Sarah Twohig

Loughborough University


The Role of Fine Sediment in Catchment Scale Flood Risk Management


Dr Ian Pattison Prof Graham Sander Dr Dapeng Yu

PhD Summary

The enhanced erosion and delivery of fine sediment from multiple sources including; river banks, agricultural land and urban areas is considered responsible for the degradation of the physical, chemical and biological status of many river catchments, resulting in numerous negative impacts. Firstly, sediment aggradation causes a reduction in river channel capacity that may increase flood risk. Secondly, an influx of fine sediment into the river is often associated with an increase in heavy metals, contaminants, and nutrient levels entering the channel, reducing the catchments water quality. Thirdly, fine sediment build up can reduce the availability of fish habitats, particularly spawning sites endangering fish populations and macro-invertebrate communities. My PhD aims to identify the sources, pathways and receptors of fine sediment within the River Wreake catchment, Leicestershire UK, to determine its influence on channel capacity and ultimately flood risk. As this catchment has already been subjected to flood mitigation, it provides an insight into the relationship between hydrology, geomorphology and engineering paradigms and evaluation of current management methods. I will be using a combination of field, laboratory and numerical modelling methods, to create an accurate representation of fine sediment connectivity and its implications for flood risk management.

What inspires you?

Growing up in Plymouth with a National Park to the north, a natural harbour to the south and flanked by two rivers meant there was plenty of dynamic landscapes to spark my interest in the natural world. My curiosity was furthered by two excellent geography teachers.

Previous Activity

2009- 2012: Portsmouth University BSc Geography 2012-2013: JBA Risk Management as an Assistant Flood Analyst. 2013- 2014: Plymouth University MRes: Assessing the coarse sediment connectivity of the River Avon, Devon. 2014: Research Assistant Plymouth University. Conducted feasibility studies for gravel augmentation for the Westcountry Rivers Trust.

Why did you choose Docotoral Research?

Though I thoroughly enjoyed working in industry, I missed geomorphology and felt compelled to follow my interests. I was fortunate to receive a funded MRes at Plymouth University, studying fluvial geomorphology. This year reaffirmed my passion for the topic and provided me with the skills and confidence to conduct independent research in this field. During this time I decided to apply for a PhD to further my experience in geomorphology and flood risk management and to continue pursuing a topic I enjoy.

Why did you choose a CENTA Studentship?

I applied for the CENTA studentship because of the interesting topic offered by Loughborough University. At the time of application the UK experienced severe storms and flooding, particularly the Somerset Levels. These events publicised the dredging debate and highlighted the importance of the advertised research topic. The CENTA studentship was highly desirable due to the importance the scheme placed on broader training and work experience to develop transferrable skills to prepare its students for future employment.

What are your future plans

I would like to remain within the flooding and geomorphology research areas once I have completed my PhD, in a role that would make a positive contribution to flood risk management. I believe that the CENTA programme has equipped us with a broad range of skills that we wouldn’t have gained from our specific research topics. These skills will benefit my future career in either academia or industry.