As part of their leakage reduction efforts in 2013, one of the UKs larger water companies employed HydroCo to assess the suitability of pressure management across their 1,012 DMAs. HydroCo was involved in collating similar data for 310 pressure managed DMAs in a project several years earlier so had an appreciation of what a labour intensive project this could be. Although the advent of SQL tools in InfoWorks could help remove a small number of the manual processes compared to the previous methodology, it would still be an extremely manual process with reduced cost-effectiveness for the water company. Furthermore, a quick turnaround was sought so that any potential leakage saving could be realised sooner rather than later.
HydroCo identified a resourceful and time approach to collating the data, whilst also capturing much more detail than had been possible in the previous study. Because the process was to be largely automated it would also remove the element of unintentional human bias from the process which could easily skew the results when attempting the rank the final outputs. It was accepted that the results, like the previous study, would effectively be a ‘first-pass’ and that it would serve to trigger feasibility studies where significant leakage savings were indicated.
The conception of the proposed new automated methodology was made possible by the completion of another project that HydroCo was instrumental in; the company wide generation of HTD (Hour To Day) factors for leakage assessment. As a key output of the HTD Factor project the pressure results of every node in all of the models at time-steps of 15 minutes were exported into spreadsheets. This was achieved by writing bespoke SQL routines within the InfoWorks environment. Other data exported for every node included, DMA, number of customers, length of main, coordinates and elevation. This information was vital in summarising the hydraulic performance of each DMA
The new process reconciled data from the following sources:-
- Hydraulic and spatial data from the model from the HTD factor exports.
- Spatial data from GIS. This was achieved by writing routines within StruMap to create plots of each DMA and achieve counts of items associated with each DMA. (e.g. customers, bursts and length of recently replaced mains).
- Current leakage rates by DMA from the Leakage Management team.
The resulting outputs took the form of a two page report per DMA. The figures demonstrate the output for two DMAs. The first page is a visual plot of the DMA showing the extent of the DMA, elevations, safeguard customers, PRVs and meters. The second page is a summary of the hydraulic performance of the DMA which also includes burst history, length of recently replaced mains and counts of other relevant features. Of most importance is the figure indicating scope for pressure reduction at night and during the day.
These outputs provided a concise interpretation of a DMA’s performance and proved very how to read. When the two pages are viewed together a ‘picture’ of a DMA’s performance is quickly understood. It was therefore easy for network managers to scan through the outputs and identify the DMAs which were suitable for pressure management. All of the output data was also collated in a spreadsheet table so that the DMAs could be sorted and filtered on any criteria.