THE FIVE TOWNS PROJECT DRINKING WATER FOR SMALL TOWNS

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1 THE FIVE TOWNS PROJECT DRINKING WATER FOR SMALL TOWNS Graeme Dick 1 1. GWMWater, Horsham, VIC ABSTRACT This paper describes how the Five Towns Project provided drinking water to 3,200 people in five remote towns. Specific attention is given to how economy was achieved by leveraging existing infrastructure and selecting systems with low ongoing costs. A paper detailing the planning and philosohpy behind the proposed project solution was presented at OzWater The project was completed in July 2014 and actual outcomes can now be compared to the theory. The paper quantifies key benefits realised through implementation of a regional water treatment strategy and discusses circumstances that may result in this approach being favourable for future drinking water supply projects. Construction, commissioning and operational efficiencies realised during implementation of the project are also discussed and compared to what might have been expected from other potential project solutions. INTRODUCTION Many of the smaller towns in the GWMWater service region are supplied with untreated water. The quality of water supplied to these towns is highly dependent on raw water quality, mainly from storages in the Grampians National Park. Major floods and landslides in January 2011 resulted in high turbidity and coloured water being supplied to most of these untreated water towns. The high turbidity and colour levels (20 NTU and 80 HU) have endured and rural customers have been unable to use the water to wash clothes or bathe. GWMWater identified five of the worst-effected towns (Rupanyup, Minyip, Donald, Jeparit and Wycheproof) for upgrade to drinking water supply. A drinking water supply means increased quality of life, opportunity for growth and is something that most communities take for granted. The Five Towns drinking water supply project was approved to proceed in April 2013 with a target completion date of July BACKGROUND GWMWater s Service Area GWMWater provides water services to 25% of the Victorian state by area, however services only 1% of the state s population. The total population of 71,000 is spread between 71 towns, with only 3 towns having more than 5,000 population (see Table 1 and Figure 7). Table 1: GWMWater region town populations Population No. of towns Towns > 5,000 3 > 1,000 and < 5,000 7 > 500 and < 1,000 8 > 200 and < < Total 71 This highly dispersed and small population creates huge challenges in providing quality water services at affordable prices. Efficient operation and maintenance management of small and remote treatment systems is equally, if not more challenging, than constructing suitable facilites at acceptable capital cost. The general lack of reliable, quality surface water availability throughout the region requires water from a few sources to be transferred huge distances to service the popluation. The cost of treatment is in addition to the already substantial cost of water distribution. GWMWater owns and operates 13,500 kilometres of water pipeline, including the 8,800 kilometre Wimmera Mallee Pipeline network. Over the last 20 years these rural pipelines have superseded the previous channel system, resulting in a massive shift in GWMWater s operational processes.

2 The Five Towns Jeparit, Rupanyup, Minyip, Wycheproof and Donald range in population from 350 to 1,350 and are located in the dryland farming Wimmerra-Mallee region of north-western Victoria (see Figure 1). Raw Water Supply All of the five towns were traditionally supplied with water from an open channel system but were connected to a piped raw water supply from the Wimmera Mallee Pipeline between 2006 and One of the key changes to water quality resulting from this supply alteration related to settling in storages. The channels were run annually and thus required large open storages at each town to hold a year of water demand. These storages provided long detention times and resulted in effective settling of solids. Australian Drinking Water Guidelines without filtration. In an effort to provide customers with clean water after the 2011 floods, the five towns water supplies were dosed with coagulant prior to storage in tanks. This approach made significant water quality improvements but certainly did not provide a drinking water quality supply. Design Demands Design demands for each of the five towns were estimated from first principles using Water Supply Code of Australia criteria and tempered with actual measured historic demands. The final design demand figures are shown in Figure 2. None of the towns have any water intensive industry and it is therefore expected that water demand is directly proportional to population. The pipeline supply now reliably provides water every day of the year and the large open storages were thus replaced with smaller enclosed tanks to balance only a few days of demand. The tanks do not allow the same opportunity for solids settlement and therefore the water quality from the supply source (Lake Bellfield) translates almost directly to the quality of water supplied to customers. Four of the five towns (ex. Jeparit) had previously been classified as drinking water supply because raw water quality had been reasonable and they had chlorine disnfection systems. After the 2011 floods and associated water quality issues, the drinking water classification was removed from these towns as they could no longer meet the Figure 2: Populations and peak day demands Figure 1: Location of the five towns and transfer pipelines

