Analysis of economic level of leakage in water distribution networks: Antalya Kaleici case study

It is essential to plan for water resources usage carefully due to increasing drought and water shortage. In this regard, leakage, occurring in water distribution networks, must be managed and reduced for using water resources efficiently. Water losses may occur in two different types in water distribution networks. Real losses arise from leakages on mains, service connections and reservoir overflows. Apparent losses are due to metering errors, illegal consumptions, and meter accuracy errors. Water is not only lost physically but also commercially. Reducing water losses in water distribution networks comes with a production cost to water utility. Decreasing water losses rates implies increasing repair costs. There is always background leakage in networks so that water losses will never be equal to zero. There is a leakage level which further reduction of leakage will not be economical. This level is called economic level of leakage. Economic level of leakage varies from one system to another. It depends on water resources availability, energy and chemical costs, water distribution network infrastructure conditions, water pressure and active leakage control cost. It is important for water utilities to determine their economic level of leakage and reduce leakages to that level. Economic level of leakage is the summation of the economic levels of the three leakage types namely background, reported and unreported leakages. Economic level of leakage can be calculated for short term and long term period. In this study, water distribution network in Antalya Kaleiçi network data sets were examined for the year 2015 & 2016. Short term economic level of leakage is estimated with rate of rise of unreported leakage using flow records from SCADA, active leakage control cost and variable cost of water. Physical water losses are estimated from water balance table with the help of ASAT customer database. As a result, economic level of leakage and current annual water losses are compared. Economic level of leakage was much lower than current annual water losses. Consequently, the water authority is encouraged to further reduce physical water losses up to the economic level.