Lat., where the Vistula, Netze, Warthe, Oder, Spree and Havel form vast swampy lowlands (in German called Brche), which have been considerably reduced by the construction of canals and by cultivation, improvements due in large measure to Frederick the Great.
Long), the Reek Canal (92 m.), the Riidersdorfer Gewasser (112 m.), the Rheinsberger Canal (1 T4 m.), and the Sacrow-Paretzer Canal (io m.), besides which the Spree has been canalized for a distance of 28 m., and the Elbe for a distance of 70 m.
The first three cross the Spree and the last two the Landwehr Canal.
The Landwehr Canal, leaving the Spree near the Schlesische Tor (gate), and rejoining it at Charlottenburg, after a course of 6 m., adds not a little to the charm of the southern and western districts, being flanked by fine boulevards and crossed by many handsome bridges.
Important engineering work was planned not only to afford a more convenient waterway between the upper Spree and the Havel (and thus to the Elbe), but was to remove from the city to its banks and vicinity those factories of which the noxious, gases and other poisonous emanations were regarded as dangerous to the health of the community.