How to drought-proof New Zealand as droughts get worse

By Waiology 03/05/2013 9


By Daniel Collins

For the most part, droughts are natural events. Rainfall and river flows wax and wane, and there will be times when there just isn’t enough water to fully meet our needs, whether to grow crops or to quench a city’s thirst.

Wairarapa drought, February 2013. (Credit: D. Allen, NIWA)
Wairarapa drought, February 2013. (Credit: D. Allen, NIWA)

And when it comes down to it, that’s really the best definition of a drought: when water supply is insufficient to meet demand. If no rain falls on the land, and there is no-one there to go thirsty, is it a problem?

But there is a growing part of drought that isn’t natural. Increases in water use, beyond the capacity of the environment to supply the water, have led to what are called “demand-driven droughts”. Changing climate has been implicated in changing patterns of drought around the world (e.g., Dai, 2013), and this is expected for New Zealand in the future.

So how can we adapt to more frequent and more severe droughts?

One option being discussed in New Zealand lately has been to increase the drought relief from the Government, but the Government has indicated that farmers will not be able to rely on this.

Another option is to build more water storage reservoirs and siphon off some winter river flows for use in spring and summer. So long as this does not increase dependency during times of plentiful rain and is reserved as a form of insurance as a drought approaches, this is a possible option, depending on economics and environmental impacts.

But we shouldn’t become fixated on just one or two strategies. There are many to choose from and it is likely that the best approach will be a balanced portfolio of options, tailored to specific needs and adaptive capacities.

Here is a longer list. For more information, read the recent Ministry for Primary Industries (MPI) report on adapting to climate change. No option is favoured over any other, and important economic considerations are beyond our scope.

Around the house. Install dual-flush toilets and don’t flush every time. Switch to a front-loading washing machine. Take marine-style showers: turn the water off when soaping up. Plant your garden with drought-resilient species. Collect rainwater from the roof and stop watering when shortages loom. Sweep the path with a broom, not a hose. Buy food with a smaller water footprint, relative to the growing region’s climate, and reduce food wastage.

Around the farm. Increase water use efficiency. Match crops and livestock (number and species) to the available water. Accumulate feed reserves if seasonal weather forecasts indicate, and start de-stocking before the feed runs out. Build on-farm water storage or collaborate in large-scale reservoirs. Schedule irrigation based on short-term weather forecasts and distribute it based on soil moisture and crop conditions. Buy drought insurance with profits from more productive years.

Around the business. Use materials and products with a smaller water footprint, relative to the producing region’s climate. Reduce the water footprint of the manufactured products, adding value in the process. Identify parts of the supply chain that are more or less drought-sensitive and build in contingency plans based on climate forecasts. Seek drought insurance and relief. Adopt relevant actions from around the house or farm.

Around the town. Encourage water conservation through education, incentives, penalties or user-charges. Reduce reticulation leakage. Landscape green spaces with drought-resilient plants and cease irrigation when shortages loom. Secure alternative sources of water and protect existing supplies. Monitor weather and climate forecasts, and phase in voluntary or compulsory restrictions in advance. Develop long-term plans for residential and industrial growth that can be balanced by future water supplies.

Around the region and country. Develop policies and plans that account for the foreseeable impacts of climate change. Adapt water quantity limits as climate change projections indicate. Encourage personal and industrial water conservation through education, incentives, penalties or user-charges. Provide financial and logistical support for costlier adaptation options. Encourage the use and development of weather forecasts, both short-term and seasonal, among water users. Identify and develop new sources of water (e.g., inter-catchment transfers; inter-seasonal storage). Quantify the available water and how this may change in the future. Foster land covers that have higher water yields, particularly during times of low flow.

In the end, the only sure-fire way to drought-proof New Zealand is to live within our climatic means. Being resilient to some drought, however, may not be so bad. Both would require us to tailor our water demand to the vagaries of the climate, develop land uses and societal practices attuned to the water cycle, and build in flexibility to ramp usage up or down as variable water supplies dictate.


