A key aspect of understanding whether a water distribution system is operating efficiently is having accurate, reliable data on production or supply volume. By monitoring flow into and across a distribution network, municipalities gain important insight impacting pumping, storage and operational decisions, chemical dosing, water loss analysis, system demand management, and asset performance management.
The Village of Buffalo Grove, located in the northwest suburbs of Chicago, had suspected that certain bulk meters at one of their pump stations had begun to drift, but didn’t know the extent of the inaccuracy. As this was the Village’s largest pump station in terms of output, inaccurate readings would prohibit the Village from performing a water balance and detecting costly leaks on its distribution system.
Testing of bulk meters is very challenging because they are large, cumbersome and cannot be easily removed without excessive cost. The Village had already determined that they were going to replace all of their bulk meters over several years but did not have the information needed to know which meter data was most unreliable and, therefore, which meters to replace first.
Aquify was able to quickly assess the Village’s bulk meter accuracies to prioritize their replacement. The first step was to compare flows from the Village’s meters, which measure discharge from each of their four pump stations, to the volumes supplied by their wholesale supplier. This analysis also needed to account for storage volume changes and was completed using Aquify’s data analytics platform. Upon completion of the supply meter data comparison, the one station was identified as having significantly larger discrepancies than the others.
Aquify then field tested the flow at this station by deploying temporary ultrasonic flow meters on both the village’s distribution lines as well as the wholesale supply lines. After further analysis, the results indicated that the pump station’s bulk meters were under-reading by approximately 16% on average. Interestingly, while the reading was inaccurate, it was repeatable which meant that the reading could be adjusted using a formula that would produce a much more realistic reading.
This insight enabled the Village to prioritize the sequencing of their meter replacement program with this station being top priority. Aquify was also able to adjust the Village’s historic data from this station and more accurately interpret readings prior to the replacement, so this data was salvaged and made available for more accurate and reliable analysis such as water loss reports through their four district meter areas (DMAs), reporting on non-revenue water (NRW) and maintaining their system hydraulic model, which is used for capital planning.