Water in Celtic Countries: Quantity, Quality and Climate Variability (Proceedings of the Fourth InterCeltic Colloquium on Hydrology and Management of Water Resources, Guimarães, Portugal, July 2005). IAHS Publ. 310, 2007, 232-241.

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Influence of 7-year old Eucalyptus globulus plantation on the low flow of a small basin

B. SOTO¹, M. A. BREA², R. PÉREZ² & F. DÍAZ-FIERROS²

1 Departamento de Bioloxía Vexetal e Ciencias do Solo. Facultad de Ciencias de Ourense, Universidade de Vigo, Spain

2 Departamento de Edafoloxía e Química agrícola, Universidade de Santiago de Compostela, Spain

eddfierr@usc.es

Abstract In the hydrological year 1997/98, a plantation of Eucalyptus globulus was planted in a basin of 10.7 ha. Hydrological monitoring of the catchment was carried out until 2003/04. Precipitation, temperature, solar radiation and humidity were measured. Flows were measured continuously with a capacitive probe in a type “V” weir. For the seven years observed, the terms of the monthly water balance were determined. The results show that at the present time, with the trees grown to 16 m height (one half of their total growth time) the annual water balance is not sensitive to the growth of the forest mass. However, the water balance for the dry season months (June, July, August and September), that define the low flow in the basin, shows a clear and sustained decrease with a reduction in the flows by 30% from the initial value.

Key words eucalyptus plantation; forest hydrology; low flow; water balance

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