Exploring rehabilitation needs and strategies for water distribution networks

As water mains become older, failure rates and leakages tend to increase, despite all maintenance efforts, incurring costly repair and rehabilitation measures. Therefore, water utilities striving to prevent their long-lived assets from decline must explore medium to long-term strategies of network rehabilitation and system improvement. Such explorations must start from the existing stock of water mains, differentiated by materials, ages and lifetimes under local conditions, and take into account the frequency of failures, losses by leakage and the extent of rehabilitation work in the past. Utilities will need to develop specific strategies, depending on their rehabilitation philosophy, and pursue them under tight economic and financial restraints. The exploration of network rehabilitation strategies can be facilitated by a model developed at Karlsruhe University [1], and cast into the user-friendly KANEW software in an AWWARF research project [2]. KANEW has been tested and applied in several European and American water utilities [3]. The approach taken, some results and a case study will be presented from Teplice water mains in Northern Bohemia.