INTERCONNECTOR DAY15

This section dealt with geology, hydrogeology, soils and water

CRITICISM OF GEOLOGY REPORT

Colin Andrew, an experienced geologist from Ardbraccan Co. Meath who is also landowner along the proposed route for the power lines and a supporter of the North East Pylon Pressure Campaign made a scathing critique of the environmental impact assessment submitted by EirGrid during an hour-long submission. He concluded that because the EirGrid planning application failed to address and include various important details it was in his professional opinion fatally flawed and inadequate. It was materially deficient, wrong, and thus incomplete and clearly unfit for purpose.

He claimed the geology report showed a poor standard of reporting with confused and inaccurate use of geological terminologies. There was a total absence of site investigation studies to appropriate standards, with no evidence of sites inspected and a failure to conduct hydrological flood risk assessments.

Dr Andrew claimed there was a failure by EirGrid to assess the potential for contaminated ground and unstable or reactive bedrock issues. He told the presiding inspector there was a lack of knowledge of the depth to bedrock and of the materials below the surface they proposed to excavate. The assessment in his view showed a lack of knowledge of the depths of excavations that would be acceptable for load-bearing and thus a lack of knowledge of the quantities of material to be transported from or to sites, with the attendant impact on the numbers of HGV movements.

There was, he said, a failure to address issues associated with mining operations such as blast vibration. Another failure was to assess the impact of overhead power lines on geophysical mineral exploration methods, along with an absence of any geological or hydrological assessment of access tracks.

Although these failings had been identified for EirGrid during their previous application six years ago, Dr Andrew said the company had failed to correct the gross inadequacies of the impact assessment.

He claimed the suitability of individual leg block foundations for the proposed 299 pylons (each pylon has four) had not been assessed in terms of the individual sites along the line. Instead, EirGrid had operated a “one design fits all” policy.

MONAGHAN CO. COUNCIL VIEW

Monaghan County Council senior planner Toirleach Gourley also called on Eirgrid to provide a site specific plan for each of the proposed towers, rather than outlining general measures. His colleague consultative chemist John Paul McEntee said under the EU water framework directive a site specific plan was required showing the location of all drainage outfall and the location of any temporary waste water treatment facilities.

Mr Gourley continued to press EirGrid on its plans for the removal of waste material from individual tower sites and queried details shown in a table included with a diagram of the amount of concrete to be used for the construction of the various types of tower foundations.

Robert Arthur of ESB International explained that the construction of the base of each pylon with four legs and the latticed steel tower was ‘a relatively modest development’. He said the company did not do site specific designs but had forty years of experience in designing such infrastructure throughout Ireland.

EirGrid admitted that during the preparation of the Environmental Impact Statement there were a number of constraints in terms of getting access to sites. Only 25% of the pylon sites had been surveyed. Notwithstanding the constraints, a robust evaluation of the likely significant effects of all aspects of the proposed development, both in respect of the line and the towers, had been undertaken for the purpose of preparing the environmental impact statement.

The working area for construction of a 400 kV tower would extend to 30 x 30m all around the footprint of the base of the tower, with the exception of Towers 166 and 168 close to Lough Morne, which had larger working areas proposed to account for additional excavations required to stabilise ground adjacent to the foundation locations. The minimum width of these working areas is proposed to be 41m at Tower 168 and 34m at Tower 166.

Each of the four corners of the lower part of the tower legs would be separately anchored below ground in a block of concrete. Approximately 10,500m3 of material would be excavated as part of the proposed development in the Monaghan/Cavan area, a figure that was subsequently challenged by the planner from Monaghan County Council.

EirGrid set out how impacts on the existing ground conditions would be restricted to the tower locations, temporary access routes, guarding locations and stringing locations. The magnitude of the impacts at the tower locations was considered to be low. Temporary access tracks consisting of aluminium road panels or rubber matting would be required at approximately nineteen tower locations. It was not proposed to use stone roads or timber sleepers as part of the proposed development.

A report by consultant hydrogeologist John Dillon acknowledged that the construction phase of the proposed development would impact on geological conditions through the use of the temporary access routes and excavations required for the tower bases. The company’s environmental statement said during construction the potential impacts to the underlying soil and geology from the proposed works could derive from accidental spillages of fuels, which could impact the soil, bedrock and groundwater quality, if allowed to infiltrate to ground.

EirGrid said the tower locations had been selected to avoid known areas of lacustrine deposits, intact peat and cutover peat where possible. Intact peat was not identified at any tower location along the line route including Cashel Bog. The predicted impact on the soils and geology was considered to be long term and negligible, according to the company. Mr Dillon said there would be monitoring of sites after the pylons had been constructed.

Figures produced by EirGrid continued to be queried by Toirleach Gourley of Monaghan County Council. When he suggested that the amount of soil to be removed from sites could be as high as 35,000 m3 based on his calculations, he was informed by Robert Arthur of ESB International that was absolutely not the case and such an amount was “totally out of the realms of possibility.”

 

 

 

 

 

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