The Greater Wellington Regional Council (GWRC) says extra watering restrictions look likely as Wellington’s summer weather continues.
The latest regional weather forecast predicts little rain for the next 14 days.
And the GWRC says that, if that outlook proves accurate, then water use is likely to rise – a scenario that could see a water shortage.
The rivers that provide about two-thirds of the water supply for Upper Hutt, Lower Hutt, Porirua and Wellington remain at low levels and are dropping – that means less water can be taken each day for supply.
Although rainfall has been average or above average over the past couple of months, it has been infrequent. This means that any rainfall runs off the ground and down the rivers quickly, resulting in only short-lived increases in river levels.
During the last spell of fine weather, approximately 100 million litres (ML) of water was being supplied from the rivers each day to help meet the increase in overall demand. Currently 130ML of water per day is available in the rivers, but without a good amount of rain in the water catchments soon, that number could drop to 100ML within the next 1-2 weeks.
Nigel Wilson, the GWRC’s Social Wellbeing Chair, says the next few weeks will be crucial for water supply.
“What happens over the next couple of weeks – in terms of water use and how the weather forecast develops – is important. We need extra care from the community over the next few weeks to keep water use to a minimum, so what we’ve got available goes further,” he says.
“If the rivers can’t supply what’s needed, we’ll have to ask for a ban on garden sprinklers and irrigation systems. We’d also have to rely more heavily on the Hutt aquifer and look at activating a consent to take more water from the Hutt River at Kaitoke.”
While water is normally held in two storage lakes at Te Marua to supplement low river flows, only one of the lakes is available this summer as the other is being earthquake-strengthened.
This stored water becomes increasingly important for meeting essential water needs as rivers dwindle, so it must be managed carefully to ensure there’s enough to last in the event of a very long, dry spell.
Councillor Wilson says: “Water use to date this summer has been quite restrained given the weather conditions, which is good news, but we need that extra degree of care from the public to continue – at least until a more regular rainfall pattern returns.”
Thje Council has these water saving tips:
- Use a flow control trigger on hoses
- Target watering close to the ground, at a rate the soil can absorb
- Put off non-essential outdoor jobs, like washing windows or the car, until autumn
For more water saving tips visit http://www.gw.govt.nz/water