Planning for dry summers

Water tanks may have received a top-up when a low pressure system dumped torrential rain on the district on Sunday, but weather forecasters are predicting a dry summer.

The mid and Far North areas received a third to 40 per cent less rain in the 12 months to October. While it is too early to accurately predict rainfall this summer, most areas will go into December with rainfall and soil moisture deficits.

To illustrate how dry the last year has been, Kaitaia received 925mm of rain during the 10 months to October. This is 32 per cent less than the usual 1350mm. Rainfall in Kerikeri was down by a third during the same period and the six months from January to July were the driest in more than 80 years.

The Council has already introduced a sprinkler ban in Kaikohe where low winter rainfall has left river and groundwater sources low. We support the Northland Regional Council which is urging people not to waste water and to take sensible precautions to prepare for potentially dry conditions in summer and autumn.

Dry weather is an annual occurrence in the Far North, so people may wonder what the Council is doing to make our drinking water supplies more drought-resilient. In Kaitaia, we are developing an aquifer bore to supplement our primary water source, the Awanui River. We have tendered for a bore and pipeline design and aim to have a preferred option by mid-2020. We plan to begin physical works in late 2020 and expect to complete these by late 2022. In Kerikeri and Kaikohe, we are assessing whether it is possible to take more water from Puketotara and Wairoro Streams without adversely impacting the ecological health of these streams which supply our water supplies. We are considering how to make our Paihia water supply more resilient and have shortlisted three options for further investigating and high-level costing. We have applied to the Northland Regional Council for resource consent to take water from a bore at Opononi-Omapere where we rely on two small streams to supply drinking water to the community. We are also inspecting our water pipe network and are replacing ageing pipes as part of an ongoing renewals programme.

These are short to medium-term measures. In the long-term, we need to cater for growth while adapting to a changing climate. NIWA predicts higher temperatures and an increased risk of drought in Northland over the next 70 years. Sea level rise may also reduce groundwater storage, impacting our water supplies. We are addressing long-term infrastructure challenges and opportunities like these as part of our Far North 2100 project. We will seek community feedback on a draft strategy that addresses high level challenges and opportunities before the end of summer.