Preparing the flood defences of Limerick city for climate change events

Deirdre Ryan
University of Limerick

For millennia, the impact of flooding on societies has been recorded in stories such as Noah and his Ark and accounts of ancient Egyptian civilisations along the River Nile. In Ireland, we have our own iconic river; the Shannon, with its history of sixth century monastic settlements and marauding Viking escapades along its 230 km journey from Co Cavan to the estuary near Limerick City.

In more recent years, serious flooding from the River Shannon caused extensive damage to areas of Limerick and County Clare. In this research, I aim to address this issue for the stretch of the Shannon from Parteen Weir to Shannon Bridge in Limerick City. Flood embankments or small earthen dams currently provide flood defences for many areas from Limerick City to Parteen Weir. As part of my research, I am developing a schedule of areas that require upgrade or maintenance works with the aim of preventing failure of the embankments in the Lower Shannon Catchment. These areas will be identified following an investigation of the predicted flood levels from Draft Shannon CFRAMS maps, historical flood levels and current embankment levels.

The procedures for the maintenance and upgrade works will be governed by the ground conditions at each site. Of particular interest in this study are the geotechnical properties and performance of the alluvial deposits along the River Shannon. These soils will dictate the methods for construction, and will govern the timescale for the works. My research will lay out procedure for repairing and maintaining embankments to ensure they are adequate to provide flood protection for those living behind them.

I am a recipient of the Employment Based Research Scholarship from the Irish Research Council. This scholarship is novel as I am carrying out my research in conjunction with PUNCH Consulting Engineers, with whom I’ve been working for the past two years. The benefit of this arrangement is that I have access to information and decades of experience that world normally be out of reach for research students. I am also gaining valuable engineering research expertise that increases my value as an engineer. A successful research outcome will help mitigate the risk to communities currently suffering the effects of flooding and I hope it will make a valuable contribution to communities living along the Lower River Shannon.