SciBlogs

LAWA’s new environmental monitoring website clears up water quality data Waiology Apr 08

No Comments

By Maree Clark and Kati Doehring
LAWAlogo
The launch of LAWA (Land, Air, Water Aotearoa) last month is a significant milestone for our country’s environmental reporting. A web-based platform, LAWA displays state and trend information for more than 1100 freshwater monitoring sites throughout New Zealand in one place, and in an easy to understand format.

It’s the first time you can look at data for a site, catchment, region or the country in one place and in a standardised way. It’s unique in that it allows everyone to learn about the state of our rivers, independently whether you’re a school child, scientist or policy maker.

Making our science available to the public by communicating it in a jargon-free and easy-to-understand format is crucial. Everyone has the right to understand and know what’s going on in their waterways and what’s being done to make a change through our science and policy. Good information is key to good decision making and LAWA is a great tool to help communities understand what’s happening in their rivers and get more involved in caring for them.

The range of potential audiences, and the variance in their water science knowledge, was top of mind when building LAWA. We wanted to be able to cater for everyone as much as possible. To do this the site has the ability to ‘drill down’ from a general overview of water quality in New Zealand through the regional and catchment state and trend information, right down to site data. At the site level, those who want to can access the sample history for each water quality parameter or even download the raw data.

Another unique feature of LAWA is its desire for two-way communication by actively encouraging dialogue between LAWA and its users. Individuals or groups can post events and stories about projects happening around rivers near them or report river observations such as pollution incidents.

Building on the momentum from the launch of LAWA’s first module, river quality, we are continuing to develop LAWA into the preeminent source of information on our water resource. We’re seeking to strengthen the information available on freshwater by adding data on flow, macroinvertebrate communities, water allocation and lake quality.

We will also be adding a coastal module, providing credible and accessible data for one of the country’s most prized resources. This will communicate data on our oceans and estuaries both from an ecological and recreational perspective. There are significant benefits of presenting freshwater, estuarine and coastal ecosystem health in one place where the connections between these environments will be emphasized. In addition to consolidating the existing coastal and estuarine monitoring data, it is anticipated that LAWA will display the data generated from coastal monitoring buoys.


Maree Clark is a water quality scientist at Horizons Regional Council and Kati Doehring is a water quality scientist at Cawthron Institute.

World Water Day, 22 March Waiology Mar 21

2 Comments

By Daniel Collins

WWD2014Since 1993, March 22 has been World Water Day. Its purpose is to raise awareness of the importance of water to society and of the challenges people face in securing sufficient and safe water. Like many efforts run by the United Nations, it fosters collaboration between the economic and hydrologic haves and have-nots, and cooperation among riparian nations*.

The water-energy nexus

The theme for this year’s World Water Day is water and energy. Water is required to generate almost all forms of energy, and energy is needed to distribute and treat water. In New Zealand, a little over half of our electricity is generated renewably at hydropower stations, and even thermal power stations need water for cooling. Summer irrigation has also changed NZ’s profile of energy use, and even electricity prices affect how much water is abstracted.

Our largest capacity hydroelectric power station is the 850 MW Manapouri scheme, conveying water from Lake Manapouri through an underground station to Doubtful Sound. Built in 1971 largely to serve the Tiwai Point smelter, it also helped to galvanise a generation of environmentalists concerned with effects of raising the lake level.

As with most uses of water, hydropower generation has its benefits and its costs, depending on your point of view: a renewable, low-carbon energy source; cheaper energy, depending on the geography and availability of other resources; loss of cultural spaces; loss of ecological habitat and natural character; different recreational opportunities; and altered risk of flooding.

