Exeter, Devon UK • May 22, 2024 • VOL XII

Exeter, Devon UK • [date-today] • VOL XII
Home Features Flooding in Exeter: How Prepared Are We?

Flooding in Exeter: How Prepared Are We?

Print Sport Editor Eloise Grainger analyses Exeter's preparedness in the face of a growing flood threat.
5 min read
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Image: Dietmar Rabich via Wikimedia Commons

In recent years, many European cities have been battling the impacts of extreme, localised flooding. The impacts of flooding are becoming more widespread and frequent, and Exeter is no anomaly to that trend. The hilly and varied topography of the city makes it particularly vulnerable to flooding.

Unsurprisingly, the areas most at risk are on the riverside. These include the Exeter Quay (a popular tourist destination with many independent shops and businesses) and the St David’s area, which proves to be problematic as the National Rail line that connects the West Country to the rest of England is located along the River Exe and winds down alongside the Exe estuary.

During high tides, locations along the estuary are susceptible to coastal flooding. The city of Exeter itself is particularly at risk of river flooding where the River Exe has the potential to burst its banks or rise high during extreme rainfall events. But there is another issue with Exeter – its steep relief. The slanting hills mean that during high rainfall periods, or during short duration but intense localised storms, the water flows quickly downhill and pools in the lower lying areas.

A particularly high-risk area is Longbrook Street, which suffered an intense flooding episode in September 2023. This severely impacted many residents, many of whom were students returning for the start of the academic year. Several properties were flooded from the high levels of rainfall brought by Storm Agnes. There were varying severities of the flooding across Exeter, but in Longbrook Street, water was reported to be up to knee-height in depth. The water also caused vehicle damage, as cars suffered from internal flooding and electrical damage. One woman claimed that her £10,000 car looked to be a write off due to the extent of the water infiltration. Students were also seen pushing stranded cars aside. A cat was rescued and taken to St David’s Vets, where it was later identified via its microchip, and was reunited with its owner. Evidently, the impacts of local flooding are widespread, affecting students, long-term Exeter residents, and animals.

Evidently, the impacts of local flooding are widespread, affecting students, long-term Exeter residents, and animals.

One resident stated that this is the 6th time in 10 years that the buildings in Longbrook Street have been flooded, and the second time it has occurred since expensive flood prevention measures were introduced. This calls into question the effectiveness of the Environment Agency’s strategies. Despite the heavy rainfall brought about by the storm surge, it was actually insufficient drainage of the pavement gullies that led to such extensive damage. The drains struggled to cope with the volume of water that was attempting to pass through the system when it was already overwhelmed by previous rainfall events. To worsen the problem the gullies then became blocked with debris. Many residents on Longbrook Street were consequently clearing the pavement drains themselves during the flooding.

Many have expressed views that a simple flood prevention measure, such as a flood door, would be sufficient to reduce impacts. Despite the council reaching planning agreements to add such preventative measures, work is still yet to be done. Many experience these issues yearly. Residents bear the costs of repairs such as carpet laying, and with these issues of flooding becoming more frequent in the coming years due to climate change, these methods to bypass the problem are becoming unreasonable, impractical, and unsustainable.

According to Devon County Council, more than 140 properties were flooded across Devon during the flash flooding, but Longbrook Street in Exeter was the most affected (cite). Some of the hardest hit areas include Cullompton, Harberton, Kenton, and Topsham. With such a high number of properties flooded it makes this one of the most significant flood events in the county. Other flooding episodes include 9 properties flooded in Countess Wear district in December 2012, 12 properties were flooded in the St James area in October 2013, then nearly 4 years ago in August 2020, 6 properties in central Exeter were impacted by flooding. It is clear that over time, more properties are flooded, and it appears to be occurring in more urbanised areas further away from river channels, i.e. further up the river catchment areas, and the topography could be the main reason for flooding in these cases. Nonetheless, flooding is becoming more frequent, and more intense.

