With 471mm of rain recorded in the three months to the start of December – just 5mm short of the all-time record set in 1929 – Jersey Water said reservoirs were full by 20 November.
Chief executive Helier Smith said it was pleasing that water levels had recovered after a long spell of below-average rainfall, which prompted the desalination plant to be used in September.
‘Our normal objective is to have reservoirs full by the end of March, ahead of spring and summer when demand for water increases and rainfall levels usually drop,’ he said. ‘But the challenge is that, even at full capacity, we only have 120 days’ worth of water. Every bit of rain we’ve had since 20 November has gone out to sea, and we won’t be able to make use of most of the winter’s rain.’
Mr Smith said that Jersey’s capacity was substantially lower than that of Guernsey, where full reservoirs equated to around 360 days’ worth of water usage.
‘As things stand we can only ever be 120 days, at most, away from shortages. We can see that our climate and weather patterns are changing and we have to adjust and achieve greater resilience to periods of drought.’
In October, Jersey Water issued a submission relating to the new Island Plan and warned that within 25 years, there could be a shortfall of up to eight million litres a day in drought years.
The company is hoping that provision will be made for increased capacity as part of the Island Plan, and identified La Gigoulande Quarry in St Peter’s Valley – currently operated by Granite Products and earmarked for future use in landfill disposal – as a viable site.
Mr Smith said that a reservoir at La Gigoulande could increase Jersey’s total capacity by up to 30%, describing it as a significant and unique opportunity that could serve the Island for centuries.
Jersey Water has also drawn up a water-resources management plan which aims to make best use of existing supplies through measures such as reducing leakage and cutting demand.
The plan is due to go out to public consultation in spring or summer of 2020.
