National Freshwater & Geothermal Resources Inquiry
EMBARGOED UNTIL DELIVERED TO THE WAITANGI TRIBUNAL MONDAY 7 NOVEMBER MIDDAY 2016
The National Freshwater and Geothermal Resources Inquiry
Summary of the evidence of Dr Mike Joy
Scheduled to present at Waiwhetu Marae on Monday 7 November 2016
My evidence to the Waitangi Tribunal plainly reveals a systemic failure by the Crown to protect the freshwaters of New Zealand. This has occurred through a litany of failures; including a failure to measure the important and meaningful symptoms of decline and a failure to implement or enforce any meaningful limits to halt declines.
These failings are starkly revealed by declines in biodiversity and ecosystem health. One of the most telling symptoms is the fact that we have what is likely to be the highest proportion of threatened and at risk freshwater fish in the developed world. Freshwater fish integrate all the processes occurring in waterways and are in effect the miner’s canaries. The proportion of threatened species increased steadily from 22% in 1990s to 74% now. The widely used fish index of biotic integrity shows clearly the significantly lower fish biodiversity at sites in pasture and urban catchments. Another freshwater ecosystem health and biodiversity measure is the Macroinvertebrate Community Index and this also shows most of lowland New Zealand rivers in pasture and urban catchments are either severely or moderately polluted. However it is important to note for all these statistics that while urban catchments are clearly polluted they make up less than 1% of the total length of rivers in New Zealand while around 40% are in pasture catchments.
Water chemistry measures reveal that at pasture and urban catchments nitrogen levels exceed the point at which nuisance algal growth occurs at most of the sites in lowland pasture catchments. The other key driver of algal blooms -- phosphorus -- also exceeds guideline levels at most of the lowland pasture sites.
The reason we measure these nutrients is because they are in many places the biggest issue for rivers, lakes, estuaries and even oceans in New Zealand as these nutrients cause eutrophication. Eutrophication is an overabundance of algal growth driven by an excess of the key plant growth nutrients -- nitrogen and phosphorus. Excess in this case means more nutrients than the natural systems can assimilate, and they react to excess nutrients with excessive algal growth. This growth then leads to changes that have negative impacts on ecology and recreational use. The excessive amounts of nutrients and sediment come from terrestrial sources and by volume agriculture is by far the biggest contributor, primarily through diffuse discharges of effluent.
An example of the effect of excess nutrients in the Manawatu River where in catchments dominated by intensive farming during summer low flows high levels of algal growth have led to massive daily fluctuations in oxygen levels. These fluctuations were so extreme that the dissolved oxygen levels in the early morning dipped to below 40% and up to extreme high levels in the afternoon. In healthy rivers the oxygen level is constant at around 100% and dips this extreme are lethal for most fish and invertebrate life. The algal blooms show up in rivers as thick mats covering the bed making them unattractive for fishing and swimming and physically bad for aquatic habitat.
When it comes to trends in water quality over time, robust records have been kept since 1989 of water chemistry and these measures reveal degradation over that time period. There have been increases in nitrogen in most lowland waterways especially those in pasture catchments. The only improvements in water quality have occurred in relation to the removal of point--source (out of pipe) discharges, and improvements in water clarity.
Apparent improvements in levels of phosphorus at pasture sites have been mirrored at natural sites so claims for improvements resulting from mitigation actions such as fencing of farm lands lack any basis.
When it comes to recreation and human health NIWA modelling to fill in gaps between sample sites shows that 62% of the length of all New Zealand rivers and streams fail the contact recreation pathogen limit. That means that there is a 1% or higher chance of getting sick swimming at most lowland waterways and the worst are those in urban and agricultural catchments. Another impact on human health in lowland rivers is cyanobacterial blooms. These are caused by excess nutrients and physical alteration of rivers. Now it is commonplace to see signs warning of these toxic blooms at much of New Zealand in summertime.
In regard to lakes New Zealand now has some of the most polluted in the world, and 44% of monitored lakes are classed as polluted and most of these are in agricultural catchments.
This classification means they have ‘flipped’ into another trophic state, so they have passed a tipping point that they will be very unlikely to return from.
More than 90% of wetlands have been destroyed nationally and those that remain are in a poor state. Most of the remaining wetland sites have an Ecological Integrity Index of < 0.5 indicating significant human induced disturbance pressures. Once again the lowest values are found in intensive agricultural areas.
Groundwaters in agricultural and urban catchments are being degraded by burgeoning nitrate levels at 39% of monitored sites. At a further 21%, groundwater is contaminated by pathogen levels exceeding human drinking standards, and this is showing up in regions drinking shallow groundwater with gastrointestinal rates now highest in the OECD.
The status quo for freshwater management has clearly failed all New Zealanders. One of the glaring reasons is that the predominant cause of impacts -- diffuse nutrient and sediment from intensive farming is not controlled (apart from a few rare exceptions like Lake Taupo).
The consenting and control of pollutants was only applied to point source discharges in most cases less than 20% of the nutrient load in a river while the 80% or more from diffuse sources was ignored.
The recent national policy statement NPS--FM labelled by the Ministry for the Environment as a ‘fresh start for freshwater’ claimed to raise ambitious expectations but was actually a big backward step. The bottom lines introduced in the National Objectives Framework (NOF) are set lower than the current water quality state and do not include many important measures and ecosystems and thus will allow for further degradation. Measures of ecosystem health are not included and ecosystems such as groundwater and estuaries are just left out. The NOF sets limits for only one nutrient -- nitrogen -- and is set at a level ten times greater than the previous guideline levels. The NOF pathogen human health limit was also weakened from 240 Ecoli/L to 1000 Ecoli/l, and benthic cyanobacteria (the cause of dog, horse and possibly human death) was left out.
Given the lag times for nutrients and sediment from past landuse change and intensification of farming in the last few decades it is likely that freshwater ecosystems will continue to decline and more will tip into a worse state. The effects of all of this degradation on aquifers and groundwater are more difficult to know at this point, due to difficulties in scientifically measuring that, but it is not likely to be positive.
A copy of Dr Mike Joy’s full report can be found at http://waitangitribunal.govt.nz/ with the reference number #D20; D20(a).