1. MANAGING WATER QUANTITY AT ALLOCATION LIMITS Freshwater Management Forum 2013 Professor Bryan Jenkins Waterways Centre: University of Canterbury and Lincoln University

2. PRESENTATION COVERAGE Major Issues around Over-Allocation Examples of Claw-back Strategies Adaptive Management Approaches Mitigating Effects on Existing Users Exchange Mechanisms and Incentives

3. WATER ALLOCATION BASED ON RMA sec 5 Enabling resource use for social, economic and cultural well being, while sustaining resource for use of future generations safeguarding life supporting capacity avoiding, remedying or mitigating adverse effects Main over-allocation concerns replenishment of aquifers ecological flows in rivers water quality effects of water use reliability of supply for existing users

4. PAREORA: EXAMPLE OF CLAW-BACK Foothill River South Canterbury -irrigation -town supply -industry

5. ALLOCATION LIMITS SET BY CATCHMENT BOARD Total consented allocation - 940 l/s (142% of 7D MALF c.f. interim limit 30%) Minimum flow - 300 l/s (45% of 7D MALF c.f. interim limit 90%) Notes: Mean Annual Low Flow (7 day): lowest flow over 7 consecutive days in a year; average of annual values over data record (660 l/s for Pareora River) Interim Limits: from Proposed NES for ecological flows

6. OUTCOME OF COLLABORATIVE AND RMA PROCESSES “A Block” Allocation - 198 l/s (30% MALF) Minimum flows next 5 years (Dec-Sep) - 50% restriction at 400 l/s - total cessation at 300 l/s Minimum flows after 5 years (Dec-Sep) - 50% restriction at 470 l/s - total cessation at 400 l/s Minimum flow for A Block holders to take to storage - 1600 l/s Establish B Block allocation - 2500 l/s at minimum flow of 5000 l/s

7. BALANCING WATER PROTECTION AND ECONOMIC DEVELOPMENT Involve those affected in a collaborative process Give the outcome of that process statutory backing Allow time for transition to increased water protection Provide water at higher river flows for storage to offset loss on run-of-river allocation Existing users get access to higher flows ahead of new applicants

8. RAKAIA SELWYN LIMITS Rapid growth in use of groundwater Sustainability limit exceeded Drop in groundwater levels and spring-fed streams First order limit 208 Mm³

9. ADDING CONTROLS FOR CUMULATIVE EFFECTS TO INTERFERENCE CONTROLS Restorative Programme for Lowland Streams Annual limits on consents in fully allocated zones Metering of groundwater wells Restrictions on wells with hydraulic connection to lowland streams Ability to vary limits based on water in groundwater system

10. GROUNDWATER ALLOCATION AND ADAPTIVE MANAGEMENT Current groundwater allocation - annual consented volume based on volume needed in a dry year (1 in 5 year drought): not needed 4 years out of 5 - instantaneous volume (rate of pumping) limited by interference effects on neighbouring bores - zone allocation limits based on average use and past irrigation practices to protect groundwater levels and flows in groundwater-fed streams

11. ANTECEDENT RECHARGE PROPOSAL At full allocation in a period of low recharge it is not possible to: - provide consented volumes, and - maintain flows in groundwater-fed streams Adaptive alternative: relate allocation to antecedent recharge: - base entitlement as fixed percentage of consented annual allocation - adaptive entitlement as variable amount based on recent recharge history

12. SIMULATION OF ANTECEDENT RECHARGE ALLOCATION 1960-2009 Source: Williams et al 2008

13. TE NGAWAI RIVER Foothill river in South Canterbury Natural flow falls below minimum flow River goes on restriction Incentive for individual users to get as much as possible as soon as possible

14. COLLABORATIVE GOVERNANCE TRIAL Water User Group of irrigators established Real time measurement of irrigation takes and river flow Results telemetered to internet site so farmers knew total take, their take and river flow Voluntary adjustments by irrigators to maintain flow above restriction levels for as long as possible

15. MITIGATION OF EFFECTS ON EXISTING USERS Creation of priority bands for existing users to help retain reliability of supply Provision of storage to complement run-of-river or groundwater supply Increased water use efficiency so that less water is needed for same level of production Establishment of exchange mechanisms to facilitate water transfers

