25 JANUARY 11 2014 www.listener.co.nz R ex Butterworth was doing very nicely on his Matamata dairy farm. Milk production was good, profits were respectable and the cows looked a picture as they grazed on the lush green pasture of the Waikato. But beneath the surface, Butterworth was aware that his pastoral idyll was leaving a dirty mark on the environment. His cows, like those of most other New Zealand dairy farmers, were excreting at will on the pad- docks. The excess nutrients were leaching through the porous ground to the shallow water table below. And their big hooves were damaging the soils. There was nothing extraordinary about the environmental impact his operation was having. Quite the contrary. The volume of cow urine dumped on the soil and the excess nitrogen that trickled down into the THE DAIRY DILEMMA New Zealand’s economy relies on dairy farming, but the industry pollutes rivers. Can this conflict be resolved? by REBECCA MACFIE ● photos by DAVID WHITE SOMETHING IN THE WATER Cleaning up: Rex Butterworth hoses down his yard. 26 LISTENER JANUARY 11 2014 THE DAIRY DILEMMA water table were less than on the average Waikato dairy farm. No one was waving a regulatory stick at him and ordering him to reduce his farm’s environmental footprint. Nevertheless, he has seen fit to invest $900,000 in new farm infrastructure that has cut the volume of nitrogen leaching through the soil to less than half the aver- age in the region. Butterworth’s cows now spend several hours each day in his two “herd homes”, where they escape from the heat and the cold, and where their urine and faeces fall through the grated floor into a huge concrete bunker. When soil and climatic conditions are right, Butterworth sprays the collected effluent onto his maize – a crop that is highly efficient at turning the nutrients into fresh new growth. The animals wander into the shelters at about 3am each day for a feed before milk- ing. They then head back to the paddock for a few hours, and return to the shelter when the sun is too fierce or the wind and rain too cold. In the depths of winter, when the soil is wet and the grass can’t take up the volume of nutrients released from their urine, they spend most of their time in the herd home. “They absolutely love it,” says Butter- worth. And so does he. At first he built only one herd home, large enough for 250 cows, because he wasn’t sure whether the benefits would outweigh the high capital cost. But he was quickly convinced, and in recent days he has completed a second. It’s making a huge difference, he says. The volume of nitrogen leaching from his paddocks has dropped to 40% below the regional average; by returning the collected effluent to the soil at times when it can be taken up by the growing plants, he’s saving big money on artificial fertiliser; because his pasture doesn’t get such a hammering from the cows’ hooves, the grass grows better; and because the animals are protected from the extremes of heat and cold, they are under less stress and produce more milk – he esti- mates his milk production has increased about 25%. At this rate, his investment in the herd homes will pay for itself in three to five years. “Before, we thought it was the natural way for the cows to eat and excrete on the paddocks, and it probably was fine when there was a cow to the acre as in the 1950s. But that’s not the case now.” PRODUCTION DRIVE In fact, it is far from the case. Not only have hundreds of thousands of hectares of New Zealand’s agricultural landscape been con- verted from sheep farms to dairying over the past two decades, but the relentless drive for increased milk production has also led to more cows excreting ever-increasing vol- umes of nitrogen-rich urine that seeps into groundwater, rivers and lakes. Along with phosphorus, which mainly enters rivers stuck to soil particles from erod- ing hillsides and stream banks, the excess nitrogen from animal urine promotes the growth of river weeds and slime, and can cause algae blooms. The population of may- flies and small waterborne insects – which support fish and bird-life – declines. Slugs and snails, which like muddy, slimy envi- ronments, thrive. Too much nitrogen can also cause the water to become toxic to fish, animals and humans who drink or come in contact with it. Thanks to a massive increase in the use of feed supplements such as imported palm kernel extract, and dramatically expanded irrigation and urea fertiliser to extend the grass-growing season, the industry’s produc- tivity has risen an astonishing 60% in the past 20 years. Dairying has spread further and further into traditional sheep country, and farmers also carry more cows per hec- tare. As Butterworth notes, stocking and production rates have changed markedly since the 1950s, but the traditional pastoral model in which cows graze in the paddocks and excrete directly onto the soil remains largely unchanged. He is an outlier in an industry that has expanded and intensified at a rate that has far outstripped its willing- ness and ability to manage the effect it is having on the environment. A major investigation by the Parliamen- tary Commissioner for the Environment, Jan Wright, spells out the threat this poses. Between 1996 and 2008, nearly 300,000ha of traditional sheep and beef