No quick decision on use of Vale quarries

No quick decisions will be made on the possible use of two Vale quarries for inert waste storage, States Trading Assets deputy managing director Richard Evans told this website, in an interview last week.

It is expected that full environmental impact assessments will be carried out on the former L'Epine and Guillotin Quarries by consultants Royal Haskoning as well as the coastal reclamation site, Longue Hougue south.

That independent review, costing around £400,000, includes looking at traffic, habitat, public health, access, plus the physical location of the sites, and will inevitably take time. 'We expect this to take a full year and so anticipate taking a policy letter to the States towards the end of 2019,' Mr Evans said.

Longue Hougue
He was speaking to the Vale Parish website because of the level of parish interest in the proposals and because concerns had been expressed that Longue Hougue Quarry, which lies between Bulwer Avenue and St Sampson's, would be a better location for inert waste as it would eventually yield land in an already industrial setting.

'With regard to the potential for Longue Hougue quarry to be utilised for inert waste, I can confirm that this was considered on the long list of potential options but was rejected, following a rigorous process.  This quarry is currently a vital reservoir for water supply, as the single largest source of water supply in Guernsey.

'Les Vardes Quarry is not available as an option to immediately follow on from the existing facility and is currently allocated in the Island Development Plan and the Strategic Land Use Plan as a strategic allocation for water storage,' he said.

In response to questions, Mr Evans acknowledged that the situation was complicated because, 'on paper', reclaiming Longue Hougue Quarry appeared to make sense if it was as simple as swapping the water storage there for the potential storage at Les Vardes.

Separately, in a statement [below] Guernsey Water has responded to concerns that a 'leak' in Longue Hougue means sea water is entering the reservoir (it can, but is managed).

Timescales
Mr Evans explained that Guernsey has a pressing need for storage for inert waste – although it actually has value – because it is currently producing about 58,000 tonnes a year, which is down from historic highs.

Les Vardes is currently being quarried by Ronez, so an early departure would mean it leaving behind extractable granite, which had economic value to the company which it would no doubt be reluctant to give away.

In addition, preparing Les Vardes for use as a reservoir and linking it to the island's existing water transfer system was a multi-million pound project that would need to be planned, funded and completed before any new reservoir could come on-line.

He added that Guernsey Water was also working on a water resource and drought management plan aimed at securing the island's water supply in the long term and taking into account the effects of climate change, so talk of releasing Longue Hougue Quarry now was premature.

Seawater situation
Asked whether Longue Hougue does in fact experience sea water leaking into it, Guernsey Water released the following statement:

'We have had a geological survey done on Longue Hougue reservoir and at one end there is a small fracture that can allow seawater ingress into the quarry. However, this is managed by keeping the reservoir as full as possible so that the top pressure stops ingress happening.

'The reservoir has destratification [this is the mixing of air through the water levels of the reservoir], to make sure we do not get any thermoclines [layers of water at different temperatures] in the reservoir and that the water is well mixed.

'We analyse for chloride regularly and our analysis shows that there is no ingress that would cause an issue with the raw water being used for drinking water.  Its levels are no higher than other stored waters we use across the island.'