FLAG stands for “Freshwater and Land Advisory Group”
The text below comprise the first 7 pages of the Friends of Golden Bay Comments on the draft FLAG report released in January 2017. Our full report including some very important appendices is a much longer document. A link to the full Friends of Golden Bay Comments including appendices can be accessed by clicking on the link below.
Friends of Golden Bay (Inc) (FoGB) promotes optimum environmental outcomes in Golden Bay. A major effort in recent years has been to study freshwater quality in the Takaka Valley so that the benefits it provides are maintained and preferably improved. We have been particularly concerned with Te Waikoropupū Springs and the associated aquifers as our research showed that nitrate levels had been increasing due to land management practices. We have been so concerned with this deterioration that we sponsored weekly sampling for nitrate and phosphate in the Springs’ complex and associated Fish Creek.
Introduction: FoGB have not been directly involved in the Takaka FLAG process although we made direct input in the early stages. We are pleased to see that FLAG has been taking the process seriously and welcome the invitation to submit on their interim decisions. The document FLAG produced is not easy to assess and so we have been forced to go back to the discussions and presentations (partly on the TDC website) to see how the decisions were arrived at and their justifications.
We noted that early on there was general agreement on objectives for water quality etc but from the middle of last year TDC staff and its consultants have been pushing for greater water takes from the rivers and aquifers and have been giving great weight to what irrigators are asking for. The Dairy NZ sponsored “expert group” in water quality illustrates this. We note that this has led to a split within FLAG, so that there is not a general consensus over some important aspects within the draft report. Further, local Iwi have still to be properly consulted.
Our approach to this review of the FLAG draft report is to assess how the proposals or options in the discussion document will ensure that freshwater quality is maintained or improved.
Key factors: The National Policy Statement for Freshwater states that water quality must be maintained or improved. Thus any practices that lead to deterioration need to avoided and practices that lead to improvement are to be encouraged. Objective B4 in MoE (2015) covers the protection of significant values of wetland and outstanding freshwater bodies (our emphasis) and suggests further guidance can be obtained from Beca (2008).
There are three key factors that must control water management in the Takaka catchment: 1. Water quality management objectives and Iwi values 2. Limiting factors e.g. pollution or stressors 3. Management e.g. water allocation The Arthur Marble Aquifer (AMA) and associated Te Waikoropupū springs have extremely high conservation values. First, limitations on toxic nutrients and other stressors must be considered and applied as they are the main limiting factor for this system. Then allocation and other management options may be considered. The current FLAG report looks at allocation before limitations; this needs addressing.
For connected systems such as the AMA the most sensitive and significant values should drive decisions (Beca 2008).
Management objectives: We agree with the objectives for water bodies that FLAG identified in the May 2015 document and noted that they related these to Iwi values. However, we also understand that the consultation process with Iwi is incomplete.
In particular, we were pleased and strongly support the maintenance of the Natural Form & Character of the water bodies, especially within the karst landscapes, National Parks and Spring systems within the Takaka Catchments. FLAG emphasised that water flows and quality from spring systems, especially Te Waikoropupū Springs, were to be maintained.
The Springs and the AMA which supply it, have extremely high conservation values because of their unique properties: high endemic biodiversity (particularly the stygofauna), landscape values, wide acceptance as a major tourist attraction in the region and their great significance to local Iwi.
We strongly support the emphasis on the rivers being suitable for swimming and the need to maintain ecosystem health in all water bodies, including groundwater.
Nutrient and other pollution: Friends of Golden Bay are primarily interested in the management of the AMA and Te Waikoropupū springs so our comments are primarily around this.
Te Waikoropupū Springs have some of the clearest freshwater in the world. This results from the oxidation of organic matter in the groundwater by biofilms and stygofauna organisms in the karst AMA. Research to date has found that many of the stygofauna are unique to the AMA and hence of great biodiversity value in themselves. However, very little is known about their tolerance to pollutants such as nitrate.
ANZECC (2000) have said, regarding groundwater fauna: “Little is known of the lifecycles and environmental requirements of these quite recently-discovered communities, and given their high conservation value, the groundwater upon which they depend should be given the highest level of protection”. Further, they state “For ecosystems requiring the highest level of protection (condition 1), the objective of water quality management is to ensure that there is no detectable change (beyond natural variability) in the levels of the physical and chemical stressors. For such highly-valued ecosystems, the statistical decision criteria for detecting any change should be ecologically conservative and based on sound ecological principles. This position should only be relaxed where there is considerable biological assessment data showing that such changes will not affect biological diversity in the system”
Dr Fenwick at NIWA has advised that: ….” the aquifers and catchments should be managed to ensure that NO3-N concentrations in spring water do not exceed 0.4 mg NO3-N/L in order to protect the springs’ high conservation values.” (NIWA 2015). Currently the Main Spring is at this level and sometimes exceeds this concentration (see Appendices 1 and 2). Because of our concerns FoGBay undertook and paid for weekly sampling from the Springs’ in order to better define the current levels of nitrate and phosphate and study how they changed over 12 months. This research is still on-going but a preliminary report is attached (Appendix 2).
