Page - 131 - in The Power of Urban Water - Studies in premodern urbanism

8 Water andDecentringUrbanism in theRomanPeriod 131 Fig. 2:Winchester (VentaBelgarum), divertedRiver Itchen, diversion originating in the Romanperiod. Riversandislandsalsoformedpartofurbandevelopment.ThedevelopmentofLondon(Londin- ium) as a town in theRomanperiod, for example, sawa lot of river canalisation and the con- struction of revetments, because of the large number of rivers and streams that existed in the areawhere the townwas founded.Themainareaof the townwasconstructedonthenorthside of theThameswhere therewere anumberof smaller rivers andstreams flowing into it, includ- ing theWalbrookand theFleet.35 Excavations in theWalbrook areahave located the course of theWalbrook togetherwith evidence of a series of superimposed revetments, each cutting the siltedor backfilled channel of its predecessor.36 The first revetmentdated to the secondhalf of the1st centuryADandthepreservedremainsprovidedsomegoodevidenceof theway inwhich the revetmentswere constructed. The evidence consisted of two rows of vertical timbers set in pairsdriven into theunderlyingdepositswithhorizontalplanks set onedgebetween themand additionalplankssecuredagainst theoutside face.37Therewasalsoa largedumpofclaybehind the revetment, representing consolidation of the ground and the riverbank. The second revet- ment,probablydatingto the2ndcentury,consistedof large timbersat least 1.7mlongand0.3m square, driven their full length into the surface of the bank. Horizontal planks varying from 0.15–0.38mwidewere fixed to these timberswithnails. Aplatformconnectedwith this revet- ment was constructed of heavy wooden planks on a foundation of densely packed vertically drivenpiles.38 On the south side of the Thames at Southwark, settlement developed in a low-lying area where therewere a number of islets of raised landwith river channels flowing between them. 35 E.g.Maloney–deMoulins 1990;Wilmott 1991. 36 Grimes 1968; Shepherd 1998. 37 Shepherd 1998, 40. 38 Shepherd 1998, 41.