Seite - 258 - in The Power of Urban Water - Studies in premodern urbanism

258 RainerSchreg in thecessationof travertine formation.Thedepositionof travertinedependsonoxygentransfer to the calcareous water. When water courses were regulated, limescale became increasingly rare.The reduced travertine formationprobablyopened theGeislingerSteige, crossing theRoh- rachvalley, alreadyprior to the foundingof the town.Whereas theRoman roadsbypassed the Rohrachvalley for largedistances, theGeislinger Steigebecamean important routeduring the EarlyMiddleAges, altering themain lines of traffic in suchaway that the topographical situa- tionofUlmgained in importance.34 Urbanwater andbighistory Theexampleof thekarst landscapeof theSwabianAlb referred to a specific regional phenom- enonof the interactionbetweenurbanisation andhydrology.However, there is amore general interdependencebetweenurbanisationandhydrology,whichwasprobably, insomeways,valid for themajority of old agrarian landscapes in Central Europe. Urbanwater is not only related to specific urban infrastructure, but is also part ofwider ecological changes andpossibly also a factor in the latemedieval crisis. Beyondurbanwater: indirect consequencesof urbanisation on thehydrologyofmoredistant rural landscapes The typicalmedieval village inmost parts of southern Germany developed only in the 10th to 13thcenturies. Within this complex process, urbanisation was certainly an important factor, even if we still do not understand the interrelation in all details.35 The discovery ofmedieval settlement areas outside the later villages – abandoned in Southwestern Germany in the 12th/ 13thcenturies, in Southern Bavaria probably already in the 10th/11thcenturies – give a clear indicationofbasic changesof rural settlement structures.36 It becomesclear, however, that the medievalvillage formationwasa long lasting, complexprocesswithmanyregionaldifferences. Thebackgroundof these changeswithin the rural settlement pattern is characterisedby social andeconomicchanges, suchas therestructuringof thearistocracy (riseof thegentry,establish- ment of castles), urbanisation, and the intensification of land use.Marginal landscapes, such as the lowmountain ranges of the Palatinate Forest, theBlack Forest, the Spessart region and theBayerischeWald (BavarianForest) gained in economic importance. There is increasingevi- denceof earlymedieval activities causing soil erosionby local clearings, as thesemountainous landscapes becamemore andmore important as energy sources for firewood andwatermills. Within theoldagrarian landscapes,wemaypresume that theestablishmentof regulated three- field crop rotation (Dreizelgen or geregelte Dreifelderwirtschaft) was amajor element in village formation.Whereasasimplecroprotationwasalreadyknown, the innovationof theHighMiddle Ageswascompulsorycrop rotation (Flurzwang),which requiredanequallydistributed landhold- ingover the threeareasof crop rotation.Regulationswere controlledby the farmers’ community (Markgenossenschaft/Gemeinde)whichnowevolved,partly in imitationofurbanadministration. 34 Schreg 2009a, 86–89. 35 Schreg 2013a. 36 Schreg 2006, 323–328; Schreg 2009c.