WWD events in New Zealand

Perhaps because water is increasingly in the news, New Zealanders don’t need as much reminding of its importance. Or perhaps because we are so concerned with water that we need to learn or do more. In Christchurch there will be two public events this Saturday to help quench you World Water Day:

  • The NZ Hydrological Society, Nature Watch NZ, and the Styx Living Laboratory Trust are running a citizen science workshop at the Travis Wetland, from 10 am – 1 pm. Listen to experts talk about stream monitoring, why it’s important, learn how you can do it in your own group, and even give it a go there. Travis Wetland Education Centre, off Frosts Road, Christchurch.
  • Castle’s and Sons Brewery is hosting a Heathcote River clean-up from 10 am. Refreshments provided afterwards. 3 Garlands Road, Woolston, Christchurch.

If you know of other events, please share them in the comments below.

* Riparian nations share the same river basin, e.g., the 10 nations with land draining into the Nile.


Dr Daniel Collins is a hydrologist and water resources scientist at NIWA.

Calling for Christchurch flood photos Waiology Mar 07

6 Comments

By Daniel Collins

The flooding that Christchurch experienced on Wednesday was extreme, leaving many houses flooded and roads closed. To build a better understanding of how vulnerable different parts of Christchurch are to flooding in the future, particularly following the earthquakes, we would like your help.

If you took any photos at or near peak water levels anywhere in Christchurch during Wednesday morning or early afternoon, please send them to NIWA (floodphoto AT niwa.co.nz)* with the street address and time, and with the subject “Flood”.

We will use the images to help identify how high the waters rose across the city. This will help us improve our models so we can provide better flood risk maps in the future.

* The NIWA email is once again working. Sorry for any inconvenience.


Dr Daniel Collins is a hydrologist and water resources scientist.

The colourful redfin bully Waiology Jan 06

2 Comments

By Amber McEwan

As the temperatures gradually get warmer, we aren’t the only ones thinking about hopping into our local river. A small, yet spectacularly attractive little native fish called the redfin bully uses this time of year to make the move from the sea to fresh water.

The male redfin bully is one of our most brightly coloured native freshwater fish (A. Perrie).

The male redfin bully is one of our most brightly coloured native freshwater fish (A. Perrie).

The redfin bully is usually a freshwater fish but they undergo a migration when they are young. Adults lay eggs in streams and rivers and when they hatch, the tiny larvae are swept downstream and out to sea. They spend 3–6 months living in the sea (often travelling long distances with inshore currents!), then venture up into river mouths and begin to gradually make their way upstream. This is a kind of migration called diadromy and it is very common in New Zealand freshwater fish.

This species is one of our most brightly coloured, especially the males which have bright red stripes and electric blue borders on their large, frilly fins. Adults are commonly around 100 mm long. Redfin bully males are exemplary fathers. After eggs are laid, dad is left to guard the nest, a job he undertakes with great ferocity! He chases away all intruders, puffing himself up and flashing his stripes and he often goes without food for long periods so he can stay close and keep his offspring safe.

The less colourful female redfin bully (A. Perrie).

The less colourful female redfin bully (A. Perrie).

Redfin bullies are found in many streams and rivers throughout New Zealand but they do prefer clean, cold water. They are nocturnal, so the best time to see them is with a strong torch at night in a local stream. Look closely—although they are colourful, they blend in well with the riverbed and tend to ‘freeze’ as camouflage which means that they can be hard to spot! Remember to be gentle with your observations, these colourful little fish are found nowhere else in the world and have a more serious conservation status than the little spotted kiwi!


Amber McEwan is a freshwater ecologist based in the Wairarapa.

Happy holidays from Waiology! Waiology Dec 23

No Comments

By Daniel Collins

After the recent water quality series, Waiology will be taking a break over the holidays, springing back to action mid-January.

Over the course of the year, Waiology published 67 articles and hosted four series – on wetlands, water governance, water quality, and native freshwater fauna. See the archives for the complete list. Based on visits to specific articles, the most popular one this year was Bob Wilcock’s on dicyandiamide (DCD), at 4500 pageviews. The second most popular, at 2500 pageviews, was my article from last year on the water footprint of milk. A few other highlights from this year were:

Thanks to all the contributors and all the visitors for making Waiology the constructive and informative forum it is. I hope you got a lot out of it.

