Risk assessment study for water supply network using GIS

In recent years, contamination of water in water distribution systems (WDS) has been recognized as a major cause of waterborne diseases. Owing to old and deteriorated pipes, and the presence of pollution sources in contact with the supply line, water boards often decide to replace the network in the interests of public health. This being a cost-intensive and time-consuming programme, decision makers need a basis for phase-wise investment planning. In view of this, Integrated Risk Assessment of Water Distribution System (IRA-WDS) for the supply network of Adikmet Subzone-I in Hyderabad, India, was undertaken. GIS maps were prepared for the water supply network, sewer network, open drains, soil and groundwater table at 1:2,200 scale and ‘pipe condition assessment’ and identification of ‘contaminant ingress’ locations were performed using IRA-WDS. Findings indicated 18 pipes in ‘very bad’ and ‘bad’ condition in the entire network. ‘High risk’ of contamination was exhibited in 20 locations, suggesting the need for rehabilitation of only 2 to 3% of pipes in the initial phase.