Reuse and sustainability of flood defences

Rainfall has always been an important quantity to measure throughout history due to its importance in predicting floods and droughts. In the present day, such predictions on the severity of flooding events are critical so that appropriate flood defences may be constructed in anticipation of these events to limit any damages. With the increasing concerns of human influenced (anthropogenic) climate change will affect rainfall, there is a growing need to quantify and incorporate these events into the design of flood defences, such as earthfill embankments. As geotechnical modelling techniques are being developed to assist in the design and upgrading of earth embankments, various failure mechanisms and the behaviour of the soil within an embankment are better understood. However, one concern which arises is that there is an uncertainty on how climate change would affect the performance of these embankments. Therefore, the main purpose of this research is to identify the key failure mechanisms that may occur throughout the embankment's life cycle, taking into account climate change effects, and to develop solutions to these issues. A site on the Thames estuary was chosen as the setting for this research. Taking into consideration a changing climate, sub-daily rainfall was produced for this site using a combination of stochastic rainfall generators and projected climate variables at the location. Following calibration and validation analyses for the foundation and embankment soils, a complete lifecycle analysis framework was established, using the previously generated rainfall as inputs to the soil-atmosphere boundary. The lifecycle framework was able to inform on both the general long-term performance of the embankment in a changing climate, and the resilience of the embankment to future extreme events. With the detailed lifecycle analysis, various strategies in reusing the embankment by raising it was also explored, to improve the embankment's adaptability to future climate.