Assessing the results of a virtual pressure management project applied in Kos Town water distribution network

Abstract

Water pressure management (PM) is one of the most cost-effective ways for a water utility to reduce water leakage, pipes’ bursts, improve the level of services provided to its customers and lower its operating expenses. The present paper presents a pilot pressure management project designed for the water distribution system of Kos Town (capital of Kos Island, Greece). Kos Town experiences extreme variations regarding its population served by the local water utility between summer and winter. The PM implementation was achieved by developing the system’s hydraulic simulation model using the commercial software, Watergems V8i. For the water demand allocation of the model, the spatial allocation of water demand at street level approach was used because the customers’ water meters were not geo-referenced. The results were compared to multiplicatively weighted Voronoi diagram method’s results and to field measurements. The simulation process took into account the respective demand patterns of the various types of urban water uses, considering the water volume being lost through leaks/breaks occurring in the pipe network, as a competitive use. Each kind of water used was divided into a pressure dependent part and a volume depended one. Both parts were introduced to the model. The designing phase of the PM included the formation of district metered areas and Pressure Reducing Valves (PRVs) installation. The reduction in pressure within acceptable regulation limits resulted in the reduced needs of System Input Volume (SIV), due to significant reduction of anticipated water losses and authorized consumption, as both these “water uses” are pressure dependent. There were many simulations of different scenarios in time (monthly) and PRVs’ configuration. Regarding the latter, several types of PRVs and their settings were tested (e.g. fixed PRVs; PRVs with modified daily pattern; PRVs combined with local pressure boosters). The virtual scenarios resulted in reducing the SIV up to 24%. The related water savings have a direct positive environmental impact on the aquifer supplying Kos Town. These outcomes persuaded the local water utility to proceed with the actual implementation of the pilot study by installing the necessary system devices (either for measuring data or for pressure reducing) in more than 40 manholes across the town.

Keywords:

• Water losses
• Pressure management
• DMAs
• PRVs

Notes

Presented at the 12th International Conference on Protection and Restoration of the Environment (PRE XII) 29 June–3 July 2014, Skiathos Island, Greece