Water management

Summer 2001 drought

In 2001, a one-in-24 year drought resulted in the Waimea River drying up almost completely, leading to severe water restrictions, millions in lost horticultural product, and the decommissioning of some bores. In seven of the last 10 years, water rationing and restrictions have been required to manage the water resource while a more sustainable approach has been developed. To understand the impact of a serious drought, read the full story about the 2001 drought, the ‘Big Dry.’

Water take rules are changing

In 2015, the Council introduced new ‘water-take’ rules intended to protect the natural values of the Waimea River, provide a more appropriate allocation of water and meet national guidelines for freshwater management. The new rules, which will come into effect in November 2019, introduce a minimum flow for the river to prevent it from drying up completely in times of drought.

Triggers for rationing

To make sure the minimum flow can be achieved, the water-take rules also introduced new rationing triggers for both rural water permit holders and urban homes and businesses. These rules will have a significant impact on residents’ way of life beginning in the summer of 2019. The river flow will not be allowed to drop below 800 litres per second.

Impact on urban households

To keep the minimum flows at the government-mandated level, access to water on the Waimea Plains will decrease through rationing. Rationing for urban homes and businesses will kick in much earlier in dry periods than it has in the past and it will be much harsher. Households in Richmond, Brightwater, Mapua or Redwood Valley (that’s 20,000 or so residents) will have to cut their water usage by 25 – 50% nearly every summer, with urban water rationing predicted in summer nine out of every ten years.

Average water used in common household tasks

Source: Combined data from BRANZ Studies in Auckland, Kapiti Coast, Waitakere Council and Metrowater.

At Stage 3 rationing under the new rules – which is expected to be 50 days most summers – urban households will have to cut back by at least 25 percent, or to approximately 525 litres per day. (In summer, in Richmond, current household use is 700 litres per day.) That may mean giving up your shower or bath each day, or only doing a load of wash every third day.

Serious water rationing at Stage 5 will happen once out of every 6-10 years and last an average of 30 days. At this stage, urban households will have to cut water use by 80 percent, or a maximum of 140 litres per day. This means showers or baths every third day, flushing the toilet only once a day, and a load of wash once a week.

 

Daily urban water 'budget' (summer)

daily urban water budget

Rural water allocations and permits

Water permits have been reassessed to achieve an overall reduction in the rural water take. That has potentially catastrophic consequences for rural businesses’ ability to operate. Rationing for permit holders will kick in earlier in dry periods and be more stringent, making it difficult to grow crops, with serious consequences for Nelson Tasman’s economic health. Rural businesses should read more detail about this on Waimea Irrigators Ltd's website where they go into the issue of the new classes of TRMP water permits for rural businesses and the Water Supply Agreements that will be registered through WIL.

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