A larger and more readable version of this graph and be found in the full Friends of Golden Bay Comments on FLAG draft report
We are disappointed that the Dairy NZ ‘expert’ panel report is still not available for proper consideration. According to the FLAG draft report and Dr Young’s presentation to FLAG, the panel may recommend a ‘trigger’ NO3-N concentration of 0.5 mg/l. We reject this suggestion of a 0.5 mg/l ‘trigger’ level because it is important to take a precautionary approach where we know so little about the organisms and their ecology. Further, we note that a ‘trigger’ level is not 3
prescriptive (i.e. it should not be exceeded) but rather suggests that it is a level when we might get concerned and look in greater depth.
Dr Mead disputes the analysis of nitrate trends in the Main Te Waikoropupū Spring that has been undertaken by the ‘expert’ panel (Appendix 1). The main issues are:
- Including the pre 1990 records
- Including data that have been analysed by different techniques. In particular Cawthron and Hill Laboratories have used methods that are known to give positively biased nitrate levels. Including the limited data from Dancing Springs or Fish Springs is also not justified as they have not been regularly measured over the time period.
- Excluding outliers without having a good reason to do so. They could just as easily be real. Further, there are robust non-parametric methods that are resistant to outliers and if these methods are used there is no need to drop outliers.
- Not being systematic in their analysis of the long-term data.
The upshot of this is that the analysis in the FLAG report understates the long-term changes in nitrate changes and overstates the recent changes. That analysis cannot be relied on.
Dr Mead’s systematic data analysis (Appendix 1) has found, for the data from 1990 to 2016:
- From 1990 to mid-1995 no linear change was apparent because of high variability. The median NO3-N was 0.33 mg/l.
- Between 1996 and 2011 NO3-N rose at 1.76% per annum.
- From 2012 to September 2016 nitrate may or may not be decreasing but has probably levelled off. Further long-term sampling will clarify this. The median concentration was 0.41 mg/l.
Dr Mead’s preliminary analysis of the FoGBay weekly sampling between February and December 2016 (Appendix 2) shows:
- The median NO3-N concentration is 0.40 mg/l in the Main Spring and 0.36 mg/l in the Fish Spring
- Both Springs showed a seasonal/climate-related variation and nitrate concentrations were generally highest in winter-spring when the Main Spring exceeded 0.40 mg/l and Fish Spring reached that concentration.
A larger and more readable version of this graph and be found in the full Friends of Golden Bay Comments on FLAG draft report
We therefore conclude that the correct approach to managing the water quality of the AMA is to not allocate more irrigation water in the unconfined aquifer until nitrate concentrations drop to well below 0.4 mg/l. We would recommend that the trigger level for allowing more irrigation be set at 0.30 mg/l. If more allocation is given at this time and nitrate levels continue to rise, it will be very difficult to ask farmers to give up their allocation. Farmers need security before they invest.
The modelling work on the effects of irrigation on nitrate-N concentrations, presented by Dr Fenemor to FLAG on 27 Nov 2015, shows that increasing the Springs’ allocation to 766 l/sec as TDC is proposing would increase the Main Springs nitrate concentration to 0.5 mg/l. This is unacceptable. It may be an underestimate because it does not fully take into account the increase that is proposed from the Waingaro where the water would be mainly used in the unconfined 4
aquifer. (There is a strange co-incidence between 0.5 mg/l nitrate-N level predicted by Dr Fenemor to result from the proposed allocation for Te Waikoropupū springs and that recommended to FLAG in Dr Young’s provisional report of the Dairy NZ ‘expert panel’ that recommends 0.5 mg/l nitrate-N as the trigger level).
We note that Young and Hay (2016) confirmed that marble does not provide significant amounts of nitrogen to the water in the AMA. However, their interpretation that the Spittle Creek nitrate-N represents the natural concentration in the deep aquifer is suspect.
Phosphate: There is an incomplete long-term record on dissolved reactive P for Te Waikoropupū Springs. We agree that P does not seem to be an issue as the concentrations are low. Similarly, the Friends of Golden Bay 2016 weekly sampling found DRP in the Main and Fish Springs had a median of 0.006 mg/l (range 0.003 to 0.008 mg/l). However, DRP in Fish Creek was often higher during the winter storms because of runoff from the farms up-stream.
