Rationing and restrictions

Except for a short time in Wellington, I have lived my life on the East Coast of New Zealand.

This means that water rationing, and restrictions, have been a constant part of my summers. As a boy I lived in a small South Canterbury town.  Every summer, homeowners had to restrict their garden watering to between 5pm and 7pm. I recall many times while we were eating dinner, the fire siren would sound and my mother, and everyone else in town, rushed out to turn off their hoses. People knew that if they did not turn off their hoses, the firemen could not operate their hoses.

There are two main reasons why councils have water restrictions.  The first reason for restrictions is when a major water pipe bursts.  This is what happened in Waipukurau at the start of this year. Before this problem was solved, the local reservoir had fallen to 25 per cent of its capacity.

The most common reason for restrictions, on the East Coast at least, is a rise in demand for water during summer. In some cases, the dry weather also reduces the amount of water that can be treated and stored. Finally, dry weather can lead to more leaks due to the soil shrinking and moving, as it dries out.

In the South Wairarapa District, the Council’s current restrictions consist of two measures. We have a year-round requirement to only water gardens every second day.  This means we do not have problems with water pressure falling during emergencies. Our second form of restriction, in place now, is to use handheld hoses to water gardens. If the situation gets worse there are further restrictions we would ask people to follow.

To expand on the issue of demand for water, here is the South Wairarapa’s water usage figures from August [2023] to January this year. These figures are the average daily demand for the month.

• August 65 million litres per day (mlpd)
• September 3.89 mlpd
• October 4.15 mlpd
• November 4.92 mlpd
• December 5.01 mlpd
• January 5.41 mlpd

There was one day in January when the demand rose to 6.32 mlpd. This works out at about 550 litres per resident.  One reason for the rise in demand is people with gardens who want to protect their prize plants from drought damage. Increased population numbers over the summer also add to the load.

Demand for water functions in the opposite way to demand for electricity, which goes up in winter and down in summer. People might ask, “why don’t we get electricity restrictions in winter?”.  That has happened. Many years ago, electricity restrictions were common in any winter where snowfall the previous winter had not filled the hydro-electric dams. When this happened, the Government would directly appeal to homeowners to restrict their electricity usage. If people ignored those demands, then rolling blackouts might follow.  That would mean the Government turned people’s electricity off in one part of the country for a period of time, then turned it back on while turning the electricity off somewhere else. This is known as “load shedding” and it happens often in South Africa and occasionally in Australia and elsewhere.

There are many reasons why it does not happen so much in New Zealand now, including the pricing mechanisms many people now use. People with smart meters can choose to operate their appliances when electricity is cheaper. There are also mechanisms such as ripple control that let electricity suppliers decide when to let you heat your water.

I foresee some of these mechanisms coming to our water supplies one day. We have just seen the Minister of Local Government put a lot of pressure on the four Wellington City Councils to get on with installing water meters. For people worried about paying for water to nourish their gardens in the future, the solution might be as simple as installing rainwater tanks.  

Martin Connelly wrote this column prior to going on leave.