Flooding has become one of the biggest dangers to heritage assets in the UK and as more rain is predicted to fall in intense downpours the impacts to the historic environment will be significant. This will undoubtedly have implications for the sustainability of significant heritage assets along with their contribution to local communities and tourism. With the effects of climate change being felt across the country the Government consulted this year on proposals to change England’s planning policies to better respond to flood risks. It was announced planning guidance will be amended to make it clear that all planning applications opposed by the Environment Agency on flood grounds should be referred to the Secretary of State to make the decision. This means that developers who want to build on flood-prone areas will have to demonstrate that their proposals are climate resilient. Owners of listed buildings, who want to make alterations to their properties, should also manage flood risk and establish protective measures while retaining and respecting the existing structure and materials.
In 2018, the Environment Agency identified that flooding posed a significant harmful consequence to cultural heritage. Working with local communities and carrying out a thorough flood risk assessment are therefore important exercises that help developers to understand the potential complexity of delivering their proposals within flood prone areas. Increased protection for heritage assets was spurred by the introduction of The Climate Change Act 2008 and the Flood and Water Management Act 2010 requiring Local Planning Authorities to address flood risk by delegating to them responsibility for flooding from local water courses, with the Environment Agency retaining responsibility for main rivers.
This threat isn’t new however. Historically, our ancestors had a good eye on the landscape locating a number of settlements and structures on topographic highs or by using materials that can tolerate a degree of saturation. Building design from the past includes features such as pitched roofs, which ensure water is shed quickly, preventing it from sitting long enough to penetrate the roof material, whilst wide eaves and cornices keep falling water away from the walls. A study of historic properties at Hebden Bridge in 2017 showed that there were virtually no post-flood problems on buildings that retained most of the historic features and fabric, and the ones that made remedial works such a removing plaster with modern materials experience problems with months of repairs followed by damp issues. The important lesson from the flooding was that the traditionally constructed buildings, maintained and repaired with traditional materials, were far more resilient. Alterations to listed buildings with these components therefore should respect the original function not only for outwardly aesthetic purposes but for their continued use and flood protection elements they offer.
Climate change is not an entirely new issue and our ancestors have been altering the landscape to deal with the effects of flooding since at least the medieval period. Between c. 950–c. 1250 there was the Medieval Warm Period, a time associated with an unusual temperature rise that created unusually wet conditions. The flood defence at Botolph's Bridge, for example, was probably constructed to protect the fertile agricultural land behind it from flood water. Other responses to flooding can also be seen in urbanised environments such as London. Tottenham Court Road for example is a medieval rerouting of the Roman Ermine Street due to its flood prone location.
The modern construction of permanent infrastructure and other tools such as habitat creation, however, can also have negative effects on the historic places. For example, in 2015, the construction of a bund (an embankment to contain flood water) affected the setting of the Grade I listed St Michael’s Church in Mytholmroyd. Unfortunately, despite this defence, the church was inundated during the December floods of 2015. During that flooding event, which was a consequence of the river bursting its banks and increasing groundwater levels, the bund was overtopped, and water rose through the floor of the church. Unfortunately, the bund was very efficient at retaining the flood water in the building, so the church took longer to recover than would have been the case in the absence of that flood defence. Later in 2020, the village experienced further flooding caused by Storm Ciara affecting the church yet again. The church was flooded to a depth of four feet and has been undergoing extensive restoration ever since. All the pews were removed to safe storage and the wooden floor was replaced before the pews were re-installed. The church installed glass panels next to and opposite the church and the river channel has been widened (up to 8m). Rewilding is another example of natural flood management response, such as expanding woodland, reintroducing species that have been absent for a millennia, they usually have an adverse effect on the setting and character of heritage assets.
As demonstrated historic buildings, structures and spaces are vulnerable not only to climate change, but the infrastructure created to protect them. Therefore, consideration should be given to whether its immediate area and whether the dwelling located in a floodplain or an area that is at high risk from flooding. The granting of consent to carry out works to protect a historic structure from flooding will be influenced by the impact of the proposals on the architectural, evidential or historic interest of the site. In some cases, such as Ironbridge, the building and insurance industries’ standard procedures for making buildings habitable again after a flood can be damaging to the special architectural, historic interest. The world heritage site has relied on temporary barriers to protect it during recent devastating floods. Permanent flood alleviation infrastructure has been denied due to its special historical and scientific significance meaning that temporary barriers are a better alternative in order to preserve its special historic and architectural quality. Proposals that affect character and setting are concepts deeply entwined in both planning and heritage protection frameworks. This is important for historic buildings and other features that are located near rivers or on the coast and have close links to the water environment, which will require novel approaches to heritage management. In the past water meadows, for example, have been a feature of many English river valleys and helpfully act as temporary water storage facilities in times of high tide.
Flood defence infrastructure can also contribute to impacts on archaeology through altering ground conditions with potential implications for paleoenvironmental remains. Paleoenvironmental remains are key to understanding past environments and how climate change affected people in the past. Floodplain environments can also illustrate the varied nature of archaeological remains encountered in dynamic coastal and river environments threatened most by the effects of climate change. These remains such as organic deposits, wooden structures and relict channels, tell the story of climate change, flooding and coastal erosion and one that can span hundreds of thousands of years.
The threat of flooding, especially in places which have been on built historic floodplains will continue to become more intense and destructive in the future, and with that many historic places are at risk of flooding as well as coastal change. Heritage professionals are working together to produce effective responses to the impacts of flooding to the historic environment by using lessons from the past to provide holistic approaches to land and building management. Heritage, by default is resilient by the fact it has survived, and we must support the local communities within these rich historic landscapes to adapt to our ever-changing environment.