Technical Input on State and Trends in Water Quality

1. The input of the Technical Leaders Group so far… Presented to the Healthy Rivers Wai Ora Committee, 5th August 2014

2. Members of the Technical Leaders Group (TLG) Bryce Cooper Mike Scarsbrook Liz Wedderburn Tony Petch John Quinn Graeme Doole Antoine Coffin Formed late May, first meeting 5th June

3. Input to the Collaborative Stakeholder Group (CSG) to date • CSG #3 at Tokoroa – State and trends in water quality • CSG #4 at Te Kuiti – Approach to incorporating technical input into process • Answering a variety of queries posed by the CSG • Now: • Determining technical information needs and gaps • Preparing technical input for CSG#5

4. State and Trends in Water Quality State – is it “good” or “poor”? and Trend – is it getting “better” or “worse”?

5. Project scope – the four contaminants

6. Water quality monitoring network • Over 60 sites in Waikato/Waipa • Sampled regularly since 1992 • Quality assured and reliable data

7. Current State – E. coli Source: NIWA 2010 WRISS

8. Current State – Nitrogen Source: NIWA 2010 WRISS

9. Sources of nutrients, Taupo Gates to Port Waikato

10. Rural sources of contaminants NIWA 2010 WRISS report

11. Summary of Water Quality State– is it “good” or “poor”? • “Excellent in places, poor in others” • Upper Waikato main-stem excellent to good • Waipa main-stem often poor • Lower Waikato main-stem satisfactory to poor • Tributary streams range from poor to excellent • Lowland lakes very poor

12. State and Trends in Water Quality State – is it “good” or “poor”? and Trend – is it “getting better” or “getting worse”?

13. Water Quality Trends.. • ..is it “getting better” or “getting worse”? • Two dimensions to trend analysis: • Direction of change – increasing or decreasing • Rate of change – slow or fast

14. A water quality record with a trend Rate = +5.8% per year

15. Water quality trends at Waikato & Waipa River sites, 1993-2012 Better  Stable Worse

16. Summary of Water Quality Trends – • is it “getting better or worse”? • On a catchment-wide basis, from 1993 to 2012 there has been a: • Decrease in phosphorus (“better”) • E.coli mostly stable, some increases and some decreases • Increases in nitrogen and turbidity (“worse”) • Dairy expansion and intensification cause of much of the increases in nitrogen and turbidity • Improved wastewater treatment likely cause for decrease in phosphorus

17. Input to the Collaborative Stakeholder Group (CSG) to date • CSG #3 at Tokoroa – State and trends in water quality • CSG #4 at Te Kuiti – Approach to incorporating technical input into process • Answering a variety of queries posed by the CSG • Now: • Determining information needs and gaps • Preparing technical input for CSG#5

18. Healthy Rivers Policy Process Approach – as the TLG see it (aligned to NPS for Freshwater Management 2014) • CSG Focus Statement • e.g., safe to swim, take food, provide well being) • Can be ‘alternative’ detail below that CSG outcomes • Assess options against Values & risk • Consensus? • Seek further scenarios? • TLGadvise using: • Guidelines (e.g., NOF) • Existing information • Experts input • TLG, using experts for: • Predictive modelling • Non-market valuation studies

19. Example of stepping-through the process Value: Swimmable Attribute: Bacteria (E.coli/100ml, 95th percentile) Attribute Levels: Excellent (<55), Satisfactory (55 – 550), Unsatisfactory (>550) Current State: % samples in following ‘swimmable’ categories Scenario Analysis: Modeloptions for reducing faecal bacteria input to waters – wastewater treatment, denying stock access to streams, etc.

20. Scenario Analysis - predictive models, a window on the future • Computer models are a well-used and trusted analytical tool • Used in natural sciences, medicine, engineering, accounting, economics, etc. • Provide predictions of the future – can play the ‘what if..?’ game • Models collect, connect and apply expert knowledge • They need good data as input, and often use data to test validity of output • Need to choose models that are ‘fit for purpose’ – that answer the question posed • They are not perfect and need careful interpretation

21. In Summary, the Approach: • Is sequential rather than simultaneous (mostly) • Is iterative rather than once-through • Needs more technical work on defining attribute limits to meet CSG Values • Requires more scenario modelling, targeted to the needs of the CSG • Is complex, requires the ‘bringing together’ of diverse technical work across market and non-market values to provide a clear options analysis • Will require decisions to be made where uncertainty exists

22. Input to the Collaborative Stakeholder Group (CSG) to date • CSG #3 at Tokoroa – State and trends in water quality • CSG #4 at Te Kuiti – Approach to incorporating technical input into process • Answering a variety of queries posed by the CSG • Now: • Determining information needs and gaps • Preparing technical input for CSG#5

23. Atmospheric N N fixation/N fertiliser P fertiliser slips & soil erosion Leached N P to stream sediment P Runoff sediment P bugs N in urine livestock excreta N as gas sediment N P bugs bank & gully erosion CSG#5 – Technical Primer on sources and mitigations Rock mineral P

24. Determining information needs and gaps to assist CSG • Much work done • Much work already underway/nearing completion, e.g., • Economic Joint Venture modelling • Non-market values research • Waipa sediment sources study • River algae growth response to N and P • Much work to do. Work plans being prepared for: • Defining attribute levels to meet Values • Scenario modelling – water quality, farm mitigations, economic effects • Incorporating maatauranga Maori