Self-Cleaning Networks Put to the Test

The Dutch drinking water companies design their water distribution systems according to the so-called New Design Rules, which allow for smaller and more branched distribution systems. Due to higher velocities these design rules hypothetically lead to resuspension and removal of particles and thus to self-cleaning networks. Three distribution networks were selected to test the validity of the new design rules. The first is a conventional (looped) network from 1986. The second network was built in 2002 and is branched but with relatively large diameters (110 and 63 mm). The third one was built in 2004 according to the new design rules: a branched PLUS network (with, at the ends, pipe diameters as small as 40 mm). By means of particle counting, flow measurements and flushing experiments it was proven that the branched PLUS network is self-cleaning, the branched network is partly self-cleaning and in the looped network sediment is building up leading to an increased discoloration risk.