sport accelerate thecurrent dynamics of the glacier? Is sustainable tourism afeasible option?Finding answers to these questions is not an easy mat -ter , for thes e answers are interconnected with the extremecomplexity of a system in which natural dynamic s and hu-man behavior s are int errelated (P inoli, 2000 ). If we utilizethe current thickness of the glacier and the 1999-2000 bal-ance figures, the glacier proves to have a survival time of35 years. However , if we consider the lon ger -term data re-sulting from the comparison of the maps available 0955-1981-1999) , the glacier's survival time (Haeberli & Hoelt-ze, 1995) increases to 70 years. Obviously, although the re-search results are highly reliable in terms of the volumeand thickness measurements, they are less reliabl e as re-gards the calculation of the glacier' s sur vival time. In fact ,the estimates are based on the very likely, but not certainsupposition that present-day climatic conditions will notchan ge, except in the sense of a further rise in tempera-ture. This will evidently have a clear-cut negative influenceon the «glacier's health» and its «skiing potential», in-creasin g the annual ablation rate. However , if an event likethe Cold Event of the second half of 20th century (Pinna,1996) were to occur, it would favour the continuation ofsummer skiing , for it increased glacier accumulation areas.If it were not to occur, Vedretta Piana, which could reachextinction as a glacier before the end of the 21st century,would no longer be usable for summer skiing already sev-eral decades before then due to the whole series of pro-cesses that generally accompany the extinction of a glacier(increase in debris cover , reduction of the accumulationarea, rise in the altitude of the snow line, changes in itslongitudinal profile and surface morphology). Th e conse -quence would be a possibility of glacier use for summerskiing for slightly over twenty years. Moreover, thi s periodcould be further reduced if the influence of man on itsmass balance were to become of massive scope.In any case , the supply of tourist-related offerings inthe Stelvio Pass district will necessarily have to be diversi-fied in order to contribute to the delicate balance betweeneconomic needs and the preservation of natural assets inthe desired direction of Sustainable Development.RE FERENCESDESIO A. (1967) - I Gbiacciaidell'Ortles Cevedale, Comitate G laciologi-co It aliano, Torino , 874 pp.DIo LAIuTI G ., PELFINI M.& SMIRAGLIA C. (in press) - If turis mo estiuo alPasso dello Stelvio (A lpi Centrali): problemi e prospettiue della[ruizi-one antropica di un gbiacciaio alpino in un 'area protetta. P roceedingsof th e Internation al Worksho p on National Park an d P rot ect Are as,Sharm el She ik 28 Ma j-2 June 2000.HAEBERLl W . & H OELZLE M. (995 ) - Application of inventory data forestimating characteristics of and regional climate change effects onmountain glaciers: a pilot study with the European Alps. Ann. G la-ciol., 21 , 206-212.PINNA M. (996) - Le uariazioni recenti del clima, Angeli, Milano , 214 pp .P INOLI M . (2000) - Manuale di gestione ambientale per l'area gbiacciaio.Montana, Mila no, 16 pp.SMIRAGLIA C. & DIOLf\I UTI G. (a cura di ) (2000) - La Vedretta Piana nelParco Nazionale dello Steluio. Caratterirzazione geonzctrica c dinami-ca. Relazione sui risultati delle ricerche sve lte nell'amb iro della con-venzione con il Co mitate di G estion e Lombardo del P arco N azio-nale delle Stelvio, Milano , pp. 55 .(ms. received 1September 2001,.accepted 1 November 20Q])201

THE PHYSICAL EVOLUTION OF AND THE ANTHROPIC IMPACT ON
A GLACIER SUBJECTED TO A HIGH INFLUX OF TOURISTS:
VEDRETTA PlANA GLACIER (ITALIAN ALPS)

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THE PHYSICAL EVOLUTION OF AND THE ANTHROPIC IMPACT ON A GLACIER SUBJECTED TO A HIGH INFLUX OF TOURISTS: VEDRETTA PlANA GLACIER (ITALIAN ALPS)

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