October 2022 Update: Ground Investigation, survey updates and more…
Ground Investigations
Limerick City and County Council appointed Priority Geotechnical Ltd in March 2022 to undertake the detailed ground/geotechnical investigations of the existing embankments throughout the Limerick FRS scheme area. The purpose of this ground investigation is to examine in detail, the composition of the existing embankments to inform the design of new flood defences.
In January 2022, Limerick City and County Council made an application to An Bord Pleanála under section 177AE of the Planning and Development Act 2000 for approval to undertake site investigations in selected locations within Limerick City, its Environs and within County Clare. These locations are in addition to the investigations which commenced in April 2022. Approval for this application was granted by an Bord Pleanála on 22 September 2022 and these works are now ongoing.
It is envisaged that the geotechnical works which commenced on site in April 2022 will be completed early 2023 to accommodate seasonal environmental constraints.
RPS Resident Engineers and ecologists are on-site to oversee the geotechnical contract and to ensure that environmentally sensitive areas are protected.
Hydrological and Hydraulic Surveys
Murphy Geospatial Ltd. has completed the bulk of the topographic survey of the embankments, river channels and structures located by the river. The survey information is being used to inform the ground investigation of the existing embankments and the development of the flood models.
A bathymetric survey of the Shannon Estuary was completed in April of this year. Data from this survey is being used to inform an updated coastal model of the Shannon Estuary.
In July 2022 Limerick City & County Council appointed ENVA to undertake a CCTV survey of the existing drainage system within the Limerick FRS Scheme Area. The CCTV survey is a video inspection of the interior of the existing drainage system. The CCTV survey is due for completion by November. The CCTV survey will provide important information which will contribute to the development of the hydraulic models.
These flood models will be used to identify flood risk and test potential flood defence options.
Defence Asset Conditions Assessment
In conjunction with the Hydrological and Hydraulic Surveys RPS is undertaking a condition assessment of the existing flood defences within the scheme area. These visual surveys commenced in July 2022. This information will be used in conjunction with detailed geotechnical and hydraulic assessments to identify engineering works required to manage flood risk in Limerick.
Environmental
Limerick City and County Council appointed Japanese Knotweed Ireland (JKI) to undertake the treatment of Invasive Alien Plant Species (IAPS) within the scheme area. This multi-annual treatment programme is designed to manage IAPS in areas where future investigation and engineering works may be undertaken. To date JKI have completed the initial treatment cycle for 2022, further treatment is scheduled in the coming years.
Ecological surveys to inform the environmental assessment of the project are ongoing. An ornithological survey of the wintering birds within parts of the scheme area is scheduled to commence in coming weeks and will continue for 12 months.