farms, mostly in Canterbury, Southland and Otago, were converted to dairying. Based on projected demand for dairy protein internationally, this trend is set to continue. Modelling done by independent economic consultancy Motu indicates a fur- ther 370,000ha will be converted to dairying by 2020. And what water quality scientists have shown is that wherever there is an increase in dairying, there is a consequen- tial decline in the health of rivers, streams and lakes. That’s because cows urinate more Butterworth’s investment in new herd shelters looks set to pay itself off in three to five years. In midwinter, the cows spend most of their time in the herd home. 27 JANUARY 11 2014 www.listener.co.nz D A V I D W H I T E than sheep, releasing far greater volumes of nitrogen into the soil – much of which slips through the soil and into waterways. Studies by the National Institute of Water and Atmospheric Research (Niwa) show that the national median rate of nitrogen leach- ing from dairy farms is about 28kg a hectare per year; from sheep farms it’s less than 5kg. The volume of nitrogen that leaks through the soil depends greatly on the landscape, climate and soil type. On Canterbury’s stony, free-draining soils, where irrigation has helped dairying to treble since 1996, annual nitrogen leaching rates can reach 90kg a hectare or even higher. One water- quality scientist describes dairy farming on these light soils as “hydroponic” farming. But Wright has not based her predic- tions on the high leaching rates common in Canterbury. She has selected extremely conservative rates, but her projections for water quality if the expansion of dairying continues as expected are deeply troubling. “The results of the modelling exercise show that the amount of nitrogen enter- ing fresh water every year in virtually every region of the country will continue to rise … The impact of this ongoing and increas- ing stress will generally be worsening water quality – more blooms of algae and cyano- bacteria, more streams trailing metres of brown slime, fewer stream insects and fish, and more wells and waterways exceeding nitrate toxicity limits,” she writes. “All of us as New Zealanders face a difficult dilemma. Our small country is a major sup- plier of protein in the form of milk powder to developing countries, and the dairy sector is now the biggest single earner of export dollars … Rising farm costs without corre- sponding price increases for wool and meat are continuing to incentivise dairy-farm con- versions. Unfortunately, this investigation has shown the clear link between expanding dairy farming and increasing stress on water quality. Even with best-practice mitigation, the large-scale conversion of more land to dairy farming will generally result in more degraded fresh water.” FAINT PRAISE Wright’s report has been greeted by Gov- ernment and dairy industry leaders with a chorus of faint praise. Environment Minister Amy Adams describes it as “helpful” and a “salutary reminder” of the need for action on water quality, but says Wright has failed to take account of the current suite of Gov- ernment freshwater reforms (of which more later). In the deep south, Federated Farmers leader Russell MacPherson accused Wright of presenting a worst-case scenario and fail- ing to take into account “existing or future mitigation measures”. He said dairy farmers had “greater awareness than ever before of their environmental impact”. Todd Muller, Fonterra’s group director of co-operative affairs, says the report “forms an important part of the discussion”, but adds that Wright has based the models underlying her conclusions on past prac- tices, and things have changed. “When we looked at the report, we thought it was a very fair assessment of where we have come from, but perhaps not as robust a view to the future as we see it. We accept that the era of unconstrained growth is now over, and if you look back over the past 15 to 20 years, it has been very light-touch regulation.” Muller argues that pending central and local government regulation and the will- ingness of farmers in recent years to address the issue, “give us a lot of confidence that sustainable dairy growth is possible”. But he acknowledges that the dairy industry has been in a state of denial about its impact on waterways. “I do accept that the way we have engaged with the community on this issue has been historically very defensive and could be perceived as trying to preserve the status quo for as long as possible.” But those days are gone, he says. For instance, in recent years, dairy farmers have fenced off some 20,000km of streams to prevent stock from defecating in the water and stomping around on banks, which causes sediment and silt to spill into rivers. Fonterra has also developed programmes to help farmers improve the efficiency with which they use irrigation water, and to help them comply with the requirements of their 28 LISTENER JANUARY 11 2014 THE DAIRY DILEMMA T he push for production in the dairy industry over the past two decades has seen a big increase in farm stocking rates, aided by a massive increase in the use of nitrogen fertiliser and imported supple- mentary feed. But Mike and Lisa Parnwell have defied the trend on their 250-cow operation in the central North Island, running