Seite - 249 - in The Power of Urban Water - Studies in premodern urbanism

RainerSchreg 15 Human Impact onHydrology Direct and Indirect ConsequencesofMedievalUrbanisation inSouthernGermany Abstract: It is theaimof this contribution towiden theperspectiveonurbanwater.Beyond the archaeological traces of water management related to towns, we need to take the ecological consequences of urbanisation into account. On the one hand, the urban infrastructure with water regulations, channelsandsewershaddirect consequenceson the localhydrology;on the other hand, urbanisation had indirect consequences on the hydrology in more distant rural areas, too.These indirectconsequenceswereprobablyamajor factorof latemedieval landscape changes, whichwere at the basis of the latemedieval crisis. The article uses the situation in SouthernGermany inorder to sketchpossible interrelationsanddemonstrate theperspectiveof humanecology. It is theaimof this contribution to sketch someof the ecological aspects of urbanwater. There is a large bodyof research inboth environmental history andarchaeology.1 There is, however, a fundamentalproblem,becausebasic categories,whichare important foranunderstandingof ecological connections, are not present in the available sources. For example, the terms ‘ener- gy’, ‘climate’ or ‘water run-off’ can neither be found inmedieval texts nor can archaeologists excavate them. Dealingwith aspects of environmental history or human ecology requires the acceptance of abstract categories and an openmind for hypotheses and interdisciplinary ex- change. Otherwise, archaeologists, at least, will be stuck in a typology of sewers and water channels. For this reason, this article will not discuss themany observations onwater usage within the town,but focusona landscapeperspective. The interactionof townsandrivershasmanydimensions,2and ischaracterizedbycomplex interactions. Iwill use some examples fromSouthernGermany to provide at least a rough im- pressionof thiscomplexity.TherearemanytownsinSouthernGermanysituatedonlargerivers, such as the Rhine or theDanube, going back to the Romanperiod or before, but themajority represents towns developingmainly in theHighMiddle Ages,most often also related to some rivers or creeks. Intended landscapemodificationduringurbanisation At first glance, it seems quite easy for archaeology, at least, to identify plannedmodifications ofwaterscapes.AtSalzburg, for example, thebuildersof the 12th-centuryAlmchannel changed the localwater coursesbydigginga tunnelbelowHohensalzburgcastle (Fig. 1). In thisway the townwas supplied with fresh water.3 Inmany other towns, water courses weremodified for mill races, thewater supplyof factories, or for flood fortification systems. In somecases,water courseswerealteredinorder toconstructnavigablewaterwaysor toprevent theriskof flooding. However, inmany cases it is quite difficult to trace anthropological changes to the land- scapeclearly.AtUlm(Fig. 2), forexample, theriverBlaupasses thewesternbluffof theWeinhof 1 Untermann2009. 2 Gunzelmann2009. 3 Zillner 1864. OpenAccess.©2020RainerSchreg, publishedbyDeGruyter. Thiswork is licensedunder theCreative CommonsAttribution-NonCommercial-NoDerivatives4.0 License. https://doi.org/10.1515/9783110677065-015