Water Journal : Water Journal May 2014
MAY 2014 WATER 39 Feature Article • In 2012 this project received the IPWEA Vic Award and the Stormwater Victoria Award in the Asset Management Category. Finally, this project was used as an opportunity to implement and trial new technical solutions: • Despite existing concerns about their durability and long-term performance, the project trials two types of porous materials -- interlocking pavers and poured in-situ paving -- in a road subject to heavy semi-trailer and forklift traf c volumes. The performance will be monitored over ve to 10 years. The interlocking pavers seem to be performing well, despite some cracking observed at the interface with the adjoining asphalt pavement; • This project is also trialling an innovative double side-entry pit to act as a primary pre-treatment system. The 'King Trap' (Kingston Pollutant Trap) was developed as an alternative low-cost, practical and effective pit that is extremely simple, robust and easy to maintain. It uses permeable pavers as a removable vertical wall to help separate silt and gross pollutant. Initial observations show that while the pollutant removal is likely to be slightly lower than more sophisticated products, the robustness is high and the cost is low; • Innovative Tide ex ttings were installed at the outfall into Mordialloc Creek to prevent back ow during high tides, which would otherwise contaminate the harvested water. While these valves are very effective, providing excellent long-term value for money, they are also very expensive and need to be imported from the US. LESSONS LEARNT • One of the key lessons from this project was the need for patience. Indeed, the potential to install a major water quality treatment and reuse scheme at this location was rst identi ed by one of council's engineers in 2005; • Developing ongoing relationships with key internal and external decision-makers early on proved useful, as it helped identify opportunities to in uence funding decisions; • The project team developed an effective working partnership with Melbourne Water by involving their experts at an early stage. This resulted in a number of enhancements and the opportunity to obtain a second opinion, which in uenced the overall scope of works; • The key driver for this project was the need to improve the road pavement and the traditional drainage system; however, the ultimate environmentally friendly solution was a key focus of the initial design and not an afterthought. It was also a major advantage for the concept and detail design to be undertaken by someone (in this case an in-house council engineer) who is both an experienced road designer and experienced in the design, construction and maintenance of WSUD projects; • From a construction perspective, the project was invaluable in building internal knowledge and expertise. It highlighted the importance of: -- Having a tender assessment model that appropriately values the contractor's expertise in delivering complex projects as opposed to being driven primarily by price. However, not recommending the cheapest tender submission can be challenging when budgets are tight. -- Being prepared to adopt a different project management model and allocate additional resources to supervision and contract management. -- Identifying a 'champion' within the council's construction team to resolve complex issues and co-ordinate with other stakeholders, specialist contractors and suppliers. -- With projects that include 'cutting edge' design features or products, educating the contractor about the unique features well in advance is critical. Resolving construction problems 'on the y' will not deliver a successful outcome. PROJECT COST The total cost of the project was $2.8m, with the following breakdown: • 7%: Research, design & development; • 49%: Pavement rehabilitation & streetscape works; • 29%: Flood protection; • 15%: Stormwater treatment and harvesting. TIMEFRAME • 2009: Review of existing Stormwater Quality Devices in partnership with Melbourne Water and Cardno; • 2010: Development of the 'King Trap' treatment pit (implemented in 2011); • 2010: MUSIC modelling; • 2011: In partnership with AECOM, development of a 'project scoring system' to strengthen the business case. This system helped con rm the project funding arrangements; • 2011: Detailed design plans and speci cations; • 2011: Water sampling and testing; • 2011: Advertise and award tenders for construction; • 2011--2012: Construction -- Stage 1: Reconstruction of Beach Avenue, gross pollutant traps (B) and underground storage system (C); Stage 2: Reconstruction of Spray Avenue and Wells Road (including porous pavements) and above-ground storage; • 2012: Report on greenhouse gas emissions; • 2013: Construction -- Stage 3: Install bioretention system and pumps. ADDITIONAL INFORMATION In addition to the speci c outcomes this project was the catalyst for the realisation of two related projects whose outcomes can be used to assist with many future proposals: • A unique Water Sensitive Cities 'Project Scoring' system was developed to help managers understand the broader bene ts and compare competing water-sensitive projects as part of business planning and funding decisions; • The design of the stormwater harvesting system also brought about a major review of stormwater quality treatment devices to compare performance, durability, maintenance requirements, whole-of-life costs and overall suitability for industrial streetscapes. While the recommendations are speci c to this project, some of the ndings could be useful to assist decision-making on other similar industrial projects. WJ ACKNOWLEDGEMENTS Thanks to the City of Kingston and, in particular, Alan West, Team Leader Engineering Design, for his contribution to the development of this case study. THE AUTHOR Katia Bratieres (email: katia.bratieres@ clearwater.asn.au) is a Civil Engineer with over six years of research and industry experience in the urban water sector. She is the Project Development Coordinator of the Clearwater Program (www.clearwater.asn.au).
Water Journal April 2014
Water Journal June 2014