GRANDS Vaux reservoir could be used as a flood defence if lower water levels were maintained, the Infrastructure Minister has said.
But Jersey Water has strongly rejected Deputy Tom Binet’s proposal, arguing that the reservoir – which it said played a ‘critical role in Jersey’s water supply’ – was not the cause of dramatic floods this year or the solution to prevent future flooding.
In January, heavy rain leading to overspill from the reservoir caused the evacuation of more than 58 households in the area, prompting the declaration of a ‘major incident’ and questions about how to avoid similar events.
Growing disagreement between the minister and the company – of which the States are the majority shareholder – about the solution to the issue resurfaced at a recent Scrutiny panel hearing.
Deputy Binet – who acknowledged that he was ‘on sensitive territory’ – said he found Jersey Water’s comments to residents that using the reservoir ‘wouldn’t be possible, would cost a fortune and [put] 25% of the Island’s water at risk’ ‘quite shocking’.
He said: ‘I’ve been looking at this the whole way through the summer and the elephant in the room for me – I’m just talking personally because I’m not trained – is that when I look at a reservoir that has no capacity when a flood comes, I really cannot get my head around how and why [it] can’t be used as a mitigating measure by reducing the level. We’ve had some interesting discussions over the course of the summer. That will be the interesting one when it comes to having a meeting with the residents.’
Jersey Water’s chief executive Helier Smith said the company was aware of the minister’s comments – made at an Environment, Housing and Infrastructure Scrutiny Panel quarterly hearing – which he said represented ‘an opinion which he has shared previously’.
‘We reiterate that the reservoir was not the cause of, and nor is it the solution to preventing, flooding in Grands Vaux,’ said Mr Smith.
‘The cause of January’s flooding has been identified as significant volumes of rainfall that overwhelmed the parish and government drainage network in the Grands Vaux valley. Jersey Water’s primary role is to ensure that we supply high-quality water to the Island’s population. Grands Vaux reservoir plays a critical role in Jersey’s water supply, contributing 20% of our total supply, and also supplying 40% of Queen’s Valley’s water. The reservoir was designed as a water storage facility and not for flood protection. It would require significant modification if it were to be used for flood defence. Without modification, the reservoir would not prevent flooding in the valley and lowering the reservoir would also risk the quality and quantity of the whole Island’s water supply.’
Over the summer, Jersey Water and the Infrastructure Department have been analysing a series of reports, which are being fed into an overarching document to be completed in time for a meeting with residents at the end of this month.
The department said that there had already been some improvements in the approach to dealing with flooding in the Grands Vaux area, including better cleaning of gullies to aid drainage when bad weather was forecast, and more detailed weather data and warnings of impending significant rainfall from the Met Office.
Deputy Binet told the Scrutiny panel that the combination of the water catchment area, the size of the reservoir and the number of nearby dwellings constituted ‘a very unfortunate set-up from start to finish’.
Jersey Water said it had already undertaken significant work to consider potential options to support the government in finding solutions for its flood mitigation planning for the area.
‘We understand that the government will be in a position to share these findings in due course,’ Mr Smith said.
