Whakatane District Council Plains 50 Year Strategy Study Whakatane District Council Plains 50 Year Strategy Study Version Date Comment 1 September 2014 Draft for comment Prepared By Opus International Consultants Ltd Jeff McLean Christchurch Environmental Office Senior Hydraulic Modeller 20 Moorhouse Avenue PO Box 1482, Christchurch Mail Centre, Christchurch 8140 New Zealand Reviewed By Telephone: +64 3 363 5400 Dan Johnson Facsimile: +64 3 365 7858 Work Group Manager Date: September 2014 Reference: 2-88131.04 Status: Draft Approved for Release By Peter Askey Principal Environmental Engineer © Opus International Consultants Ltd 2014 i Contents Executive Summary ....................................................................................................1 1 Background .........................................................................................................1 2 System Description and Current Operation........................................................ 2 2.1 General ................................................................................................................................... 2 2.2 Sources ................................................................................................................................... 2 2.3 Paul Road Borefield............................................................................................................... 2 2.4 Reservoirs .............................................................................................................................. 4 2.5 Pressure Zones....................................................................................................................... 4 3 Level of Service and Water Entitlement ............................................................. 7 3.1 Pressure.................................................................................................................................. 7 3.2 Fire Flow Availability ............................................................................................................ 7 3.3 Water Entitlement ................................................................................................................. 7 4 Timeframes and Planning Scenarios .................................................................. 8 4.1 Phasing ................................................................................................................................... 8 4.2 Operational and Asset Changes .......................................................................................... 10 4.3 Ministry of Health Subsidy for Edgecumbe ...................................................................... 10 4.4 Emergency Supply to Whakatane ...................................................................................... 10 4.5 Resolve Issues with Current Operation .............................................................................. 11 4.6 Paul Road and Link to Network .......................................................................................... 11 4.7 Phase A .................................................................................................................................. 11 4.8 Phase B .................................................................................................................................. 11 4.9 Phase C .................................................................................................................................. 12 4.10 Phase D ................................................................................................................................. 12 4.11 Phase E .................................................................................................................................. 12 4.12 Phase F .................................................................................................................................. 12 4.13 Extension to 15 m contour ................................................................................................... 13 5 Key Assumptions ............................................................................................... 15 5.1 General .................................................................................................................................. 15 5.2 Demand and Modelling ....................................................................................................... 15 5.3 Paul Road .............................................................................................................................. 15 5.4 Awakeri Reservoir ................................................................................................................16 5.5 Design and Cost Estimating ................................................................................................ 17 6 Scenario Outputs and Costing .............................................................................1 6.1 Overall Summary .................................................................................................................... 1 6.2 Resolve Low Pressures with Current Operation ................................................................. 3 6.3 Develop Paul Road and Pipeline to Whakatane WTP ........................................................ 4 6.4 Phase A Development ........................................................................................................... 4 6.5 Phase B Development ........................................................................................................... 5 2-88131.04 | September 2014 Opus International Consultants Ltd ii 6.6 Phase C Development ........................................................................................................... 5 6.7 Phase D Development ........................................................................................................... 5 6.8 Phase E Development ........................................................................................................... 5 6.9 Phase F Development............................................................................................................ 6 6.10 Extension to 15 m Contour ................................................................................................... 6 2-88131.04 | September 2014 Opus International Consultants Ltd 1 Executive Summary The Plains 50 Year Strategy Study (Strategy) has developed from the initial 50 Year Strategy Study carried out in 2010, and the Plains and Awakeri Extension Water Upgrade Strategy, which was prepared in 2007. Since 2010 a number of options have been considered, and amendments made to the Strategy. In 2013 Whakatane District Council received funding from the Ministry of Health to develop the Paul Road borefield and supply Edgecumbe. The Strategy provides information for Whakatane District Council (WDC) to assess the options for future supply for the Plains over the next 50 years, and the upgrades required above the funded works to supply Edgecumbe. The Strategy describes a framework for development of the Plains water supply over a 50 year period. The Strategy details the assumptions behind the proposed development, and computer modelling of the supply. Development is to begin with the Paul Road borefield being developed as a new major source of water for the Plains, and resolving low pressure issues across the scheme, as well as fire flow compliance issues in Edgecumbe. There is a major decision to be made about whether the Paul Road source will be used to provide an emergency supply of water to Whakatane. Two options for emergency supply have been considered in the Strategy; 4 ML/d or 8 ML/d supply to Whakatane. The 4 ML/d supply would require blending with the current Whakatane River source, or restrictions to be applied if the emergency supply was required during peak demand. The Strategy identifies the upgrades required to resolve low pressure or fire flow issues across the scheme, and the upgrades required to service proposed new connections as the water supply is developed. The cost estimate to supply the Plains for the 50 Year Strategy is $26.8M. To provide emergency supply to Whakatane will cost an extra $3.4M for 4 ML/d or $8.3M for 8 ML/d. Work on the Paul Road borefield and pipeline to Edgecumbe are due to begin in the current financial year 2014-15. The pipe size to be installed will depend on what decision is made on the emergency supply to Whakatane. The proposed pipe size and cost share is shown below. Emergency Supply Emergency Supply Plains Supply to 50 Item to Whakatane to Whakatane Year Boundary (4 ML/d) (8 ML/d) Pipe Size (all PE100 DN225 Edgecumbe DN400 DN500 PN12.5) to Awakeri Road DN355 Plains Edgecumbe cost share $2.2 M $2.2 M $2.2 M Plains cost share $1.6 M $1.6 M $1.6 M Whakatane cost share - $1.1 M $3.5 M 2-88131.04 | September 2014 Opus International Consultants Ltd 2 The cost for each stage of the development of the Plains water supply and approximate timing is shown below: 2-88131.04 | September 2014 Opus International Consultants Ltd 1 1 Background The Plains 50 Year Strategy Study (Strategy) has developed from the initial 50 Year Strategy Study carried out in 2010, and the Plains and Awakeri Extension Water Upgrade Strategy, which was prepared in 2007. Since 2010 a number of options have been considered, and amendments made to the Strategy. In 2013 Whakatane District Council received funding from the Ministry of Health to develop