Yarra Valley Water provides water supply and sewerage services to 1.5 million people in the Yarra River catchment area of Melbourne, in the state of Victoria. It began operations on 1 January 1995, following the restructuring of Melbourne’s water industry in 1994.
The company is owned by the State Government of Victoria and operates under a Board of Directors, with an operating license issued under the Water Industry Act. It has two regulators: the Essential Service Commission, which sets its prices, and the Environmental Protection Authority, which manages the environmental aspects of its operation.
The company serves an area of 3,955km2 of Melbourne’s northern and eastern suburbs, which contain 8,380km of water mains and 8,350km of sewer mains. For the last three years, it has been an extensive user of InfoWorks CS, and two years ago upgraded its 2,000 node versions of the wastewater software solution to unlimited node versions in its push towards the creation of ´all pipe´ models of its network.
In 1998, all of the company’s hydraulic models were built and calibrated using HydroWorks, a Wallingford Software modeling product that is no longer sold, but in 2002 the decision was made to start rebuilding and recalibrating the models to include all pipes within the network. The drivers behind this included:
- Minimizing the number of assumptions (such as friction coefficients to simulate flow through manholes and around bends which had been removed, adding large storages to one manhole to accommodate those which had been removed and so on);
- Being able to analyze the catchment down to individual property level, as much of the major hydraulic upgrade works are now completed and Yarra Valley Water is focusing on a more localized/customer level;
- Advances in computer technology to allow larger networks to be run within acceptable timeframes;
- The need to upgrade all licenses to 'unlimited node' to allow the work to go ahead
The company had used HydroWorks to create models of the sewer system down to reticulation level – the smallest pipes in its system. These were used for strategic planning – particularly for analyzing system performance, reducing wet weather overflows and assessing servicing options to meet growth.
The Yarra Valley Water sewer network is represented by 40 models in all. Of these, nine have been rebuilt with all pipes included, while the remainder have been converted from their previous HydroWorks format and skeletonized down to pipes with diameters of 225mm or greater.
Model rebuilding is being undertaken using a software package developed in-house, which creates csv files and MapInfo sub-catchment shapes for importing directly into InfoWorks. These models have already been successfully used for strategic planning – particularly for analyzing system performance, reducing wet weather overflows and assessing servicing options to meet growth.
More recently, InfoWorks data has been used by the operations area for incident management and has proved invaluable for predicting spill locations based on a given rainfall event. Team Leader for the Sewer Asset Management Group, Glenn Wilson said: 'InfoWorks has become a vital link between key areas of the business and provides reliable and consistent information throughout the planning process.'
Forward planning of the sewerage network generally falls into the following key categories:
- System upgrades to meet the EPA containment standard (including pump station upgrades, preventing emergency relief structures from spilling, and eliminating spills from manholes);
- System extensions to cater for growth;
- System performance analysis to identify areas of current of future concern.
Once modeled, cost estimates of the required works are passed onto the ESC, which compiles the information in order to determine the end price for the customer.
Senior Planning Engineer, Don Taylor says: 'Yarra Valley Water must be confident that the planned works not only represent a solution that works, but also represent the least community cost and most sustainable solution, and it has been using InfoWorks CS to achieve this objective.'
The company has been building models using an in-house tool known as SMI – Sewer Modeling Interface - which draws data from the Asset Management, GIS, and customer billing databases. It is using InfoWorks CS for all sewer modeling, and using property polygon data in MapInfo format to create its sub-catchment polygon files.
A paper written by Wallingford Software’s Support Manager, Ann Pugh, based on one of Yarra Valley Water’s all pipe models proved that there are significant differences between all pipe and skeletonized models. 'Yarra Valley Water has now set a precedent that many more water companies are now following,' she says.
She adds: 'The models are more expensive to calibrate, but the accuracy is much higher and there is much more information available for analysis, in terms of having results for every pipe. The models have already been used to plan major hydraulic upgrade works with a higher degree of certainty around the chosen solution.'
Yarra Valley plans to continue to rebuild and recalibrate the remainder of its models and investigate the use of a network dongle that will allow the models to be made available to all staff across the business at any time.
It also plans to link the model results back into the GIS system, as with all-pipe models the GIS asset ID is loaded into InfoWorks against each pipe. It has been found already that the all-pipe models are highlighting several 'customer' problems that were not previously evident and will need to be addressed in the company’s capital plan.