Modelling the effect of land use change in the upper Severn catchment on flood levels downstream (ENRR471)

Land use is one of several significant factors affecting quantity and timing of flood runoff, and is arguably more accessible to human control than other factors such as climate, soils and channel hydraulics. Major changes occurred over the latter part of the 20th century. For instance the area of rough pasture in the Cambrian Mountains declined from 78% in 1948 to 55% in 1983, the majority of this land being converted to coniferous forest. However there is little evidence of effects of extensive land use changes on the flood hydrology of catchments. Studies on the catchment scale, for instance the large networks of catchments used in the preparation of the UK Floods Studies Report and the Flood Estimation Handbook, have not turned up simple relationships between land use and flood hydrology, except in the case of urbanisation.