There is no river anywhere near, but last week the Brighton suburb of Bevendean was drying out after a flood. Carpets, sodden furniture, washing machines and freezers were being thrown into skips, mud hosed out of houses. People knew what to do; it had happened before. Muddy water, runoff from fields planted with winter cereals, had flowed down a normally dry valley and into the houses. Four small dams meant to protect houses filled and overflowed. But much of the damaging flow resulted from a field that bypassed the dams. In this field, a gully 1.5 metre deep and several hundred metres long had been cut in the early hours of 12 October. It discharged hundreds of tons of mud into houses and roads.
Bevendean, like other sites around Brighton, has a long history of flooding and serious soil erosion. In 1982 the farmer at Bevendean, on being asked if he had an erosion problem, replied no. He later pointed to a field where he had lost a cow in a gully. Bevendean houses were also flooded in 1985 and 1987.
Between 1976 and 1993 there were 60 floodings in the Brighton area. A substantial number will have been added this autumn. In October 1987 at Rottingdean, 3km from Bevendean, around 400,000 of damage was done to about 30 houses. Half of these costs were borne by household insurers.
There is a pattern to the muddy flooding. Almost all incidents occur in the months of October and November, and all involve runoff from fields prepared for, or sown with winter wheat. Because the fields are bare, even moderate amounts of rainfall result in muddy flows leaving the fields by cutting gullies. Farmers often claim that these are ‘freak events’. One farmer making this claim was asked when was the previous case of flooding of the nearby village. He replied ‘last year’.
Over the hill from Bevendean is the well-known vineyard of Breaky Bottom. The farmhouse, built in a dry valley in 1827, was not flooded until 1976. Then again in 1982, 1987 and last month. The muddy-flooding has increased since the slopes up-valley began to be cultivated with cereals. Under grass there was no threat as there was little runoff and no erosion. A series of October floods in 1987 resulted in considerable damage to house and vines and a long-running legal dispute, resulting in undisclosed damages being paid to Peter Hall at Breaky Bottom. The case sought to prove that cultivation of steep slopes for wheat constituted a predictable risk of downvalley flooding. That it was done in the knowledge of the risk, and that nothing had been done to mitigate that risk, and that therefore, land use and farming practices were more responsible than the heavy rain. Central to the case, and others like it, is the assertion that it is how, when and where the valley-slopes are cultivated – not the fact that it rains hard as the main cause of muddy-flood damage. Farmers thus have a responsibility to manage land wisely, including an awareness of downvalley risk of flooding.
This is not only a South Downs problem. In other parts of the country where houses are adjacent to farmland, the incidence of muddy-flooding has increased since the adoption of winter cereals in the 1970s. Particularly at risk is the Isle of Wight, Devon, Somerset, Kent and parts of the east and west Midlands. In some areas summer storms have also caused devastation to maize, potatoes or linseed crops, flooding houses in towns such as Faringdon in Oxfordshire and Bishopsteignton in Devon.
The Ministry of Agriculture, Fisheries and Food (MAFF) have recently published a series of advisory booklets for farmers on ‘Controlling Soil Erosion’. The ‘Soil Code’ also devotes several pages to the risks of runoff and erosion. The risk of damage to properties and roads is clearly recognised and farmers are told how to assess that risk. They are advised if the problems are ‘regular and severe’ to seek further advice and to consider switching to grass. The approach is voluntary, but at least the advice is now freely available.
There are success stories that show how property can be protected from muddy floods. At Rottingdean, a deal between the farmer and his landlord Brighton Borough Council led to a reduction in the area of cereals and the construction of a substantial dam. There has been no flooding since 1987. At Sompting near Worthing, after several repeated muddy-floods of houses, the farmer constructed small dams and put areas of the catchment under grass using through Set Aside payments. No property damage has occurred since 1993. Such examples of good practice in preventing muddy-floods need to be more widely known. In the southern Netherlands, Belgium and northern France, radical approaches involving co-operation between local communities, farmers, and EU funding have begun to make progress in providing protection.
Recent media reports have linked flooding in southeastern England to climate change. There is certainly an element of storms and exceptional rainfall, but housing developments on floodplains have also contributed to the catalogue of damage. Floodplains are meant to provide a natural service by storing water like a sponge – not be cluttered with houses. With the issue of runoff from agricultural land, it is easy to demonstrate that landuse is critically important. Damage occurs where property is in close proximity to bare cultivated fields, and these sites are quite predictable. Damage will not occur every year, but in relatively wet autumns such as 1982, 1987, and 2000. Farmers at these sites are engaged in a risk-taking activity (commonly called a gamble) and can expect to lose every few years. But the real losers are the insurance companies, the local councils, and the householders. Costs of damage to crops are minimal compared to those associated with the flooding of houses. In the short-term, muddy-flooding of properties is a cost that is borne by non-agricultural sectors of society.