What to expect when Canterbury is dry

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In dry conditions, some waterways may look concerningly low or even appear to dry up completely, and rivers that naturally run dry, like the Waikirikiri/Selwyn, may be drier for longer stretches.

We understand many want us to top-up drying waterways with water from other streams, but this isn’t always possible.

Creating diversions from other rivers and streams requires careful management to balance any potential negative effects elsewhere. Resource consent is required under the Resource Management Act (RMA) to take water from any other waterway.

What is our role

As regulators, we are legally obliged to follow the law when making decisions related to resource consents, so we would consider any applications within the legal framework provided by the RMA.

The Canterbury plains get less rainfall than most of the country. In dry times, there isn’t enough water to maintain minimum environmental flows in our rivers while also topping up other waterways that are becoming dry.

It is also important to note that during dry times, a waterbody may look like it has dried up, but the water beneath can be very deep or still flowing and therefore able to sustain aquatic life, such as invertebrates, through extended dry periods.

If you have urgent concerns about biodiversity or water quality issues, you can report an environmental incident and we will follow this up.

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Fish can become distressed within our waterways for many reasons, both naturally occurring (like weather conditions and when migrating) and through human activity, such as changes to waterways or chemical spills.  

An increase in extreme weather, like droughts and floods, means that our waterways are more likely to dry up or change paths within a shorter time period - and people may come across fish stranded in remote locations.

When waterways dry up gradually, fish are often able to move to better habitats. When they dry up more suddenly, such as when a flow channel becomes blocked or shifts, fish can become stranded.  

With more than 78,000km of rivers in Waitaha, fish strandings will sometimes happen in remote locations, without us knowing at the time. 

We don’t like to see ecological and cultural harm occur, but it isn’t always possible to change the outcome of these events. 

If you come across fish (including tuna/eel) that are stranded, dead or appear unwell, please contact us to report the incident and we will work with mana whenua and partner agencies to determine if a response is required. We’re also keen to hear from the community if they are concerned about a potential fish stranding event. 

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Soil moisture stress from droughts can have long-lasting impacts on pasture and stock production on farms.

Not only are drought-affected farms carrying lower stock numbers, but feed stress means lambing and calving percentages can be affected, and the animals born may not grow as well as they would under normal climatic conditions.

Soil moisture levels are critical for grass growth and even once dry conditions ease, it can take some time for soil moisture levels to build back to be able to support pasture growth.

Contact MPI to find out what help is available for farmers, growers, and their families during drought.

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Water is essential to life and its availability has a major impact on the health and wellbeing of farm animals.

Under drought conditions, access to clean stock water is even more important as animals may drink up to three times more in hot, dry conditions, particularly if they are pregnant or lactating, or if they are eating supplementary feed.

When stock do not have access to clean water, it may encourage them to push through fences or gates, potentially causing harm to waterbodies or wetlands.

Under the Resource Management Act (RMA), you are permitted to take water from surface or groundwater without a resource consent for the reasonable drinking needs of your livestock, provided the taking or use does not, or is not likely to, harm the environment.

Stock water reticulation systems provide the most water security for animals in drought situations. MPI has further information to help you look after your animals in dry or drought conditions. Download MPI's - Animals affected by dry or drought conditions 

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Farmers who need to take water to irrigate require resource consent to ensure water is used efficiently and responsibly. Each resource consent has its own specific conditions attached. Find out if you need a resource consent.

During dry conditions, irrigation restrictions are put in place to protect the health and ecosystems of our waterways, while sustaining the local economy. Sometimes the environmental conditions mean irrigation restrictions come in place earlier and last longer than usual.

What is our role

Irrigators need to understand the minimum flow conditions on their resource consent and keep up to date with any water restrictions. We update flow and restriction information every day on our water restrictions webpage.

For farmers with irrigation, we can provide advice and support around Good Management Practices and compliance to ensure efficient use of irrigation. For on-the-ground support, our Customer Advisory team can put you in touch with your local land management advisor.

We receive a large number of enquiries from the public in summer asking why farmers are irrigating when it’s dry and rivers are running low.

While we appreciate people’s concern for our environment, there are many ways people can get access to water in dry times without affecting low flows.

It’s important to understand that landowners with irrigators take and store water in different ways. Water can come from groundwater (wells or bores), surface water (rivers, lakes or creeks) or an irrigation scheme (such as Amuri Irrigation Company (AIC), Central Plains Water (CPW) or Mayfield Hinds Valetta (MHV) Water).

All water taken from New Zealand rivers has a ‘minimum flow’ level set. This is the lowest level a river is allowed to drop and when a river’s flow reaches this level, the water take must stop.

So, although farms that irrigate using surface water are likely to experience water restrictions during prolonged dry periods when river flows are low, those who irrigate using groundwater or water from a scheme or large-scale storage reservoir may not have the same restrictions.

Many Canterbury farmers – especially dairy farmers – have recognised that water will not always be available and invested in on-farm water storage or dams for the dry times. At times when their water source is not restricted, irrigators take water within their consent limits and fill their dams, and when restrictions are in place, they are free to use their stored water.

In places where rivers are running low, there may still be plenty of water hidden underground. Irrigators who have access to groundwater through bores may still be able to irrigate when it’s dry and restrictions are in place.

Some of the biggest irrigation schemes, including CPW and MHV, use water taken from large alpine rivers like the Rakaia and Rangitata, and provide it to irrigators on the plains. While these schemes are also subject to minimum flow restrictions on the alpine rivers, they can often take and store water when it’s plentiful, and distribute it to irrigators when restrictions are otherwise in place.

