Ōhau River, at the point where the Waiopehu Hut Loop track from Poads Road meets it. Photo / Christopher Tuffley
Ōhau River, at the point where the Waiopehu Hut Loop track from Poads Road meets it. Photo / Christopher Tuffley
The likelihood of a hot, dry summer has compelled the Horowhenua District Council to issue a suite of water conservation tips in an effort to guard finite supplies.
Horowhenua Mayor Bernie Wanden said clean, safe drinking water shouldn’t be taken for granted.
“Weather reports suggest we are in for a long dry summer. By working together we can reduce the amount of water our district uses. We won’t need to take as much water from our beautiful rivers and there will be cost savings too,” he said.
Low river flows are predicted, which could force strict water restrictions to be rolled out in the coming months, so the council was encouraging residents to adopt “altruistic and easy habits” to conserve water as simple habits changes could save thousands of litres of water an hour.
A herd of cows takes a cooling dip in the Ōhau River near Levin. Photo / Ashleigh Collis
“As most of our water comes from rivers in our district, we need to take water sustainably. There is a limit to how much water we can treat and store, and in summer water demand increases as people fill pools, water their gardens more often and use water to cool down,” a council statement released this week said.
“Most of our water comes from rivers and a stream that flow from the Tararua Range; and Foxton, Foxton Beach and Shannon are supplied or supplemented by bores. Because of the locations, water sources and treatment needs, we have four different water treatment systems located in Shannon, Tokomaru, Foxton and Levin.”
“The flow of our rivers determines whether water restrictions are needed. If the river flow is low because of low rainfall, or we have consistently high temperatures causing evaporation and rain is not forecasted for a while, we have to set water restrictions so our demand isn’t more than our supply.”
Council has resource consent with a limit of 15,000 cubic metres (m3) of water to be taken from the Ōhau River each day, except when the flow of the river drops below a certain level – then, 13,000m3 could be taken.
However, while the average daily water take is 9600m3 a day from the Ōhau River, it can peak at around 14,000m3 when demand is high.
A sudden deluge of heavy rain does not solve the river flow problem. If rainfall is too heavy or has caused a slip upriver, the water turbidity (muddiness) may be too high to treat.
Excessive rain can also make it harder to treat river water to make it safe to drink because it can fill the waterways with dirt, sticks and debris. Sometimes water treatment plants need to be shut down until the water has an acceptable level of turbidity for treatment.
The council has also been working towards the most significant infrastructure project in recent history – the Poads Road Water Supply Reservoir, aimed at constructing a large water supply reservoir on council-owned land between Poads Road and the Ōhau River.
But it was a few years away yet.
The reservoir will be between 600,000 and 700,000m3 and built outside of the river corridor and above the flood level.
A new subsurface intake in the Ōhau River will supply the reservoir and provide for fish passage. The council will seek a new water take for the remaining core allocation (the total amount of water which can be taken sustainably) of water from the Ōhau River to fill the reservoir.
No water will be taken from the new intake when the river is at low flow.
In the meantime, HDC was committed to finding and fixing leaks. New state-of-the-art monitoring systems adopted in 2018 have improved standards of pipe installation and quality control, pressure testing new networks and connectors to ensure there are no leaks.
Some 40 per cent of Horowhenua properties already have water meters, and new digital leak detectors will be installed throughout the district within the next two years to identify and remedy leaks to save water.
· Use mulch – good quality mulch can reduce water lost to evaporation by 70 per cent
· If you use a sprinkler or drip lines in your garden, set a timer to remind yourself to turn it off
· Water your lawn only if it really needs it. To test this, step on the grass. If it springs back up, it doesn’t need watering. If it stays flat, it does
Horowhenua loses more than 20 per cent of its water through leaks. From water dripping from taps and toilets to more significant losses through broken pipes, it all adds up. Identifying water leaks at your property is a simple task that can greatly benefit you and our community.
· Turn off your taps, hoses and showers and listen for running water.
Water leaks aren’t always obvious and they can cause damage to your property or even compromise the structural integrity of your home. By fixing leaks you are not only reducing this risk to yourself, but the whole community also benefits through the reduced demand on water supplies and the treatment process. Learn more about finding and fixing leaks by visiting horowhenua.govt.nz/WaterLeakCheck.
Property owners are responsible for repairing leaks on the private side, and the council takes care of leaks in the public network. There is a monitoring system to detect any abnormalities in the network, but the council also says it appreciates notification from the community if leaks are suspected in the district.
In November 2023, the council received a call from a resident concerned that a particular patch of grass outside a property always seemed to be soggy and had moss consistently growing on it, but other areas didn’t. Within hours of calling the council the leak, which was causing 12,000 litres of water (enough water for 30 people each day) to be lost per day, was fixed.
To report a leak, call 06 366 0999 or enquiries@horowhenua.govt.nz or use the “Report it” function in Antenno. Antenno, a free mobile app which allows two-way engagement between council and community, is available to download from the App Store or on Google Play; just search “Antenno”.
