Quarries future uses questioned

Tuesday 11 September 2018

Questions over how Les Vardes quarry and the former Longue Hougue quarry could be used in future won't help the ongoing debate over how Guernsey will dispose of inert waste under its new rubbish and recycling strategies.

The States body which is responsible for our waste had asked if two disused quarries in the north of the island could be considered for the dumping of inert waste in the future, but that idea was quickly shut down.

Guernsey Water has now said that its plans for Longue Hougue reservoir, and Les Vardes Quarry, currently being used by Ronez, could not be amended so they could be utilised in plans for inert waste disposal either with little appetite apparent to challenge that. 

Inert waste includes substances such as sand and concrete, which are neither chemically nor biologically reactive and will not decompose. 

The States Trading and Supevisory Board had asked Policy and Resources for £300,000 to allow staff to carry out an environmental impact assessment on the possibility of dumping inert waste in L'Epine and Guillotin quarries.

Pictured: The L'Epine and Guillotin quarries in the Vale 

STSB had thought that as both quarries are outside the main centre, there would be limited potential to develop any land created by infilling them - for example building on that land in the future so it had suggested using one or both for dumping inert waste which can't be shipped off island with other rubbish for incineration in Sweden.

But P&R said spending that much tax payers money on researching a project that was unlikely to see the light of day was a concerning idea. The Vice President of the Committee, Deputy Lyndon Trott, said P&R were approached earlier in the year by Environment & Infrastructure and STSB for funding but made the decision to refuse because both E&I and STSB acknowledged the sites were "small and inferior options" to the site expected to be used at the Longue Hougue.

Pictured: The initial plan to investigate the use of two quarries in the Vale for the dumping of inert waste was rejected by P&R as reported by Express here. 

Since P&R said no to the money request, Guernsey Water said it's had a number of requests for information about the "current and future use of Longue Hougue reservoir."

Longue Hougue is currently used for water storage and has a capacity one third greater than St Saviour's reservoir which produces the island's main water supplies.

Guernsey Water said for that reason and others, Longue Hougue is of "critical importance for the future of the island’s water supply."

The utility firm is working on a publication for release later this year on Guernsey's 'Water Resources and Drought Management Plan', which Guernsey Water's General Manager, Steve Langlois, said will consider "long term water supply and demand."

He said it will also take into account many factors that may impact the island’s water supplies over the next 25 years, such as population changes and the impact of climate change on water collection, storage and use.

“The need to have adequate water resources is of critical importance to Guernsey’s future.  While the current level of protection from drought is comparable to other water companies in the south of England, our long term needs and our future supplies are finely balanced,” said Mr Langlois.

Pictured: The Longue Hougue reservoir

It has been suggested that Longue Hougue could be used for the disposal of inert waste - and that Les Vardes Quarry, currently used by Ronez, could be used for water storage from 2022. 

But Guernsey Water said that wouldn't work.

With a capacity of 1.16m cubic metres, Longue Hougue is the largest reservoir on the island, providing water for public use every day, contributing more than 26% of Guernsey’s total water resources. Guernsey Water said it has no evidence there is any risk to the island's water supply by sea water getting into the reservoir, and that staff have tested the chloride (salt) levels in Longue Hougue reservoir weekly since 2009, proving there is negligible difference between the levels there and in our other main reservoirs such as St Saviours.

Guernsey Water says this means Longue Hougue is a vital component of the island’s “finely balanced” water supply and that  “any change in the use of Longue Hougue reservoir without introducing an alternative would leave Guernsey at unacceptable risk of drought.”

Mr Langlois also said there is too little time to find an alternative reservoir to Longue Hougue by the time it would be needed for inert waste disposal, in less than four years time. He also said Les Vardes couldn't be used for water storage in the time necessary to change those plans now. 

“The timeframe of the current inert waste strategy is considerably shorter than would be needed to replace Longue Hougue reservoir with an alternative, such as Les Vardes quarry," said Mr Langlois. 

“Converting Les Vardes quarry into a reservoir would be totally unfeasible within this period, mainly because it is expected to remain in operation by Ronez well beyond the timeframe being considered. It would also require major investment over a substantial period of time. There is no existing network of raw water pipes close by, and those nearest are smaller than would be needed to fill the reservoir and transfer water to our water treatment works.  During this timeframe it is simply not a viable option.”

Pictured top: Longue Hougue reservoir and Les Vardes quarry