Mayor David Cull, Dunedin Council - Case Study – Dunedin’s Three Waters Strategy

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Mayor Dave Cull delivered the presentation at the 2014 NEW ZEALAND INFRASTRUCTURE SUMMIT.

The New Zealand Infrastructure Summit brings you the most up to date infrastructure news combining case studies and key presentations, addressing developments in the some of the main infrastructure hubs, such as Auckland and Christchurch.

For more information about the event, please visit: http://www.informa.com.au/nzinfra14

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Mayor David Cull, Dunedin Council - Case Study – Dunedin’s Three Waters Strategy

  1. 1. Dunedin City Council 3 Waters Strategy NZ Inaugural Infrastructure Summit Mayor Dave Cull
  2. 2. Context Urban centre with large rural hinterland c 125,000 people, including 23,000 students Heritage, culture and biodiversity
  3. 3. Before the Strategy  Previous strategy focussed on water and wastewater quality  Single issue; Single solution;  High service; High cost  Identified gap in strategic planning capability  Integrated improvement strategy • Departmental restructure • 3 Waters Strategy project
  4. 4. Development Approach  Review strategic drivers  Review technical constraints of existing infrastructure  Engaged with the community on their concerns and priorities  Produced strategic timeline of issues and potential solutions  Developed strategic principles to guide future decision making
  5. 5. Dunedin’s Water Challenges  Limited growth  Shift in economy away from water intensive industry  Excess capacity in parts of our infrastructure  Gravity fed water supplies  Climate change predicted to increase catchment yield (although more seasonal)
  6. 6. Dunedin’s Water Challenges  Increasing flood risk  Sea level rise – rising groundwater  Vulnerable to single point failures in our critical infrastructure.  Relative isolation requires greater resilience
  7. 7. Dunedin’s Water Challenges  Infrastructure is ageing  Some pre 1900 infrastructure still in use.  Renewals peak is looming Renewals forecast as at 2010
  8. 8. Dunedin’s Challenges  High sunk infrastructure costs  Looming renewals requirements  Slow growth  Environmental and other pressures = Affordability challenges
  9. 9. Strategic Priorities  7 high level statements  Outline long term principles and commitments to guide future planning and decision making.  Deals with uncertainty by allowing us to adjust and respond as change happens
  10. 10. How does this affect decision making?  Change of thinking • More focus on using and rationalising existing assets • Integrated approaches to give multiple benefits • Flexibility and resilience for different potential futures • Improved cross council planning e.g. 2nd generation district plan
  11. 11. Security of Supply – System Overview  INSERT SCHEMATIC MAP OF MAJOR PIPELINES AND TREATMENT PLANTS
  12. 12. Security of Supply Strategy 2008 - Previously unrelated problems and projects Serious lifelines risk – 2 main raw water supply pipes over same, vulnerable, 1936 bridge. Only one source of water supply for the Hill suburbs Deep Creek Pipeline Renewal programme ($15m+ budget) High future costs to maintain and renew two raw water pipelines (gravity fed = low OPEX). Ross Creek Dam Stability problems Risk of losing consents for un-utilised water resources 2014 - One Integrated Solution
  13. 13. 2008 : Second Taieri Crossing  Initial budget c$6m  Cost estimates escalating up to $15m  Time for a rethink!
  14. 14. Ross Creek Dam Stability Disused water reservoir Well used community recreation asset Dam stability problems have led to lowering of water levels
  15. 15. 2014: Integrated thinking  What we are doing • Stabilise Ross Creek Dam (in progress) • Build pumping station from Southern Treatment plant to Mount Grand Treatment Plant (in progress) • Bring some redundant water infrastructure back into supply (2018-2020) • Future rationalisation of 2 supply pipelines to one (c2036)
  16. 16. What we are NOT doing  No second crossing across the Taieri Required  Not renewing the Deep Creek Raw Water Pipeline (decommission when Deep Stream pipeline requires renewal) • The criticality of the infrastructure will be reduced to such a level that we can provide continuous supply without them (at higher cost, and with some restrictions)
  17. 17. Benefits  All parts of metropolitan Dunedin can be served by 2 treatment plants and any of 4 water supply sources  Resilience to loss of any single part of the supply system, including the Taieri Bridge Crossing or either one of the treatment plants.  High level of resilience to catchment drought or fire  Dam stabilised and Ross Creek amenity value restored  Asset lifecycle costs significant reduced  Savings of $12m in the first 10 years.
  18. 18. In Conclusion  Infrastructure challenges need to be seen in the right local context.  Dunedin’s 3 Waters Strategy responds to our local context by: • Ensuring integrated decisions • Rationalising infrastructure • Increasing flexibility and resilience • Doing more with less…

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