their farm in much the same way that Mike’s father used to. Their stocking rate of 2.5 cows a hectare is lower than other dairy farms in his area – most have about three cows to the hectare – and they bring in relatively little supplementary feed. They use a small amount of palm-kernel extract (although they are trying to move away from it) and they apply very little urea fertiliser. And instead of irrigating, jokes Mike, “we pray”. Last year they were hit by the drought and milk production dropped 20%, but they came through unscathed. “You just have to farm to the weather.” A few years ago, the owner of the land that they farm, Swiss-born Dolphy Mathis, decided he wasn’t happy about the cows being exposed to the heat and cold, so he invested $300,000 in two herd homes. Mike says the cows have done better since the shelters have gone in, and he has made savings on feed, much of which used to get trampled into the ground. With its light stocking rate and care- ful pasture management, the Parnwells’ property last year leached about 18kg of nitrogen a hectare – less than a third of the average in his region. And their milk production per cow is 40% above the New Zealand average. Last year the Parnwells won the farming business of the year award for the Central Plateau. To Alison Dewes, a former vet who is part of the Headlands consultancy group working with farmers to reduce their envi- ronmental footprint while maintaining their financial viability, the Parnwells are an exemplar of the farming system that may help address New Zealand’s looming water-quality crisis. She says they have chosen stocking rates that would have been common before the 1980s, when nitrogen leaching rates were 30-40% lower than today’s average. “There was a paradigm shift in the 1980s, when a study was published that linked higher stocking rates to higher pro- duction, and since then the dairy industry throughout New Zealand has joined that trend. And then along with that came nitrogen fertiliser sales to boost grass growth, because the cows weren’t getting fed properly. Then in 2003, New Zealand started importing palm kernel extract, and now we import 1.7 million tonnes a year Less is more Farmers can reduce their environmental footprint and maintain financial viability. to support the feed gaps for these high stocking rates on these farms … More than 10% of New Zealand’s milk solids are now reliant on imported stock feeds. “Farmers do their budgets based on output, so they get locked into these high-input-high-out- put management systems. It’s a treadmill, and there can be a high social cost associated with it.” A byproduct of this high-input-high-output regime has been much higher rates of nitrogen leaching. But Dewes says good farmers can reduce their inputs of fertiliser and palm kernel, cut their stocking rates and, with good pasture and animal management, maintain their production and profit- ability – and cut nitrogen leaching by up to 50%. Moreover, by cutting their cost of production, including spreading effluent as widely as they can across their land when the pasture can make best use of the nutrients, their businesses can become more resilient to financial and climatic stresses. There’s less pres- sure on the land, and less pressure on animal health. She says the alternative is to do as the likes of Rex Butterworth (see main story) have done – main- tain high stock rates, but invest heavily in capital infrastructure such as herd homes or stand-off pads that drastically reduce the volume of uncontrolled animal effluent deposited on to the paddocks. But if Dewes is becoming an influential voice of reason in farming and environ- mental circles, much of the damage from intensive dairying may already be done. In the upper Waikato, tens of thousands of hectares of pine plantations have been removed to make way for pasture for cows – a massive land use change that Dewes says will produce bacterial loads equiva- lent to the untreated sewage of a city of more than 800,000 people. In Canterbury, land use change from sheep to dairy- ing has left almost 70% of the region’s waterways damaged or at risk from high nutrient loads, and has led to rising nitrate levels at a third of monitored wells. Environment Canterbury recently moved to implement a new plan that sets region-wide limits on water pollution and will impose tighter rules for new dairy conversions, but existing farmers with high rates of nitrogen leaching will be allowed to continue to pollute. According to Massey University fresh- water ecologist Russell Death, both the Canterbury plan and a rule proposed by the Hawke’s Bay Regional Council for the Tukituki catchment would allow these waterways to become more polluted than the Mississippi, yet still be compliant with the regulations. – Rebecca Macfie 29 JANUARY 11 2014 www.listener.co.nz Alison Dewes: A high social cost. resource consents for the management of dairy-shed effluent. The co-operative has also introduced a voluntary nitrogen-management pro- gramme, under which farmers provide data on their rate of nutrient leaching, so that individuals can compare their performance with others in their area. In the past, Muller, notes, few farmers would have had any idea of the volume of nutrients leaching through their soils. LOOMING