The assessment of legitimate water use during the low demand period at night is a critical component in the assessment of leakage and is included in the methodology contained in "Managing Leakage", the report of the National Leakage Initiative. The night leakage component is estimated from the distribution input less the legitimate usage that can be determined.
Although some of the larger metered trade customers will be explicitly measured by loggers or other means, there will be many consumers for which an assessment of their night use is the only practical option. The standard allowances made for the trade night use will typically under-estimate the legitimate use and therefore over-estimate leakage.
ANTS is a PC software product for advanced statistical analysis of meter readings from trade customers. Its primary purpose is to provide an auditable and statistically acceptable estimate of the mean night trade use for those assessed trade consumers. Associated confidence intervals are also defined.
ANTS provides a database for all trade meters and their associated accounts readings which is initially populated from the customer accounts records and is designed to receive updates of these records at intervals.
The trade meter information can be explored by leakage practitioners in a manner which is typically not possible within mainframe customer accounts systems. Filtering and sorting of the data on fields such as operational area, postcode, annual consumption etc. are readily facilitated.
ANTS also holds all types of manual readings (i.e. customer accounts readings, occasional readings (e.g. for drop tests) and statistical sample readings). Logger data may also be summarised and entered into ANTS. The database is designed to hold a full history of flow information for each meter.
As an information management system alone, ANTS provides a single repository of data for the leakage practitioner and network modeller which leads to more productive management of customer data. However the main function of ANTS centres on the statistical facilities for:
definition and management of stratification sets (for customer types with the same night use characteristics - e.g. the WRc categories in Managing Leakage)
selection of random sample sets based on the defined stratification
the definition of data collection rounds for the sample readings
the export of round data to and the import of sample results from hand-held field data capture equipment
the statistical analysis of results obtained including analysis of stratification performance and re-stratification
the extension of sample sets using the initial readings to focus the sampling
the identification of meters which should change status from assessed to logged and vice versa based on the captured data
The software provides extensive reporting of the data and results together with export and import facilities to link with other systems.
ANTS is designed for both supervisory (whole Company) and local area-based use with facilities to export and import both databases and stratification sets.
ANTS runs under the Microsoft WindowsTM family of operating systems.
