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A FRAMEWORK FOR SETTING FLOW AND ALLOCATION LIMITS - NELSON JOE HAY 15 DECEMBER A FRAMEWORK FOR SETTING FLOW AND ALLOCATION LIMITS - NELSON JOE HAY 15 DECEMBER 2016

A BIT ABOUT ME • • • Resident in the Maitai catchment Freshwater Biologist, A BIT ABOUT ME • • • Resident in the Maitai catchment Freshwater Biologist, Cawthron Institute for last 13 years (last 5 ½ yrs as a contractor) Member of Fo. M Maitai FMU group member Involved in research and provide advice to councils and other stakeholders throughout NZ Mainly relating to water allocation management and freshwater fish

FLOW IS A DEFINING FEATURE OF STREAMS Flow a “master variable” in streams. § FLOW IS A DEFINING FEATURE OF STREAMS Flow a “master variable” in streams. § Influences many aspects of stream ecology, including: § Channel form § Transport of sediment, nutrients and food down a river system § and the distribution and behaviour of organisms. §

WHAT FLOW FEATURES NEED ATTENTION? WHAT FLOW FEATURES NEED ATTENTION?

FLOW REQUIREMENTS OF DIFFERENT SPECIES Slow water species Fast water species FLOW REQUIREMENTS OF DIFFERENT SPECIES Slow water species Fast water species

DETERMINING ENVIRONMENTAL FLOW NEEDS – WHERE DO WE START? 1. Identify instream values 2. DETERMINING ENVIRONMENTAL FLOW NEEDS – WHERE DO WE START? 1. Identify instream values 2. Define instream management objectives 3. Focus on critical values • those that have highest value and highest flow needs • in larger rivers these are typically salmonids and birds 4. Focus on critical flow related environmental requirements (attributes) • physical habitat (space) • fish passage • food • water quality (temperature, oxygen, etc. ) MFE 1998 - Flow Guidelines for Instream Values

NPS-FM WATER QUANTITY OBJECTIVES § 1. § 2. § 3. § 4. To safeguard NPS-FM WATER QUANTITY OBJECTIVES § 1. § 2. § 3. § 4. To safeguard life-supporting capacity, ecosystem processes and indigenous species including their associated ecosystems in sustainably managing the taking, using, damming, or diverting of fresh water. To avoid any further over-allocation of water and phase out existing over-allocation. To improve and maximise the efficient allocation and use of water. To protect the significant values of wetlands and outstanding freshwater bodies.

KEY COMPONENTS OF FLOW MANAGEMENT (REQUIRED BY NPS-FM) • Minimum flow is the flow KEY COMPONENTS OF FLOW MANAGEMENT (REQUIRED BY NPS-FM) • Minimum flow is the flow at which abstraction must be restricted or cease § • Provides refuge for instream values during periods of low flow Allocation limit is the rate (or volume) that water can be extracted § § Protects instream values by controlling length of low flow period and maintaining some flow variability Maintains reliability of supply to abstractors

ENVIRONMENTAL FLOW REGIME ENVIRONMENTAL FLOW REGIME

TWO MAIN INSTREAM FLOW ASSESSMENT METHODS § Historical flow methods § Habitat methods TWO MAIN INSTREAM FLOW ASSESSMENT METHODS § Historical flow methods § Habitat methods

§ Habitat methods Suitability Brown trout adult feeding habitat preferences Velocity Suitability Depth Habitat § Habitat methods Suitability Brown trout adult feeding habitat preferences Velocity Suitability Depth Habitat Substrate index

Historical flow methods Biological response § Historical flow method Flow Historical flow methods Biological response § Historical flow method Flow

Biological response HABITAT METHODS VS HISTORICAL FLOW METHODS Historical flow method Habitat method Flow Biological response HABITAT METHODS VS HISTORICAL FLOW METHODS Historical flow method Habitat method Flow

TECHNICAL ASSESSMENT METHODS • Historical flow methods • Generalised habitat modelling • Hydraulic habitat TECHNICAL ASSESSMENT METHODS • Historical flow methods • Generalised habitat modelling • Hydraulic habitat modelling Water quality modelling Ecohydraulics modelling ++ many more • • • Assume status quo is best Assume linear response to flow Non-specific Easily applied Assumes habitat (or WQ) is limiting Non-linear flow response Linked with specific values Data hungry Expensive Controversial

PROTECTION LEVELS • Risk management • High value then accept minimal risk § minimum PROTECTION LEVELS • Risk management • High value then accept minimal risk § minimum flow provides 90 -100% habitat retention at naturalised MALF § allocation limit 10 -20% of MALF • Lower value then accept more risk § minimum flow provides 70 -80% habitat retention at naturalised MALF § allocation limit 20 -30% of MALF

COMMON APPROACH IN OTHER REGIONS • • Historical flow methods to guide broad-scale flow COMMON APPROACH IN OTHER REGIONS • • Historical flow methods to guide broad-scale flow management decisions Detailed instream habitat analysis for rivers with very high values and/or large flow alteration Protection levels based on risk assessment Allocation limits set based on security of supply