Have a very Merry Christmas, Happy New Year, and a great time for whatever you get up to. And remember, if you spend time in or beside any water – liquid or frozen – stay safe. Here’s a light-hearted public service announcement from 1951 about water safety…

YouTube Preview Image
Dr Daniel Collins is a hydrologist and water resources scientist at NIWA.

Un-muddying the waters: Series conclusion Waiology Dec 20

2 Comments

By Daniel Collins

Un-muddying the Waters : Waiology : Oct-Dec 2013After 10 weeks and 26 articles, Waiology’s series on water quality draws to a close. We have heard from 26 different contributors from 10 different organisations. Articles spanned topics from states and trends in observational data to diverse management solutions. There were some glaring omissions, for which I apologise, but not all requests translated into articles for one reason or another.

It is hard to provide a summary of the series, and no such summary could canvas the entirety of the science and management or water quality in New Zealand, but I shall offer you some of the more pertinent points.

  • Water quality is generally declining due to land use intensification, and without significant action from a range of sectors it is likely to degrade further. Climate change could add to the problem.
  • Agriculture is the primary culprit for the decline, and dairying in particular, but let’s not forget urban pollution and emerging contaminants, and nor should we tar an entire industry for the activities of a fraction.
  • Also, don’t forget estuaries – they’re on the receiving end of catchment contaminant runoff.
  • Consequences of poor water quality include elevated health risk, shifts or declines in freshwater biodiversity, and diminished recreational opportunities.
  • Recreational water quality guidelines for swimming suitability don’t satisfactorily reflect the science.
  • Water quality limits are being set at the national and local levels, incorporating science, economics, and the myriad of values held dear by community members. But to be effective the limits need to as precise as the desired outcomes.
  • Many management solutions are being implemented to maintain or improve water quality, from the stream and farm to the catchment and country, informed in part by scientific and economic modelling, but these efforts will take time to pay off.

While the series was running, it was also interesting to see that the news cycle was punctuated by water quality events of its own. The hearings for the Ruataniwha Plains water storage proposal began. The Government’s second round of freshwater reforms were announced, along with an initial suite of water quality limits with the National Objectives Framework. The Parliamentary Commissioner for the Environment released another report on water quality. And a report from Lincoln University identified water as New Zealander’s environmental issue of greatest concern (PDF).

Of ten aspects of our environment, rivers and lakes were ranked the worst condition in the Lincoln report, though they were not necessarily bad. In terms of management, people were also most negative about river and lakes combined, followed by groundwater. The main threats for freshwaters were thought to come from farming, followed by sewage and stormwater, and then industrial activities. And over the 13 years of these Lincoln reports, more and more people blame farming for freshwater degradation.

But why do people believe what they believe? How do these beliefs diverge from reality (if they do)? And how do they affect directions in the science and management? These are three Science, Technology and Society questions that I would dearly love answered.

So turning back to the series, what did you learn? Are the waters less muddied for you now, so to speak? If you would, please fill out the feedback form for the series, it would be most helpful. I would also be some reward for the time I put into the series after hours.

Waiology will of course continue next year with more than just water quality on the agenda. Your requests would help guide article selection.

And finally, in the interests of providing an accessible resource for future readers, here is the final list of articles.