CRISIS But are these worthy-sounding initiatives to encourage “good farming practices” enough to deal with the looming crisis in water qual- ity that Wright foresees? Research led by Bob Wilcock of Niwa suggests not. For the past 12 years, Wilcock has been involved in monitoring the health of five streams to track the effects of the Clean Streams Accord, the voluntary agreement drawn up in 2003 that encourages farmers to fence off streams, put bridges and culverts over creeks where cows cross and develop nutrient budgets. Each of the monitored streams runs through dairy farming coun- try: the Toenepi (Waikato), Waiokura (South Taranaki), Waikakahi (South Canterbury), Bog Burn (Southland) and Inchbonnie (West Coast). The results show that when farmers complied with the accord, the amount of phosphorus getting into streams either stabilised or declined, water clarity improved, and E coli levels fell. But nutrient levels in the rivers remained much higher than those in similar streams that had been undisturbed by agriculture – and nitrogen levels continued to rise. That’s because fenc- ing off streams and planting out the banks helps stop sediment and phosphorus getting into the water, but it does nothing to stop highly soluble nitrogen from cow urine leak- ing through the pasture and into waterways. The problem with nitrogen is that the methods known to reduce leaching rates most dramatically – the herd homes Rex Butterworth built, concrete stand-off pads to remove cows from the pasture for a few hours each day and artificial wetlands to soak up excess nutrients – are also extremely expensive for farmers. In a study underpinning Wright’s report, economists from Motu concluded that wide- spread adoption of herd homes, stand-off pads and artificial wetlands was unlikely by 2020. Instead, they concluded, farmers were likely to make smaller improvements – more efficient fertiliser use, improved cow genetics and compliance with industry best-practice guidelines as defined in the Sustainable Dair- ying: Water Accord (which last year replaced the old Clean Streams Accord). Wright con- cludes farmers are likely to “hold the line” on nutrient leaching, increasing productiv- ity while keeping nutrient losses steady. The problem is that, in the meantime, another 370,000ha of farmland will be converted from sheep or pine forests to dairy ing, enabled by big irrigation schemes such as the controversial Government- backed Ruataniwha project in Hawke’s Bay and the Central Plains Water scheme in Canterbury. As Chris Kelly, the former chief execu- tive of New Zealand’s biggest dairy farmer, Landcorp, told Radio New Zealand’s Country Life last year: “More dairy means more cows, more cows means more nitrogen – because it’s not the fertiliser that you put on, it’s the urine from the cows – and more nitrogen potentially means more leaching into water- ways, and you know the effects of that.” COMPLETE RETHINK But Environment Minister Adams assures us that the Government is on the case and that Wright’s report is unduly pessimistic. After 20 years of inaction on freshwater manage- ment – a period during which the Resource Management Act enabled the explosion of dairying in sensitive environments such as Canterbury – rules are being developed that, she says, will protect the quality of our lakes The dairy industry has been in denial about its impact on waterways. From here, the Wairoa flows through Dargaville and into the Kaipara Harbour. These are the main arteries of the Kaipara moana, the major nursery of many species includ- ing snapper. This harbour is vital to the mauri (life force) of our rivers and coastal fisheries. My tupuna and most of my dad’s whanau were born and raised on these rivers. Many lie buried there. The rivers are us, and we are the rivers. They are our very sustenance. Many Pakeha, par- ticularly those whose forefathers farmed the land, share an affinity for these rivers along with the tangata whenua. Together, we are their kaitiaki. And we are concerned that intensive farming is too severe on the sustainability of our waterways. We must respond together, to halt and turn back this serious decline. In 2010, my uncle Henry and I visited our old homestead on the Wairua River. The river was stagnant and green and stank of cattle effluent. Tuna (eels) and whitebait are in severe decline in waters too fetid for them. Tuna were a main sustenance for hapu who live by the awa. Massey University fresh- water scientist Professor Mike Joy has said that fish such as tuna and white- bait are the coal mine canaries of our waterways. This message resonated in my mind and we decided to do something about this decline in our awa. We formed the Kaitiaki Tuna Heke Aotearoa Trust to focus on water quality in the Wairua River catchment and all 30 LISTENER JANUARY 11 2014 THE DAIRY DILEMMA and rivers from further degradation. “We do have to completely rethink the way we manage water,” she acknowledges. As a result of the work of the Land and Water Forum – a collaborative effort to get farming, industry and environmental groups to agree on a way forward on water quality – the Government introduced a National Policy Statement for fresh water in 2012. The statement expressed the noble aim that the overall quality of fresh water in all regions