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KAPITI WATER SUPPLY: GETTING IT RIGHT Phillip Stroud (Kapiti Coast District Council), Andrew Watson & Nathan Baker (CH2M Beca Ltd) Abstract number of setbacks since Council’s application to augment the supply from the Otaki River Over the last five years the water supply for was declined in 2001. The consequence of that Waikanae, Paraparaumu and Raumati on the application being declined was that Council Kapiti Coast has gone from being a locally developed a groundwater supply in the contentious issue, to now having a clear way Waikanae area for augmentation, but the water forward. quality of that source (hardness and saltiness) was disliked by the community. This paper describes how Kapiti Coast District Council, in resolving to commit to a well- As the population of the community continued resourced project and a robust process for to grow through the 2000s, the capacity of the addressing its water supply issues, has supply was once again under pressure, and reached a position where it now has a definitive planning commenced on the search for a water supply plan for the next 100 years. publicly acceptable long term sustainable solution. Because of the high level of interest in Key Words water supply by the community, and the contentious history, in 2008 Council committed water supply; Kapiti; innovation; sweating to a well-resourced project that would bring the assets; community engagement; iwi community on board and deliver a 50 year partnership; resource consent. water supply solution. Planning, Setting Up, and Resourcing In its 2008 resolution to address the long term issues of the WPR water supply, Council Introduction committed a budget of $23 million for the project in its 2009 LTCCP. As part of the After more than 20 years of struggling to get a setting up of the project, Council appointed a water supply that meets the needs of its dedicated in-house Project Manager who held growing community, Kapiti Coast District this role until 2013. Council (Council) now has a clear way forward. This paper describes Council’s journey from a Council decided to procure the necessary position where historically it was grappling with technical resources for delivering the project. A the future of its water supply, to having a carefully staged process was used for the definitive water supply plan for the next 100 selection of the lead consultant: years. Expression of interest (EoI) using Tenderlink The outcomes of this project demonstrate the (11 submissions were received) benefits of local government taking a broad Evaluation of the EoIs and shortlisting to and holistic approach to asset planning, as this four can result in new ways to sweat existing assets Request for Proposal from the four that are prudent in both financial and resilience terms. shortlisted consultants Evaluation of proposals and further Background to Project shortlisting to two Formal presentation by, and Interviewing of, Water supply on the Kapiti Coast for the the two shortlisted consultants communities of Waikanae, Paraparaumu and Selection of preferred consultant Raumati (WPR) has been a locally contentious Agreement of commercial terms and setting issue for over 20 years. The supply has had a of project budgets 1 50 year planning horizon). Headroom has also The procurement process worked well for been included to account for uncertainty in the Council, and the interview in particular was population and demand forecasts – this found to be a useful test of the consultants’ equates to about 6,000 m³/day. proposed teams. A very similar process was used in 2014 for another major Council project. The 50 year planning horizon forecasted a demand of 32,300m3/day, about 40% more Engineering Details than the existing consents for both the abstraction from the Waikanae River and the Current Waikanae, Paraparaumu & Raumati borefield (23,000 m3/day). (WPR) Water Supply Selection of River Recharge Option The current WPR water supply is based on a run-of-river system on the Waikanae River. The The first stage of the project involved reviewing abstracted river water is treated at the and consolidating over 150 reports that had Waikanae Water Treatment Plant (WTP) been prepared over the previous 25 years, and before being distributed to the community. In developing a long-list of 41 options. The long- dry summer periods, when the river is in low list was reviewed for high level fatal flaws and flow (nearing 750 L/s), the minimum flow reduced down to 32 options. The second stage requirements of the river mean that the river involved extensive community and stakeholder abstraction has to be reduced and at times consultation to establish local values, as well cease. The run-of-river source then needs to as criteria and weightings against which those be supplemented by, or entirely replaced by, values could be measured. The criteria groundwater from the borefield in Waikanae. included: affordability, reliability of supply, The groundwater is piped via dedicated water quality (including taste), technical, pipelines to the Waikanae WTP. environmental and social. Water quality was assigned the highest weighting of all of the Water from the borefield is criticised by criteria. consumers for its taste and hardness, and causing scaling problems with electrical Multi-criteria analysis (MCA) was used to appliances. shortlist down from the 32 options to eight options (three dam options, two storage pond Forecast Demands options, and three groundwater options). Those eight options were carried forward into the third Water demands were forecasted for the WPR stage. community out to 2060. Future gross peak day demand for the WPR water supply has been The third stage, which commenced in April set at 490 L/person/day for forecasting, which 2010, involved a wide range of investigations; assumes that demand management, water further consultation, preliminary statutory conservation measures and loss reduction planning, and concept design and cost work will achieve savings to reduce the current estimating. Stage 3 was completed in peak demands to 490 L/person/day or less. September 2010 with Council selecting River After the local body elections in 2010 the new Recharge with Groundwater (RRwGW) as its Council took a fresh look at universal metering, preferred solution. The subsequent stages and resolved to introduce it to help manage involved groundwater and ecological demand and better understand water losses. investigations, groundwater modelling, concept Council anticipates that it will take two years design, assessment of environmental effects, from the first water meter bill (being issued July cultural impact assessment and consenting. 2014) for peak demand to reduce from current The consents for the project were granted in levels (being around 590L/person/day) to the September 2013. target 490L/person/day. Stage 3 of the project investigated three dam This per capita demand target was applied to options, two storage pond options, and three Council’s population projection data to derive a groundwater options from within the WPR peak daily demand for WPR. Council’s policy is catchment. In addition, two options to take from to allow for a medium population growth the Otaki River were added into this stage, to scenario in its forecasting (26,000 people in the ensure that Council had sufficient information 2 in front of it to make the best decision possible Description of RRwGW (the Otaki River had previously been ruled out as a source as it was not consistent with The underlying concept of RRwGW is that Council’s Water Strategy preference for in- rather than putting the groundwater into the catchment sources). The key output from the water supply for community consumption, the Stage 3 work was the ranking of the options water piped to the treatment plant will be following a detailed evaluation on the basis of discharged to the Waikanae River, immediately risk-based cost estimates and a range of other downstream of the water supply intake. The values determined from the consultation groundwater discharge will bolster river flows (engineering, water quality, yield/security, immediately downstream of the intake and thus environmental impacts, and social enable more water to be taken from the river impacts/community acceptance). while maintaining the minimum flow. Figure 1 shows the basic concept of RRwGW. RRwGW was the top ranked, followed by a 2 million m3 dam on the Maungakotukutuku Stream (a tributary of the Waikanae River). RRwGW came out on top because it made prudent use of the infrastructure of the existing borefield and could be efficiently staged over time to meet increasing demand, therefore being more economically viable than the immediate high upfront cost of building a dam. RRwGW had no identified fatal flaws, and achieved the highest ranking in terms of the environmental, social, cultural and technical values. The Maungakotukutuku Dam (the second ranked option) was the culmination of Fig. 1 Basic Concept of River Recharge extensive investigations of all possible dam sites in the area. KCDC realised that this site represented a way of further future-proofing the WPR water supply. So, although the project’s To increase the yield from the borefield, the planning horizon was 50 years, this realisation design of RRwGW allowed for the addition of allowed a 100-year vision to be locked in by four new wells, the decommissioning of one Council resolving to purchase the land and well with poor water quality, and a number of signal its intention to develop a dam on the site other changes to ultimately have eleven wells in about 50 years’ time in the District Plan. The for the 50 year planning horizon. New land purchase involved negotiating with five interconnecting pipelines from the new wells landowners, removal and biodiversity offsetting are also required. of a covenant, and the development of a three way land management agreement between Community, Iwi and Stakeholder DOC, a private landowner and Council.

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