  1. Un-muddying the Waters: Series on NZ water quality. Daniel Collins, NIWA.
  2. A primer on water quality. Clive Howard-Williams, NIWA.
  3. An overview of the water quality in New Zealand rivers. Rob Davies-Colley, NIWA.
  4. Pipes, ponds and beyond: Measuring and managing urban stormwater quality. Jonathan Moores and Jenni Gadd, NIWA.
  5. Bugs in the system: How do we make sense of recreational water quality? Gary Bedford, Taranaki Regional Council.
  6. Effects of water quality on freshwater fish. David Rowe, NIWA.
  7. Water quality – What about the fish and the anglers? Neil Deans, Fish and Game NZ.
  8. Estuaries on the receiving end of catchment runoff. Judi Hewitt, NIWA.
  9. Proposed national bottom lines for water quality. Daniel Collins, NIWA.
  10. Why freshwater management needs to include estuaries? Malcolm Green, NIWA.
  11. Managing nitrogen in the Lake Taupo catchment. Bill Vant and Jon Palmer, Waikato Regional Council.
  12. Monitoring the diversity of NZ groundwater quality. Magali Moreau, Chris Daughney and Zara Rawlinson, GNS Science.
  13. Science and policy merge in water plan. Paul Reynolds, Ministry for the Environment.
  14. Overcoming obstacles to setting water quality limits. Ned Norton, NIWA/Environment Canterbury, and Helen Rouse, NIWA.
  15. Nuisance periphyton – too much of a good thing. John Quinn, NIWA.
  16. Nitrate in Canterbury groundwater. Carl Hanson, Environment Canterbury.
  17. Emerging organic contaminants: A threat to New Zealand freshwaters? Sally Gaw, University of Canterbury.
  18. Water quality models – are they good enough for management? Sandy Elliott, NIWA.
  19. Estuary water quality for ecosystem health and recreation, Christchurch. Lesley Bolton-Ritchie, Canterbury Regional Council.
  20. How does agriculture affect New Zealand’s water quality? Bob Wilcock, NIWA.
  21. Vague expectations get vague results: Freshwaters need targets. Mike Scarsbrook, DairyNZ.
  22. Understanding groundwater quality – why it’s not easy. Chris Daughney and Magali Moreau, GNS Science.
  23. Impacts of climate change on water quality. Daniel Collins, NIWA.
  24. How much dairying is too much in terms of water quality? Daniel Collins, NIWA.
  25. Better water quality won’t happen overnight … but it must happen. Jenny Webster-Brown, Canterbury and Lincoln Universities.
  26. Water quality series: What do you think? Daniel Collins, NIWA.

Dr Daniel Collins is a hydrologist and water resource scientist at NIWA.

Water quality series: What do you think? Waiology Dec 19

No Comments

By Daniel Collins

Un-muddying the Waters : Waiology : Oct-Dec 2013We have almost finished Waiology’s series on water quality, with 25 articles running from the science to solutions. I would now like to take the time to ask what you think about the series and Waiology in general.

Please take a few moments to answer the following survey. All 12 questions are optional. It would be of considerable help in shaping how Waiology serves you in the future. Individual feedback will be kept anonymous and pooled results will be shared on Waiology depending on sample size. And you can always contact me directly. Thanks!

1. What did you like most about the water quality series?

2. Which was your favourite article? (Select from the list below)

3. What did you like least about the water quality series?

4. What topics would you like covered in the future?

5. What about freshwater is most important to you? (preferably up to three) (use the ctrl key to select multiple options)

6. Who do or would you like to receive freshwater science information from? (use the ctrl key to select multiple options)

7. How do you like to learn about freshwater science? (use the ctrl key to select multiple options)

8. Why do you follow Waiology?

9. How do you follow Waiology? (use the ctrl key to select multiple options)

10. Is water related to what you do for a living?

11. If yes, where do you work primarily?

12. Where do you live?



Are you a human? Please enter the following text.
captcha

Better water quality won’t happen overnight … but it must happen Waiology Dec 18

10 Comments

By Jenny Webster-Brown

Un-muddying the Waters : Waiology : Oct-Dec 2013If we cannot stop ongoing water quality degradation, and effectively restore degraded water environments, we stand to lose much that we value about New Zealand and our way of life. We will lose recreational opportunities, fisheries and our reputation for primary produce from a “clean” environment. We will lose functioning ecosystems, the ecosystem services they provide and the beauty of our iconic water features. We will have to pay for increasingly higher technology to treat drinking, stock and even irrigation water … like so many drier, more populous or older nations, who have long since lost their natural water amenities. This is not what we have known, or what we wish for our children, or their children. To improve water quality, we need only three things: the will, the means and the time.

