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Managing the groundwater resources of the Earnscleugh Terrace Aquifer

Managing the groundwater resources of the Earnscleugh Terrace Aquifer OTAGO REGIONAL COUNCIL WORKSHOP – 18 March. Welcome / overview Policy presentation: aim, key concepts, process Science presentation: aquifer hydrology Q & A session Small group session

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Managing the groundwater resources of the Earnscleugh Terrace Aquifer

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  1. Managing the groundwater resources of the Earnscleugh Terrace Aquifer OTAGO REGIONAL COUNCIL WORKSHOP – 18 March

  2. Welcome / overview • Policy presentation: aim, key concepts, process • Science presentation: aquifer hydrology • Q & A session • Small group session • Conclusion / Where to from here • Tea & coffee • Today

  3. Setting a • maximum allocation volume & • aquifer restriction levels • for the Earnscleugh terrace aquifer • in the Water Plan • Project aim

  4. Total volume of groundwater that may be taken from an aquifer by resource consents. • Measured in m3/year. • To avoid aquifer depletion/compaction and groundwater contamination, ensure surface water outflows. • Further allocation is available if combined consented takes < MAV

  5. Set in Schedule 4A of the Water Plan - takes into account hydrology, environmental, social economic, cultural, considerations • OR • Set as 50% mean annual recharge (interim/default MAV)

  6. Permitted vs. consented takes • Existing consents vs. applications for new takes • Groundwater takes not allocated as primary allocation (surface water)

  7. Aquifer levels at which restrictions apply to groundwater takes • Takes usually restricted by 25%, 50% or 100% • To maintain groundwater levels in localised areas of high demand or during droughts • No default set in the Water Plan • Determined based on local environmental, socio/economic, cultural considerations

  8. Consented takes • Community water supplies (Schedule 3B) • Permitted takes under Rule 12.2.2.2

  9. Workshop #1 (Today) Explain Water Plan basics Discuss science – technical recommendation Listen community aspirations and values Consultation key stakeholders, incl. Iwi Workshop #2 (Optional) Discuss suggested management option Consultation draft Notify proposed plan change RMA process Changes put into effect

  10. Earnscleugh Terrace Aquifer Simon East, Groundwater Scientist

  11. Earnscleugh Terrace Aquifer boundary

  12. Earnscleugh Terrace

  13. Geology map

  14. Earnscleugh Terrace cross section

  15. Groundwater contours

  16. Partially consumptive takes • 2 takes • Assessed maximum annual take of 31.8 Mm3 • Possibly as much as 75% of water returned to the aquifer • Actual use may be as low as 50% • Consumptive takes • 8 takes • Assessed maximum annual take of 1.01 Mm3 • Actual use may be as low as 30% Groundwater wells and take permits

  17. Non-consumptive takes

  18. Earnscleugh gold mine

  19. Earnscleugh gold mine

  20. Monitoring well locations

  21. G42/0119 groundwater level monitoring

  22. G42/0190 groundwater level monitoring

  23. Why are groundwater levels declining? • Increased groundwater pumping? • Less rainfall? • Lower surface water flows? • Changes to irrigation?

  24. Rainfall trend and groundwater level

  25. Recharge and discharge

  26. Water balance

  27. Gaining river Losing river Surface water interaction

  28. Maximum allocation volume (MAV) • Policy 6.4.10A sets the default MAV as 50% of the mean annual recharge (MAR) • Water race leakage not included as it is only a temporary source of recharge • Range front, Omeo Creek and Clutha River recharge not included at this stage as they haven’t been fully assessed

  29. Current allocation Default MAV 12.75 Mm3/year Consumptive takes 1.01 Mm3/year Partially consumptive takes 31.82 Mm3/year Estimated assessed maximum allocation 32.83 Mm3/year Available allocation 0.00 Mm3/year

  30. Options for management • Accept the default MAV (50% of MAR) • Develop a tailored MAV: • Consider a higher MAV by undertaking further investigations to determine additional recharge components • Consider a lower MAV based on the maximum likely irrigation requirement for the zone or for the protection of other values • Consider a groundwater restriction level to provide protection from groundwater level decline

  31. Community input into the allocation process Community involvement in identifying values and aspirations is an integral part of the process of setting allocation limits. Combined with the science input, community involvement helps to achieve the best outcome.

  32. How do you use water from the aquifer? • Have low groundwater levels ever affected you? • How often does this happen? How were you affected? • What is important about the aquifer? • To you personally. For the local economy, environment, and community (social/cultural importance). • How would you like to see water from the aquifer being used in the future?  • Are there any future growth opportunities? Are there any risks to this growth happening?

  33. Small Group Discussions Report Back

  34. Further Feedback • Provide any further feedback by 1 April 2014 • Email: policy@orc.govt.nz • Post: 70 Stafford Street, Private Bag 1954, Dunedin • Phone: 0800 474 082 • Workshop materials, feedback forms will be put on the website: www.orc.govt.nz

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