Official Information Request - Linton Park Dam

Sent: Friday, 18 August 2023 2:07 pm
Subject: LGOIMA request - Linton Park Dam

I refer to your Official Information request on 27 July 2023 regarding the Linton Park Dam, and provide the following responses to your questions:

1. What was the objective of the dam?
   The fundamental objectives of this project were to address dam safety deficiencies in the existing dam, comply with updated dam safety guidelines and ensure the protection of downstream properties during future flooding events, including allowance for climate change effects.
2. Provide the documented evidence of the need for the dam?
   Attached is a report “Linton Park East Flood Detention Pond - Dam Safety Assessment - Proposed remedial works to address dam safety deficiencies” Tonkin and Taylor (Consultants) – Attachment 1.
3. What was its scheduled completion date?
   There was no specific date for completion in the contract, but work was originally envisaged to be fully complete by March 2023.
4. What is its current projected completion date?
   The actual completion date will depend on variables such as weather, site conditions and materials supply. Our current estimate is that works will be complete in early 2024.
5. What was its original contracted cost?
   The contract sum was $10,622,501.43.
6. What is its current projected completion cost?
   The final cost will not be known until work is complete. It will depend on variables including those in 4 above, final measured quantities, and variations that the contractor may be entitled to claim under the conditions of contract. Any changes to the contract sum will be reported to Council when known.
7. Who initiated the project?
   Rotorua Lakes Council, in accordance with its stormwater management master plan process and its responsibilities relating to public safety.
8. Who is responsible and accountable for the design?
   The design was carried out by Tonkin and Taylor and peer reviewed by WSP Consultants. The design was also reviewed by a Waikato Regional Council designated peer reviewer as part of the required building consent process.
9. Where is the finance derived from for the project?
   $6.8M was provided by the Crown through its Three Waters Stimulus Fund, administered by the Department of Internal affairs. The remainder will be funded by RLC.
10. Provide the economic evaluation of the project?
    The driver for the project was prudent management of risk rather than pure economic return. Refer to the attached report to the Operations and Monitoring Committee on 2 September 2021 for more information – Attachment 2.
11. Who is the Council person responsible and accountable for managing this project?
    Ultimate responsibility for the project as the client (RLC) representative rests with the Deputy Chief Executive – Infrastructure and Environment. However, day to day client responsibilities are delegated to managers within the Infrastructure and Environment group in accordance with their position descriptions. The contract is based on the NZ Standard NZS 3910:2013 - Conditions of Contract for Building and Civil Engineering Construction. Under the terms of the Contract, Council are the Principal, Downer are the Contractor and Tonkin and Taylor personnel are nominated as the “Engineer to the Contract” and the “Engineers Representative” respectively. The roles of these persons are spelt out in NZS 3910 but effectively they manage the contract on behalf of the client (RLC). These services are provided by Tonkin and Taylor under a separate contract. As the dam is classified as having a high PIC (Potential Impact Classification), the construction is required to have a high level of constant monitoring.
12. What computer based project management programme if any being used for this project?
    Both the contractor and consultant have project management systems in place as required to meet the terms of their contracts.
13. What are the engineering management qualifications held by the Council manager of this project?
    Council staff involved in managing this project hold various qualifications including Chartered Professional Engineer, Bachelor of Engineering and New Zealand Certificate in Engineering. The Engineer to the contract holds Chartered Professional Engineer status. Years of individual engineering experience range from 43 years down to 12 years.
14. Is a part of the dammed area classified as wetlands?
    Yes, part of the area behind the dam has been delineated as wetland using the MfE Wetland delineation hydrology tool for Aotearoa New Zealand. Refer to attached wetland delineation plan –Attachment 3.
15. Is it legal to dam wetland areas?
    The short answer is yes in some circumstances.
    The Linton Park stormwater detention dam only functions as a dam for short periods of time in extreme rainfall events. Most of the time the Mangakakahi Stream flows through the site unimpeded, and the wetlands function naturally. For short periods of time the wetland will be inundated. Periodic inundation is quite natural for many wetlands.
    Activities in and around wetlands are controlled under Resource Management Act (RMA) regulations, namely the National Environmental Standard for Freshwater (NES-F) and by Regional Plans.
    The original Linton Park detention dam has a resource consent from Bay of Plenty Regional Council.
    The modified dam is classified as specified infrastructure and therefore clause 53 of the NES -F prohibiting any earthworks within a wetland that may lead to the drainage or partial drainage of a wetland does not apply. Instead, any vegetation clearance, earthworks, or the take, use, damming or diversion of water requires resource consent as a discretionary activity.
    Under the Bay of Plenty Regional Natural Resources Plan, Rule WL R9 (Rule 85), the modification of a wetland is also a discretionary activity.
    The current works are being undertaken under the emergency works provisions of the RMA which negate the requirement to obtain resource consent prior to works commencing. A revised resource consent will be applied for once the work is complete as the modified dam will operate differently than the original dam.
16. The dam height is significantly above Edmund Road, is Edmund Road intended to be a part of the dammed flood area and impassable during heavy rain?
17. Similarly flooding of Edmund Road will also likely flood a number of adjacent properties, is Council going to be accountable for this introduced flooding?
18. Provision of a contour plan of the whole dam catchment showing the full dammed height water boundary?We have previously supplied a contour plan showing the design dammed height. We attach that plan again (Attachment 4). It can be seen that during the design flood (in excess of 100 year return period), the water level will cover parts of Edmund Road. It can also be seen that under this scenario, no residential properties will be flooded.
19. When can it be expected that the cycle/walkway will be opened?
    We anticipate that the cycle/walkway will be opened shortly after construction is complete, hopefully in early 2024.

You have the right to seek an investigation and review by the Ombudsman of this response/decision. The Ombudsman’s Office can be contacted by calling 0800 802 602, emailing info@ombudsman.parliament.nz, online at www.ombudsman.parliament.nz, or by post to The Ombudsman, PO Box 10152, Wellington 6143.

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Regards