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


9 Responses to “How to drought-proof New Zealand as droughts get worse”

  • Thanks for another great article – this grabbed me:
    “Another option is to build more water storage reservoirs and siphon off some winter river flows for use in spring and summer. So long as this does not increase dependency during times of plentiful rain and is reserved as a form of insurance as a drought approaches …”
    It seems to me from listening to the rhetoric about the development of irrigation, that irrigation schemes often develop as a response to drought. That’s ok! The trouble is, that once the irrigation is developed people do become dependent on it. When the next drought comes along everyone is in dire straits again because water is shorter than it has been and profits are lower than the years when there wasn’t drought. This is not just about the choices individual farmers make either – land prices go up when land is irrigated so new farmers have to service higher mortgages. It’s quite hard to see how to stop this cycle and certainly at the moment I don’t hear it being talked about at all. An awareness of it and discussion of it is important so good to see something of a start here.

    Also people reading this might be interested in this website http://semiaridagriculture.com/ which discusses the realities of farming in different ways. The photo on the front page was this guys farm (the green one) farmed under the same weather and irrigation conditions as the farm next door (the barren one). Both were in the Hakataramea valley. I wonder if our focus on dairying and irrigation has closed our eyes to some of the other possibilities?

  • Out of curiosity, on the food front, how do you find out the water-footprint of it? There’s not really a lot of information on the packaging of porridge (oatmeal), or rices or the like.

  • Chrys, yes, that point about reservoirs (and demand-driven drought) could do with some more consideration, and some economics (as in behaviour) and water resources analysis in NZ. As for the juxtaposed images in that link, I feel I must put my sceptic hat on just a smidgen. I’m sure differences in management have had a substantial effect, but it looks like at least two other factors are not constant: landscape position and weather at the time of photography. [Daniel]

  • Brendan, you’ve hit on one of my pet interests! There are various sources of information out there (e.g., this cool infographic: http://visual.ly/reducing-your-water-footprint; and this website: http://www.waterfootprint.org/?page=files/productgallery), but, no, exactly what you’re looking for does not exist. Watch this space, I guess. And there are a few complications that I omitted of course: the volume of water is far from the only factor to consider in terms of sustainability. [Daniel]

  • While I agree that we should save as much water as we can especially in the increased likely hood of higher temperature and increased droughts, we are not short of water, it falls on the West coast and most of us live and farm on the East coast. I think we should build dams in the Western hills and syphon water into our Eastern rivers to keep the water flowing.Even if we save water in the house it is not going to save the countryside.

  • Bob, building reservoirs on the West Coast and funnelling water through the mountain is an idea that has been around for a while, but there are severe impediments: cost, sediment delivery and in-filling, and earthquakes. If we were to rank all of these options, this one would probably only become palatable when we’ve tried a lot else and the price of irrigation water hass sky rocketed. But you are very right that some regions have more water than they “need” and that inter-region transfers could balance this. This older Waiology article paints a useful picture here: http://sciblogs.co.nz/waiology/2011/10/06/how-much-water-does-new-zealand-have-again/ [Daniel]

  • Where do you think wetlands, natural or created, should sit in this scene? Are they likely to be a effective or efficient means of securing water in a farming landscape? If they were, there could be a great biodiversity return too, not to mention the reinstating of other ecosystem services. I am referring to wetlands in the traditional sense of swamp, bog, fen, marsh.

  • Wetlands offer a myriad of ecosystem services, but reducing the severity of droughts is typically not one of them (contrary to popular belief). A handy review by Bullock and Acreman (2003) showed that wetlands were much more likely to reduce low flows, indeed they typically have higher evaporation rates. But some wetlands did increase or sustain low flows. And some wetland vegetation species act to suppress evaporation (Waikato has at least one example of this). So if wetlands were to be used to mollify droughts, we’d first need to identify which plants, which topographic positions, and which hydrological conditions have a positive effect – research that is yet to be done. See this earlier Waiology article for a bit more context and the BA2003 link: http://sciblogs.co.nz/waiology/2013/02/04/what-makes-wetlands-wet-lands/ [Daniel]

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