3 BUSINESS CASE OUTCOMES Options considered for provision of drinking water to the five towns are summarised below. 1. Centralised treatment single water treatment plant serving both urban and rural customers on the Wimmera Mallee pipeline network. 2. Regional treatment utilising existing water treatment plants (WTPs) to service additional towns via transfer pipelines. 3. Local treatment construction of new water treatment plants in each town. A Business Case assessment of these three options was completed and determined that the regional treatment strategy was preferable due to lower capital and operational costs. Key design assumptions influencing favourable capital expediture estimates included: 1. Transfer pipelines of relatively small size (DN ) and in rural areas expected to keep capital costs low (see Figure 3). 2. One pipeline (Rupanyup) was suitable to be converted from rural to drinking water supply and avoid need to build a new pipe. 3. Two tranfer pipelines (Donald and Wycheproof) were able to operate under gravity and did not require construction of pump stations. 4. Existing water treatment plants in neighbouring towns had sufficient spare capacity to supply additional towns without augmentation of the treatment process (additional storage tanks required). Key design assumptions influencing favourable ongoing operation and maintenance expediture estimates included: 1. PVC pipelines have a notional design life of 80 years. 2. Large clear water storage (CWS) tank volumes for balancing allow rationalisation of pump and pipe sizing. 3. Existing WTP production is increased without creating new operational sites. ACTUAL PROJECT SCOPE The key concept design assumptions made in Buisness Case development generally held true. Final detailed designs supported the prelimnary concepts for major project infrastructure requirements such as pipe sizing and ability to supply under gravity. Internal stakeholder risk workshopping identified a number of additional scope items to be considered within the project. These items generally related to replacement or maintenance of existing infrastructure to reduce the risk of water quality and reliability issues arising after completion of the project. The full scope of infrastructure works completed under the Five Towns project is summarised in Table 2. Water Treatment Plant Works Although theoretical design production capacities of the existing WTPs was sufficient to supply the additional towns, a number of WTP components required overhaul or replacement to reliably meet full design production rates. The WTPs had generally not been required to run at full production since being constructed years ago. Town Reticulation Works Each of the five towns had previously been supplied with unfiltered water and the reticulations were therefore expected to be holding substantial sediment deposits. An air scouring program was instigated to clean the reticulations as close as possible to introduction of the new water supply. The reticulation valves were also given an overhaul, with several inoperable valves being replaced in each of the towns. Town Tank Cleaning Four of the five towns water supplies had been dosed with coagulant prior to CWS tanks for 2 years. As such, there was expected to be significant solids build-up in the base of the tanks. The tanks were cleaned by divers as close as possible to introduction of the new water supply. Table 2 Construction scope elements of the five towns water supply project Wycheproof Donald Minyip Rupanyup Jeparit Supply source Charlton St Arnaud Murtoa Rainbow Pipeline 26 km 38 km 21 km Existing 31 km Pump Station No No Yes Yes CWS Tanks Chlorinator Upgrade Upgrade Upgrade Upgrade New WTP upgrades Yes Yes Yes Yes Cleaning & upgrade of town reticulation Yes Yes Yes Yes Yes Tank cleaning Yes No Yes Yes No Other 1.5 km rural pipeline duplication - 10 ML open raw water storage at Murtoa Modifications to existing rural pipeline -

