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Pollardstown Fen Road By-pass, Co. Kildare -

the threats to Ireland's largest fen SAC

Pollardstown fen is an area of alkaline peatland which obtains its nutrients from calcium rich spring water. Most fens develop further into raised bogs once the peat becomes thick enough the prevent mineral rich groundwater affecting the system. Raised bogs contain acid peat and their only source of nutrients is rainfall. In the case of Pollardstown the succession to raised bog has been prevented by he input of alkaline rich water from a number of important springs.

Pollardstown Fen is of international importance as this type of fen is now rare in Ireland and Western Europe. In addition a number of rare plants and animals occur on the fen. The area of the fen is 220 hectares and is situated on the Northern edge of the Curragh, Co. Kildare.

Pollardstown is a National Nature Reserve since 1986. It is also a candidate Special Area of Conservation under the EU Habitats Directive. Three habitats listed on Annex I of the Habitats Directive occur in the area they are:- Alkaline fen, calcareous fen and petrifying springs with tufa formation. Six species which are a priority for conservation and are listed in the directive also occur at the site. The presence of these habitats and species obliges Duchas the state conservation agency to afford the fen maximum protection under EU law.

In 1993 when the first environmental impact study was carried out on the proposed Kildare by-pass. The Irish Peatland Conservation Council lobbied Kildare County Council and expressed concern regarding the possible hydrological effects the motorway development would have on Pollardstown Fen. These concerns were subsequently ignored by the County Council when the plan for the by-pass was approved.

The planned building of the road will involve cutting six metres deep into the mid Kildare aquifer which supplies the Fen with its vital nutrient rich water. The original idea of sinking the road to such a depth was to protect the "amenities of the area" which did not however, extend to include Pollardstown Fen.

Preliminary work on the site was halted in 1998 by the European Commission just prior to the construction contracts being signed, following a complaint made by An Taisce. The Irish authorities then accepted that the road as designed would have adverse effects on the entire areas water supply. To overcome these problems the developers proposed to seal the sunken road in a plastic membrane to keep back the flow of water.

Towards the end of 1999 the Department of the Environment and Kildare County Council sent reports to Europe in support of the plastic lining proposal. Their expert's opinion is that the expected change in water level in the fen will be a decrease of between 20cm and 30cm. This same expert reported that a fall of 50cm in Holland resulted in permanent acidification on a fen there. If a similar significant drop in Pollardstown Fens water table occurred, this would be detrimental to the habitats and species of the fen, reducing the conservation value of the site and adversely affecting its biodiversity.

A further concern is that the proposed design is not tried and tested in a similar area and there are a number of problems that could arise. A similar project has been undertaken in Holland but the geology of that area is less permeable and as a consequence less water loss was involved and less upward pressure affected the system.

Many believe the best solution would be to build the road on the surface so as to have as small an impact as possible on the hydrology of the fen and surrounding area.

At present the European Commission are considering the likely effect of the development and their position in regard to funding of the project, which will cost in the region of 50 million pounds.

If the project proceeds then it is crucial that a detailed water management plan is put in place and that strict monitoring of the fens hydrology is undertaken by Dúchas.

IPCC awaits the decision of the European Commission with interest.

For updates on the case check out our 2000 & 2001 press releases in the News Archive opposite.