OTHER CONSIDERATIONS • • Flow statistics – 7 Day or 1 Day Naturalising flow OTHER CONSIDERATIONS • • Flow statistics – 7 Day or 1 Day Naturalising flow statistics Minimum flow equals cease take Restriction trigger and number of steps Security of supply Supplementary allocation (high flow harvesting) Scaling limits within catchments Cumulative allocation Consented and permitted

RECOMMENDED FRAMEWORK • • • Historical flow approach across all classes (except Maitai and RECOMMENDED FRAMEWORK • • • Historical flow approach across all classes (except Maitai and Roding where habitat modelling available) Where naturalised flow statistics are not available, set more conservative interim limits Minimum flow equals % of naturalised 7 Day MALF High value sites 90 -100% Lower value sites 70 -80% Allocation limit equals % of 7 Day MALF High value sites 10 -20% Lower value sites 30% Minimum flow equals cease take

Whangamoa FMU Collins River Collins at Drop Structure 1960 -2016 Mean Median 542 220 Whangamoa FMU Collins River Collins at Drop Structure 1960 -2016 Mean Median 542 220 Existing minimum flow Existing consented allocation Existing potential peak permitted abstraction 7 Day MALF 63. 6 0 0

COLLINS RIVER AT DROP • • Flow recorder site Flow record not influenced by COLLINS RIVER AT DROP • • Flow recorder site Flow record not influenced by abstraction 6 species of native fish recorded Moderate sized stream

COLLINS RIVER AT DROP COLLINS RIVER AT DROP

COLLINS RIVER– SECURITY OF SUPPLY COLLINS RIVER– SECURITY OF SUPPLY

Wakapuaka FMU Wakapuaka River @ Hira Wakapuaka at Hira 1978 -2016 Existing minimum flow Wakapuaka FMU Wakapuaka River @ Hira Wakapuaka at Hira 1978 -2016 Existing minimum flow Mean Median 1344 733 7 Day MALF 306 245 0. 3+10+5. 7 Existing consented allocation =16 Existing potential peak permitted abstraction 47. 4

WAKAPUAKA RIVER AT HIRA • • • Flow recorder site Flow record influenced by WAKAPUAKA RIVER AT HIRA • • • Flow recorder site Flow record influenced by abstraction upstream (including Teal and Lud) 8 species of native fish recorded Locally important trout fishery, of high local value Large stream

WAKAPUAKA RIVER AT HIRA WAKAPUAKA RIVER AT HIRA

WAKAPUAKA RIVER AT HIRA WAKAPUAKA RIVER AT HIRA

Stoke FMU Orphanage Stream Orphanage at Ngawhatu 2004 -2016 Mean Median 78 25 Existing Stoke FMU Orphanage Stream Orphanage at Ngawhatu 2004 -2016 Mean Median 78 25 Existing minimum flow Existing consented allocation Existing potential peak permitted abstraction 7 Day MALF None specified 0 0. 1 4. 8

ORPHANAGE STREAM AT NGAWHATU • • Flow recorder site Flow record influenced by small ORPHANAGE STREAM AT NGAWHATU • • Flow recorder site Flow record influenced by small permitted abstraction 11 species of native fish recorded Small stream

ORPHANAGE STREAM AT NGAWHATU ORPHANAGE STREAM AT NGAWHATU

ORPHANAGE STREAM AT NGAWHATU • Or 80% of MALF minimum flow? Depends on mgmt. ORPHANAGE STREAM AT NGAWHATU • Or 80% of MALF minimum flow? Depends on mgmt. objectives.

Maitai FMU Todds Valley Stream Todds at SH 6 36 Mean Median 28. 6 Maitai FMU Todds Valley Stream Todds at SH 6 36 Mean Median 28. 6 14 Existing minimum flow Existing consented allocation Existing potential peak permitted abstraction 7 Day MALF 3. 8 2. 3 0. 8 8. 1

TODDS VALLEY STREAM AT SH 6 • • • Synthesised flow record Flow record TODDS VALLEY STREAM AT SH 6 • • • Synthesised flow record Flow record influenced by large volume abstraction 7 species of native fish recorded Small stream Potential peak permitted take exceeds low flows

TODDS VALLEY STREAM AT SH 6 TODDS VALLEY STREAM AT SH 6

TODDS VALLEY STREAM AT SH 6 • Or 100% of current MALF? Since flow TODDS VALLEY STREAM AT SH 6 • Or 100% of current MALF? Since flow statistics already influenced by proportionally large abstraction

Maitai FMU Maitai River Maitai at Avon Tce 2005 -2016 Mean Median 2416 882 Maitai FMU Maitai River Maitai at Avon Tce 2005 -2016 Mean Median 2416 882 Existing minimum flow 7 Day MALF 358 35. 8 Existing consented allocation 309. 7+5. 1 =314. 8 Existing potential peak permitted abstraction 16. 5+2. 5 =19

MAITAI RIVER AT AVON TERRACE • • • Flow recorder site Flow record influenced MAITAI RIVER AT AVON TERRACE • • • Flow recorder site Flow record influenced by large abstraction upstream (municipal supply) 11 species of native fish recorded Large stream Habitat modelling undertaken for upper and middle reaches

MAITAI RIVER AT AVON TERRACE MAITAI RIVER AT AVON TERRACE

MAITAI RIVER AT AVON TERRACE MAITAI RIVER AT AVON TERRACE