4 VALUE FOR MONEY Project Component Costs The total capital cost of the project was $12.2 M, compared to a budget of $11.1 M and Business Case estimate of $12.1 M. A summary of the expenditure on each project component is provided in Table 3. Table 3: Summary of Project Component Costs Project Component Cost Cost ($M) (%) Transfer pipelines Tank clear water storages Pump stations Open raw water storage Chlorinators Existing asset maintenance External design & investigation Land access GWMWater internal costs Total $12.2 M 100% It is shown that expenditure on actual construction of hard infrastructure accounted for about 80% of the total project cost, while the soft components (design, land access, investigation, overheads) was only 20%. This split of costs represents and high proportion of direct expenditure on infrastructure and arguably, indicates that better than average value for money was achieved through delivery of the project. The achievement of this high proportion of project expense on actual infrastructure construction can be partly attributed to the infrastructure installed being relatively simple. However it should be noted that expenditure on land access, environmental and cultural heritage investigations would have been significantly lower if local WTPs had been built. Procurement Strategy Contract pricing for infrastructure works was generally lower than estimated. This can be attributed to a number of factors: 1. Construction market: The relatively low volume of water infrastructure projects in Victoria at the time of the project resulted in highly competitive tender prices. 2. Nature of the works: The bulk of the value of project works (small diameter PVC pipelines, steel panel tanks and pump stations) was relatively simple in nature. This maximised the number of suitable contractors able to tender. 3. Separation of contracts: GWMWater chose to tender separate contracts based on type of works rather than issue single tenders for multidisciplinary works. For example, the pipeline contract involved only pipe-laying and the tanks contract was only to install tanks. 4. Separable Portions: The nature of the works involved repetition of similar construction works at each town. This meant that Separable Portions were able to be used effectively in the tendering process. This approach mitigated timing and contract delivery risks without adversely impacting value for money. Figure 3 Typical terrain for the five towns pipelines construction

5 COST OPTIMISATION Supply Security The final water balance of the five towns supply systems is summarised in Table 4. The general principles of water supply security applied to each system were: 1. Each town should have at least one peak demand day of clear water storage available locally. 2. End towns should have at least two peak demand days of clear water storage available locally. 3. Each end town should have sufficient clear water to cater for three consecutive peak demand days and still satisfy the first criterion. The Charlton and Murtoa water treatment plants have slightly lower design production capacity than the estimated peak daily demand. This shortfall is absorbed by the ability to draw down clear water storages. The capacity of transfer pipelines supplying Donald and Wycheproof is lower than peak day demands at these towns. Again, this shortfall is absorbed by the ability to draw down clear water storages. For each supply system an Operating Philosophy document was prepared, which outlined what operational steps should be taken in the event of supply outage or higher than estimated demand period. In all cases, the operating philosophy was to shut off transfer to the end towns in the event of supply difficulties. This was due to the relatively high ratio of clear water storage capacity to demand at these towns compared to the source towns. The relative level of water supply security at each town is shown graphically in Figure 4. All towns supplied meet the stipulated supply security criteria with Donald having the lowest level of supply security and Rupanyup the highest. Figure 4 Water supply security in each town Asset Rationalisation The supply system designs achieve the desired level of supply security by balancing transfer system capacity and water storage capacity. The level of supply security achieved by most of the five towns is conservative, chiefly due to large storage tanks already existing at Wycheproof, Minyip and Rupanyup. For small towns the construction of additional clear water storage volume is a cost effective way to increase the level of supply security whilst downsizing transfer systems. Peak day demands at small towns in the GWMWater region are typically 3-4 times average day demands and occur only a few days in each year. Therefore supply shortfalls can be buffered by investment in clear water storage volume. Transfer System (source end town) WTP design production (kl/day) Table 4 Water balance data for the five towns Transfer system capacity (kl/day) Peak demand (kl/day) Source town End town Clear water storage (kl) Source town End town Charlton Wycheproof 3, , ,400 n 5,000 St Arnaud Donald 8,000 1,350 3,200 1,600 3,200 3,200 n Murtoa Minyip ,000 1,200 2,000 n 3,000 Murtoa - Rupanyup ,000 Rainbow - Jeparit 2, ,000 n n New storages constructed during five towns project