16. WAIMAKARIRI RIVER ALLOCATION “A” Block allocation of 22 cumecs with minimum flow of 46 cumecs Application from Central Plains Water for 25 cumecs If Central Plains given same status as existing users then significant reduction in reliability New flow allocation - AA 5 cumecscommunity and stock water - A 17 cumecs: minimum flow 46 cumecs - B 27 cumecs: minimum flow 68 cumecs (1:1 sharing)

17. INCREASE WATER AVAILABILITY THROUGH STORAGE Much of surface water irrigation supply is run-of-river When peak demand exceeds available river flow then irrigation restricted Annual water availability sufficient to meet annual demand but requires storage Concerns about sustainability of storage schemes in relation to river systems Consideration of: - diversion to tributary storage (Waitohi) - off-river storage (Rangitata South) - aquifer recharge (Central Plains) - on-farm storage (Canterbury Plains)

18. INCREASED WATER USE EFFICIENCY More efficient irrigation methods - match irrigation application to times of and degree of soil moisture deficit Lower irrigation application rates - reduce leakage from macropore flow Improve reliability of supply - ‘just in time’ rather than ‘just in case’ Use piped distribution rather than open channels - water savings, reduced on-farm pumping Redistribution of irrigation source - enhance recharge by using surface water in upper catchment and groundwater in lower catchment

19. EXCHANGE MECHANISMS Collaborative agreements - Te Ngawai water user group Transfers under RMA - problem of consenting Cap and trade - Murray Darling basin; Lake Taupo nitrates Brokerage - concept in CWMS

20. WATER MARKETS IN MURRAY DARLING BASIN Cap on diversions in 1994: property rights in water created Increase in value of entitlements and increase in irrigator wealth In the “long dry” - allocations insufficient to keep all valuable permanent plantings in production but enabled non-producers to sell allocation - increased downstream salinity such that irrigators could not use water but able to sell allocation Source: Young, 2011

21. RESULT OF DIVERSION CAP AND TRADING Increased water use efficiency reduced return flows Increased capture of overland flows Sale of end-of-season storage Over allocation problems worsened River Murray stopped flowing in 2002 Cap should have been on nett use rather than diversion Need incentives to carry forward unused stored water 1500 GL of cap equivalent needed to restore health

22. COMMONWEALTH INTERVENTIONS 500 GL secured for environment (2004-9) Additional commitment for $3.1 b purchase of water entitlements Investment in irrigation efficiency $5.8 b Taxpayer cost ($8.9 b) for 15,120 irrigators ($588,000 per irrigator) Subsidised investment worked to disadvantage to those farmers who had paid for their improvements

23. LAKE TAUPO APPROACH Target: reduce nitrogen load by 20% to bring lake back to 1990 levels Farms occupy 18% of land but contribute more than 90% of the manageable nitrogen Market for nitrogen: farmers and Lake Taupo Protection Trust Farmer can either reduce nitrogen load or purchase nitrogen discharge allowance Trust has $81.5m fund and will stand in the market to purchase nitrogen discharge allowances and/or farmland

25. Predicted N load for Lake Taupo from all northern and western streams and seeps Map of modelled Mean Transit Time of the water from land to lake in western lake catchment Lake Taupo M.A. Gusyev, M. Toews, U. Morgenstern, M. Stewart and J. Hadfield (submitted). Calibration of a transient tritium transport model to tritium time series data from rivers and streams in the western Lake Taupo catchment, New Zealand. Hydrol. Earth Syst. Sci, (submitted) MS No.: hess-2012-318

26. CONCEPT OF BROKERAGE Providing incentives for existing users to improve water use efficiency and land use practices affecting water quality - linking efficiency requirements to access to reliable water from storage - inefficient or unproductive water to be bought out and water re-allocated for environmental or productive purposes - third party investment in efficiency gains in exchange for water savings

27. MANAGING AT AVAILABILITY LIMITS Issues: aquifer replenishment, ecological flows, water quality effects, supply reliability Approaches: involvement, statutory backing, time to adjust, alternative access Adaptive Management: incorporate natural variability, integrated measurement Existing Users: priority bands, storage, improved efficiency, exchange mechanisms Exchange mechanisms: collaborative governance, transfers, cap and trade (?), brokerage