The provision of geotechnical engineering expertise to assist in the design and assessment of management measures for Clara Bog Special Area of Conservation

Tender description

Regan et al. (2019) identified potential management measures to arrest subsidence and reinstate (or at least elevate) groundwater heads and reduce hydraulic gradients between peat and substrate to restore the bog's hydrological balance. The management measures aim to fill part of the cutover bog to the south of Clara West by forming a bund between the bog and glacial deposits in the surrounding area and infilling behind the bund. A preliminary geotechnical design for the bund was prepared in 2015, which assessed two available options. Option one involved constructing a bund from glacial deposits, by excavating peat and backfilling with glacial material. A second option considered using geo-grid reinforced peat founded on top of the existing cutover peat. To prevent preferential seepage through the bund, the preliminary design included a toe drain and a lower permeability barrier. There is potential for a body of open water forming behind the bund. Indicative costings were also provided for both options. The Wetland Restoration Scheme is co-funded by the Government of Ireland and the European Union through the EU Just Transition Fund Programme 2021-2027. The overall objective of the EU Just Transition Fund 2021-2027 is to enable regions and people to address the social, employment, economic and environmental impacts of the transition towards the Union’s 2030 targets for energy and climate and a climate-neutral economy of the Union by 2050, based on the Paris Agreement. The Department of Housing, Local Government and Heritage (DHLGH) has been awarded funding of €12m from the EU Just Transition Fund 2021-2027 for a wetlands restoration scheme to be undertaken on a range of wetland sites, in Ireland’s Just Transition Fund (JTF) territory. Under the Wetlands Restoration Scheme, it is proposed that the management options previously considered for Clara Bog are implemented. Therefore, to progress with the detailed design of a preferred management option NPWS are seeking to procure geotechnical expertise to review existing geotechnical information and to undertake a programme of site investigations and to lead the detailed design of the preferred management option.