A Laboratory Investigation on the Effects of Intermittent Water Supply and Remedial Measures

The intermittent water supply (IWS) of water distribution systems is a common practice caused by the imbalance between available water resources and customers' demands. Transition to the continuous water supply (CWS) is desirable to reduce quality, equity distribution, and pipe integrity issues but is often practically unachievable in the short or medium term. The World Bank funded a laboratory activity at the Water Engineering laboratory of the University of Perugia, Italy, to investigate how remedies can be introduced to mitigate the impacts of IWS and preserve pipe integrity, facilitating the transition from IWS to CWS. The results of the tests with different feeding conditions, downstream outflows, and air valve dimensions and locations are described and discussed in this paper, culminating in typical interventions that can be implemented to reduce, if not completely eliminate, the undesirable consequences.Almost one billion people worldwide are estimated to receive water intermittently, especially in low- and middle-income countries. Intermittent supply has a significant impact on the water quality, equity of water distribution among users, accuracy of the customer meters, and the structural condition of the pipes. Water distribution systems are not usually designed for such an operating approach, and interventions are required to preserve the pipe integrity, particularly in the transition to a continuous water supply. The World Bank funded a laboratory investigation to assess in a controlled environment the causes of the harmful consequences and the remedies that can be introduced to alleviate their impact. This study is of importance not only in preserving existing networks in the transition to a continuous supply situation but also in ensuring that the large sums being invested in new infrastructure will not be wasted.Transition from intermittent to continuous water supply of water distribution systems could be unachievable A laboratory investigation of effects and remedies that can be introduced to mitigate the impacts of intermittent water supply is presented Air release valve design and location and control of the upstream conditions are crucial and must be properly analyzed