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During prolonged dry conditions, even when rivers are running low, there may still be plenty of water underground in our aquifers. This groundwater can be accessed through boreholes and can be a more reliable alternative to municipal water supplies as it is not subject to the same restrictions as surface water sources, such as rivers and dams, which can be impacted by drought or reduced rainfall.

What is our role

Our role as a regional council is to monitor groundwater across the region and regulate activities that might affect water quality.

Under the Land and Water Regional Plan (LWRP) you can drill a bore to access this water without resource consent, provided the bore meets the requirements of a permitted activity.

If you have your private water source, the responsibility for the maintenance and testing of drinking water rests with you. Learn more about how to keep your drinking water safe.

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Toxic algae (also called cyanobacteria) is a naturally occurring algae with the potential to bloom, producing toxins that can harm or even kill dogs, people and other animals.

Blooms form when cyanobacteria start to multiply very quickly, usually due to changes in environmental conditions such as warm temperatures, sunlight, low or stable river flows, and high levels of nutrients.

What is our role

At the beginning of each season, we give sites long-term grades on their suitability for recreation, based on five years of monitoring data and sanitary surveys. Over the summer, we monitor more than 100 popular recreational sites and the results are available on the Land and Water Aotearoa (LAWA) website.

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Recreation and amenity opportunities provided by Canterbury's water bodies are a significant social, cultural and economic benefit to the region.

Low water levels in both lakes and rivers can impact activities such as boating, fishing, water-skiing and kayaking, and may mean people have to travel further or to coastal locations to undertake their favourite water sports.

What is our role

Our main role in supporting recreational activities is water monitoring and actions to improve water quality. We monitor water levels in many lakes and rivers across the region and publish this data on the Land and Water Aotearoa (LAWA) website.

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During prolonged drought conditions, the coastal river mouths of our Canterbury rivers and streams are more likely to remain closed or have reduced outflows for longer periods.

This situation mostly arises from a combination of extended low flow conditions, combined with sea conditions, increasing the deposition (build-up) of beach shingles.

The effects of this can result in flooding of river mouth hut communities and a deterioration of water quality conditions in hāpua (lagoons) and estuaries. It can also impact fish passage in and out of rivers, and recreational and cultural activities like fishing.

Small to medium-sized foothill-fed rivers are affected, such as the Waipara, Ashley, Ashburton, Ōrāri, Ōpihi and Waihao Rivers. However, extreme conditions can also cause brief periods of closure of the larger braided alpine rivers.

Coastal dune lakes and hāpua such as Te Waihora/Lake Ellesmere and Wainono Lagoon also remain closed for longer periods and can become more difficult to manage.

Other natural systems also experience extended periods of disconnection with the sea, such as Muriwai/Coopers Lagoon, and many small coastal lagoons along the north and south Canterbury coastline.

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Mahinga kai/mahika kai means 'to work the food' and relates to the traditional value of food resources and their ecosystems, as well as the practices involved in producing, procuring, and protecting these resources. This practice remains a foundation of Ngāi Tahu values today.

Prolonged drought conditions can negatively affect the habitats and environments of these taonga species now critically endangered or under threat.

What is our role

While the active protection of mahinga kai is a key foundation of the Treaty of Waitangi, as well as being critical in regulations and policies, it is also simply part of wider environmental stewardship or kaitiakitanga.

Supporting mahinga kai sits alongside ecosystem health and biodiversity as an essential environmental objective in our region. Importantly, the protection and enhancement of mahinga kai also provide for the well-being of people, and their ongoing identity.

Everyone has a part to play in protecting and enhancing mahinga kai, although as the current guardians of the land where mahinga kai species live, there are clear responsibilities on landowners. Across the region, farmers are now required to achieve a mahinga kai target or objectives when implementing their Farm Environment Plans.

This requires an understanding of and ability to identify mahinga kai values on the farm and manage risks using good management practices.

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Hydroelectric schemes use gravity to drive water through turbines, converting the energy generated into electricity. The water then flows back into a river or stream below the hydro plant.

Some hydro schemes are storage-based and have large lakes that can store water for use during prolonged dry periods. Run-of-river systems don’t have dams and can only be generated based on the amount of water flowing down the river.

In storage-based hydroelectric schemes, such as Lake Opuha Dam in the Mackenzie Country, winter and spring river flow is stored in the lake and released in summer for irrigation, stock watering, horticulture and industrial use, making them crucial for farming systems.

New Zealand has a relatively small hydro storage capacity, with most hydro schemes only able to generate electricity based on good river flows. Most of our reservoirs are only able to take up to 60 days of storage, which is small compared to other countries. Tasmania in Australia, for example, has a storage capacity that will last for up to 18 months.

New Zealand’s low storage capacity means during prolonged dry periods, hydroelectricity availability quickly runs low. In these areas, prolonged dry conditions can result in extremely low hydro storage levels and this can reduce the ability of power companies to generate electricity.

What is our role

Our role as a regulator is to ensure activities continue to comply with the conditions of their resource consents.

The Electricity Authority monitors New Zealand’s hydro generation and storage, including how it changes throughout the year. See current and past national hydro storage levels.

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Wildfires are unplanned, uncontrolled fires occurring where vegetation, like wilding pines, helps them spread rapidly, putting lives and property at risk.

Parts of mainland Canterbury are increasingly vulnerable to these wildfires due to hotter, drier and windier conditions caused by the changing climate and a decrease in national funding for wilding pine control.

The Lake Ōhau fire in 2020 showed how devastating a fire in a residential area can be, it burnt through over 5500 hectares of land, destroying 44 homes – over half the homes in the village.

Fire and Emergency New Zealand (FENZ) is the leading agency on fires and fire risk. We are working with community groups and FENZ to reduce the risk of wildfires through wilding pine control work on council land and around education and advocacy of the risk wilding pines pose.