must be “maintained or improved”. The document offered little guidance as to how this was to be achieved, but in Novem- ber, Adams moved to back it up by releasing a proposed National Objectives Framework (referred to in policy and scientific circles as the NOF) that set “bottom-line” standards below which regional councils must not let water quality fall. Regional councils are then expected to work in a collaborative manner with their communities to set local limits on pollution that may be much stricter than the national bottom lines. Adam says the NOF is “not a silver bullet; it’s a start,” and it’s not hard to find those who believe the NOF is an important step forward. David Hamilton, professor of fresh- water ecology at Waikato University and a member of the science reference group that advised officials on the NOF, says the proposed rule book has gone further than what had been expected. It is far from per- fect, he says, but “there had to be a line in the sand drawn. “Scientists have been highly engaged in this, and they have been asked to put their necks on the line to some extent by putting numbers on a limits-based system … They are providing a directive to regional coun- cils: ‘Here is the structure, now go away and put together some limits.’” But some critics fear the “bottom-line” limits set by the NOF are so low that it may cause more harm than good to water quality. “Good rivers would be allowed to get worse under the NOF,” says Neil Deans of advocacy group Fish & Game. He says the rules are written in such a way that regional councils will be able to let some rivers dete- riorate, offsetting the damage by improving the quality of other rivers, so that the overall water quality in the area is maintained. The rules require regions to account for water quality in terms of “freshwater man- agement units” (FMUs), which can be as large or small as they choose. Deans says this would allow, for instance, increasing pollution of the Ashley River catchment in North Canterbury to be cancelled out by an improvement in a catchment in the Mackenzie Country. “The ability to trade off like this makes a nonsense of the goal of protecting [water quality] values.” Wright agrees the NOF lacks any guid- ance as to how councils are to establish the boundaries of their freshwater management units, leaving the way open for the kind of outcome Deans describes. She says the National Policy Statement requires all councils to set objectives for water quality by 2030, but there is no time- line for when those objectives must be achieved. And as her report predicts, water quality in many parts of the country will already be in a “bad way” by 2020 as a result of the continued expansion of dairying. Even if regional councils do bring in stricter local rules, conversions of sheep and forestry land to dairying that are currently under way or occur in the near future will not be reversed, Wright points out. INSECT HEALTH Another major flaw in the NOF, say critics, is that two of the most important measures of ecosystem health in rivers and lakes have been left out. It fails to include requirements regarding the health of insects and aquatic creatures living in and on a river – measured by the long-established Macroinvertebrate Community Index – despite this being a direct and clear measure of the health of the freshwater environment. And instead of imposing a limit on nitrate levels that protects the health of the aquatic ecosystem, the proposed bottom-line limit The rivers are us; we are the rivers We must work to halt and reverse the serious drop in water quality, says Millan Ruka. Ruka: gathering the evidence. “We do have to completely rethink the way we manage water.” He waka eke noa. A canoe that we are all in with no exception. We are all in this together. M y awa are the Wairua and Mangakahia Rivers of North- land, which journey from their catchments to become the Northern Wairoa River. the other waterways in Tai Tokerau. We changed our name to Environment River Patrol – Aotearoa (ERP-A) and developed assessment methods and skills in GPS photography to provide evidence of detri- mental effects to the Northland Regional and Whangarei District councils, Fonterra and Federated Farmers. Our philosophy is to be compassionate, patient and professional in our work. All reports are sent to the Northland Regional Council (NRC) and farmers’ organisations. ERP-A does not engage with farmers on the waterways and we do not trespass. The mission is to ensure the council performs its mandated duty to look after our envi- ronment and its waterways. Fonterra has evolved to respond directly to reports, but its self-regulation needs independent assessment. Fonterra says a stream must be more than 300mm deep and 1m wide to be fenced, but it is based on a summer assessment, even though there may be twice the flow in winter. ERP-A’s reports have been instrumental in gaining many kilometres of fenc- ing and creating public awareness that authorities need to do better to cope with the expected expansion of dairy farming. Environment Commissioner Jan Wright’s well-researched and accessible Water Qual- ity New Zealand forecasts further declines. Increasingly, beef and dairy breeding stock are replacing dairy stock on the pas- ture bordering