6 For example, the St Arnaud Donald transfer pipeline operates under gravity and was designed to deliver 250kL less than Donald s peak day demand. Two clear water storage tanks of 1,600kL capacity each were installed at a cost of $230,000 each and these were able to cater for the supply shortfall over short periods. An alternative approach to the design of this system would have been to size the transfer pipe to supply the full peak day demand and halve the CWS volume. The pipe upsizing required would have cost an additional $800,000 and only saved the cost of one CWS tank valued at $230,000. The Murtoa water treatment plant is not designed to supply the full amount of peak demand when supplying Murtoa, Minyip and Rupanyup. The cost of increasing WTP production by augmenting the treatment system could be substantial ($~1.2M), but the cost of buffering the supply shortfall with additional clear water storage tanks is only about $240,000. The economics of using CWS tanks to buffer peak demand is dependent on the actual peak demand levels. For towns with peak demand of < 2 ML/day it is relatively economic to provide multiple days storage in tanks whereas for towns with > 2 ML peak day demand it may be more economical to increase supply capacity to match peak day demand. LESSONS LEARNED The Five Towns project was completed on time and in line with the allocated budget. The key objectives of the project were successfully achieved. This success can be partly attributed to good planning and partly to dealing with issues as they arose during delivery of the project. Key lessons learned during the project are summarised below. Involve Stakeholders A project team with representatives from all GWMWater Divisions met regularly (3-weekly) throughout the project. This allowed a businesswide awareness of the project and provided a mechanism for input. Regular involvement of all parts of the business meant that there were no surprises or roadblocks encountered. Timely Environmental Assessments It transpired that the greatest threat to the success of the project was a moth. Flora and fauna surveys identified potential habitat for the Golden Sun Moth (GSM) on two of the pipe routes. GSM is listed as a critically endangered species under the Environment Protection and Biodiversity Conservation (EPBC) Act. Figure 5 Cost of providing supply security The optimal method of achieving supply security was not strictly applicable to all towns in this project as a number of CWS tanks already existed at required locations. On a fully greenfields project, the sizing of storages and transfer systems could be further rationalised to optimise economic provision of a desired level of supply security. GSM live underground and are only visible in December when they emerge to mate. Given that GWMWater was ready to start construction in November, this caused some scheduling issues. Without an EPBC Act permit, no construction was allowed and the permit would not be given until a December field survey had been completed. This issue was managed by reorganising the construction program and completing 600 metres of horizontal directional drilling through a single area where GSM were found. The lesson learned from this is to identify and consider these seasonal environmental issues as early as possible in a project to prevent major delays in delivery. Upgrade Existing Assets The Five Towns project mostly involved construction of new assets on greenfield sites, but every transfer system connected into existing infrastructure at either end. Figure ML Clear water storage tank These start and end points of the project were purely notional as it was found that many of the existing operational assets were in poor condition.

7 The decision was made to upgrade these assets under the project scope to reduce the risk of supply issues during and after system commissioning. The success of the project would have been soured if associated systems failed soon after commissioning. Failure of existing assets on systems even vaguely related to the project works may have reflected poorly on the project. The additional investment made in upgrading water treatment plants and town reticulations ensured smooth commissioning and perceived success of the project. Commissioning is Key The chosen approach of constructing pipeline transfer systems and tanks meant that the commissioning process for each town was relatively simple. Each of the systems was commissioned and operating as intended within a week of construction completion. This is in stark contrast to the commissioning process that could be expected for a new water treatment plant. The timeline for the project was always tight and this meant that streamlined commissioning processes were critical to successfully meeting completion timeframes. CONCLUSION The Five Towns project was completed on time and in line with the Business Case cost estimate. The objectives of the project were achieved and the systems have now been operating successfully for close to a year. The project has set a precedent for providing drinking water to other small towns where similar regional water treatment strategies may be viable. The regional water treatment strategy adopted to deliver the Five Towns Project proved to be successful on a number of levels. The result is that drinking water is now being provided to 3,200 people in small towns without significantly increasing maintenance and operation requirements for GWMWater. The Five Towns project realised the advantages of construction work in regional areas and implemented a water treatment strategy is a sustainable model for providing drinking water to small towns in regional areas. The five towns now have a consistent high quality water supply which will improve their standard of living and allow further growth of the communities. Public reaction to the project has been overwhelmingly positive despite the tariffs of serviced customers increasing due to the increased quality of water. This indicates the value these communities place on a high quality water supply.

8 Figure 7: GWMWater operational area