Local factors contribute heavily to the extent of flooding. Topography and relief of the land isn’t the only contributor – land already heavily saturated from other rainfall episodes mean that the capacity for soil absorbing the rainfall is reduced. Heavily saturated soil progresses into secondary impacts, such as mud slides. Urban environments, such as the city itself, mean water can’t infiltrate or percolate into the soil due to impermeable tarmac or concrete landscapes, which leads to a greater surface run off. This then overwhelms the drainage systems, and blockages worsen the issue even further. Exeter is widely recognised as being the greenest UK city, which should mean its abundance of green space and tree populations would be perfect in infiltrating heavy rainfall and absorbing surface water. Yet Exeter is still susceptible to serious floods despite the vast amounts of vegetation. Exeter suffers particularly from sudden outburst floods created by storms, as the drainage system often can’t cope with the volume in a short period.

Exeter suffers particularly from sudden outburst floods created by storms, as the drainage system often can’t cope with the volume in a short period.

However, events like this will become more commonplace as our planet becomes warmer. This is because increased atmospheric temperatures will mean more moisture can be held in the air. This means climate change results in more intense rainfall and increases the chances of this happening on a more regular basis.

Exeter has a historical track record for flooding incidents, which can be dated back to the 13th century. This ancient city makes it hard to modify in terms of developing engineering strategies to prevent flooding. But there have been developments in the last decade to attempt to combat the issue. The Exeter Flood Defence scheme is managed by the Environment Agency and supported by Exeter City Council and Devon County Council, both of which contributed £3 million each to fund the project. A further £6 million was given by the government to support the project, and the outstanding fees were funded by the Flood Defence Grant in aid.

The project was put in place as the Environment Agency recognised that the dated defences from the 1960s and 70s would be breached during extreme flooding. The Exeter Flood Defence Scheme aims to reduce flood risk to more than 3000 homes and businesses in the city. The developments spanned two phases between 2014 and 2021. The works in phase 1 included the flood relief channel and side spill weir at the top of the channel being lowered. The effect of this meant that more water can pass through this canal during high rainfall periods, which reduced the risk of flooding during high levels of river discharge. Phase 1 carried over into phase 2 as the dredged material from deepening the canal was repurposed into raising the river embankments elsewhere. As well as increased river channel capacity, new flood gates and control structures had been built by the quay as part of phase 2.

The Exeter Flood Defence Scheme aims to reduce flood risk to more than 3000 homes and businesses in the city.

Temporary flood defences, however, still seem to be preferred by Exeter residences over permanent structures. Many refused a flood wall to be built at the quayside as it would spoil the picturesque views. Instead, temporary flood defence barriers were put in place. For Storm Ciaran in November 2023, demountable floorboards were installed to protect and defend the quay from predicted flooding. This requires close communication between the Met Office, who issue warnings of expected flooding, and those who put the defences into action. This solution enables the best of both worlds – only solid poles remain visible on the quayside on a normal day, which doesn’t disrupt the views, but when warnings are announced, it is able to transform the area to become protected against rising water levels by connecting the panels to the poles.

Wildlife has also been a huge factor in these developments. 2 fish passes in the canal mean migration can still commence as not to disturb animal behaviour patterns. New wetland areas and a community orchard have also arisen from the project, so to increase biodiversity in the area.

For Exeter, particularly with its historical heritage and tourist-attracting scenery, more emphasis on management of the issues is key. It doesn’t seem that one silver bullet will solve Exeter’s flooding problems, rather each case needs to be interrogated individually. For residents of Longbrook Street, simple council cooperation to install flood doors appears a suitable solution. Managements of drainage systems and increasing their capacity would be a good fit for the city, and this has been discussed in a report published by the Devon County Council. Investigation is ongoing into the opportunities to upgrade drainage systems locally and provide additional gullies to cope with increased water volume. Communication between varying parties is paramount, and this will lead to a patchwork of flood defence solutions to reduce Exeter’s impacts of flooding. 

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