Author(s)

L. Ainola, T. Koppel & N. Kändler

Abstract

The main problems in the exploitation of oversized water distribution networks are related to the deterioration of water quality in the network pipes. The changes in water quality are evoked primarily by the ageing of water and different sedimentations. Therefore the flow velocities and their optimisation are essential factors for the rehabilitation of water networks. The dependence of water age on the time in network pipes is investigated. The differential equation for the determination of water age in the typical cases of daily water demands is solved. The problem of optimal flow velocity in pipes is discussed. The topology of urban water distribution system with optimal flow velocities is considered, the number of water mains determined and their supply sectors defined. The diameters of mains for the cases of optimal flow velocities and different consumption of water are determined. With regard to these aspects the detailed investigation of water distribution network of the City Centre of Tallinn is carried out and possibilities for the rehabilitation of the network are explained.

Keywords