This is the final invited article in this Waiology series on aspects of water quality. On the basis of the preceding articles, augmented by my own experience as a water quality scientist, I would like to reflect on where we currently stand with respect to these three requirements. A ‘will’ to improve water quality is clearly evident. Over the last 5 years we have seen an unprecedented level of activity from national government seeking to change NZ’s freshwater management policy, via various primary industry initiatives, the broad, consensus-based Land and Water Forum and the ‘Fresh Start for Freshwater’ programme. A greater role for community decision-making in setting water quality targets for local catchments is a key component of the Freshwater Reforms.

A Lincoln University research student measuring changes in water quality parameters over a 24 hr period in Lake Ellesmere/Te Waihora,  to understand how this large shallow lake responds to catchment land use.  (Photo: J. Webster-Brown)

A Lincoln University research student measuring changes in water quality parameters over a 24 hr period in Lake Ellesmere/Te Waihora, to understand how this large shallow lake responds to catchment land use. (Photo: J. Webster-Brown)

The ‘means’ include the new National Policy Statement for Freshwater Management, highlighted in two of the Waiology articles (1, 2), and its recent amendment to include a more prescriptive National Objectives Framework (NOF). However, the devil is, as always, in the detail. The devil, in this case, is in the science information that underpins this new policy. Water quality degradation is a classic “wicked problem”, with multiple contributing factors, unexpected interactions and often inexplicable environmental responses. The Waiology blog has included articles by some of NZ’s top freshwater scientists, conveying their understanding of the cause and effects of the ongoing water quality decline; causes such as urban stormwater drainage and agricultural activities, and effects as manifested in surface freshwaters, ground waters and estuaries. The authors have also often noted the limits of their current understanding, the difficulties imposed by insufficient data, and how this creates uncertainty in predicted outcomes. This same uncertainty can lead to disagreement amongst scientists asked for comment or advice, as it has with the setting of numerical ‘attribute states’ in the NOF, for example.

To quote author Sheldon Kopp … ‘All important decisions must be made on the basis of insufficient data’. Although robust scientific debate is considered a healthy way to get at the truth in the world of science, it is not particularly helpful to policy makers or to the communities tasked with making decisions about the value of a water body. So how can scientists best support the immediate needs of this brave new world of freshwater management? While acknowledging the need for better data and information about water environments, we can try to communicate the concepts and facts that we do have confidence in, as simply as possible and without contradiction. We can help the policy-writers formulate straightforward, practical policies. Recent freshwater management policy introduces increasingly unfamiliar terminology and complex application principles. In the field of water quality science, there are many examples of simpler guidelines and standards taking precedence over more rigorous, but difficult to use, alternatives.

Scientists can help to manage expectations, by providing guidance on realistic targets for water quality and being honest about likely timescales for change. Which brings us to ‘time’. Even if every positive action taken has the anticipated positive effect, improvements in water quality will not be immediate or perhaps, in some cases, even detectable within our lifetimes. This is just the beginning of a critical time for NZ water quality and good things, in the words of Mainland Cheese, do take time. More reliable predictions of future conditions will be critical during this period to reassure those who grow impatient, that change won’t happen overnight … but it will happen.


Professor Jenny Webster-Brown is a water quality chemist, and the Director of the Waterways Centre for Freshwater Management at the universities of Canterbury and Lincoln.

How much dairying is too much in terms of water quality? Waiology Dec 17

2 Comments

By Daniel Collins

Un-muddying the Waters : Waiology : Oct-Dec 2013On 21 November the Parliamentary Commissioner for the Environment, Jan Wright, released her second report on water quality. It warned that business-as-usual dairy expansion by 2020 would leave our lakes and rivers more degraded than they are now, even with improved mitigation. I’d now like to re-cap what the report concluded, how it got there, and how it was received.

