Flooding and flood plain cpt Bruce Shortland
Since World War II our agricultural landscapes have been radically altered. Fewer hedgerows, degraded habitats and intensive farming mean that our countryside is less able to store water.
Changing the way we manage the countryside is essential if we are to manage flooding impacts to stop serious damage to people and property. Landscapes that are rich in wild habitats like peat bogs, reedbeds, broadleaved woodlands, wetlands and species-rich grasslands are more effective at holding and storing water. In many places more water is now reaching the floodplain more quickly because of the loss of these natural habitats and the drainage systems that have been constructed over many years. In some areas farming practices are leading to vast quantities of soil being washed off the land into watercourses and the sea. Even now, during heavy rain, slurry from dairy farms is washing off fields – this is another source of silt and pollution that damages our fragile rivers.
Changing the way we manage the countryside is essential if we are to manage flooding impacts to stop serious damage to people and property
Because the land’s capacity to store water has been damaged this means that the problems caused by extended dry periods are also made worse.
Much attention has focused on the damage that 2014 flooding caused to people, property and farmland on the Somerset Levels, one of the lowest, flattest areas in Britain. In ancient times the Levels were entirely under water; today the area supports highly valuable wetlands, internationally recognized for their importance to wildlife. Much of the landscape is also farmed following historic drainage of other wetland areas. Somerset Wildlife Trust work closely with farmers in the area to help manage water and also raise funds for water control structures. They say that dredging is only one part of the solution. SWT suggest that a range of solutions needs to be used to address flooding in the Levels - see their five key principles here.
In Somerset and beyond, it is vital that the Government invests in modelling the outcomes of different approaches to managing flood risk and that it takes an evidence-based approach to building a flood resilient future.
How we are helping
Reversing the destruction of our wetland habitats
Counter-intuitive as it may seem, reconnecting watercourses with their natural floodplains and creating the conditions to allow flooding in some areas could safeguard towns and villages after a deluge, slowing the rush of water and allowing it to harmlessly seep away. As well as protecting people, these measures also help wildlife, including wading birds such as curlew, snipe and ringed plover, along with mammals such as otters and water voles and many other species from moths to marsh harriers.
It is not just the obvious open water wetlands that function to store water during flood events. Special and beautiful habitats such as species-rich grasslands also play an important role.
Devon Wildlife Trust has been working with farmers to restore areas of a special kind of species-rich wet grassland called culm grassland. As well as supporting rare wildlife such as the marsh fritillary butterfly, well-managed culm grassland can act as a sponge, holding water following rainfall and releasing it slowly over time.
Early results from a recent study of the hydrology of these grasslands undertaken by Devon Wildlife Trust in association with the University of Exeter indicate that species-rich grasslands may be better at preventing downstream flood risk than intensively managed grasslands or grasslands that have scrubbed-up or developed mature woodland cover. These grasslands also play a part in protecting and enhancing water quality as Devon Wildlife Trust's Working Wetlands project has demonstrated. Take your own virtual tour here.
Devon Wildlife Trust's Beaver Project is showing how beaver dams can hold water back and slow down the water, storing it in ponds and reducing the flood risk downstream.
The Great Fen is a 50-year project to create a huge wetland area in Cambridgeshire run by The Wildlife Trust for Bedfordshire, Cambridgeshire and Northamptonshire. One of the largest restoration projects of its type in Europe, the landscape of the fens between Peterborough and Huntingdon is being transformed for the benefit both of wildlife and of people. The land started to be drained for farming in the 17th century - more than 99% of this habitat with many rare species of plants and animals disappeared. Two of the last fragments of wild fen, Woodwalton Fen and Holme Fen, became National Nature Reserves (NNRs), but even they are too small and isolated to support the special wildlife of the original fens. The plan is to create an enveloping landscape of 3,700 hectares around the existing NNRs. It will incorporate areas where winter flood waters can be stored after heavy rainfall, helping to protect surrounding towns, villages and farmland from the risk of flooding.
