The Geographical Information System (GIS) based water quality assessment of a drinking water distribution system in the Denizli City

Abstract

Nowadays, continuous, healthy water supply and total water quality management have emerged as an important issue in engineering applications In a wide ranging assessment, the quality of the drinking water is being monitored in the distribution system, until it is supplied to the end user It includes regular sampling and testing performed for assessing compliance with guideline values The major purpose of this study was to monitor, evaluate and control the water quality in distribution system by using GIS to assess the drinking water quality in Denizli The drinking water necessity in Denizli is supplied from various drinking water sources as Gokpinar, Derindere, Kozlupinar and Benlipinar springs and more than 30 deep wells. The storage reservoir volume fed by the water sources vanes from 20 m(3) to 5500 m(3) Almost 56% of Denizli drinking water distribution system consists of asbestos cement and cast iron pipes The non-revenue water in the water supply system is about 50% In the old distribution systems, epidemic illness risk is at high rate and the free residual chlorine has to be kept at certain amount Therefore, the free residual chlorine amount has to be measured during the summer months against the epidemic danger The chlorine reacts with the organic matter and the amount decreases; it forms the carcinogenic trihalomethanes (THMs) In this study, three organic matter precursors, namely total organic carbon (TOC) concentration, UV absorbance at 254 nm and free residual chlorine concentration has been measured in 30 points at various parts of the Denizli city water distribution system and mapped by GIS