The report

The purpose of the report was to illustrate how land use change could affect future nutrient runoff – nitrogen and phosphorus – based on a simple, business-as-usual scenario for 2020.

Motu used a combined economics-land use model called LURNZ to project what land use changes are likely by 2020, driven by commodity process and knowledge of land use practices and landscape characteristics. Sheep and beef farming were expected to give way to dairying, forestry, and even reversion to shrubland.

A team from AgResearch, Motu and Horizons Regional Council then assessed what mitigation measures would likely be adopted by 2020, such as wintering barns or artificial wetlands. In the end, they assumed that nutrient losses for a given area would remain about the same even as productivity increased – more intense production for the same environmental cost, what DairyNZ promotes as ‘holding the line’.

Large-scale land use change to dairy farming leads to an increase in the amount of nitrogen that gets into freshwater. (From the PCE report)

Large-scale land use change to dairy farming leads to an increase in the amount of nitrogen that gets into freshwater. (From the PCE report)

The land use changes and increased agricultural efficiencies then fed into NIWA’s water quality model, CLUES. This produced projections of nitrogen and phosphorus yields based on land use and landscape characteristics.

In general, based on the single scenario considered, phosphorus loads were expected to change little while nitrogen loads were expected to climb. There was a roughly linear relationship between change in dairying area and change in annual nitrogen load. The report’s conclusion was simple: Anticipated expansion of dairying area would lead to increased nitrogen levels in our rivers and lakes, even with anticipated improved management.

Mixed reactions

News of the report understandably precipitated a range of responses from the agricultural and freshwater communities.

Fish and Game NZ’s CE Bryce Johnson welcomed the report, saying

“…it serves as a stark warning that the nation is at a crossroads: we can either continue with the Government’s and primary production sector’s agenda of doubling agricultural output by 2025 – completely wrecking the environment, our waterways, our estuaries and beaches, our tourism sector, our international brand, and the kiwi way of life in the process – or we can look at smarter ways to grow the economy.”

IrrigationNZ’s CEO Andrew Curtis dismissed the report as an unfair representation of recent land use management innovations.

“IrrigationNZ believes win-wins are possible for agriculture and the environment… . It’s disappointing the report disagrees with this. However that’s what happens when you get carried away with gross assumptions that are then modelled.”

Canterbury and Lincoln University’s Professor Jenny Webster-Brown called the report a wake-up call, based on valid modelling and defensible assumptions.

“However, it would be wrong to treat this outcome as inevitable. … We can use this combined land use-nutrient leaching model to see how the outcome changes for alternative economic and land use scenarios. Identifying alternative agricultural and horticultural uses for our land, ones that can provide a similar economic benefit but have significantly less impact on water quality, would surely be a major step forward in future proofing NZ’s water quality.”

AgResearch’s Rich McDowell, on the other hand, calls the assumptions about mitigation simplistic, going on to say:

“…the PCE report does not give due consideration to current policy (which tend to focus on obvious bad practice) and the recently announced freshwater reforms which could require a step change in N and P management on-farm.”

And these are but a fraction of the responses to the report, public and private.

So what now?

The report is a reminder that unless we significantly improve nutrient management in relation to dairy farming, and/or put limits to the extent of dairy farming, then water quality will degrade across New Zealand. The report was not a simulation of what will come to pass, but one of many possible scenarios. Management is of course improving (e.g., Horizon’s One Plan, Environment Canterbury’s proposed Land and Water Regional Plan, National Objectives Framework), and in time we’ll see their effects. But we cannot be sure how far technical and policy innovations will take us until it happens.

Scenario-based modelling studies, like the PCE’s, are an insightful way of presenting alternative visions for New Zealand’s future, adding to the national conversation of where we wish to be heading. Another part of that conversation was put forward by Shaun Hendy and Paul Callaghan in their recent book, ‘Get Off the Grass’. Nations never get rich through agriculture, they say, so we should diversify our portfolio of economic earners. And setting water quality limits at the national and local scale is yet another part of the conversation being held to answer how much dairying, and intensive land use in general, is too much.


