Seite - 204 - in The Power of Urban Water - Studies in premodern urbanism

204 ChristianRohr Den 12 January Anno 1573 ist die gros Eysgüß khu(m)mben vnd in der höch gewesenwie der strich hie vndten verzaichent ist vndhat gewert zwelff tag langundgrossen [s]chadengethan (On 12 January in the year of 1573 therewas a huge ice flood,which reached the level shownby the line below. It lasted for 12 daysand caused immensedamage).36 Historical floodmarksareuseful onlyup toapoint forhydrological research, becausewehave to consider natural dynamic processes in thewatercourse, anthropogenic impact on the river andonthe inscriptions themselves (e.g. theyaresometimes freshlypaintedordisplaced).How- ever, wemay rather use themas signs ofmemory for ‘cultures of floodmanagement’, that is, as a ‘mementonaturae’ to keep risk awareness alive. The ice floodof 1784 The Lakagígar (Laki) volcanic eruption in Icelandduring 1783was followedby a very cool fall and severewinter in 1783/1784,whichwas characterisedby low temperatures, frozen soil, ice- bound watercourses and high rates of snow accumulation across much of Europe. Sudden warming coupledwith rainfall led to rapid snowmelt, resulting in a series of flooding phases. The first phase of flooding occurred in lateDecember 1783 and early January 1784 in England, France, theLowCountriesandhistoricalHungary,but thesecondphaseat the turnofFebruary toMarch 1784wasof greater extent, generatedby themeltingof anunusually largeaccumula- tion of snow and river ice. This phase affected catchments across France and Central Europe, where it is still considered one of the most disastrous known floods throughout the Danube catchment and in southeast Central Europe.37 Cities like Vienna, Bratislava andBudapest suf- fered severe damage from the ice floods, as did Paris, Prague andWürzburg. It is remarkable that theGerman termKatastrophe apparently appeared for the first time related to the natural disasters in 1784, used inanarticle of theZürcher Zeitung.38 The sources for this extremewinter and the ice floods are excellent for many places and in particular for Vienna.39 Narrative sources, including newspapers, are available as well as contemporary images40 and private documents; gauge and weather stations with sub-daily measurementsprovidedobservationsontemperature (inRéaumur),airpressure,winddirection and the water level of the Danube River. TheWiener Zeitung, which appeared twice a week, includednot onlynumerous reports onheavy rain, floods and coldweather related toAustria, Bohemia, France, Germany, historical Hungary, Italy, Portugal, Russia and Spain, but also in- strumentalmeteorological and demographic data fromVienna. Hydrologicalmeasurements at the Vienna-Tabor gaugeweremade under the direction of the K. K.Wasserbau-Administrator Jean-Baptiste Bréquin (1712–1785) andwere published in theWiener Zeitunguntil his death in January 1785.41 Theweather situationand the impactof the ice floodcan thereforebe reconstructed insome detail: after an extremely cold January, in particular around 7January 1784, daily temperatures rose frombelow0°C to 10°Con25and26February,which–coupledwith rainfall – caused the rapid (i.e. within hours) breaking of the river ice. During the night of 26–27 February, ice and 36 Rohr 2013, 137. 37 ForaEuropean-scale reconstructionof thisevent, seeBrázdil etal. 2010.Foradetailedanalysisof thesituation inSaxony, seePoliwoda 2007, 59–84; for theRhineland (cities of BonnandCologne), seeEnnen 1999. 38 Zürcher Zeitung, 15March 1784. Cf. Poliwoda 2007, 30. 39 For the situation inViennaandalong theDanubeRiver inLowerAustria, see alsoStrömmer 2003, 209–213. 40 For Vienna see, for instance, a coloured copperplate print by Hieronymus Löschenkohl (1784), showing the floodedLeopoldstadt quarter inVienna (Vienna,WienMuseum, Inv.No.HMW13431). 41 See indetail Schönburg-Hartenstein–Zedinger 2004.