Assessing the holistic flood risk within the Broads catchments, East Anglia

Lead supervisor: Dr Helen He

Location: Tyndall Centre for Climate Change Research, School of Environmental Sciences, University of East Anglia

Duration: 6 weeks

Suitable undergraduate degrees: Environmental Science

Project background

The Norfolk and Suffolk Broads (hereinafter referred to as the Broads) is Britain’s largest designated wetland across the English counties of Norfolk and Suffolk. The Broads is primarily made up of expansive floodplains, serving as diverse habitats for a number of rare plant and animal species (Panter et al., 2011). It consists of an extensive network of meandering rivers and shallow lakes that cover a total area of 303 km² at the downstream end of the 3200 km² Broadland Rivers Catchment (Pasquier et al., 2020). The Broads is particularly vulnerable to floods due to its low-lying land and its flood risks are projected to increase due to the climatic warming and sea level rise.

The overarching aim of this project is to quantify the temporal and spatial distribution of flood hazards and risks within the Broads, pertaining to economic, social, and environmental elements. The specific objectives are three folds:

1. In-depth analysis of flood hazards at a specific warming level including 2, 3 and 4 ⁰C,
2. Evaluate the response of the flood system to mitigation measures, and
3. Identify areas of high risk for both the individual and composite of the economic, social, and environmental elements.

The project will be using the latest UKCP18 local projections at an hourly time step and a cascade of a hydrological model and a hydraulic model to quantify flood hazards and risks in the Broads. The new UKCP18 local projections provide climate outputs at a spatial resolution of 2.2km comparable with operational weather forecast models. It is based on the Convection-Permitting Model that are better at simulating small-scale behaviour including atmospheric convection leading to intense storm events (MO, 2019). The hydrological model will be set up at an hourly time step with a spatial resolution of  km that can take advantage of the new local projection outputs. The hydraulic model will feature a 1D-2D framework, allowing the simulation of unsteady flow within Broadland river networks and floodplains in order to capture hydrodynamic intricacies.

The project will involve Anglian Water’s Regional Flood Risk team. The mitigation measures of flood defence works and nature based solutions will be formulated in consultation with the Regional Flood Team. The project will produce quantification of flood hazards and risks in the Broads at a specific warming level and with or without flood mitigation measures. The latest climate forcing inputs along with the state-of-the-art hydrological and hydraulic models will enhance the robustness of the flood risk analysis. The results can provide the stakeholders with the scientific evidence for strategic planning of adaptation and mitigation measures. The developed index methodology will also provide a basis for ongoing flood risk research, permitting incorporation into alternate studies or flood risk management. The research output will be in the form of a research report and a manuscript to be submitted to a peer-reviewed journal.

References:

Panter, C., Hossman, H., & Dolman, P. M. (2011). Biodiversity audit and tolerance sensitivity mapping for the Broads. Broads Authority Report. Norwich, UK: University of East Anglia.

Pasquier U, R Few, M Goulden, S Hooton, Y He, K Hiscock (2020) “We can’t do it on our own!” – Integrating stakeholder and scientific knowledge of future flood risk to inform climate change adaptation planning in a coastal region. Environmental Science and Policy. https://doi.org/10.1016/j.envsci.2019.10.016.

MO (Met Office), Hadley Centre (2019): UKCP Local Projections at 2.2km Resolution for 1980-2080. Centre for Environmental Data Analysis.