Wiltshire Wildlife Trust is involved in restoring the River Avon through the Wessex Chalk Streams Project which, in time, should help to protect Salisbury which has suffered from significant flooding. There’s an article about the project here. The project is seeking to reconnect the river with its floodplain and is restoring reed beds to enhance the water storage capacity of the floodplain.
Working with farmers to restore habitats on farmland and also reduce flooding impacts
Wildlife Trusts everywhere advise farmers on how to create farmland habitats that can improve a farm's ability absorb water. Read an article that appeared in The Daily Telegraph about one farmer's journey to rewild his grassland in Devon here. There are some fascinating examples on our farming page.
We are also delivering small scale but highly effective schemes to reduce flooding impacts on farmland, working with farmers to find areas of the farm that can store rainfall in extreme events while also protecting crops and valuable areas of grassland.
Shropshire Wildlife Trust is working with a farmer in the north of the county whose land was subject to extensive surface water flooding and run off, with this ultimately running into a tributary of the River Perry. The scheme is still under construction but a basin has been created where the water and silt can be captured, holding back flows. This work has already reduced the incidence of surface water flooding on the access track to the farm and fields further up the sub-catchment. The excavation of a long swale - a low area of marshy land - allows free drainage of previously blocked field drains. The new basin and swales and buffer strips around them will be seeded with wildflower and grass mixes in the spring.
A similar scheme implemented by Staffordshire Wildlife Trust saved farmland from flood damage by making small-scale changes to land management and creating new wetlands.
Following the floods in 2012 and 2012/3 Somerset Wildlife Trust helped with restoration of habitats across the Levels. The Trust made extra efforts on their nature reserves to get grazing, hay cutting and rush cutting done during the good weather in 2013 - they were helped by neighbouring farmers who are also their graziers. Dealing with short term impacts is only part of the equation. Somerset Wildlife Trust are committed to finding long-term solutions to water management that allows the majority of the Levels and Moors to remain as farmland but climate change predictions, extreme weather events and restrictions in public spending suggest that some change is inevitable. In some places extra maintenance may be necessary to make sure main rivers can convey water to the sea. Elsewhere land use may have to change on some farmland to make space for water. The Trust is helping by looking for new income streams for farmers and is also trying to establish an evidence base to show how farmers on peat soils are contributing services to society like carbon storage in peat soils, storage of floodwater and avoidance of pumping costs. See Somerset Wildlife Trust's 50 year vision for the Brue Valley here.
Sussex Wildlife Trust are a partner in the Trees on the River Uck (or TrUck) which is a pilot project that aims to reduce rapid water flow in the River Uck catchment, through strategic woodland creation, installation of hedgerows, and small scale natural enhancements where possible. TrUck was formed in recognition of the benefits of a natural catchment scale approach to river health, people and wildlife. They are building on their research by working with local farmers and landowners to deliver these benefits, providing and planting trees and hedges free of charge, and helping with creation of features that help to store more water in the landscape such as scrapes and ponds. Sussex Wildlife Trust hope to spread the scheme to other catchments within the county.
Restoring upland peat habitats
Peatlands cover 12% of the UK and their restoration has never been a more pressing issue - unfortunately, 80% are in a poor condition because they’ve been drained of water or are damaged by peat extraction.
The uplands of Montgomeryshire are just one example of many areas where over-grazing by sheep has caused soil compaction, resulting in increased flooding of lowland areas downstream.
Montgomeryshire Wildlife Trust's scheme at Pumlumon covers 40,000 hectares and aims to restore and re create damaged habitats. The habitats need to be grazed by livestock to maintain their wildlife interest, but grazing patterns are being changed, with a reduction in intensive sheep grazing. Drainage ditches across the bogs are being blocked so that the water is held back in these upland areas, reducing flooding downstream.
The Wildlife Trusts are calling for a million hectares of peatlands to be restored by 2020. Find out more about The Wildlife Trusts’ many peatland restoration projects around the UK. For info on uplands, farmland and other important habitats see our habitat explorer.