Seite - 252 - in The Power of Urban Water - Studies in premodern urbanism

252 RainerSchreg Fig. 4:Regensburg, sediments at the excavationof the ‘Donaumarkt’. maincourseof theDanubenowusedariverbedclose to thenorthernflankof thevalley,causing theRegensburg towncouncil to redirect the river back to the city. Thenorthernbankwasonly partiallyunder the town’s control and therefore a longdebateover the legal rights on the river startedwith theBavarianduke.12 At Bamberg, whichwas situated at the foot of the old Babenburg castle within a riverine landscape of water channels and islands, we can also trace changes of urbanwater.13Within the Staufian period, the riverside opposite to the castlewas fortified by a new townwall; this affectedalso the topography.Anold river channel,wheremanysubfossil treeshadbeendepos- ited, mainly in the Roman period, was first transformed into a small ditch and later filled in completely (Fig. 5). Groundwater levelwas risingduring theLateMiddleAges, as indicatedby soil marks.14 During later centuries, the hydrological topographywas adapted to themultiple uses of urban water as a waterway and as an energy source, but also as a water supply for tanneries and sewers.15 Today there isplentyof evidenceofmedieval construction inconnectionwithwaterduring the firstmillennium in Central andWestern Europe, primarily coming from an archaeological interest in long-distance trade.Whatwecan learn from this research is that alteringhydrologi- cal landscapeswas common practice already in the firstmillennium.16 Environmental history provides abroad record ofwater regulation in various landscapes, but only in a fewcases has archaeological evidenceof this been identified.17 Topographies of urban water thus need to be thoroughly researched in order to identify possible landscapemodifications in the course of urbandevelopment. 12 Knoll 2013, 298. 13 Gunzelmann2009. 14 Schöpplein 2016, 51f. 54f. 15 Hanemann–Dengler-Schreiber 2009. 16 Kröger et al. 2017;Werther–Kröger 2017. 17 Castanet 2011; compare theongoing researchproject atHeidelbergUniversity: Landunter?–Hochwasser und HochwasserschutzmaßnahmenamOberrhein zwischendem frühenundhohenMittelalter <https://www.geog.uni- heidelberg.de/geomorph/land_unter.html> (23.04.2019).