Impact of lowland forests in England on water resources: Application of the Hydrological Land Use Change (HYLUC) model

[1] The U. K. Government's 1995 White Paper on Rural England [ Her Majesty's Stationery Office, 1995] proposed a doubling of the area of woodland within England by the year 2045. Questions were later raised concerning the possible impacts on water resources of such a large change in land use. This paper presents results of field study investigations of the water use of grass, heath, oak, and pine vegetation at Clipstone Forest, Nottinghamshire, United Kingdom, which were used to calibrate the water use model HYLUC and derive predictions of the impact of different vegetation types on recharge in this locality. Average annual recharge plus runoff ( millimeters) over a 32.5 year period and the uncertainties due to spatial sampling, calculated with the HYLUC model, were 136 +/- 11 for the grass site, 122 +/- 3 for the heath site, 76 +/- 5 for the oak site, and 34 +/- 8 and 38 +/- 3 for two pine sites. In this region of Britain the long-term recharge beneath pine is approximately one quarter that under grass and essentially only occurs in years of above average rainfall. Oak woodland is also predicted to have a significant impact by reducing recharge plus runoff by almost one half as compared with grassland.