Climate change and the impact on Limerick City's flood embankments

Flooding across the Lower River Shannon basin occurred during a high rainfall event combined with high tides and storm surges in February 2014. Limerick City was one of the areas worst hit. As a result of the high-water levels generated during the storm event, a non-engineered embankment protecting the Saint Mary’s Park area in Limerick City failed and allowed flood waters to enter properties on the low-lying areas of this small island community destroying homes. This thesis identifies design improvements to the embankments along the River Shannon to protect against climate change. A review of geotechnical site investigations carried out in the Limerick City region was carried out to inform the method for improvement works. Data gathered indicated the presence of soft clay in many areas along the River Shannon. The parameters gathered were used to generate geotechnical models of generalised ground profiles in the region and the settlements resulting from increased loadings resulting from embankment increases were estimated, along with an analysis of bearing capacities of the soils. An analysis of previous flood events, published River Shannon Catchment Flood Risk and Management Study maps, and published topographical data identified areas vulnerable to flooding, and also a priority assigned to each based on the consequence of flooding at these locations The risk register developed as part of this study identifies areas along the River Shannon where the embankments are at risk of being overtopped as a result of increased flood levels arising from climate change. A series of actions are presented for difference locations dependent on the ground conditions encountered and a timeframe for these actions. The priority level of the improvements to embankments is a function of the risk and consequence of flooding. The outcome of the strategic embankment improvement programme identifies the Castletroy Wastewater Treatment Plant as an area at risk and requiring urgent action. The hydraulic modelling completed with this thesis outlines the effectiveness of the programme by outlining the impact of flooding on the area currently and into the future.