Helier Smith also said that a new reservoir might have to be built – one of a number of options which could potentially lead to a hike in Islander’s bills.
He added that efforts made by his company to encourage Islanders and businesses to be conservative with their usage would simply not go far enough to address an eight million litre deficit expected to hit the Island by 2045.
Last week, the company announced that the Island was currently using millions more litres of water from its reservoirs each day than it was able to replace and that the desalination plant – which turns sea water into drinking water – was likely to be brought into action this week.
It follows an 18-month period of below-average rainfall in which the cumulative total was 25% below what was expected by Jersey Met – a deficit of around 350mm of rain.
And Mr Smith added that due to the Island’s reliance on rain for water, it was very vulnerable to drought.
‘From the beginning of this year we have had 25% less rain than average and that is just a sign of things to come.
‘We are predicting that over the next 25 years there will be an 8% reduction [the equivalent of 8 million litres per day during drought years] in the amount of water that we will have to use and everyone will need to get to grips with water efficiency.’
On 24 July, air temperatures rose to 36°C – equalling the highest figure ever recorded in Jersey.
Months earlier, the hottest February figure ever recorded was reached, when the mercury got as high as 16.9°C
Figures provided by Jersey Met show that this year’s summer was the equal sixth hottest on record.
Four of the Island’s top five hottest summers recorded have occurred in the past 17 years.
Now, Mr Smith, who has been with Jersey Water since 2002, added that measures to address the expected deficit could be costly.
‘With regards to reducing demand, while we will do what we can to reduce usage, this will simply not be enough,’ he said.
‘We will have to put in further reserves – whether that is further desalination, bringing more catchment online or creating more water storage.
‘If we are looking at either desalination or a new water-storage facility, that may be millions of pounds – the scale of water-resource projects is large and it is a significant long-term investment.’
A water-resource management plan is currently being developed by the company. It is being designed to show the best way forward to ensure that the Island has sufficient water resources for years to come.
Mr Smith said it was likely that the desalination plant – which is currently run relatively infrequently – could be turned on permanently during drought years.
‘The modelling shows that during normal years – we want it to be a standby plant – it is likely that we will need to run it much more frequently than we do at the moment,’ he said.
‘And during drought years it is likely that we will need to run it all the time, which will have an impact on our costs and possibly even our customer’s bills – if we start having to run it for long periods of time.
‘Without pre-judging the 2020 water-resource management plan, the solution is to both add desalination and storage, but it will be about managing costs and risks effectively.’