The Blog

Flooding Is Bad News for People and Wildlife, But Science Can Provide the Answers

There has been an exceptionally high number of storms in the UK since the start of December. With more rainfall on the way this is already the wettest winter ever recorded, and in line with what is expected to become more common with climate change...

Today sees the launch of the RSPB's Centre for Conservation Science. Our research covers a wide variety of subjects, including one area which has been top of the news agenda recently - the link between flooding, wildlife and land management.

There has been an exceptionally high number of storms in the UK since the start of December. With more rainfall on the way this is already the wettest winter ever recorded, and in line with what is expected to become more common with climate change.

Flooding is a natural process that can provide important benefits to wildlife. For example, temporary inundation of floodplain meadows can help to support rare plants by providing seasonal changes in the amount of nutrients and moisture they receive throughout the year. Fish and aquatic insects also benefit from rivers well-connected to their floodplains because they use sheltered backwater channels as breeding areas.

But, as well as devastating local communities, these extreme floods also affect wildlife in these areas.

At the coast, we've been particularly worried about bitterns - a member of the heron family. Just over a decade ago, the UK bittern population was in an extremely precarious position. The few remaining birds were concentrated in a few freshwater sites in coastal areas, such as the RSPB reserve at Minsmere, many of which were highly vulnerable to storm surges which kill the fish on which bitterns depend. After painstaking research to understand the ecology of the bitterns, we now understand their needs sufficiently to have been able to start to restore and recreate reebed habitat further inland, away from the risk at the coast. The bittern responded well to these changes, and we now have the highest number of these birds in the UK for centuries.

Another response to flood risk at the coast can benefit both people and wildlife. Managed realignment is a process where sea defences are removed and tidal habitats created and a very successful one was officially opened recently at Medmerry near Chichester. Such projects accommodate excess water and dampen the force of waves providing flood relief for local communities, while also creating vital habitat for wading birds.

With flooding increasing, we need to ask what's behind this? And also, can we do anything about it?

Large-scale climate patterns control the amount of rain falling in the UK. Recently, we have observed an increase in very wet periods, leading to more water in our rivers and hence more flooding. This trend is expected to continue in the future under climate change, with current projections suggesting that by 2080 winter rainfall could increase by more than 30%.

However, this is only half the story. While we have little direct control over how much rain falls, we have far more scope in deciding how our countryside is managed. Just like at the coast, we need to consider how to accommodate occasional excessive amounts of water, but we also can influence the speed and amount of water that flows into our rivers in the first place.

For example, some agricultural practices have been linked to increases in flood risk in recent years. Overgrazing and trampling by animals reduces plant cover and compacts soil layers, lowering their ability to absorb water that instead runs rapidly across the surface and into rivers. The installation of upland drainage ditches and removal of trees and hedgerows also serve to quicken the pace at which water flows off the land. This creates large pulses of river water that travel quickly towards downstream communities, in contrast to slower rises and falls in river levels that we would expect in the absence of these land management practices.

The RSPB is working together with farmers, water companies and landowners to develop schemes solve these problems. For example we are working with United Utilities on a £11.6m project in northwest England where we are planting new woodland areas, which could help to reduce peak river flows by 30%.

Our early results in this area are promising, and also suggest these land management practices could have wider benefits for wildlife. For example, RSPB research shows that blocking peatland drains can increase soil moisture that in turn leads to higher cranefly numbers, which are an important source of food for golden plovers, dunlin, and many other upland bird species.

These findings indicate that restoring natural upland habitats may not only contribute to reducing flood risk for downstream areas, but could also help some bird species adapt to the drier summers predicted under climate change.