waterways. Photographic evidence clearly shows unfenced cattle, with few if any water troughs, fouling near or directly in the water. Our campaign to date has emphasised respect and non-confrontation but the lack of response in the new NRC Policy Statement suggests that complacency will prevail; ERP-A responded in November by posting online GPS-tagged photos show- ing where these events happen. We do not name farmers, but seek to create pressure by identifying exactly detrimental effects are happening. We started by self-funding all our equip- ment, including vehicles, kayaks, river motorboat, cameras and computers and were later blessed to receive operational funding from a Maori-funded agency. But this funding will soon expire, and we will need an alternative source. We have no idea what this will be but the work will continue regardless. It is surprising that the Government will fund research into the problem, but provides nothing for monitoring patrols to assess and report on waterways or monitor the performance of regional councils to ensure they are performing to best-practice standards. Millan Ruka (Te Uriroroi/Te Mahure) is a ranger with Environment River Patrol – Aotearoa. 31 JANUARY 11 2014 www.listener.co.nz J O H N S T O N E My tupuna and most of my dad’s large whanau were born and raised on these rivers. in the NOF is set at the level of nitrate tox- icity. That means the rule will have been breached only when the level of nitrates in the water reaches the point where 20% of aquatic species start to be poisoned. Deans says most rivers are nowhere near this level of nitrate contamination, and the NOF therefore allows for a significant dete- rioration. “Remember, this is attempting to define the life-supporting capacity [of a waterway] – and yet it’s defining it in terms of toxicity. That’s inherently absurd. It’s like trying to define species threat in terms of extinction.” The risk, says Deans, is that “people will seize on the numbers [set in the NOF] and say ‘Oh, we are nowhere near that level yet.’ ” Adams is unfazed by such criticism; indeed, she appears to agree with it. “I agree that a Macroinvertebrate Community Index and total dissolved nitrogen level would be useful things to have, and work is going on with those. “But when you say I haven’t included this or I haven’t done that, I haven’t done any of these things. This is what the science reference panel have come up with. They said this is what we can agree on so far, and this is where we think is a sensible place to start, and we are still work- ing on the rest.” But some of the leading lights on the scientific reference group to which Adams refers think the absence of the Macroin- vertebrate Community Index and tighter nitrogen limits are serious omissions. David Hamilton, who was a member of the panel and also chairs the New Zealand Society of Freshwater Scientists, agrees the absence of the index – a measure that scientists have worked with for 20 years – is a flaw. And he’s also “uneasy” about the use of nitrate toxic- ity limits “because if you are to have streams throughout New Zealand that are close to those toxicity levels, then you have really completely let the brakes off on nitrogen”. “If you look at where New Zealand sits with regard to nitrate levels through its streams pretty much throughout the coun- try, you would be looking at that and saying there’s a lot of headroom. If we were to use that toxicity limit without [tighter] council limits, then we would have a major issue and nitrate would be going up very strongly.” MASSIVE TASK He says there’s wide variance in the ability of waterways to tolerate different nitrate levels, and regional councils will have to urgently “get their acts together” and develop local limits that are appropriate. But the task is massive. Canterbury, which four years ago began a collaborative process of drawing up local water-quality plans for the 10 key catchments in the region, has so far completed just two of those plans – one for the Hurunui catchment and one for Selwyn/Te Waihora, an area that includes the severely degraded Lake Ellesmere (Te Waihora). In the meantime, as the technically demanding and excruciatingly slow process of setting local rules continues, thousands of hectares continue to be converted to dairying. Hamilton: “That really concerns me … in some cases [where there is strong pressure for further dairy conversions], it’s almost as if there should be a moratorium to say, ‘Let’s hold development for two or three years, let’s see what our systems are doing and monitor them closely, and if we are going to develop community-based limits, let’s get those limits in place first before these very big investments in dairy infrastructure and irrigation take place.’” He warns that aquatic systems don’t degrade in a linear and predictable pattern. “Many of our systems are quite resilient up to a point, and beyond that point, which we call a tipping point or a regime shift, they can degrade very quickly. And pulling them back once they have gone through that degradation is a huge challenge. “You only have to look at [the heavily polluted] Te Waihora (Lake Ellesmere) or Lake Horowhenua to see just what those challenges involve. They are huge.” l Beyond a certain tipping point, rivers degrade very quickly.