Dissolved oxygen: NIWA (2015) notes that critical levels for stygofauna are poorly understood but it will become a problem when concentrations get low. Dissolved oxygen (DO) has not been regularly measured in the Main spring (median 5.7 mg/l; range 1.1 to 9.5 mg/l; N = 27 from 1970). Two extremely low levels were recorded in 1999 and 2000 and the very high concentration was in 2004.
NIWA (2015) emphasised “dissolved oxygen appears to become a critical factor at low aquifer levels when the hydraulic gradient is reduced and the rate of water replacement (containing more dissolved oxygen) is slowed. Thus, managing water levels to ensure near natural velocities/flows through the aquifer matrix, in tandem with managing organic carbon concentrations within groundwater, seems likely to sustain higher dissolved oxygen concentrations…”. Therefore, it is important to stop water take at MALF. Flatling (i.e. keeping the flow at or below MALF for long periods) might be something FLAG should consider when considering water allocation rules.
The FLAG report has recommended a trigger level of 45% saturation for DO which is 80% of the few data recorded as percentages. We consider using the 80% level as inappropriate for a system with very high conservation values (ANZECC 2000). NIWA (2015) suggested that 6.0 mg/l should be used as a guideline. NIWA’s precautionary approach should be accepted in the meantime.
Organic carbon concentrations are not being measured in the Springs’ water.
Other Pollutants: The FLAG report does not cover or discuss other pollutants and this is a major omission as they could affect the stygofauna. Some guidance is provided by NIWA (2015).
Water clarity: The FLAG draft report briefly discusses water clarity and recognises that this has not been measured recently. Clarity needs to be re-measured and FoGBay initial discussions with Dr Davis Colley indicated it could be done without divers. Action required.
The Dairy NZ ‘expert’ panel suggested that the trigger level be 50 m which is 21% below what it was when measured in 1993. While an 80% level of protection is reasonable for many rivers, ANZECC (2000) recommend that for high conservation sites, such as Te Waikoropupū , should be allowed for (i.e. it should be 63 m). If a number of readings over a period of a year or more were available other statistical methods could be applied (see ANZECC 2000).
Positive management changes: Friends of Golden Bay applauds that in the last 10-15 years farmers have generally moved to keep stock out of major waterways and planted, albeit narrow, riparian strips. These practices reduce direct pollution of the waterways and reduce sedimentation but have smaller impacts on the movement of nitrate into the rivers and the AMA. Keeping animals out of waterways needs to be extended to all farm animals in the Takaka Catchment. Smaller watercourses or swales may sometimes need to be fenced off.
Dairy farmers have also improved their dairy waste disposal systems particularly as there had been old reports of farmers dumping this and other waste down tomos. Some irrigators have also implemented improved irrigation systems. It is possible that the levelling-off in Main Spring nitrate-N since 2012 may be a result of improved farm management (Appendix 1). However, Dr Mead’s analysis identified that these changes may have partly resulted from changes in water flow rate.
We would argue that both water and nutrient management plans be made compulsory, particularly in the unconfined aquifer area, that these be actively monitored by TDC and the results become part of the public record in the interests of transparency. Auditing systems should be a condition of future consents. Further, those being allocated water should be required to contribute towards the monitoring and auditing costs.
FoGBay look forward to seeing more explicit proposals from FLAG.
Adaptive Management: The only realistic use of this management technique for the AMA is when the aim is to reduce the current pollution – in the case of nitrate-N this would be to ensure the concentration goes down. One problem lies in the long transit time for groundwater and the size of the AMA, which will delay the detection of any changes. If further water allocation is allowed and the pollution gets worse, it will be difficult to change back because of the long-term nature of water consents.
Water allocation: FoGBay support the FLAG decision that water allocation should stop at MALF. In the FLAG Meeting Notes for 24/7/2015, FLAG members agreed that water allocation to major users, such as irrigators, would be prevented from drawing down river flows to below MALF. Dr Young on page 17 of his 2006 report to TDC emphasised this point also (see Young, R. 2006. Available from http://www.cawthron.org.nz/publication/science-reports/framework-flow-management-takaka-river-catchment/ ).
A presentation on actual data from Harwood and Lindsay Bridge showed that for many species, optimum habitat was above MALF (see FLAG 2015-07-24 – Presentation and Notes – Setting Ecological Values).
