The Balquhidder catchment water balance and process experiment results in context—what do they reveal?

Abstract

The Balquhidder catchment results are discussed within the context of increasing knowledge of the underlying processes responsible for the hydrological effects of land-use change. Forests, in the wet uplands of the UK, will reduce water yield irrespective of whether they replace grass or heather moorland. The impacts of afforestation on low flows are less easy to generalise; it is recognised that although high evaporation rates from mature, closed-canopy forest will have a depressing effect on low flows, land drainage, which is often associated with upland forestry, may increase low flows in the short to medium term. Further research is necessary to investigate both the evaporation rates from immature forests and the impacts of drainage on low flows, in an upland context. This information should allow forest management schemes to be devised involving staggered planting, shorter rotation forestry and optimal drainage network design to minimise the adverse effects of forests on low flows.