Master Plan Implementation - Challenges and Lessons Learnt
Annual Conference
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The rapid growth of Hamilton has brought with it significant challenges, including maintaining suitable clean water services in the future. Seven years ago, Hamilton City Council (HCC) and Mott MacDonald embarked on a joint journey to develop a comprehensive water strategy addressing current system performance issues and future shortfalls. This resulted in the development of a 30-year Master Plan recommending network upgrades to address current and forecast system performance issues identified using a detailed water supply hydraulic model.
As options started to be implemented, multiple challenges arose:
- From a planning and modelling perspective, the model’s limitations were highlighted during the early phase of options implementation. The model includes a single set of controls and was based on peak day conditions whereas operations and demands vary daily. Despite being calibrated the model still depicts a “flawless” image of the network. However, due to incorrect valve status in the network, multiple operational issues occurred during the upgrades implementation. This experience affected the trust that the project team had in the model and in the proposed solution. Another challenge identified during the implementation of upgrades was the modellers limited involvement past the planning phase, which resulted in design issues and postponing the original program of work.
- From an operational perspective, multiple challenges had to be overcome as the zones were being implemented. An erroneously closed valve resulted in part of the network to run out of water during the implementation of a new water supply zone, while zone boundary valves were found to be passing. A valve check including specialised acoustic equipment had to be carried out to identify the passing valves. A pump station was installed, this was initially intended to (and designed for) solely pumping into a reservoir but it was found that this pump is also used to service customers demand, far from its designed duty point and flow range. In a different zone, booster pumps were not adequately designed, resulting in postponing the zone closure. No bypass was included in the design of a new reservoir, which reinforced the resistance to implementing the zone closure.
These challenges are being addressed to ensure a smoother implementation in the future:
- From a planning perspective, the GIS and population data are being updated and the model recalibrated. An automated model validation tool is being developed to model any demand and control scenario based on real time data. The modellers are now working with the design team to ensure assumptions and recommendations are well understood.
- From an operational perspective, lessons learnt are collected from early implementation work. Boundary valves are planned to be verified for passing water as they are being closed. A valve check was carried out inside the boundary of a new zone to prevent areas running out of water due to erroneously closed valve. 20% of the valves on major pipes were found to be closed in this zone, confirming the need for a comprehensive valve check prior any zone closure.