Applicable background minimum night flow for leakage management of small district metered areas in Korea

In case of Seoul city in Korea, the level of water leakage from any distribution system is evaluated by comparison of measured minimum night flows (NFMs) with a fixed allowable leakage level. However, infrastructure condition of District Metered Areas (DMAs) could be misjudged, because characteristics of the system are not considered properly. Therefore the components of NFM were estimated in residential and business DMAs by using data of night uses collected by modified option A test and real losses from water balance analysis. A new background minimum night flow equation was developed by the components of NFM. Applicability of the equation was tested on various revenue water % residential and business DMAs. As a result, it is concluded that the new background night flow developed in this study is more reasonable in Korea and could be used to judge whether the DMAs have economically recoverable unreported bursts prior to leakage detection activity.