Dr Daniel Collins is a hydrologist and water resources scientist at NIWA.

Impacts of climate change on water quality Waiology Dec 16

2 Comments

By Daniel Collins

Un-muddying the Waters : Waiology : Oct-Dec 2013Climate change goes beyond warmer weather and more extreme floods and droughts. Effects are expected to include changes to the water quality of our rivers and lakes as well. This has implications for the vulnerability and sensitivity of freshwater ecosystems, as well as water quality limit-setting and catchment nutrient management. These issues, and more, were discussed at a Department of Conservation workshop held last week on the implications of climate change for freshwater conservation.

Middle-of-the-road projections of climate change indicate about a rise of about 2 degC in average temperatures across New Zealand by 2080-2099 compared with 1980-1999.

Middle-of-the-road projections of climate change indicate a rise of about 2°C in average temperatures across New Zealand by 2080-2099 compared with 1980-1999.

One of the most important aspects of water quality is temperature, and as the air warms so too will the water. New Zealand has already seen an increase in air temperature of about 1°C over the last century; over the next century, projected changes are closer to 2°C, depending on how global greenhouse gas emissions develop. Warmer waters would shift the range of freshwater fish south and higher in elevation, depending on the species. The ranges of some species may increase, while others may decline. For natives, this would be influenced further by shifts in the ranges of predator species such as trout. Warmer waters also make algal blooms more common.

Water temperature is also susceptible to changes in the flow regimes of rivers and streams. With more frequent or longer droughts over much of the country, particularly the east, we can expect more pronounced periods of low flow, at least the smaller catchments. These lower flows would mean that water temperatures climb even higher.

At the other extreme, the more intense rainfalls would lead to more intense erosion, delivering sediment to waterbodies – another important aspect of water quality. But we must be careful about extrapolating here. While the most intense storms are likely to become more intense, the less intense storms may not and there may be fewer of them. Studies of long-term erosion under climate change have thus been equivocal.

For nutrient such as nitrate (N) and phosphorus (P), there is little we can say at present, as a lot will depend on land use change. One study out of the University of Waikato warns that by the end of the century the warming of lakes could have a similar effect on trophic status as a 25-50% increase in catchment nutrient loads.

With rising sea levels of about 50-100 cm by 2100, lakes, rivers, wetlands and aquifers along the coast would experience an increase in salinity. Intermittently closed and open lakes would be open to the sea more often, and salt wedges and tidal influence in streams would reach further inland, both influencing aquatic habitat and biodiversity.

Waterborne diseases are also on researchers’ radars with an interactive map of projected impacts recently released by ESR in collaboration with other organisations. Changes in temperature and precipitation, floods and droughts, can influence the potential to contract these diseases for better or for worse.

But on top of climate change we also have land use change, and the two will act in concert. Some land use changes are themselves liable to result from climate change, whether for the purposes of mitigation (e.g., carbon-farming forests or smaller herds of methane-emitting ruminants) or adaptation (e.g., shifts in crop choice and management in response to water resource stress).

So what can we do about all of this? In some respects water quality is almost bound to change (temperature, salinity near the coast), in others it’s unclear (sediment). The first suite of options to consider, then, would be those with no regrets: riparian planting along streams, erosion control, no more than optimal fertiliser use, and so on. These are actions with benefits no matter how the climate changes. Another matter to consider, at some point in the future, is the setting of water quality and catchment load limits that account for the “likely effects of climate change”, as recommended by the Land and Water Forum‘s third report. And of particular relevance to DoC would be the development of conservation strategies that account for the biodiversity threats posed by degrading or shifting water quality in a warming world.


Dr Daniel Collins is a hydrologist and water resource scientist at NIWA.

Network-wide options by YD - Freelance Wordpress Developer