The Torbay case study is focused on the effects of coastal flooding on critical infrastructure within Torbay. The objective of the case study was to analyse the effects of coastal, pluvial and fluvial flooding on CI as a result of climate change over the next 100 years within Torbay. Included within the analysis was adaptation proposals to reduce the risk of flooding to CI from coastal events within the town of Paignton.
Torbay is located in South Devon (UK) and covers an area of approximately 62 km2. The region includes three urban towns (Torquay, Paignton and Brixham) and hosts more than 3 million tourists every year that contribute over £450 million to local economy.
The area has suffered from flooding, during intense rainfall events, over many years from a number of different sources, including surface water run-off, highway flooding, sewer flooding, main river and ordinary watercourse. In addition the coastal areas of Torbay suffer coastal flooding due to overtopping of the sea defences during high tides that coincide with easterly winds. Figure 1 shows the effects of Storm Emma (March 2018) at Torquay sea front.
Figure 1: Storm Emma, Torquay
Historically, the consequences of these flooding events has resulted in many residential and commercial buildings in the town centres of Torquay, Paignton and Brixham being flooded together with roads being closed. As Torbay relies on tourism for it’s economy, flooding of this nature has a very significant economic impact on the area.
Rising sea levels, as a result of climate change, will increase local flood risk both in coastal regions from increased risk of overtopping of the sea wall and inland from main rivers and watercourses due to the interaction with drains, sewers and watercourses. As sea level is predicted to rise by over 1m in Torbay over the next 100 years the frequency and impact of overtopping of the sea defences will increase resulting in more infrastructure and properties being affected by flooding.
Data provided by Torbay Council and the CI operators was utilised to analyse the risk of flooding to the CI. The analysis has identified both the direct and indirect effects on CI together with the costs associated with this damage. This work was carried out using the EU-CIRCLE CIRP tool, with the hydraulic modelling using CADDIES (a two-dimensional cellular automata based model) being incorporated into the CIRP tool. Flood visualisation has been developed for use within the case study using serious gaming techniques.
Figure 2 shows the predicted coastal flooding as a result of overtopping within Paignton for the 1 in 200 year storm event plus 50 years of climate change.
Figure 2: Coastal Overtopping Flood Propagation in Paignton
An adaptation scenario was assessed within the case study where a secondary coastal defence was included behind the existing coastal defence in Paignton. The benefits provided by this secondary defence can be demonstrated within the CIRP tool and the visualisation for the 200 year event with 50 years of climate change as shown in figure 3.
Figure 3: Paignton Adaptation Scenario
Slide 1 – Identifies predicted combined coastal/pluvial flooding in Paignton for 2065
Slide 2 – Identifies predicted coastal flooding in Paignton for 2065
Slide 3 – Identifies predicted flooding in Paignton following adaptation scheme for 2065