Subsequently, in 2015 Dr Young stated that, in his opinion, it was OK to allocate below MALF; it seems that this is based on MoE (2015) and the 2008 MoE draft guidelines for water allocation (Beca 2008) and not on further research in the Takaka Catchment. In FLAG discussions it was stated TDC had rejected the use of hydraulic-habitat modelling (and presumably the better drift-NREI model) because of costs, so the advice of Dr Young had been sought. Recently a report was 6
released that recommended using the historic flow method, partly because it was used elsewhere in the country (Young and Hay 2016). This report does not consider the ecology of the AMA, which is critical for the management of this interconnected system, but concentrates on the rivers. In May 2015 Dairy NZ suggested that for rivers and for the Springs a 20% allocation would be reasonable. We strongly reject this as it does not take into account the high conservation values of the area. Dr Young has been careful to point out that his recommendations were just a starting point for further decisions by FLAG.
In FoGBay’s opinion, if proper research cannot be done, then there should be no further allocation of water in the unconfined AMA zone. Clearly to do so would be risky. The current 500 l/sec limit in the unconfined aquifer should be maintained in the meantime.
The current allocation of 500 l/sec would represent about 6% of the Main Spring MALF but as the FLAG discussions indicate this an overestimate, the actual effect on the Springs may be only about 2%. The proposal to increase this to 10% of MALF is unacceptable where we have an aquifer system with such high conservation values.
The FLAG interim proposals suggest that the unconfined aquifer should be divided into three zones. We disagree with this approach. Water used for irrigation is often applied to areas where leaching of nitrate will be high – sites with high rainfall, stony soils, prevalence of sinkholes etc. The FLAG report and Young and Hay (2016) suggested approach ignores this and focuses on the river’s ecology. The protection of the AMA should be the priority and this is influenced by all irrigation in the unconfined zone.
The Waingaro zone clearly illustrates this problem. The TDC proposal is to allocate 550 l/sec in this zone instead of the current permitted 111 l/sec, but there is to be a stop-take when MALF would be reached at the confluence of the Waingaro and Takaka Rivers. The report calculates that there is an additional 184 l/sec that could be allocated (it is unclear how this figure was derived). Significantly it ignores that this water would largely be used in the unconfined zone.
However, we agree that there should be a stop-take at MALF and recommend that this be applied to all current permits when they come up for renewal in 2019. This would protect the flow of the Waingaro and should have a positive effect by reducing nitrate ending up in Te Waikoropupū. It will also ensure that very low dissolved oxygen does not become a stressor on the stygofauna. Similar stop-takes at MALF should be applied to all permit holders in the unconfined aquifer zone. The 2008 MoE draft water allocation guidelines stress that ‘for connected systems…. the most sensitive or significant value will drive the selection of methods for all resources’.
Confined Aquifer Zone of the AMA: The report proposes allowing an increased take from the AMA in this zone. This also poses some risks. If the bore hits a conduit to the Springs it will have a direct effect on its flow. If it is on the seaward of the springs it may alter the seawater barrier. The idea of a no-take zone around the Spring is a good idea but may be insufficient to protect the Springs. As Professor Williams has emphasised, at low water flows, any take in this zone could have a direct effect on the Springs. Please reconsider.
Justifications for increased water allocation: The FLAG proposals do not give an economic justification for allocating more water to irrigation water nor do they discuss how, if it is increased, it should be allocated within the wider community. We note that some farmers have not found it necessary to have intensive irrigation and a few have dams to store water for use over summer. 7
The report bends over backwards to give farmers greater security of supply but this should not be at the expense of the overarching aim of maintaining or improving water quality.
Water Conservation Order: An application for a WCO for the Springs and AMA is under action and this is noted in the FLAG draft proposals. FoGBay strongly support this application and believe that FLAG should do so as well.
Other methods of controlling nitrate inputs: Piers Maclaren has suggested informally that limiting stock numbers in the unconfined AMA may be a way of a ensuring that nitrate leaching could be limited. Cow numbers by themselves would not be adequate. For example, MAF stock unit (SU) figures show that dairy cow SU vary widely with cow live weight and milksolid yields. Presumably SUs would be related to feed intake and to urine discharge. SU figures are also available for sheep, deer etc. which could be used if they relate directly to nitrate leaching. Because animals are sometimes wintered off farm, SU x grazing days/year would seem a better unit.
Even if this were used as a control tool it would still be necessary to monitor nitrate and other critical limiting factors such as dissolved oxygen and clarity.
Another technique would be to limit N leaching per ha as has been proposed elsewhere in NZ. This would presumably use Overseer® to estimate leaching, as measuring it directly would be expensive.
ANZECC. 2000. Australian and New Zealand guidelines for fresh and marine water quality. Volume 1. Australian and New Zealand Environment and Conservation Council, Agriculture and Resource Management Council of Australia and New Zealand.
Beca. 2008. Draft Guidelines for the Selection of Methods to Determine Ecological
Flows and Water Levels. Report prepared by Beca Infrastructure Ltd for MfE.
Wellington: Ministry for the Environment.